ICINCO 2020 Abstracts


Area 1 - Industrial Informatics

Full Papers
Paper Nr: 57
Title:

Domain Optimization for Hierarchical Planning based on Set-Theory

Authors:

Bernd Kast, Vincent Dietrich, Sebastian Albrecht, Wendelin Feiten and Jianwei Zhang

Abstract: The design of planning domains for autonomous systems is a hard task, especially when different parties are involved. We present a domain optimization algorithm for hierarchical planners that uses a set-based formulation. Due to an automatic alignment we can compose models from different sources to a larger domain for efficient planning. The combination of domain optimization and hierarchical planning can handle large scale domains very efficiently. Our algorithm reduces the effects of the non-optimality that comes with the hierarchical approach. We demonstrate the scalability with a task and motion planning problem. In the scenario of a robotic assembly with up to 62 parts and plan lengths of over 1000 steps the planning times are kept within 15 minutes. We show the execution of our plans on a real-world dual-robot setup.
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Short Papers
Paper Nr: 117
Title:

The Pipeline Concept as Key Ingredient for Modular, Adaptive Communication for Cyber-physical Systems

Authors:

Stefan Linecker, Jia L. Du, Anderson V. Silva and Reinhard Mayr

Abstract: We are currently experiencing another phase within the digital transformation. This phase is prominently called the Internet of Things. It is enabled by the progress in energy efficiency, cost and capability both in sensor-actuator electronics and in data transmission technologies. The envisioned Internet of Things will consist of billions of connected cyber-physical systems. To fully harvest the potential of this development, a strategy for robust, interoperable and future-proof network communication between a myriad of different systems in a global network is required. The ongoing TriCePS project develops both a framework and the missing building blocks to fulfill those requirements. In this paper, the authors propose the pipeline concept as such a building block.
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Paper Nr: 99
Title:

A Holistic Approach for the Development of a Digital Twin Focused on Commissioning and Control of Electromechanical Feed Axes

Authors:

Manuel Norberger, René Apitzsch, André Sewohl, Holger Schlegel and Matthias Putz

Abstract: The conventional commissioning of a machine offers numerous starting points for the use of modern methods and technologies. With virtual commissioning, the conventional sequential work tasks can be parallelized, which represents an economic advantage. For the virtual commissioning of machines and systems, an appropriate knowledge of automation technology and processes is necessary. This information can be found in the abstracted image, the digital twin. The digital twin is an application-dependent complex entity. Drive control is part of such an application. In the industrial environment, parameterization is usually carried out once on the basis of empirical methods during commissioning. Knowledge and methods from science and research for optimal adjustment are rarely used. In this publication a holistic approach to the implementation of the digital twin including automation technology of a system with an electromechanical feed axis as well as an approach for recording the information necessary for parameterizing the drive control is shown. The focus is on the ability of the digital twin to process information about the dynamics of the drive system.
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Area 2 - Intelligent Control Systems and Optimization

Full Papers
Paper Nr: 13
Title:

Convexification of Semi-activity Constraints Applied to Minimum-time Optimal Control for Vehicles with Semi-active Limited-slip Differential

Authors:

Tadeas Sedlacek, Dirk Odenthal and Dirk Wollherr

Abstract: Semi-active actuators provide a good compromise between low energy consumption and high performance. Thus, they are deployed in many engineering applications, often combined with other actuators into complex systems requiring an integrated control concept for optimal performance. Optimal control can be used to objectively evaluate the performance of such systems as well as to deduce optimal control input trajectories and optimal passive system designs. We present a novel approach which enables considering a broad class of semi-active actuators in optimal control problems via convex sets. This procedure is exemplarily depicted for semi-active limited-slip differentials which are used in automotive applications for lateral torque distribution. The performance benefit gained by installing a semi-active limited-slip differential at the rear axle of a vehicle is objectively quantified by numerically computing time-optimal trajectories on a racetrack via direct optimal control with Hermite-Simpson collocation. Although the overall problem remains nonconvex for this particular application, this procedure is a first step towards a fully convex implementation. By iteratively increasing the upper boundary for the differential torque in multiple optimisations, we identify the smallest upper differential torque boundary for optimal laps and determine the lap time sensitivity regarding this limit.
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Paper Nr: 15
Title:

A Novel Model to Analyse the Effect of Deterioration on Machine Parts in the Line Throughput

Authors:

E. Garcia, N. Montes, N. Rosillo, J. Llopis and A. Lacasa

Abstract: This paper presents evidence on how the variability of machine parts can affect the throughput of an assembly line. For this purpose, a novel model based on mini-terms and micro-terms has been introduced as a machine subdivision. A mini-term is a cycle time subdivision that can be selected by the user for several reasons: the replacement of a machine part or simply to analyse the machine more adequately. A micro-term is a mini-term subdivision and it can be as small as the user wishes. Therefore, the cycle time of a machine is the sum of mini-terms or the sum of the micro-terms. This paper focuses its attention on a welding line in a Ford Factory located in Almussafes (Valencia) where a welding unit was isolated and tested for some particular pathologies. This unit is divided in three mini-terms: the robot motion, the welding motion and the welding task. The cycle time of each mini-term is measured by changing the deteriorated components for others in the time. The deterioration of a proportional valve, a cylinder, an electrical transformer, the robot speed and the loss of pressure are tested within a range that cannot be detected by alarms and maintenance workers, that is, the range of normal production. The real welding line is modelled and a novel simulation algorithm is created based on mini-terms. The experimental measurements are introduced in the simulation model and the effect of the pathologies in the production rate is computed. As a result, the pathologies with greater variability have a deeper impact in the production rate mainly due to the bowl phenomenon effect. On the contrary, the pathologies with low variability have a low effect in the production rate. In fact, this paper demonstrates that the maximum rate capacity can be achieved if the machine variability is near zero.
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Paper Nr: 58
Title:

Using Semi-implicit Iterations in the Periodic QZ Algorithm

Authors:

Vasile Sima and Pascal Gahinet

Abstract: The periodic QZ (pQZ) algorithm is the key solver in many applications, including periodic systems, cyclic matrices and matrix pencils, and solution of skew-Hamiltonian/Hamiltonian eigenvalue problems, which, in turn, is basic in optimal and robust control, and characterization of dynamical systems. This algorithm operates on a formal product of matrices. For numerical reasons, the standard pQZ algorithm uses an implicit approach during the iterative process. The shifts needed to increase the convergence rate are implicitly defined and applied via an embedding, which essentially allows to reduce the processing to transformations of the data by Givens rotations. But the implicit approach may not converge for some periodic eigenvalue problems. A new, semi-implicit approach is proposed to avoid convergence failures and reduce the number of iterations. This approach uses shifts computed explicitly, but without evaluating the matrix product. The shifts are applied via a suitable embedding. The combination of the implicit and semi-implicit schemes proved beneficial for improving the behavior of the pQZ algorithm. The numerical results for several extensive tests have shown no convergence failures and a reduced number of iterations.
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Paper Nr: 64
Title:

Definition of a Walking with Starting and Stopping Motions for the Humanoid Romeo

Authors:

A. Kalouguine, V. de-León-Gómez, C. Chevallereau, S. Dalibard and Y. Aoustin

Abstract: The aim of this paper is to develop a complete walking with a starting, periodic and stopping motion for a 3D humanoid robot with n actuated variables. The dynamic behaviour of the center of mass of the humanoid robot is defined by a model called Essential model. The ZMP is imposed, the horizontal position of the CoM is free. The n − 2 other generalized variables of the humanoid robot are controlled and their trajectories can be for example chosen as a sinusoidal function of time. The gait parameters are determined based on data obtained from human walking. Numerical tests are presented for a complete walking motion. The perspectives are to test the obtained trajectories experimentally.
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Paper Nr: 67
Title:

Implementation of Centralized MPC on the Quadruple-tank Process with Guaranteeing Stability

Authors:

Roza Ranjbar, Lucien Etienne, Eric Duviella and José M. Maestre

Abstract: This work presents an implementation of a stabilizing model predictive control applied to a nonlinear system. In this work, the quadruple-tank system has been considered. For this process, a precise control benchmark was available and worked on previously. To ensure the asymptotic stability of this nonlinear system, we made a discretized linearized model and applied a centralized MPC controller with terminal cost constraint. The effectiveness of the proposed strategy is illustrated by simulations.
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Paper Nr: 91
Title:

Control of Sewer Flow using a Buffer Tank

Authors:

K. M. Nielsen, T. S. Pedersen, C. Kallesøe, P. Andersen, L. S. Mestre and P. K. Murigesan

Abstract: Flow variations of the inlet to a wastewater treatment plant (WWTP) are problematic due to the biological purification process. A way to reduce variations from industrial areas is to insert a buffer tank. Traditionally the only on-line measurement is the inlet flow to the wastewater treatment plant and reliable measurements in the system are difficult to establish. A control scheme using only one on-line measured variable is shown to be able to give considerable reduction in the flow variations. To implement the control scheme two models are introduced. A linear model (delay model) from the buffer tank to the wastewater treatment plant and an autonomous model describing the daily variations in the household sewer flow. A Model Predictive Controller has been designed and tested in a laboratory set-up with good results.
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Paper Nr: 104
Title:

Towards Fully Automated Inspection of Large Components with UAVs: Offline Path Planning

Authors:

Constantin Wanninger, Raphael Katschinsky, Alwin Hoffmann, Martin Schörner and Wolfgang Reif

Abstract: Automation mechanisms are increasingly established in the field of visual inspections. UAVs can be used for particularly large components, such as those used in ship production and for critical infrastructures. This paper concentrates on the problem of visual inspection in the field of perspective-dependent route planning. It is shown how the requirements for such a system can be implemented and elaborated. Furthermore we investigate how sensor positions can be calculated offline, based on optical and geometrical requirements and how a trajectory can be planned which contains the found sensor positions for each given area on the component. It is shown how the systems architecture can be designed in order to be able to adapt it to different requirements for the planning of sensor positions and trajectory. The implementation was tested in a simulation environment, evaluated using a benchmark data set and it was shown how above-average results can be achieved on this data set.
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Paper Nr: 119
Title:

Adaptive Fault-Tolerant Control Allocation Schemes for Overactuated Systems with Actuator and Bias Faults

Authors:

Waseem Akram, Francesco Tedesco and Alessandro Casavola

Abstract: Fault-Tolerant control is of paramount importance in marine technology, especially for autonomously guided vehicles. It can be achieved by exploiting actuators redundancy, which adds flexibility to the system by guaranteeing maneuverability, even in the presence of actuator faults. The main idea in the control allocation scheme here proposed is at distributing the control effort among the remaining healthy actuators without changing the nominal control law. In this paper, we propose an enhanced adaptive control allocation algorithm for over actuated systems. The proposed algorithm works under actuators loss of effectiveness with possible thruster stuck situations under both input saturation and rate of change constraints. The effectiveness of the proposed scheme is shown by simulating a marine surface vehicle model on a path-following problem.
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Paper Nr: 127
Title:

CoachGAN: Fast Adversarial Transfer Learning between Differently Shaped Entities

Authors:

Mehdi Mounsif, Sébastien Lengagne, Benoit Thuilot and Lounis Adouane

Abstract: In the last decade, robots have been taking an increasingly important place in our societies, and shall the current trend keep the same dynamic,their presence and activities will likely become ubiquitous. As robots will certainly be produced by various industrial actors, it is reasonable to assume that a very diverse robot population will be used by mankind for a broad panel of tasks. As such, it appears probable that robots with a distinct morphology will be required to perform the same task. As an important part of these tasks requires learning-based control and given the millions of interactions steps needed by these approaches to create a single agent, it appears highly desirable to be able to transfer skills from one agent to another despite a potentially different kinematic structure. Correspondingly, this paper introduces a new method, CoachGAN, based on an adversarial framework that allows fast transfer of capacities between a teacher and a student agent. The CoachGAN approach aims at embedding the teacher’s way of solving the task within a critic network. Enhanced with the intermediate state variable (ISV) that translates a student state in its teacher equivalent, the critic is then able to guide the student policy in a supervised way in a fraction of the initial training time and without the student having any interaction with the target domain. To demonstrate the flexibility of this approach, CoachGAN is evaluated over a custom tennis task, using various ways to define the intermediate state variables.
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Short Papers
Paper Nr: 1
Title:

Working Progress towards Lawn Mower Automation

Authors:

Alfredo C. Plascencia, Vítězslav Beran, Jaroslav Rozman and Aguilar A. Armando

Abstract: This paper is a working progress towards an automation of the Spider lawn mower (SLM) which is a four synchronized steering wheel mobile robot. During the functioning, the SML must follow cutting grass edge with no overlapping of a strip of cut grass and also satisfy slippage constrains. To this end, a small prototype called Andromina which is a four-independent steering wheel mobile robot has been chosen to verify the control approach. This paper proposes to implement a mathematical model that takes into account the kinematics and dynamics of the mobile robot and also a nonlinear control strategy like the state feedback linearization. The most important advantage of the proposed model-control strategy is that it takes into account the nonlinearities of the system and a control law becomes a linear one. The path following tracking error has been verified by the statistical approach called analysis t-test and also results of real data simulations have shown the effectiveness of the proposed control strategy applied to a four-independent steering nonholonomic wheeled mobile robot.
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Paper Nr: 3
Title:

RBF Neural Network based Trajectory Control and Impedance Control of a Upper Limb Tele-rehabilitation Process

Authors:

Ting Wang and Yanfeng Pu

Abstract: In the passive tele-rehabilitation process, the safety is the most important thing for patients avoiding the secondary damage of the impaired upper limb. Aiming at adjusting the appropriated contact force in time during the training exercises, an adaptive impedance control is proposed for the slave side. At the same time, the trajectory control based on the Hamilton-Jacobi-Inequality theory and the RBF Neural network is performed for the master manipulator operated by therapists. The stability is analyzed and numerical simulations show the efficiencies and high performances of the proposed method.
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Paper Nr: 44
Title:

An Excited Binary Grey Wolf Optimizer for Feature Selection in Highly Dimensional Datasets

Authors:

Davies Segera, Mwangi Mbuthia and Abraham Nyete

Abstract: Currently, feature selection is an important but challenging task in both data mining and machine learning, especially when handling highly dimensioned datasets with noisy, redundant and irrelevant attributes. These datasets are characterized by many attributes with limited sample-sizes, making classification models overfit. Thus, there is a dire need to develop efficient feature selection techniques to aid in deriving an optimal informative subset of features from these datasets prior to classification. Although grey wolf optimizer (GWO) has been widely utilized in feature selection with promising results, it is normally trapped in the local optimum resulting into semi-optimal solutions. This is because its position-updated equation is good at exploitation but poor at exploration. In this paper, we propose an improved algorithm called excited binary grey wolf optimizer (EBGWO). In order to improve on exploration, a new position-updating criterion is adopted by utilizing the fitness values of vectors 𝑋⃗ଵ, 𝑋⃗ଶ and 𝑋⃗ଷ to determine new candidate individuals. Moreover, in order to make full use of and balance the exploration and exploitation of the existing BGWO, a novel nonlinear control parameter strategy is introduced, i.e. the control parameter of 𝑎⃗ is innovatively decreased via the concept of the complete current response of a direct current (DC) excited resistor-capacitor (RC) circuit. The experimental results on seven standard gene expression datasets demonstrate the appropriateness and efficiency of the fitness value based position-updating criterion and the novel nonlinear control strategy in feature selection. Moreover, EBGWO achieved a more compact set of features along with the highest accuracy among all the contenders considered in this paper.
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Paper Nr: 50
Title:

Optimal Reachability with Obstacle Avoidance for Hyper-redundant and Soft Manipulators

Authors:

Simone Cacace, Anna C. Lai and Paola Loreti

Abstract: We address an optimal reachability problem in constrained environments for hyper-redundant and soft planar manipulators. Both the discrete and continuous devices are inextensible and they are characterized by a bending moment, representing a natural resistance to leave the position at rest, an inequality constraint forcing the bending below a fixed threshold, and a control term prescribing local bending. After introducing the model and characterizing the associated equilibria, we set the problem in the framework of optimal control theory and we present some simulations related to its numerical solution.
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Paper Nr: 51
Title:

Real-time Electrode Misalignment Detection Device for RSW Basing on Magnetic Fields

Authors:

D. Ibáñez, E. García, J. Martos and J. Soret

Abstract: Electrodes misalignments are considered one of the most important mechanical factors involved in RSW (Resistance Spot Welding). Misalignment causes quality problems as undersized weld, expulsions or nonrounded-weld. Man-power needed in the automotive production lines is increased so as to repair the lack of quality, which means an increase in the cost of production. Consequently, an implantable solution for the automotive industry should be developed in order to detect misalignment when this happens. This research gives an answer by measuring the electrode misalignment by means of the generated magnetic field for the electrodes. The proposed method is validated by Multiphysics simulation measurement. Finally, this method is put into practice by creating a device tested in an automotive production line at the assembly and body plant in Ford Valencia. Together with the device, a communication system is implemented to carry out predictive management. This research initiates a novel line of research for the early and online detection of misalignment problems in welding guns.
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Paper Nr: 52
Title:

Stability of Barrier Model Predictive Control

Authors:

Maxime Pouilly-Cathelain, Philippe Feyel, Gilles Duc and Guillaume Sandou

Abstract: In the last decades, industrial problems have tried to take into account constraints explicitly in the design of the control law. Model Predictive Control is one way to do so and has been extensively studied. However, most papers related to constrained Model Predictive Control often omit to consider nondifferentiable constraints and stability is not ensured when constraints are not satisfied. The aim of this paper is to propose a formulation of the cost function of a Model Predictive Control to ensure stability in face with input and state nondifferentiable constraints. For this purpose, a set where all constraints are satisfied is defined by means of the invariant set theory. Once this set is defined, the system is enforced to reach it and stay in, while guaranteeing stability thanks to the choice of a well suited Lyapunov function based on the cost function.
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Paper Nr: 75
Title:

Minimising the User’s Effort during Wheelchair Propulsion using an Optimal Control Problem

Authors:

Ouazna Oukacha, Chouki Sentouh and Philippe Pudlo

Abstract: This paper proposes a study of the optimal control problem with state constraint, using two types of a power-assist wheelchair propulsion. The cost function is given by the metabolic function, which represented by a compromise between the work exerted by the joints muscles (mechanical effect) and an efficiency function that converts chemical into mechanical energy (biomechanical effect). The dynamic wheelchair is given by a simple model, which connects the push force to the wheelchair speed. An upper bound constraint is considered in order to limit the energy consumed by the motor. This study used an approach that calls the Pontryagin’s maximum principle, the optimal solution varies with the parameters of the problem. Finally, a numerical comparison is enabled using two types of assistance: constant and proportional. This numerical comparison is based on the framework of the optimal control theory with two different costs. The first cost is given by the integral of the squared user’s force and the second by the integral of the metabolic function. This Numerical results show that the user provides less effort with metabolic cost than with the energy user’s force.
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Paper Nr: 101
Title:

Damage Detection and Diagnosis for Offshore Wind Foundations

Authors:

Bryan Puruncajas, Yolanda Vidal and Christian Tutivén

Abstract: Structural health monitoring for wind turbines (WT) in remote locations, as offshore, is crucial (Presencia and Shafiee, 2018). Offshore wind farms are increasingly realized in water depths beyond 30 meters, where lattice foundations (as jacket-type) are a highly competitive substructure type (Moulas et al., 2017). In this work, a methodology for the diagnosis of structural damage in jacket-type foundations is stated by means of a small-scale structure -an experimental laboratory tower modeling an offshore-fixed jacket-type WT. In the literature, a lot of methodologies for damage detection can be found (Li et al., 2015). Among them, the vibration-based methods are one of the most prolific ones. However, they are, primarily, focused on the case of measurable input excitation and vibration response signals, with only few recent studies focused on the vibration–response–only case, the importance of which stems from the fact that in some applications the excitation cannot be imposed and often is not measurable. This work aims to contribute in this area, as the vibration excitation is given by the wind and analyzed by a convolutional neural network (CNN), with a classification accuracy result of 93 %.
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Paper Nr: 109
Title:

A New Neural Network Feature Importance Method: Application to Mobile Robots Controllers Gain Tuning

Authors:

Ashley Hill, Eric Lucet and Roland Lenain

Abstract: This paper proposes a new approach for feature importance of neural networks and subsequently a methodology using the novel feature importance to determine useful sensor information in high performance controllers, using a trained neural network that predicts the quasi-optimal gain in real time. The neural network is trained using the Covariance Matrix Adaptation Evolution Strategy (CMA-ES) algorithm, in order to lower a given objective function. The important sensor information for robotic control are determined using the described methodology. Then a proposed improvement to the tested control law is given, and compared with the neural network’s gain prediction method for real time gain tuning. As a results, crucial information about the importance of a given sensory information for robotic control is determined, and shown to improve the performance of existing controllers.
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Paper Nr: 121
Title:

Real-time Prognosis of Failure of the IGBT in a Conversion Chain

Authors:

Kokou Langueh, Ghaleb Hoblos and Houcine Chafouk

Abstract: In this paper, the problem of prognosis of failure of Insulated Gate Bipolar Transistors (IBGT) in a DC-DC converter is studied. Indeed, the degradation of IGBT can be caused by several factors (electrical, thermal and mechanical stresses,aging, ...). This degradation can be assessed in relation to the variation of the internal resistance of the IGBT. Likewise, we determined the remaining useful life (RUL) of the IGBT compared to the variation of its internal resistance and the duty cycle of the IGBT control signal, which are both estimated in this paper.
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Paper Nr: 123
Title:

Detection and Estimation of Helicopters Vibrations by Adaptive Notch Filters

Authors:

Antoine Monneau, Nacer K. M’Sirdi, Sébastien Mavromatis, Guillaume Varra, Marc Salesse and Jean Sequeira

Abstract: ∗ This paper addresses online vibration detection in helicopters using Adaptive Filters. Adaptive Notch Filters (ANF) are used to estimate and track the time varying frequencies of the vibrations. We estimate and track the amplitudes and phases of time varying frequencies of the vibrations. This allows the detection of abnormal oscillations in the helicopter flight to keep control of the aircraft. In the application presented, we show the detection of severe vibrations that occurred during a helicopter flight test. This proves the effectiveness of proposed ANF to track and reject narrow band perturbations.
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Paper Nr: 125
Title:

Overview on Modeling for Control of Autonomous Road Vehicles Platoon

Authors:

Nacer K. M’Sirdi, Abdelhak Dahmani and Habib Nasser

Abstract: This is an overview on the models used to control fleets of road vehicles. In general, simplified vehicle models are used and their coupling features are introduced through the (individual) controllers. The robustness and precision of motion control needs geometric, kinematic and dynamic descriptions. We propose a modeling methodology for robots platooning to introduce specific features in the platoon behavior. This overview proposes reference models to link the fleet vehicles and assign a character to the group independent from control.
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Paper Nr: 14
Title:

Evaluation of Change Point Detection Algorithms for Application in Big Data Mini-term 4.0

Authors:

E. Garcia, N. Montes, J. Llopis and A. Lacasa

Abstract: The present study analyses in depth the algorithms of change point detection in time series for the prediction of failures through the monitoring of mini-terms in real time. The mini-term is a new concept in the area of failure prediction that is based on the measurement of the time it takes for a component to perform its task. The simplicity of the technique has made it feasible to build industrial Big Data for the prediction of failures based on this concept. There are currently more than 11,000 sensorized mini-terms at Ford factory in Almussafes (Valencia). For the present study, 10 representative real cases of the different change points that have been detected up to the present were selected and, these cases were analysed by using the change point algorithms, which are representative of the great majority of algorithms described in the literature in their different versions. As a result, their accuracy was measured when detecting the change point and its computational cost. A discussion of the results is shown at the end of the paper.
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Paper Nr: 92
Title:

Ensuring Confidentiality of Information When Processing Operational Production Plans in Cloud Services

Authors:

Radda A. Iureva, Sergey V. Taranov, Alexander V. Penskoi and Artem S. Kremlev

Abstract: This paper proposes two methods for ensuring the confidentiality of information transmitted to cloud services when processing the operational production schedule. The first method consists of the consistent classification of critical information and the depersonalization of symbolic parameters, which may be personal or commercial secret, concerning the type of anonymized data. The second method, as an additional gain, involves homomorphic encryption of numerical parameters.For each of the proposed methods, the disadvantages and advantages of its use and implementation are described.
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Paper Nr: 97
Title:

Efficient Construction of Neural Networks Lyapunov Functions with Domain of Attraction Maximization

Authors:

Benjamin Bocquillon, Philippe Feyel, Guillaume Sandou and Pedro Rodriguez-Ayerbe

Abstract: This work deals with a new method for computing Lyapunov functions represented by neural networks for autonomous nonlinear systems. Based on the Lyapunov theory and the notion of domain of attraction, we propose an optimization method for determining a Lyapunov function modelled by a neural network while maximizing the domain of attraction. The potential of the proposed method is demonstrated by simulation examples.
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Area 3 - Robotics and Automation

Full Papers
Paper Nr: 12
Title:

Learning to Close the Gap: Combining Task Frame Formalism and Reinforcement Learning for Compliant Vegetable Cutting

Authors:

Abhishek Padalkar, Matthias Nieuwenhuisen, Sven Schneider and Dirk Schulz

Abstract: Compliant manipulation is a crucial skill for robots when they are supposed to act as helping hands in everyday household tasks. Still, nowadays, those skills are hand-crafted by experts which frequently requires labor-intensive, manual parameter tuning. Moreover, some tasks are too complex to be specified fully using a task specification. Learning these skills, by contrast, requires a high number of costly and potentially unsafe interactions with the environment. We present a compliant manipulation approach using reinforcement learning guided by the Task Frame Formalism, a task specification method. This allows us to specify the easy to model knowledge about a task while the robot learns the unmodeled components by reinforcement learning. We evaluate the approach by performing a compliant manipulation task with a KUKA LWR 4+ manipulator. The robot was able to learn force control policies directly on the robot without using any simulation.
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Paper Nr: 18
Title:

A Deep Learning Tool to Solve Localization in Mobile Autonomous Robotics

Authors:

Sergio Cebollada, Luis Payá, María Flores, Vicente Román, Adrián Peidró and Oscar Reinoso

Abstract: In this work, a deep learning tool is developed and evaluated to carry out the visual localization task for mobile autonomous robotics. Through deep learning, a convolutional neural network (CNN) is trained with the aim of estimating the room where an image has been captured, within an indoor environment. This CNN is not only used as tool to solve a room estimation, but it is also used to obtain global-appearance descriptors of the input image from its intermediate layers. The localization task is addressed in two different ways: globally, as an image retrieval problem and hierarchically. About the global localization, the position of the robot is estimated by using a nearest neighbour search between the holistic description obtained from a test image and the training dataset (using the CNN to obtain the descriptors). Regarding the hierarchical localization method, first, the CNN is used to solve the rough localization step and after that, it is also used to obtain global-appearance descriptors; second, the robot estimates its position within the selected room through a nearest neighbour search by comparing the obtained holistic descriptor with the visual model contained in that room. Throughout this work, the localization methods are tested with a visual dataset that provides omnidirectional images from indoor environments under real-operation conditions. The results show that the proposed deep learning tool is an efficient solution to carry out visual localization tasks.
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Paper Nr: 27
Title:

A Bio-inspired Quasi-resonant Compliant Backbone for Low Power Consumption Quadrupedal Locomotion

Authors:

Edgar A. Parra Ricaurte, Julian D. Colorado, S. Dominguez and C. Rossi

Abstract: Many quadrupeds are capable of highly power efficient gaits thanks to their flexible backbone. This is used during different stages of the gait in order to store and release elastic energy, also helping a smooth deceleration and a fast acceleration of the different parts of the body involved during running. In this work we present our current studies aimed to reproduce such phenomena for efficient robot locomotion. In addition, we studied how to amplify such effect when the frequency of the oscillations is brought close to the natural resonant frequency of the compliant structure. We demonstrated that a flexible artificial structure representing the backbone, muscle and tendons, driven to quasi-resonant oscillations is capable of dramatically reducing the power required to maintain oscillations. At the same time, these reach a bigger amplitude. Such effect will be used to design fast running and energy efficient quadruped robots.
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Paper Nr: 28
Title:

Fuzzy Gradient Control of Electric Vehicles at Blended Braking with Volatile Driving Conditions

Authors:

Valery Vodovozov, Eduard Petlenkov, Andrei Aksjonov and Zoja Raud

Abstract: The paper is devoted to intelligent control of road electric vehicles aiming at reducing energy losses caused by traffic jams, changing velocity, and frequent start-stop modes of driving. A blended braking system is described that integrates both the friction and the electric braking strengths in volatile driving conditions, including gradual and emergency antilock braking. The vehicle model reflects multiple factors, such as air resistance, road slope, and variable friction factor. A new gradient control method recognizes unstable tire properties on changing road surfaces at different velocities. In the motor and battery model, the state of charge and electric current/voltage restrictions of the hybrid energy storage are taken into account. The braking torque, actuated by the Mamdani’s fuzzy logic controller established in the Simulink® environment, is allocated between the front and rear friction and electric brakes. Comparison of simulation and experimental results confirms that the outcomes of this research can be considered in the design of braking systems for electric vehicles with superior energy recovery.
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Paper Nr: 29
Title:

PHRI Safety Control using a Virtual Flexible Joint Approach

Authors:

J. Diab, A. Fonte, G. Poisson and C. Novales

Abstract: Physical Human-Robot Interaction (PHRI) emphasize on human safety. In literature, two techniques were presented to improving this critical factor concerning moving devices; the first solution is purely mechanical, while the second one is based on the control. In this paper, we describe a new approach combining the two previous solutions. Our proposed paper explores a control scheme involving the use of a virtual component with an adjustable stiffness supposed to be placed between the motor shaft and the robot link. This scheme proposes a Variable Impedance Actuator (VIA) robot control methodology based on the integration of a virtual component, reflecting the behaviour of a real intrinsic Series Elastic Actuator (SEA). This novel method is potentially beneficial in reducing injuries in human/robot interaction by combining a mechanical operating principle and a control approach in order to reduce the collision forces in collaborative applications. This proposed approach was simulated and validated using a UR3 robot model, showing great capacities in reducing collision’s peak forces. This paper begins with particular attention to the robot dynamics, then the articulation flexibility and force estimation have been tackled and finally ending the control architecture.
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Paper Nr: 35
Title:

Vector based Control Routines for Swarms of Path Finding Robotic Devices

Authors:

Colin Chibaya

Abstract: Swarm intelligence systems where robotic devices encoded with primitive actions executed at individual levels in order to cause swarm level emergent behaviour are appealing to the fields of nanotechnology and bioinformatics. Interaction between robotic devices allow improved swarm level properties with features more than the sum of the contributions of the individual robotic devices that form the swarm. However, it is challenging to pinpoint particular primitive actions which drive robotic devices towards deliberately engineered emergent behaviour. We propose an XSet model inspired by the behaviours of message passing agents. The proposed XSet model supports direct device to device interactions in which implicit communication spaces arise. In this context, an XSet puts together primitive actions, parameters, and meta information which stipulates when primitive actions are useful to robotic devices. We assess path finding and path following abilities of message passing robotic devices and compared the measures thereof to the relative performances of the stigmergic counterparts. Better message passing performances are observed when time in simulation is sufficiently long, when the population of robotic devices in the swarm is high. Besides giving a new swarm control model, message passing XSets bring us closer to more generalized swarm control rules.
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Paper Nr: 46
Title:

Global Estimation for the Convoy of Autonomous Vehicles using the Sliding-mode Approach

Authors:

M-Mahmoud Mohamed-Ahmed, Aziz Naamane and Nacer K. M’sirdi

Abstract: In this paper, a global estimation approach is proposed to estimate the states of motion (longitudinal, lateral and yaw angle) of a convoy of autonomous vehicles, which is composed of four cars and also the inter-distance between each two neighboring vehicles. The approach used is based on the first-order sliding mode (FOSM) and second-order sliding mode (SOSM) observer without and with linear gain (FOSML and SOSML), to estimate and compare at the same time the estimation approach used for each vehicle in convoy. To validate this approach, we use data from SCANeRTM-Studio of a convoy moving in a defined trajectory. The robustness of the observers towards estimation errors on the model parameters will be studied.
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Paper Nr: 47
Title:

Free-form Trap Design for Vibratory Feeders using a Genetic Algorithm and Dynamic Simulation

Authors:

Daniel F. Haraldson, Lars C. Sørensen and Simon Mathiesen

Abstract: The task of feeding parts into a manufacturing system is still extensively handled using classical vibratory bowl feeders. However, the task of designing these feeders is complex and largely handled by experience and trial-and-error. This paper proposes a Self-Adaptive Genetic Algorithm based learning strategy that uses dynamic simulation to validate feeder designs. Compared to previous approaches of ensuring parts are oriented to a desired orientation by both deciding on a set of suitable mechanisms and then optimizing them to the specific part, this strategy learns a free-form design needing little prior domain knowledge from the designer. This novel approach to feeder design is validated on two different parts and it creates designs of hills and valley that reorients the parts to a single orientation. The found designs are validated both in simulation and with real-world experiments and achieve high success rates for reorienting the parts.
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Paper Nr: 48
Title:

Wilson Score Kernel Density Estimation for Bernoulli Trials

Authors:

Lars C. Sørensen, Simon Mathiesen, Dirk Kraft and Henrik G. Petersen

Abstract: We propose a new function estimator, called Wilson Score Kernel Density Estimation, that allows to estimate a mean probability and the surrounding confidence interval for parameterized processes with binomially distributed outcomes. Our estimator combines the advantages of kernel smoothing, from Kernel Density Estimation, and robustness to low number of samples, from Wilson Score. This allows for more robust and data efficient estimates compared to the individual use of these two estimators. While our estimator is generally applicable for processes with binomially distributed outcomes, we will present it in the context of iterative optimization. Here we first show the advantage of our estimator on a mathematically well defined problem, and then apply our estimator to an industrial automation process.
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Paper Nr: 53
Title:

Sim-to-Real Transfer with Incremental Environment Complexity for Reinforcement Learning of Depth-based Robot Navigation

Authors:

Thomas Chaffre, Julien Moras, Adrien Chan-Hon-Tong and Julien Marzat

Abstract: Transferring learning-based models to the real world remains one of the hardest problems in model-free control theory. Due to the cost of data collection on a real robot and the limited sample efficiency of Deep Reinforcement Learning algorithms, models are usually trained in a simulator which theoretically provides an infinite amount of data. Despite offering unbounded trial and error runs, the reality gap between simulation and the physical world brings little guarantee about the policy behavior in real operation. Depending on the problem, expensive real fine-tuning and/or a complex domain randomization strategy may be required to produce a relevant policy. In this paper, a Soft-Actor Critic (SAC) training strategy using incremental environment complexity is proposed to drastically reduce the need for additional training in the real world. The application addressed is depth-based mapless navigation, where a mobile robot should reach a given waypoint in a cluttered environment with no prior mapping information. Experimental results in simulated and real environments are presented to assess quantitatively the efficiency of the proposed approach, which demonstrated a success rate twice higher than a naive strategy.
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Paper Nr: 68
Title:

Solution of the Forward Kinematic Problem of 3UPS-PU Parallel Manipulators based on Constraint Curves

Authors:

Adrián Peidró, Luis Payá, Sergio Cebollada, Vicente Román and Óscar Reinoso

Abstract: Algebraic elimination methods for solving the forward kinematic problem of parallel manipulators are fast and obtain all solutions, but they require eliminating all unknowns except one, and solving a high-degree univariate polynomial whose coefficients often have expressions too complex to be obtained symbolically. This prevents parameterizing these coefficients in terms of all the kinematic parameters involved, which requires repeating the elimination process again whenever these kinematic parameters change. To avoid this, this paper presents an new method to solve the forward kinematics of 3UPS-PU parallel manipulators by eliminating only one unknown, reducing the system to an easily parameterizable set of planar constraint curves in the space of the remaining unknowns, which contain all real solutions of the forward kinematics. By sampling points from these curves densely, and sorting the sampled points using k-d trees, the proposed method manages to search all real solutions along these curves. The proposed method is compared to previous methods that obtain all solutions and is shown to perform about 100 times faster than these methods, but is less general than them.
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Paper Nr: 73
Title:

Interval-based Sound Source Mapping for Mobile Robots

Authors:

Axel Rauschenberger and Bernardo Wagner

Abstract: Auditory information can expand the knowledge of the environment of a mobile robot. Therefore, assigning sound sources to a global map is an important task. In this paper, we first form a relationship between the microphone positions and auditory features extracted from the microphone signals to describe the 3D position of multiple static sound sources. Next, we form a Constraint Satisfaction Problem (CSP), which links all observations from different measurement positions. Classical approaches approximate these non-linear system of equations and require a good initial guess. In contrast, in this work, we solve these equations by using interval analysis in less computational effort. This enables the calculation being performed on the hardware of a robot at run time. Next, we extend the approach to model uncertainties of the microphone positions and the auditory features extracted by the microphones making the approach more robust in real applications. Last, we demonstrate the functionality of our approach by using simulated and real data.
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Paper Nr: 106
Title:

Analyzing Decision Polygons of DNN-based Classification Methods

Authors:

Jongyoung Kim, Seongyoun Woo, Wonjun Lee, Donghwan Kim and Chulhee Lee

Abstract: Deep neural networks have shown impressive performance in various applications, including many pattern recognition problems. However, their working mechanisms have not been fully understood and adversarial examples indicate some fundamental problems with DNN-based classification methods. In this paper, we investigate the decision modeling mechanism of deep neural networks, which use the ReLU function. We derive some equations that show how each layer of deep neural networks expands the input dimension into higher dimensional spaces and generates numerous decision polygons. In this paper, we investigate the decision polygon formulations and present some examples that show interesting properties of DNN based classification methods.
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Paper Nr: 124
Title:

Model Predictive Control for Cooperative Insertion or Exit of a Vehicle in a Platoon

Authors:

Simone Graffione, Chiara Bersani, Roberto Sacile and Enrico Zero

Abstract: Vehicle platooning has a central role in the road management by self-driving or autonomous vehicles (AVs). The main issues in this context are the agreement of communication and control instructions among vehicles in order to maintain a safe inter vehicular distance and a specific desired speed according to the planned travel. This paper proposes a longitudinal Model Predictive Control (MPC) to carry out vehicles’ safe manoeuvres to let an external vehicle to be inserted in the platoon or alternatively to let a vehicle of the platoon to leave it. The control strategy considers a cooperative approach where the leader coordinates the exchange of information with the followers and with the vehicle which notifies its intent to enter (or to leave) the platoon. All the vehicles are equipped with technologies to monitor their own state in terms of position and speed while the leader receives, elaborates the data and, by the control process, distributes the optimal control decisions to the whole platoon. The proposed control algorithm minimizes the tractive forces and the square deviations of positions and speeds in respect to predefined references. The MPC longitudinal control of the vehicle, based on a non-linear cinematic model, provides the optimal control values related to the torques to be applied to vehicles’ acceleration or deceleration in order to perform safe entering and exiting manoeuvring. The results of the simulations demonstrate the effectiveness of the proposed approach with reduced execution time.
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Short Papers
Paper Nr: 2
Title:

Design and Experimental Study of a Pneumatic Bionic Stingray Undulatory Soft Robot

Authors:

Songzi Guo, Jinhua Zhang, Yuhan Yang, Haiyan Cheng and Jun Hong

Abstract: Underwater organisms have always been providing inspiration for the design and development of novel underwater propulsion and bionic robots. At present, stingray has been taken as a bionic object due to its stable motion and robust mobility. In this study, a stingray propelled by flexible pectoral fins was taken as a bionic object. Based on this, a new idea for the design of high-performance bionic underwater propulsor was proposed. An analysis was conducted regarding the design, fabrication and experiments of the bionic stingray wave propulsion soft robot based on pneumatic drive. As revealed by the experiments of propulsion performance, the influencing factors for average propulsion include varying frequencies, fin stiffness and the gaps between substrate and the fins. This is expected to provide guidance on our design of a stingray robot in respect of efficient mobility.
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Paper Nr: 9
Title:

Analysis of Different Human Body Recognition Methods and Latency Determination for a Vision-based Human-robot Safety Framework According to ISO/TS 15066

Authors:

David Bricher and Andreas Müller

Abstract: Today, an efficient and flexible usage of lightweight robots in collaborative working spaces is strongly limited by the biomechanical safety regulations of ISO/TS 15066. In order to maximize the robot performance without contradicting the technical standards and recommendations, a safety framework is introduced, which makes use of state-of-the-art deep learning algorithms for human recognition and human body part identification. Particularly, a generic vision-based method for the determination of the occurring latencies is proposed. To this end, the different latency contributions from the recognition process up to the process of adapting the robot speed to an ISO-conform level are analyzed in detail.
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Paper Nr: 17
Title:

An Evaluation of New Global Appearance Descriptor Techniques for Visual Localization in Mobile Robots under Changing Lighting Conditions

Authors:

Vicente Román, Luis Payá, Sergio Cebollada, Adrián Peidró and Óscar Reinoso

Abstract: Autonomous robots should be able to carry out localization and map creation in highly heterogeneous zones. In this work, global appearance descriptors are tested to perform the localization task. It focuses on the use of an omnidirectional vision sensor as unique source of information and global appearance to describe the visual information. Global-appearance techniques consist in obtaining a unique vector that describes globally the image. The main objective of this work is to propose and test new alternatives to build and to handle global descriptors. In previous experiments the images have been processed without considering the spatial distribution of the information. In contrast, in this work, the main approach is that relevant information will be in the central rows. For this reason central rows information is given a higher weight comparing to other zones of the image. The results show that this consideration can be an interesting presumption to take into account. The experiments are carried out with real images that have been taken in two different heterogeneous environments where simultaneously humans and robots work together. For this reason, variations of the lighting conditions, people who occlude the scene and changes on the furniture may appear.
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Paper Nr: 31
Title:

Mid-air Imaging for a Collaborative Spatial Augmented Reality System

Authors:

Dashlen Naidoo, Glen Bright and James T. Collins

Abstract: Aerial imaging can be used to deliver mid-air imagining in a collaborative Spatial Augmented Reality system. This research aimed to overcome the current disadvantages of Augmented Reality headsets, which include physical discomfort, visual discomfort, high cost and its single user operation. The concept design presented delivered multiple user interaction simultaneously while delivering an increased field of view. This was done through the ASKA3D aerial imaging plate used to deliver mid-air projection, in conjunction with a camera used for view dependant rendering of mid-air images. This design delivered an Augmented Reality experience without the need for robust technology and solely focused on the method of mid-air image projection. The system was successful in delivering a high-quality mid-air image. A Quality of Experience model was found to be the most suited method for user-assessment of this multimedia device. The overall average percentage rating for the system was 69.4% which was considered successful given that what was evaluated was only one part of a whole system to be built.
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Paper Nr: 37
Title:

Disturbance Compensator for a Very Flexible Parallel Lambda Robot in Trajectory Tracking

Authors:

Fatemeh Ansarieshlaghi and Peter Eberhard

Abstract: This research investigates the design of a nonlinear position controller and a disturbance observer to estimate and compensate disturbances on a very flexible parallel robot to improve trajectory tracking and control performance. The used robot has very flexible links and can be considered as an underactuated system since it has fewer control inputs than degrees of freedom for rigid body motions and deformations. Hence, these flexibilities must be taken into account in the control design. To obtain high performance in the end-effector trajectory tracking, an accurate and efficient nonlinear controller is required. This nonlinear controller includes a position controller and a disturbance observer. The nonlinear feedback controller is designed based on the feedback linearization approach and its stability is proofed by the Lyapunov candidate function. The disturbances that are investigated in this work are the friction forces of the drives of the robot, acting forces on the robot’s end-effector, and their combination. The designed nonlinear controller is implemented on the simulated model of the robot under different disturbances. The simulation results show that the end-effector tracks desired trajectories with higher accuracy and better performance in comparison to other controllers in previous works. Also, by the designed nonlinear position controller and the disturbance observer the robot tracks the desired trajectory with the highest robustness under disturbances in comparison to the previous work.
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Paper Nr: 42
Title:

Stiffness Analysis of a New Tensegrity Mechanism based on Planar Dual-triangles

Authors:

Wanda Zhao, Anatol Pashkevich, Alexandr Klimchik and Damien Chablat

Abstract: The paper deals with the stiffness analysis and stability study of a new type of tensegrity mechanism based on dual-triangle structures, which actuated by adjusting elastic connections between the triangle edges. For a single segment of such mechanism, the torque-deflection relation was obtained as a function of control inputs and geometric parameters. It was proved that a single section of the mechanism can has either a single or three equilibrium configurations that can be both stable and unstable. Corresponding conditions of stability were found allowing user to choose control inputs ensuring the mechanism controllability, and the obtained results are confirmed by the simulation examples. The structure composed of two segments in serial was also analysed and an equivalent serial structure with non-linear virtual springs in the joints was proposed. It was proved that the stiffness of such structure decreases while the external loading increases, which may lead to the buckling phenomenon.
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Paper Nr: 55
Title:

Proactive-cooperative Navigation in Human-like Environment for Autonomous Robots

Authors:

Wanting Jin, Paolo Salaris and Philippe Martinet

Abstract: This work1 deals with the problem of navigating a robot in a constrained human-like environment. We provide a method to generate a control strategy that enables the robot to proactively move in order to induce desired and socially acceptable cooperative behaviors in neighboring pedestrians. Contrary to other control strategies that simply aim to passively avoid neighboring pedestrians, this approach aims to simplify the navigation task of a robot by looking for cooperation with humans, especially in crowded and constrained environments. The co-navigation process between humans and a robot is formalized as a multi-objective optimization problem and a control strategy is obtained through the Model Predictive Control (MPC) approach. The Extended Headed Social Force Model with Collision Prediction (EHSFM with CP) is used to predict the human motion. Different social behaviors of humans when moving in a group are also taken into account. A switching strategy between purely reactive and proactive-cooperative planning depending on the evaluation of human intentions is also furnished. Validation of the proactive-cooperative planner enables the robot to generate more socially and understandable behaviors is done with different navigation scenarios.
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Paper Nr: 61
Title:

Design and Preliminary Evaluation of a Dextrous Encounter Type Force Feedback Interface

Authors:

Anthony Chabrier, Florian Gosselin and Wael Bachta

Abstract: Force feedback interfaces aim at allowing natural interactions with a virtual or distant environment with a physical sense of presence. Commercially available systems suffer however two limitations. First, most of them are equipped with a handle whose geometry constraints the movements that can be efficiently simulated to the manipulation of tools shaped like the handgrip. Second, the handle is always grasped in hand and the user feels the friction and inertia of the system even in free space, hence a limited transparency. Dexterous interfaces were introduced to cope with the first issue, while encounter type devices, which are detached from the user’s hand and contact it only when haptic feedback is required, allow to tackle the second limitation. To date however, no device efficiently integrates both principles. The aim of this paper is to introduce a new device intended to do so, i.e. to be both dexterous, allowing to simulate any grasp type (limited to two fingers in a first step), and of encounter-type, hence an improved transparency. Its design is presented in details, and first experimental results showing the ability of the device to follow user’s movements are introduced.
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Paper Nr: 70
Title:

Centimeter-scaled Self-Assembly: A Preliminary Study

Authors:

Martin Jílek, Miroslav Kulich and Libor Přeučil

Abstract: Passive self-assembly represents a general kind of bottom-up assembly process for objects, where the assembling particles exhibit no explicit, active ”sense and affect” featuring, but embedded properties only. Although the majority of the previous work in the field has been performed on a microscopic scale, in the field of chemistry and nanotechnology, we identify a strong relation to macroscopic cases and principles studied in robotics. We show that passive self-assembly processes might be promising also towards the development of new, completely passive (multi)robot systems, driven entirely by environmental perturbations. This work sketches insight into fundamental principles of driving a centimeter-scale self-assembly system while observing the behavior of single particles. Investigations show, that not all the principles previously studied in the microscopic scale do hold also in the macroscopic cases of centimeter-scale particles. Thus, this article proposes the macroscopic problem specification and an experimental self-assembly system design consisting of entirely passive elements. We tackle a theoretical description of the system model and the necessary simplification towards a two-handed tile assembly model (2HAM) together with real-world experimentation design. We evaluate experimental results, discuss the feasibility of shake-driven macroscopic self-assembly, and elaborate their major properties together with estimated future work.
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Paper Nr: 71
Title:

Bridging the Reality Gap: Investigation of Deep Convolution Neural Networks Ability to Learn from a Combination of Real and Synthetic Data

Authors:

Omar Gamal, Keshavraj Rameshbabu, Mohamed Imran and Hubert Roth

Abstract: Recent advances in data-driven approaches especially deep learning and its application on visual imagery have drawn a lot of attention in recent years. The lack of training data, however, highly affects the model accuracy and its ability to generalize to unseen scenarios. Simulators are emerging as a promising alternative source of data, especially for vision-based applications. Nevertheless, they still lack the visual and physical properties of the real world. Recent works have shown promising approaches to close the reality gap and transfer the knowledge obtained in simulation to the real world. This paper investigates Convolution Neural Networks (CNNs) ability to generalize and learn from a mixture of real and synthetic data to overcome dataset scarcity and domain transfer problems. The evaluation results indicate that the CNN models trained with real and simulation data generalize to both simulation and real environments. However, models trained with only real or simulation data fails drastically when it is transferred to an unseen target environment. Furthermore, the utilization of simulation data has improved model accuracy significantly.
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Paper Nr: 72
Title:

Design and Integration of a Dexterous Interface with Hybrid Haptic Feedback

Authors:

Florian Gosselin, Claude Andriot, François Keith, François Louveau, Guillaume Briantais and Pascal Chambaud

Abstract: Haptic interfaces allow natural physical interactions with virtual environments. By measuring the user’s movements and providing force feedback, they recreate a physical sense of presence in the virtual world, thus improving the user’s immersion. These characteristics led to their adoption in various VR applications, e.g. fitting, training or ergonomic studies. Until recently however, most of the commercially available systems were equipped with a handle which constraints the simulated movements to the manipulation of tools having a shape similar to the handgrip. More dexterous devices which do not constraint the hand’s posture are required to allow for the simulation of more various grasps and fine manipulation. Such interfaces are currently the subject of intense research, with new products arrived recently on the market. Some of these devices allow generic force feedback on the fingers thanks to multidirectional actuation. They remain however complex and cumbersome. To overcome this limitation, some other devices limit the number of actuators. More compact solutions can be obtained this way, but force feedback is limited to only few directions. In this paper, we present a different approach. By combining force and local pseudo-force feedback, we aim at allowing a rich and multidirectional haptic feedback in a light and compact fashion. This paper presents an innovative haptic glove implementing such hybrid haptic feedback developed for interactions with digital mock-ups, with details on its main components and its integration in a VR application.
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Paper Nr: 78
Title:

Reduced Error Model for Learning-based Calibration of Serial Manipulators

Authors:

Nadia Schillreff and Frank Ortmeier

Abstract: In this work a reduced error model for a learning-based robot kinematic calibration of a serial manipulator is compared with a complete error model. To ensure high accuracy this approach combines the geometrical (structural inaccuracies) and non-geometrical influences like for e.g. elastic deformations that are configuration-dependent without explicitly defining all underlying physical processes that contribute to positioning inaccuracies by using a polynomial regression method. The proposed approach is evaluated on a dataset obtained using a 7-DOF manipulator KUKA LBR iiwa 7. The experimental results show the reduction of the mean Cartesian error up to 0.16 mm even for a reduced error model.
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Paper Nr: 90
Title:

Deep Learning Algorithm for Object Detection with Depth Measurement in Precision Agriculture

Authors:

Aguirre Santiago, Leonardo Solaque and Alexandra Velasco

Abstract: Autonomous driving in precision agriculture will have an important impact for the field. This is why several efforts have been done in this direction. We have developed an agricultural robotic platform named CERES, which has a payload of 100 Kg of solid fertilizer, 20 liters for fumigating purposes, and a weeding system. Our research points to make this robot autonomous. In this paper, we propose a method, based on deep learning algorithms, to combine object detection with depth measurements for object tracking and decision making of an agro-robot. For this, we combine an object detection algorithm carried out with YOLOv2 and a depth measurement strategy implemented with a ZED Camera. The main purpose is to determine the distance to the obstacles, mainly people, because we require to prevent collisions and damages either for people and for the robot. We have chosen to detect people because, in the desired environment, these are frequent and unpredictable obstacles, and the risk of collision may be high.We use a host computer, achieving a detection network with an average accuracy of up to 72% in detecting the class Person. While using a NVIDIA Jetson TX1, the accuracy increases up to 84% due to the powerful dedicated GPU destined to process Convolutional Neural Networks(CNN).
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Paper Nr: 98
Title:

Study of a Hybrid Actuated Exoskeleton for Upper Limb Rehabilitation

Authors:

Dimitar Chakarov, Ivanka Veneva, Mihail Tsveov and Pavel Venev

Abstract: In this paper, an upper arm rehabilitation exoskeleton is studied. An appropriate solution is sought for the exoskeleton design and actuation that provides transparency and natural safety as well as sufficient force and performance. To achieve this, a hybrid actuation with back-drivable electric and pneumatic drives is studied. A hybrid actuation controller is introduced, in which pneumatic drive takes care of the initial force response, and the electric drive complements the pneumatic drive. In the paper, the feasibility of the basic therapy modes "patient in charge" and "robot in charge" is simulated. An approach for dynamic estimation of elastic propulsion in the second joint through imposed motions is used. The influences of the inertial, frictional, gravitational, and elastic forces that resulted from the hand and the exoskeleton impedance are reported. The pneumatic drive's influence as an elastic balance of the gravitational forces is considered. Finally, a conclusion and discussion are added.
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Paper Nr: 108
Title:

An Integrated Object Detection and Tracking Framework for Mobile Robots

Authors:

William K. Juel, Frederik Haarslev, Norbert Krüger and Leon Bodenhagen

Abstract: In this paper, we propose an end-to-end-solution to the problem of multi-object tracking on a mobile robot. The tracking system consists of a process where we project 2D multi-object detections to the robots base frame, using RGB-D sensor data. These detections are then transformed to the map frame using a localization algorithm. This system predicts trajectories of humans and objects in the environment of the robot and can be adapted to work with any detector and track from multiple cameras. The system can then be used to build a temporally consistent costmap to improve navigation strategies.
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Paper Nr: 110
Title:

On the Application of Safe-Interval Path Planning to a Variant of the Pickup and Delivery Problem

Authors:

Konstantin Yakovlev, Anton Andreychuk, Tomáš Rybecký and Miroslav Kulich

Abstract: We address a variant of multi-agent pickup and delivery problem and decouple into two parts: task allocation and path planning. We employ the any-angle Safe-Interval Path Planning algorithm introduced in our recent work and study the performance of several task allocation strategies. Furthermore, the proposed approach has been integrated into a control system to verify its feasibility in deployment on real robots. A key part of the system is a visual localization system which is based on the detection of unique artificial markers placed in the working environment. The conducted experiments show that generated plans can be safely executed on a real system.
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Paper Nr: 115
Title:

Reliable Modeling for Safe Navigation of Intelligent Vehicles: Analysis of First and Second Order Set-membership TTC

Authors:

Nadhir M. Ben Lakhal, Othman Nasri, Lounis Adouane and Jaleleddine H. Slama

Abstract: Developing high fidelity models to compute the Time-To-Collision (TTC) between vehicles is addressed in this work. A TTC interval value is over-approximated while considering several uncertainties via interval analysis. Furthermore, to decrease modeling inaccuracy, a novel second-order set-membership TTC formalization is introduced by solving a polynomial equation with interval coefficients. This latter is derived from vehicles’ motion equations. Hence, an approach based on correlation analysis is exploited to improve the uncertainty evaluation. The simulation results applied on an adaptive cruise control system of both high/low-order TTC formalizations prove that the low-order model inaccuracy is compensated. Thanks to interval analysis and correlation characterization, a great balance between modeling accuracy and simplicity is reached.
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Paper Nr: 122
Title:

Deep Learning with Transfer Learning Method for Error Compensation of Cable-driven Robot

Authors:

Aydar Akhmetzyanov, Maksim Rassabin, Alexander Maloletov, Mikhail Fadeev and Alexandr Klimchik

Abstract: This paper proposes the application of Deep Learning methods for kinematic error compensation. Particular attention is paid to simulation-based error estimation and the use of the Transfer Learning method for error compensation to reduce physical experiments with a real robot. The obtained results were applied and validated for 4-dof (degrees of freedom) cable-driven parallel robot. The problem of error compensation for the cable-driven parallel robot is highly non-linear. Nevertheless, deep learning-based methods for a considerable training dataset provides better accuracy than simple linear error compensators. To overcome this drawback, we applied the transfer learning method and used the knowledge of robot kinematics simulated in Unity. Unity cable-driven robot simulation was implemented, and the central hypothesis was verified first in the simulated environment. The proposed Transfer Learning method allowed to speed up the process of robotics system integration and recalibration due to the significant sample efficiency improvement.
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Paper Nr: 63
Title:

RTFM: Towards Understanding Source Code using Natural Language Processing

Authors:

Maximilian Galanis, Vincent Dietrich, Bernd Kast and Michael Fiegert

Abstract: The manual configuration of today’s autonomous systems for new tasks is becoming increasingly difficult due to their complexity. One solution to this problem is to use planning algorithms that can automatically synthesize suitable data processing pipelines for the task at hand and thus simplify the configuration. Planners usually rely on models, which are created manually based on already existing methods. These methods are often provided as part of domain specific code libraries. Therefore, using existing planners on new domains requires the manual creation of models based on the methods provided by other libraries. To facilitate this, we propose a system that generates an abstract semantic model from C++ libraries automatically. The necessary information is extracted from the library using a combination of static source code analysis to analyze its header files and natural language processing (NLP) to analyze its official documentation. We evaluate our approach on the perception domain with two popular libraries: HALCON and OpenCV. We also outline how the extracted models can be used to configure data processing pipelines for the perception domain automatically by using an existing planner.
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Paper Nr: 74
Title:

Combination of Algorithms for Object Detection in Videos on Basis of Background Subtraction and Color Histograms: A Case Study

Authors:

Theo Gabloffsky and Ralf Salomon

Abstract: This paper presents a combination of algorithms for an object detection and recognition in videos. These algorithms are based on a background subtraction and an histogram comparison. The algorithm were implemented and used for the detection of curling stones in videos from a dataset. These dataset includes three different types of videos, which reaches from (1) only the curling stone is on the over (2) an athlete is behind the stone and (3) an athlete moves in between the field of view from the camera. While analysing the videos, the time was measured which the algorithms needed for their calculations, As the results show, the implemented algorithms are able to recognise position of the curling stone with an detection rate of 100% under best circumstances and with 71.11% under worst conditions.
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Paper Nr: 77
Title:

The Computation of the Inverse Kinematics of a 3 DOF Redundant Manipulator via an ANN Approach and a Virtual Function

Authors:

Shahnaz Habibkhah and Rene V. Mayorga

Abstract: In this paper a method based on Artificial Neural Networks (ANNs) is presented to solve the Inverse Kinematics (IK) of 3 degrees of freedom (DOF) redundant manipulators. In order to obtain the manipulator’s joint angles coordinates and solve the IK problem with acceptable accuracy; the forward kinematics equations of the manipulator are used to obtain position of the end effector, and also a virtual auxiliary function is included in the ANN approach. Then, the trained ANN’ ability to track a designed target trajectory is tested inside the workspace of the manipulator in two scenarios with different inputs data to the ANN.
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Paper Nr: 83
Title:

PD Sliding Mode Controller based Decoupled Aerial Manipulation

Authors:

Kamel Bouzgou, Laredj Benchikh, Lydie Nouveliere, Yasmina Bestaoui and Zoubir Ahmed-Foitih

Abstract: This paper presents the design of 3-Dof multi-link robot arm that is mounted on the multirotor. To be considered the dynamic characteristics of the manipulation platform, the decoupled dynamic models of the system are derived. The main advantage of the first joint is introduced for more robustness and stability during hovering. The PID controller will be implemented for position and attitude of multirotor control, whereas, a sliding mode controller will be designed for a manipulator robot, which is then compared with the sliding surface that has been integrated with the proportional-derivative (PD) controller. The performance of the proposed technique is demonstrated through a simulation using Simulink and Matlab environment.
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Paper Nr: 107
Title:

Functional Architecture using ROS for Autonomous UAVs

Authors:

Johvany Gustave, Jamy Chahal and Assia Belbachir

Abstract: Unmanned Aerial Vehicles (UAVs) are used for several applications due to their stability and versatility. In this paper, we developed a functional architecture for autonomous UAVs using Robot Operating System (ROS). Due to its flexibility and its easy-to-use implementation, our architecture simplifies embedding autonomous behaviours for any kind of UAV. This hierarchical architecture is divided into three layers: decision, control and perception layer. In this paper, all the layers and their implementation under ROS are explained and detailed.
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Paper Nr: 113
Title:

Survey and Preliminary Results on the Design of a Visual Light Communication System for Radioactive and Underwater Scenarios

Authors:

Giovanni Napoli, José M. Avilés, Raúl M. Prades and Pedro S. Valero

Abstract: The use of radio-frequency communication systems is very well known and also it is broadly used in the design of mobile robotics. In fact, it can be very well applied in rescue robotic systems, such as the ones that present smoke and fire. In radioactivity scenarios the robot might get problems to communicate, in the presence for example of magnets. Also, in underwater fields radio-frequency solutions need to improve the communication distance, while sonar systems present variable delays and limited bandwidth, which are difficulties to provide remote visual feedback to the operator. This paper states that field robotic systems, such as the ones in radioactivity and underwater scenarios, need to complement the current communication systems with multi-modal solutions, in order to enhance operation safety and reliability, while better adapting to the mission unexpected situations. For this, Visual Light Communication solutions have been studied in detail and a preliminary prototype, which is presented in this paper, has been designed. This prototype would need further work to be applied successfully in real radioactive and underwater scenarios, as stated in the conclusions.
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Paper Nr: 114
Title:

Backstepping Controller Applied to a Foldable Quadrotor for 3D Trajectory Tracking

Authors:

Saddam H. Derrouaoui, Yasser Bouzid, Mohamed Guiatni, Halfaoui Kada, Islam Dib and Noureddine Moudjari

Abstract: This paper presents a novel design and architecture control of a foldable quadrotor. This design is based on a variable geometry that can be changed during the flight. It is able to modify the orientation of its arms independently, thanks to its special morphology. This quadrotor, exploits simple mechanisms i.e. rotating arms. We stress that the control of this category of robots is not obvious compared to the conventional ones. So, a detailed generic model and backstepping control that take into account the variation of the center of gravity and the inertia are presented. Simulation results are also provided in order to illustrate the performances of this controller.
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Area 4 - Signal Processing, Sensors, Systems Modelling and Control

Full Papers
Paper Nr: 26
Title:

Functional Model-based Resource Management: An Application to the Electric Vehicle Thermal Control

Authors:

Baptiste Boyer, Philippe Fiani, Guillaume Sandou, Emmanuel Godoy and Cristina Vlad

