Results 61-80 of 232.     A Reference Architecture for Deploying Component-based Robot Software and Comparison with Existing ToolsHochgeschwender, Nico ; Biggs, Geoffrey; Voos, Holger in Proceedings of the IEEE International Conference on Robotic Computing (2018)Detailed reference viewed: 161 (7 UL) Attack-tolerant Control and Observer-based Trajectory Tracking for Cyber-Physical SystemsBezzaoucha, Souad ; Voos, Holger ; Darouach, Mohamedin European Journal of Control (2018)In the present paper, a model-based fault/attack tolerant scheme is proposed to cope with cyber-threats on Cyber-Physicals Systems. A common scheme based on observers is designed and a state feedback ... [more ▼]In the present paper, a model-based fault/attack tolerant scheme is proposed to cope with cyber-threats on Cyber-Physicals Systems. A common scheme based on observers is designed and a state feedback control based on an aperiodic event-triggered framework is given with control synthesis and condition on the switching time. Classical fault tolerant control with Bi-linear Matrix Inequality () approaches are used to achieve novel and better security strategy based on an event-triggered control implementation. The purpose of using the event-based implementation would be to reduce (limit) the total number of transmissions to only instances when the networked control system (NCS) needs attention. Simulation results on a real-time laboratory three tank system are given to show the attack-tolerant control ability despite data deception attacks on both actuators and sensors. A detection/isolation scheme based on residual observers bank is also proposed. [less ▲]Detailed reference viewed: 322 (10 UL) Robust Online Obstacle Detection and Tracking for Collision-free Navigation of Multirotor UAVs in Complex EnvironmentsWang, Min ; Voos, Holger ; Su, Daobiligein 15th International Conference on Control, Automation, Robotics and Vision (ICARCV), Singapore 18-21 November 2018 (2018)Object detection and tracking is a challenging task, especially for unmanned aerial robots in complex environments where both static and dynamic objects are present. It is, however, essential for ensuring ... [more ▼]Object detection and tracking is a challenging task, especially for unmanned aerial robots in complex environments where both static and dynamic objects are present. It is, however, essential for ensuring safety of the robot during navigation in such environments. In this work we present a practical online approach which is based on a 2D LIDAR. Unlike common approaches in the literature of modeling the environment as 2D or 3D occupancy grids, our approach offers a fast and robust method to represent the objects in the environment in a compact form, which is significantly more efficient in terms of both memory and computation in comparison with the former. Our approach is also capable of classifying objects into categories such as static and dynamic, and tracking dynamic objects as well as estimating their velocities with reasonable accuracy. [less ▲]Detailed reference viewed: 175 (32 UL) Model predictive cooperative localization control of multiple UAVs using potential function sensor constraintsDentler, Jan Eric ; Kannan, Somasundar ; Bezzaoucha, Souad et alin Autonomous Robots (2018)The global localization of multiple mobile robots can be achieved cost efficiently by localizing one robot globally and the others in relation to it using local sensor data. However, the drawback of this ... [more ▼]The global localization of multiple mobile robots can be achieved cost efficiently by localizing one robot globally and the others in relation to it using local sensor data. However, the drawback of this cooperative localization is the requirement of continuous sensor information. Due to a limited sensor perception space, the tracking task to continuously maintain this sensor information is challenging. To address this problem, this contribution is presenting a model predictive control (MPC) approach for such cooperative localization scenarios. In particular, the present work shows a novel workflow to describe sensor limitations with the help of potential functions. In addition, a compact motion model for multi-rotor drones is introduced to achieve MPC real-time capability. The effectiveness of the presented approach is demonstrated in a numerical simulation, an experimental indoor scenario with two quadrotors as well as multiple indoor scenarios of a quadrotor obstacle evasion maneuver. [less ▲]Detailed reference viewed: 283 (35 UL) Model-Driven Interaction Design for Social RobotsCornelius, Gary Philippe ; Hochgeschwender, Nico ; Voos, Holger in 4th International Workshop on Model-driven Robot Software Engineering, Marburg, Germany, 2017 (2017, December)Robotic software development frameworks lack a possibility to present,validate and generate qualitative complex human robot interactions and robot de-velopers are mostly left with unclear informal project ... [more ▼]Robotic software development frameworks lack a possibility to present,validate and generate qualitative complex human robot interactions and robot de-velopers are mostly left with unclear informal project specifications. The devel-opment of a human-robot interaction is a complex task and involves different ex-perts, for example, the need for human-robot interaction (HRI) specialists, whoknow about the psychological impact of the robot’s movements during the in-teraction in order to design the best possible user experience. In this paper, wepresent a new project that aims to provide exactly this. Focusing on the interac-tion flow and movements of a robot for human-robot interactions we aim to pro-vide a set of modelling languages for human-robot interaction which serves as acommon, more formal, discussion point between the different stakeholders. Thisis a new project and the main topics of this publication are the scenario descrip-tion, the analysis of the different stakeholders, our experience as robot applicationdevelopers for our partner, as well as the future work we plan to achieve. [less ▲]Detailed reference viewed: 314 (26 UL) Evasive Maneuvering for UAVs: An MPC ApproachCastillo Lopez, Manuel ; Olivares Mendez, Miguel Angel ; Voos, Holger in ROBOT'2017 - Third Iberian Robotics Conference, Sevilla, Spain, 2017 (2017, November 22)Flying autonomously in a workspace populated by obstacles is one of the main goals when working with Unmanned Aerial Vehicles (UAV). To address this challenge, this paper presents a model predictive ... [more ▼]Flying autonomously in a workspace populated by obstacles is one of the main goals when working with Unmanned Aerial Vehicles (UAV). To address this challenge, this paper presents a model predictive flight controller that drives the UAV through collision-free trajectories to reach a given pose or follow a way-point path. The major advantage of this approach lies on the inclusion of three-dimensional obstacle avoidance in the control layer by adding ellipsoidal constraints to the optimal control problem. The obstacles can be added, moved and resized online, providing a way to perform waypoint navigation without the need of motion planning. In addition, the delays of the system are considered in the prediction by an experimental first order with delay model of the system. Successful experiments in 3D path tracking and obstacle avoidance validates its effectiveness for sense-and-avoid and surveillance applications presenting the proper structure to extent its autonomy and applications. [less ▲]Detailed reference viewed: 214 (22 UL) A Perspective of Security for Mobile Service RobotsCornelius, Gary Philippe ; Hochgeschwender, Nico ; Voos, Holger et alin Iberian Robotics Conference, Seville, Spain, 2017 (2017, November 22)Future homes will contain Mobile Service Robots (MSR) with diverse functionality. MSRs act in close proximity to humans and have the physical capabilities to cause serious harm to their environment ... [more ▼]Future homes will contain Mobile Service Robots (MSR) with diverse functionality. MSRs act in close proximity to humans and have the physical capabilities to cause serious harm to their environment. Furthermore, they have sensors that gather large amounts of data, which might contain sensitive information. A mobile service robot’s physical capabilities are controlled by networked computers susceptible to faults and intrusions. The proximity to humans and the possibility to physically interact with them makes it critical to think about the security issues of MSRs. In this work, we investigate possible attacks on mobile service robots. We survey adversary motivations to attack MSRs, analyse threat vectors and list different available defence mechanisms against attacks on MSRs. [less ▲]Detailed reference viewed: 339 (67 UL) Observer-based Event-triggered Attack-Tolerant Control Design for Cyber-physical SystemsBezzaoucha, Souad ; Voos, Holger ; Darouach, Mohamedin 14th International Workshop on Advanced Control and Diagnosis, Bucharest, Romania, November 2017 (2017, November)In the present paper, a model-based fault/attack tolerant scheme is proposed to cope with cyber-threats on Cyber Physicals Systems. A common scheme based on observers is