Abstract: Environmental and economical constraints lead to designing more and more complex systems. To face these issues, Model Based System Engineering proposes an approach based on an interconnected multi point of view system modeling. Each representation of the system has a different abstraction level that is valuable at different stages of the system design and suits its own objectives respectively: 1) purposes and global constraints definition, 2) architecture choices, components sizing and strategies testing, 3) accurate simulation results on various scenarios. Interconnections between the different levels have two objectives: on one hand be able to define the requirements of a lower level using higher level information and on the other hand send back simulation variable values from a lower level to evaluate the higher level requirements satisfaction. Resource management is carried out through a functional model, which is a macroscopic and low-complexity model of the system providing fast simulation results. In this paper, this multi-level methodology is applied to the thermal system management of an electric vehicle in order to optimize its resource management. The different levels design and the development of their interconnections are detailed.
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Paper Nr: 45
Title:

Backlash Identification in Industrial Positioning Systems Aided by a Mobile Accelerometer Board with Wi-Fi

Authors:

Mathias Tantau, Lars Perner, Mark Wielitzka and Tobias Ortmaier

Abstract: In electromechanical motion systems performance measures such as positioning accuracy, dynamic stiffness and control bandwidth are severely limited by backlash. Several control schemes based on backlash compensation or switching control of hybrid systems are known, but many of these approaches require the exact backlash width as an input parameter. Several existing approaches for backlash identification are limited in accuracy because the load-side velocity is required but it is not directly measurable. In this paper a method for backlash identification tailored to electromechanical motion systems with rotary motor and translationally moving load is proposed. A mobile sensor board with inertial measurement unit (IMU) is mounted temporarily on the load and serves to acquire the accelerations during the experiment. The connection to the host-PC is wireless, time synchronisation is not required. It is shown in experiments on a testbed with an adjustable backlash coupling but otherwise industry-like equipment that high accuracies can be achieved.
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Paper Nr: 69
Title:

Current Loop Stability Analysis of a VIENNA-type Three-phase Rectifier for an Imaging System Power Supply Application

Authors:

Matthieu Darnet, Emmanuel Godoy, Daniel Sadarnac and Stephane Gautrais

Abstract: High power supply for imaging systems needs to meet increasing demand in speed, power and voltage control. A Vienna-type three-phase rectifier prototype has been developed by GE Healthcare to handle it. This power supply has a significant stability issue because its load has a pulsed profile, and the ranges of power demand, input voltage, and grid impedance are wide. First, a model of the rectifier and its control has been made. Second, a current loop stability analysis has been investigated. Stability margins have been drawn for all the range of output power, input voltage and grid inductance for the current loop. Stability has been shown for all the operating points. However, a poorly damped input filter brings potential oscillations and reduces stability margins. Delay margins are also particularly low. Finally, a validation of the rectifier model has been made with measurements on the prototype.
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Paper Nr: 103
Title:

Scalable Electric-motor-in-the-Loop Testing for Vehicle Powertrains

Authors:

Thomas D’hondt, Yves Mollet, Arthur J. Joos, Leonardo Cecconi, Mathieu Sarrazin and Johan Gyselinck

Abstract: Model-Based System Testing (MBST) combines physical testing and simulation models to enable the validation of complex systems early-on in their design cycle. Therefore, it shows great potential for the validation of increasingly complex Electric Vehicle (EV) powertrains. In this work, the MBST methodology is applied to a downscaled powertrain, including a Permanent-Magnet Synchronous Machine (PMSM) and a 3-phase switch-mode inverter. This System-under-Test (SuT) is integrated into an X-in-the-Loop (XiL) test bench, where real-time simulation models of the rest of the vehicle are used to impose realistic boundary conditions to the SuT. These include the emulation of the vehicle inertia, its friction losses and the regenerative braking controller. Both hardware and software architectures required to achieve this setup are presented. Subsequently, a methodology used for computing scaling factors that match the power levels of the full vehicle to the miniature test bench is proposed. Finally, the combined physical-virtual system is evaluated on a driving cycle to validate its behaviour. The usage of a downscaled SuT constitutes the first step towards full-scale E-powertrain-in-the-loop testing, as well as a valuable multi-purpose didactical XiL setup.
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Short Papers
Paper Nr: 4
Title:

Deep Learning for Posture Control Nonlinear Model System and Noise Identification

Authors:

Vittorio Lippi, Thomas Mergner and Christoph Maurer

Abstract: In this work we present a system identification procedure based on Convolutional Neural Networks (CNN) for human posture control models. A usual approach to the study of human posture control consists in the identification of parameters for a control system. In this context, linear models are particularly popular due to the relative simplicity in identifying the required parameters and to analyze the results. Nonlinear models, conversely, are required to predict the real behavior exhibited by human subjects and hence it is desirable to use them in posture control analysis. The use of CNN aims to overcome the heavy computational requirement for the identification of nonlinear models, in order to make the analysis of experimental data less time consuming and, in perspective, to make such analysis feasible in the context of clinical tests. After testing the performance of the CNN on validation and test sets, two examples are presented and discussed from the qualitative point of view: the identification of parameters using data from human experiments and using data of a simulated model with some differences with respect to the one used to build the training set. Some potential implications of the method for humanoid robotics are also discussed.
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Paper Nr: 65
Title:

Improving Activity Mining in a Smart Home using Uncertain and Temporal Databases

Authors:

Josky Aïzan, Cina Motamed and Eugene C. Ezin

Abstract: In the context of smart home, activity mining appears as an interesting and promising solution for learning activity of daily living. This paper is an extension of a previous a research work titled Activity Mining in a Smart Home from Sequential and Temporal Databases. It proposes an activity mining method based on uncertain and temporal sequential pattern mining to deal with data uncertainty and events temporal relationships. It allows to track regular activities and to detect changes in an individual’s behavioural pattern. Uncertain sequential pattern mining algorithm is firstly applied to the input sequence database to extract typical sequences and secondly a clustering approach based on sequence alignment methods is performed in order to obtain separated typical activities. The results obtained are enough good compared to existing related works.
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Paper Nr: 82
Title:

Robustness Estimation of Large Deviations in Linear Discrete-time Systems with Control Signal Delay

Authors:

Nina Vunder and Natalia Dudarenko

Abstract: The article deals with robustness estimation of large deviations in free motion of linear discrete-time systems to parameter variations of the state matrix. A tracking discrete-time system with the modal control law is considered in the paper. The modal control law is designed taking into account the value of delay and the deviation. It is assumed that parameters of the system are linearly dependent on the uncertainties. The problem is solved with the state space approach and the sensitivity theory methods. An upper bound estimation of trajectory deviations for discrete-time systems is obtained. The estimation contains the condition number of the eigenvectors matrix of the system state matrix. Therefore, sensitivity functions of singular values of the eigenvectors matrix are used to calculate the robustness estimation of the deviations. Based on the obtained equations, an algorithm for the robustness estimation of large deviations in linear discrete-time systems with parametric uncertainties is proposed. Two cases of control signal delay are considered in the paper. The first case relates to predictable delay of control signal, and the second one relates to unpredictable delay of control signal. The results are supported with an examples.
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Paper Nr: 84
Title:

Simulative Investigation of Transfer Function-based Disturbance Observer for Disturbance Estimation on Electromechanical Axes

Authors:

Chris Schöberlein, Armin Schleinitz, Holger Schlegel and Matthias Putz

Abstract: In the field of machine tools, applicable solutions for monitoring process forces are becoming increasingly important. In addition to sensor-based approaches there are also methods which utilize the already available signals of the machine control. Usually, the motor currents and, when applicable, position values of the feed axes are considered. By applying reduced order models of the machine axes, non-process components are subtracted from the measured signals. However, these approaches are often utilizing simplified models or require additional a-priori knowledge, for example construction data or actual parameter values. The former in particular has a negative impact on the quality of the estimations. To overcome these disadvantages, this paper presents a novel observer structure based on the mechanical system transfer function of the feed axis. One main advantage is achieved by applying scalable and automatically generated models with focus on distinct frequency ranges. All necessary information is provided by a frequency response of the speed control plant, as it is typically obtained during the commissioning phase of electromechanical feed axes. By inverting the system transfer function and considering an additional disturbance transfer function, the quality of the estimation can be significantly improved compared to previous approaches.
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Paper Nr: 86
Title:

Reduced-order Modeling of Parameter Variations for Parameter Identification in Rubber Curing

Authors:

Tobias Frank, Mark Wielitzka, Matthias Dagen and Tobias Ortmaier

Abstract: A reduced-order modeling approach for thermal systems with varying parameters in rubber curing processes is presented in this manuscript. For complex geometries with multiple components a finite element analysis with fine mesh elements is often the only feasible approach to calculate temperature distributions over time. A major drawback, however, is the resulting large system scale, which entails high computation times. Thus, real-time capable execution or a high number of iterations to solve for optimization problems are infeasible approaches. Model order reduction algorithms are a promising remedy, but physically interpretable parameter preservation is not obtained, when using common approaches. Thus, a method to extract parameter dependencies from numerical element matrices and reduce the model order is presented in this manuscript. Preservation of physically interpretable parameters is accomplished by applying linear reduction projectors to affine interpolated system matrices. Thus, parameter variations can be accounted for without costly recalculation of reduction projectors. Hence, a computation efficient model description is obtained, enabling a tunable balancing between computation time and accuracy. To demonstrate the effectiveness of the approach, parameter identification of material properties and heat transition coefficients is performed and validated with measurement data of two different sample systems. For the largest sample system computation time has been reduced from half an hour for a full order simulation to an averaged time of 0.3 s, with approximation error of 0.7 K.
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Paper Nr: 87
Title:

Performance Analysis of the Force Control for an Electromechanical Feed Axis with Industrial Motion Control

Authors:

Andre Sewohl, Manuel Norberger, Chris Schöberlein, Holger Schlegel and Matthias Putz

Abstract: Control of process forces provides significant economic benefits for many use cases. The force is often the limiting factor for the design of the processes and the choice of parameters. As a controlled variable, it is predestined to ensure stability and safety of many processes. Direct influence also enables increasing productivity and improving part quality. However, force control has not yet become established for manufacturing processes in machine tools with electromechanical axes and industrial control. A major problem area is the lack of real-time capability. Due to the delay times in signal processing, real-time capability is not guaranteed for dynamic movements of feed axes. High-resolution and fast measurement inputs are particularly relevant here. Industrial control manufacturers have made significant progress in this area. In this publication, the experimental setup of an electromechanical feed axis is presented, which is equipped with new industrial control components. The implementation of the force control is also described. Focus is on the investigations regarding the controller performance. The set point and disturbance behaviour as well as the reaction to the process start are considered.
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Paper Nr: 89
Title:

Real-time Implementation and Evaluation of Magnetometerless Tracking System for Human and Humanoid Posture Control Benchmarking based on Inertial Sensors

Authors:

Vittorio Lippi, Kai G. Brands and Thomas Seel

Abstract: This work describes a tracking system designed for humanoid robots, exoskeletons and humans oriented to posture control and balance experiments. The system aims to provide a tool that allows for repeatability of balance experiments across different robotics platforms and control algorithms with the ultimate aim of providing a standardized framework for performance benchmarking. To make the system suitable for different geometries and materials, it relies just on inertial sensors. The system is evaluated with a marker-based optical tracking, performing a trial of a typical posture control and balance experiment. In particular the frequency response function of the body segments respect to the support surface tilt is evaluated.
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Paper Nr: 95
Title:

Parameter Estimator for Twin Rotor MIMO System based on DREM Procedure

Authors:

Nikita Shopa, Dmitry Bazylev, Sergey Vrazhevsky and Artem Kremlev

Abstract: The paper deals with a problem of parameter identification for a model of Twin Rotor MIMO System laboratory bench, which is described by a nonlinear multi-channel system with cross-couplings. The chosen method is based on the Dynamic Regressor Extention and Mixing (DREM) procedure that guarantees monotonic convergence of the estimations even in case of multiple related parameters simultaneously identification. Results are verified by computer simulation.
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Paper Nr: 100
Title:

Hand Detection Algorithm: Pre-processing Stage

Authors:

Raissa Likhonina

Abstract: The present work describes a new approach to hand detection based on QRD Recursive Least Squares (RLS) Lattice algorithm and probabilistic approach to system identification. The described method is supposed to be used as a pre-processing stage for a hand gesture recognition application based on ultrasound technology. The approach includes a noise cancellation concept and uses linear Finite Impulse Response (FIR) based regression models in MATLAB environment. Within the algorithm the hypothesis testing technique is implemented. The work shows the results of computation using real data from an ultrasound device. The final version of the algorithm is supposed to be implemented on the embedded Xilinx Zynq device.
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Paper Nr: 102
Title:

Improved IMU-based Human Activity Recognition using Hierarchical HMM Dissimilarity

Authors:

Sara Ashry, Walid Gomaa, Mubarak G. Abdu-Aguye and Nahla El-borae

Abstract: Although there are many classification approaches in IMU-based Human Activity Recognition, they are in general not explicitly designed to consider the particular nature of human actions. These actions may be extremely complex and subtle and the performance of such approaches may degrade significantly in such scenarios. However, techniques like Hidden Markov Models (HMMs) have shown promising performance on this task, due to their ability to model the dynamics of such activities. In this work, we propose a novel classification technique for human activity recognition. Our technique involves the use of HMMs to characterize samples and subsequent classification based on the dissimilarity between HMMs generated from unseen samples and previously-generated HMMs from training/template samples. We apply our method to two publicly-available activity recognition datasets and also compare it against an extant approach utilizing feature extraction and another technique utilizing a deep Long Short-Term Memory (LSTM) classifier. Our experimental results indicate that our proposed method outperforms both of these baselines in terms of several standard metrics.
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Paper Nr: 118
Title:

Future Parking Applications: Wireless Sensor Network Positioning for Highly Automated in-House Parking

Authors:

Andrea Jung, Paul Schwarzbach and Oliver Michler

Abstract: One of the bottlenecks for motorized individual transportation for end-to-end trips is the search for parking space. Common solutions to minimize spatial needs are in-house parking garages, but even in those, finding available parking lots can be quite time consuming. In this contribution we therefore present a cheap and retrofittable parking system, enabling automated entrance to parking lot reservation, navigation and clearing for already existing parking garages. One of its key component is a robust indoor positioning based on Wireless Sensor Networks (WSN) enabling vehicle independent and automated routing. We will provide a general overview of WSN measurement principles and propose two possible technology candidates, a 2.4 GHz narrow-band technology and Ultra-Wide Band (UWB). Furthermore, a robust range-only positioning approach utilizing Markov Localization, called Probability Grid Positioning (PGP), is presented. With the help of UWB and IEEE 802.15.4 ranging modules the algorithm is qualitatively evaluated with measurements in a car park in Leipzig, Germany. Our proposed PGP approach leads to overall smoother trajectories compared to a state-of-the-art Least Squares Estimation (LSE) and thus achieves accurate and robust positioning in demanding heavy-multipath environments. This can build the foundation for future work in the field of highly-automated in-house parking.
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Paper Nr: 120
Title:

Design and Application of a Reconfigurable Control to a Cyber-Physical System

Authors:

Imane Tahiri, Alexandre Parant, François Gellot, Alexandre Philippot and Véronique Carré-Ménétrier

Abstract: In the previous edition of ICINCO, authors have presented a theoretical comparison between centralized and distributed control reconfiguration of Discrete Event Systems (DES). In this paper, we propose to enlarge the proposition until the implementation step into a Programmable Logic Controller. The control is based on a distributed architecture including time-delayed events and supervisory control theory. Moreover, in a context of Industry 4.0, the verification and simulation phases are performed on a digital twin before implementation on the real system.
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Paper Nr: 128
Title:

Lyapunov Stability of a Nonlinear Bio-inspired System for the Control of Humanoid Balance

Authors:

Vittorio Lippi and Fabio Molinari

Abstract: Human posture control models are used to analyse neurological experiments and control of humanoid robots. This work focuses on a well-known nonlinear posture control model, the DEC (Disturbance estimate and Compensation). In order to compensate disturbances, unlike other models, DEC feedbacks signals coming from sensor fusion rather than raw sensory signals. In previous works, the DEC model is shown to predict human behavior and to provide a control system for humanoids. In this work, the stability of the system in the sense of Lyapunov is formally analysed. The theoretical findings are combined with simulation results, in which an external perturbation of the support surface reproduces a typical scenario in posture control experiments.
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Paper Nr: 129
Title:

Evaluation of Lyapunov Function Candidates through Averaging Iterations

Authors:

Carlos Argáez, Peter Giesl and Sigurdur Hafstein

Abstract: A complete Lyapunov function determines the behaviour of a dynamical system. In particular, it splits the phase space into the chain-recurrent set, where solutions show (almost) repetitive behaviour, and the part exhibiting gradient-like flow where the dynamics are transient. Moreover, it reveals the stability of sets and basins of attraction through its sublevel sets. In this paper, we combine two previous methods to compute complete Lyapunov functions: we employ quadratic optimization with equality and inequality constraints to compute a complete Lyapunov function candidate and we evaluate its quality by using a method that improves approximations of complete Lyapunov function candidates through iterations.
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Paper Nr: 130
Title:

CPA Lyapunov Functions: Switched Systems vs. Differential Inclusions

Authors:

Sigurdur Hafstein

Abstract: We present an algorithm that uses linear programming to parameterize continuous and piecewise affine Lyapunov functions for switched systems. The novel feature of the algorithm is, that it can compute Lyapunov functions for switched system with a strongly asymptotically stable equilibrium, for which the equilibrium of the corresponding differential inclusion is merely weakly asymptotically stable. For the differential inclusion no such Lyapunov function exists. This is achieved by removing constraints from a linear programming problem of an earlier algorithm to compute Lyapunov functions, that are not necessary to assert strong stability for the switched system. We demonstrate the benefits of this new algorithm sing Artstein’s circles as an example.
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Paper Nr: 33
Title:

Development of Portable Sound Source Direction Estimation Device

Authors:

Kenta Goto, Hiroki Kijima, Mizuki Usuda and Yoshihisa Uchida

Abstract: In this study, we propose a portable sound source direction estimation device (CASH-H) for people suffering from hearing loss and for the elderly. CASH-H, which is the proposed device, is one that estimates sound source direction by using sound signals from two microphones, and then transmits the estimated direction data to the user. This study proposes and evaluates a sound source estimation method by signal processing. The sound source direction is calculated from the reception time difference between the two microphone signals. In order to improve the measurement accuracy and measurable distance, an amplifier circuit and an IIR digital filter were used. The sound source direction estimation was performed with a mean angle error of 1.09 ° and angle standard deviation of 4.23 °. The measurable distance was up to 40 m under the experimental conditions.
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Paper Nr: 38
Title:

Gait-based Person Identification using Multiple Inertial Sensors

Authors:

Osama Adel, Yousef Nafea, Ahmed Hesham and Walid Gomaa

Abstract: Inertial sensors such as accelerometers and gyroscopes have gained popularity in recent years for their use in human activity recognition. However, little work has been done on using these sensors for gait-based person identification. Gait-based person identification turns out to be important in applications such as where different people share the same wearable device and it is desirable to identify who is using the device at a given time while walking. In this research, we present the first multi-sensory gait-based person identification dataset EJUST-GINR-1 and present our work on gait-based person identification using multi-sensory data, by mounting 8 wearable inertial sensory devices on different body locations and use this data to identify the person using it. Two of these sensors are smart watches worn on both wrists. We explore the correlation between each body location and the identification accuracy, as well as exploring the effect of fusing pairs of sensory units in different locations, on the final classification performance.
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Paper Nr: 40
Title:

Multi-sensor Gait Analysis for Gender Recognition

Authors:

Abeer Mostafa, Toka O. Barghash, Asmaa A. Assaf and Walid Gomaa

Abstract: Gender recognition has been adopted recently by researchers due to its benefits in many applications such as recommendation systems and health care. The rise of using smart phones in everyday life made it very easy to have sensors like accelerometer and gyroscope in phones and other wearable devices. Here, we propose a robust method for gender recognition based on data from Inertial Measurement Unit (IMU) sensors. We explore the use of wavelet transform to extract features from the accelerometer and gyroscope signals along side with proper classifiers. Furthermore, we introduce our own collected dataset (EJUST-GINR-1) which contains samples from smart watches and IMU sensors placed at eight different parts of the human body. We investigate which sensor placements on the body best distinguish between males and females during the activity of walking. The results prove that wavelet transform can be used as a reliable feature extractor for gender recognition with high accuracy and less computations than other methods. In addition, sensors placed on the legs and waist perform better in recognizing the gender during walking than other sensors.
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Paper Nr: 94
Title:

Ammonium Sensor Fault Detection in Wastewater Treatment Plants

Authors:

David Tena, Ignacio Peñarrocha-Alós, Roberto Sanchis and Rubén Moliner-Heredia

Abstract: We develop a fault detection strategy for the output ammonium sensor present in wastewater treatment plants. The only assumed measurements are the output ammonium concentration, the aeration of the reactor and the incoming volumetric flow to the plant. The incoming ammonium concentration is not measured, resulting in an important source of uncertainty. We use a IIR model based on Volterra series for predicting the ammonium measurement and we design a fault detector based on a filter applied on the prediction error and a threshold comparator to decide whether the sensor is faulty or not. The faults in the sensor are assumed to produce a slowly decreasing gain due to dirtiness in its surface. The fault detector design is based on the trade-off between fault detection sensitivity and disturbance rejection (due to measurement noise and model uncertainty). The design parameters are based in understandable fault indices: time needed to detect the fault, gain deviation at the time of detection, and poured volume of ammonium until the fault is detected. We use the benchmark BSM1 to validate the results as a common frame in the study of waste water treatment plants.
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