designed and a state feedback ... [more ▼]In the present paper, a model-based fault/attack tolerant scheme is proposed to cope with cyber-threats on Cyber Physicals Systems. A common scheme based on observers is designed and a state feedback control based on an aperiodic event-triggered framework is given with control synthesis and condition on the switching time. Classical fault tolerant control with Bilinear Matrix Inequality (BMI) approaches are used to achieve novel and better security strategy based on an event-triggered control implementation. The purpose in using the event-based implementation would be to reduce (limit) the total number of transmissions to only instances when the networked control system (NCS) needs attention. An illustrative example of the proposed approach applied to a three-tank system is presented. [less ▲]Detailed reference viewed: 221 (5 UL) Deadzone-Quadratic Penalty Function for Predictive Extended Cruise Control with Experimental ValidationSajadi Alamdari, Seyed Amin ; Voos, Holger ; Darouach, Mohamedin ROBOT 2017: Third Iberian Robotics Conference, Sevilla, Spain 22-24 November 2017 (2017, November)Battery Electric Vehicles have high potentials for the modern transportations, however, they are facing limited cruising range. To address this limitation, we present a semi-autonomous ecological driver ... [more ▼]Battery Electric Vehicles have high potentials for the modern transportations, however, they are facing limited cruising range. To address this limitation, we present a semi-autonomous ecological driver assistance system to regulate the velocity with energy-efficient techniques. The main contribution of this paper is the design of a real-time nonlinear receding horizon optimal controller to plan the online cost-effective cruising velocity. Instead of conventional L2-norms, a deadzone-quadratic penalty function for the nonlinear model predictive controller is proposed. Obtained field experimental results demonstrate the effectiveness of the proposed method for a semi-autonomous electric vehicle in terms of real-time energy-efficient velocity regulation and constraints satisfaction. [less ▲]Detailed reference viewed: 151 (9 UL) Implementation and validation of an event-based real-time nonlinear model predictive control framework with ROS interface for single and multi-robot systemsDentler, Jan Eric ; Kannan, Somasundar ; Olivares Mendez, Miguel Angel et alin 2017 IEEE Conference on Control Technology and Applications (CCTA) (2017, August 30)This paper presents the implementation and experimental validation of a central control framework. The presented framework addresses the need for a controller, which provides high performance combined ... [more ▼]This paper presents the implementation and experimental validation of a central control framework. The presented framework addresses the need for a controller, which provides high performance combined with a low-computational load while being on-line adaptable to changes in the control scenario. Examples for such scenarios are cooperative control, task-based control and fault-tolerant control, where the system's topology, dynamics, objectives and constraints are changing. The framework combines a fast Nonlinear Model Predictive Control (NMPC), a communication interface with the Robot Operating System (ROS) [1] as well as a modularization that allows an event-based change of the NMPC scenario. To experimentally validate performance and event-based adaptability of the framework, this paper is using a cooperative control scenario of Unmanned Aerial Vehicles (UAVs). The source code of the proposed framework is available under [2]. [less ▲]Detailed reference viewed: 250 (20 UL) Operational space control of a lightweight robotic arm actuated by shape memory alloy wires: A comparative studyQuintanar Guzman, Serket ; Kannan, Somasundar ; Aguilera Gonzalez, Adriana et alin Journal of Intelligent Material Systems and Structures (2017)This article presents the design and control of a two-link lightweight robotic arm using shape memory alloy wires as actuators. Both a single-wire actuated system and an antagonistic configuration system ... [more ▼]This article presents the design and control of a two-link lightweight robotic arm using shape memory alloy wires as actuators. Both a single-wire actuated system and an antagonistic configuration system are tested in open and closed loops. The mathematical model of the shape memory alloy wire, as well as the kinematics and dynamics of the robotic arm, are presented. The operational space control of the robotic arm is performed using a joint space control in the inner loop and closed-loop inverse kinematics in the outer loop. In order to choose the best joint space control approach, a comparative study of four different control approaches (proportional derivative, sliding mode, adaptive, and adaptive sliding mode control) is carried out for the proposed model. From this comparative analysis, the adaptive controller was chosen to perform operational space control. This control helps us to perform accurate positioning of the end-effector of shape memory alloy wire–based robotic arm. The complete operational space control was successfully tested through simulation studies performing position reference tracking in the end-effector space. Through simulation studies, the proposed control solution is successfully verified to control the hysteretic robotic arm. [less ▲]Detailed reference viewed: 168 (10 UL) Area exploration with a swarm of UAVs combining deterministic Chaotic Ant Colony Mobility with position MPCRosalie, Martin ; Dentler, Jan Eric ; Danoy, Grégoire et alin 2017 International Conference on Unmanned Aircraft Systems (ICUAS) (2017, July 27)The recent advances in Unmanned Aerial Vehicles (UAVs) technology permit to develop new usages for them. One of the current challenges is to operate UAVs as an autonomous swarm. In this domain we already ... [more ▼]The recent advances in Unmanned Aerial Vehicles (UAVs) technology permit to develop new usages for them. One of the current challenges is to operate UAVs as an autonomous swarm. In this domain we already proposed a new mobility model using Ant Colony Algorithms combined with chaotic dynamics (CACOC) to enhance the coverage of an area by a swarm of UAVs. In this paper we propose to consider this mobility model as waypoints for real UAVs. A control model of the UAVs is deployed to test the efficiency of the coverage of an area by the swarm. We have tested our approach in a realistic robotics simulator (V-Rep) which is connected with ROS. We compare the performance in terms of coverage using several metrics to ensure that this mobility model is efficient for real UAVs. [less ▲]Detailed reference viewed: 309 (51 UL) Risk-averse Stochastic Nonlinear Model Predictive Control for Real-time Safety-critical SystemsSajadi Alamdari, Seyed Amin ; Voos, Holger ; Darouach, Mohamedin The 20th World Congress of the International Federation of Automatic Control, IFAC 2017 World Congress, Toulouse, France, 9-14 July 2017 (2017, July 11)Stochastic nonlinear model predictive control has been developed to systematically find an optimal decision with the aim of performance improvement in dynamical systems that involve uncertainties. However ... [more ▼]Stochastic nonlinear model predictive control has been developed to systematically find an optimal decision with the aim of performance improvement in dynamical systems that involve uncertainties. However, most of the current methods are risk-neutral for safety-critical systems and depend on computationally expensive algorithms. This paper investigates on the risk-averse optimal stochastic nonlinear control subject to real-time safety-critical systems. In order to achieve a computationally tractable design and integrate knowledge about the uncertainties, bounded trajectories generated to quantify the uncertainties. The proposed controller considers these scenarios in a risk-sensitive manner. A certainty equivalent nonlinear model predictive control based on minimum principle is reformulated to optimise nominal cost and expected value of future recourse actions. The capability of proposed method in terms of states regulations, constraints fulfilment, and real-time implementation is demonstrated for a semi-autonomous ecological advanced driver assistance system specified for battery electric vehicles. This system plans for a safe and energy-efficient cruising velocity profile autonomously. [less ▲]Detailed reference viewed: 188 (8 UL) An LMI-Based H_infty Discrete-Time Nonlinear State Observer Design for an Anaerobic Digestion ModelChaib Draa, Khadidja ; Voos, Holger in World Congress of the International Federation of Automatic Control, Toulouse 9-14 July 2017 (2017, July)This paper is devoted to the design of an H1 discrete-time nonlinear state observer for an anaerobic digestion model. Indeed, the designed observer can be used for di erent class of systems, mainly linear ... [more ▼]This paper is devoted to the design of an H1 discrete-time nonlinear state observer for an anaerobic digestion model. Indeed, the designed observer can be used for di erent class of systems, mainly linear systems, LPV systems with known and bounded parameters, and nonlinear Lipschitz systems. We use an LMI approach to guarantee the H1 asymptotic stability of the estimation error despite the disturbances a ecting the system dynamics and measurements. The synthesised LMI is relaxed due to the inclusion of additional decision variables which enhance its feasibility. This was possible due to the use of a suitable reformulation of the Young's inequality. Simulation results are given to show the robustness of the designed observer. [less ▲]Detailed reference viewed: 92 (3 UL) On the Unknown Input Functional Observer Design via Polytopic Lyapunov Function: Application to a Quadrotor Aerial Robots LandingBezzaoucha, Souad ; Voos, Holger ; Darouach, Mohamedin IFAC-PapersOnLine (2017, July)In this paper, a constructive procedure to design functional unknown input observer for nonlinear continuous time systems under the Polytopic Takagi-Sugeno framework (also known as multiple models systems ... [more ▼]In this paper, a constructive procedure to design functional unknown input observer for nonlinear continuous time systems under the Polytopic Takagi-Sugeno framework (also known as multiple models systems) is proposed. Applying the Lyapunov theory, Linear Matrix Inequalities (LMI)s conditions are deduced which are solved for feasibility to obtain observer design matrices. To reject the effect of unknown input, classical approach of decoupling the unknown input for the linear case is used. A comparative study between single and Polytopic Lyapunov function is made in order to prove the relaxation effect of the Multiple functions. A solver based solution is then proposed. It will be shown through applicative example (a Quadrotor Aerial Robots Landing) that even if the proposed LMIs solver based solution may look conservative, an adequate choice of the solver makes it suitable for the application of the proposed approach. [less ▲]Detailed reference viewed: 104 (7 UL) LMI-Based H_infty Nonlinear State Observer Design for Anaerobic Digestion ModelChaib Draa, Khadidja ; Voos, Holger ; Alma, Marouane et alin IEEE Mediterranean Conference on Control and Automation, Valletta 3-6 July 2017 (2017, July)This note deals with the design of an $H_{\infty}$ nonlinear state observer for the anaerobic digestion model. Positively, the designed observer is an unified one that can be used for different class of ... [more ▼]This note deals with the design of an $H_{\infty}$ nonlinear state observer for the anaerobic digestion model. Positively, the designed observer is an unified one that can be used for different class of systems, mainly linear systems, Linear Parameter Varying (LPV) systems with known and bounded parameters, and nonlinear Lipschitz systems. Applying the Lyapunov theory and theH¥ criterion, Linear Matrix Inequality (LMI) condition is synthesised and solved to obtain the designed observer gains. The novelty of our work consists in the relaxation of the synthesized LMI condition through the inclusion of additional decision variables. This was possible due to the use of a suitable reformulation of the Young’s inequality. Stability, effectiveness and potency of the theoretical results are confirmed by the simulation results. [less ▲]Detailed reference viewed: 88 (4 UL) Fast Stochastic Non-linear Model Predictive Control for Electric Vehicle Advanced Driver Assistance SystemsSajadi Alamdari, Seyed Amin ; Voos, Holger ; Darouach, Mohamedin 13th IEEE International Conference on Vehicular Electronics and Safety, Vienna, Austria 27-28 June 2017 (2017, June 27)Semi-autonomous driving assistance systems have a high potential to improve the safety and efficiency of the battery electric vehicles that are enduring limited cruising range. This paper presents an ... [more ▼]Semi-autonomous driving assistance systems have a high potential to improve the safety and efficiency of the battery electric vehicles that are enduring limited cruising range. This paper presents an ecologically advanced driver assistance system to extend the functionality of the adaptive cruise control system. A real-time stochastic non-linear model predictive controller with probabilistic constraints is presented to compute on-line the safe and energy-efficient cruising velocity profile. The individual chance-constraint is reformulated into a convex second-order cone constraint which is robust for a general class of probability distributions. Finally, the performance of proposed approach in terms of states regulation, constraints fulfilment, and energy efficiency is evaluated on a battery electric vehicle. [less ▲]Detailed reference viewed: 206 (9 UL) Real time degradation identification of UAV using machine learning techniquesManukyan, Anush ; Olivares Mendez, Miguel Angel ; Geist, Matthieu et alin International Conference on Unmanned Aircraft Systems ICUAS. Miami, USA, 2017 (2017, June 13)The usages and functionalities of Unmanned Aerial Vehicles (UAV) have grown rapidly during the last years. They are being engaged in many types of missions, ranging from military to agriculture passing by ... [more ▼]The usages and functionalities of Unmanned Aerial Vehicles (UAV) have grown rapidly during the last years. They are being engaged in many types of missions, ranging from military to agriculture passing by entertainment and rescue or even delivery. Nonetheless, for being able to perform such tasks, UAVs have to navigate safely in an often dynamic and partly unknown environment. This brings many challenges to overcome, some of which can lead to damages or degradations of different body parts. Thus, new tools and methods are required to allow the successful analysis and identification of the different threats that UAVs have to manage during their missions or flights. Various approaches, addressing this domain, have been proposed. However, most of them typically identify the changes in the UAVs behavior rather than the issue. This work presents an approach, which focuses not only on identifying degradations of UAVs during flights, but estimate the source of the failure as well. [less ▲]Detailed reference viewed: 169 (13 UL) Unknown Input Functional Observers Design for Polytopic Discrete Time SystemsBezzaoucha, Souad ; Voos, Holger ; Darouach, Mohemedin Proceedings of 6th IEEE International Conference on Systems and Control (ICSC) 2017 (2017, May)In this paper, a step by step algorithm is given to design functional unknown input observer for nonlinear discrete time systems under the Polytopic Takagi-Sugeno framework (also known as multiple models ... [more ▼]In this paper, a step by step algorithm is given to design functional unknown input observer for nonlinear discrete time systems under the Polytopic Takagi-Sugeno framework (also known as multiple models systems). Applying the Lyapunov theory and the L2 attenuation, Linear Matrix Inequalities (LMI)s conditions are deduced which are solved for feasibility to obtain observer design matrices. To reject the effect of unknown input, classical approach of decoupling the unknown input for the linear case is used. A solver based solution is proposed. The novelty of the proposed approach consists in solving simultaneously both structural constraints and LMIs, which ensure a mean for the efficient design of the gains of the observers. To illustrate the proposed theoretical results, an application example of model reference tracking control applied to an electro-mechanical model of a motor with a time varying parameter is discussed. [less ▲]Detailed reference viewed: 68 (1 UL) A contribution to Cyber-Security of Networked Control Systems: an Event-based Control ApproachBezzaoucha, Souad ; Voos, Holger ; Darouach, Mohamedin Proceedings of 2017 3rd International Conference on Event-Based Control, Communication and Signal Processing (EBCCSP 2017) (2017, May)In the present paper, a networked control system under both cyber and physical attacks is considered. An adapted formulation of the problem under physical attacks, data deception and false data injection ... [more ▼]In the present paper, a networked control system under both cyber and physical attacks is considered. An adapted formulation of the problem under physical attacks, data deception and false data injection attacks, is used for controller synthesis. Based on the classical fault tolerant detection (FTD) tools, a residual generator for attack/fault detection based on observers is proposed. An event-triggered and Bilinear Matrix Inequality (BMI) implementation is proposed in order to achieve novel and better security strategy. The purpose in using this implementation would be to reduce (limit) the total number of transmissions to only instances when the networked control system (NCS) needs attention. It is important to note that the main contribution of this paper is to establish the adequate event-triggered and BMI-based methodology so that the particular structure of the mixed attacked/faulty structure can be re-formulated within the classical FTD paradigm. Experimental results are given to illustrate the developed approach efficiency on a pilot three-tank system. The plant model is presented and the proposed control design is applied to the system. [less ▲]Detailed reference viewed: 171 (4 UL)