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See detailOperational space control of a lightweight robotic arm actuated by shape memory alloy wires: A comparative study
Quintanar Guzman, Serket UL; Kannan, Somasundar UL; Aguilera Gonzalez, Adriana UL et al

in Journal of Intelligent Material Systems & 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 ▲]

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See detailArea exploration with a swarm of UAVs combining deterministic Chaotic Ant Colony Mobility with position MPC
Rosalie, Martin UL; Dentler, Jan Eric UL; Danoy, Grégoire UL et al

in 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 ▲]

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See detailRisk-averse Stochastic Nonlinear Model Predictive Control for Real-time Safety-critical Systems
Sajadi Alamdari, Seyed Amin UL; Voos, Holger UL; Darouach, Mohamed

in 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 ▲]

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See detailAn LMI-Based H_infty Discrete-Time Nonlinear State Observer Design for an Anaerobic Digestion Model
Chaib Draa, Khadidja UL; Voos, Holger UL

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 ▲]

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See detailOn the Unknown Input Functional Observer Design via Polytopic Lyapunov Function: Application to a Quadrotor Aerial Robots Landing
Bezzaoucha, Souad UL; Voos, Holger UL; Darouach, Mohamed

in 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 ▲]

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See detailLMI-Based H_infty Nonlinear State Observer Design for Anaerobic Digestion Model
Chaib Draa, Khadidja UL; Voos, Holger UL; Alma, Marouane et al

in 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 ▲]

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See detailFast Stochastic Non-linear Model Predictive Control for Electric Vehicle Advanced Driver Assistance Systems
Sajadi Alamdari, Seyed Amin UL; Voos, Holger UL; Darouach, Mohamed

in 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 ▲]

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See detailReal time degradation identification of UAV using machine learning techniques
Manukyan, Anush UL; Olivares Mendez, Miguel Angel UL; Geist, Matthieu et al

in 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 ▲]

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See detailUnknown Input Functional Observers Design for Polytopic Discrete Time Systems
Bezzaoucha, Souad UL; Voos, Holger UL; Darouach, Mohemed

in 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 ▲]

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See detailA contribution to Cyber-Security of Networked Control Systems: an Event-based Control Approach
Bezzaoucha, Souad UL; Voos, Holger UL; Darouach, Mohamed

in 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 ▲]

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See detailLMI-Based Discrete-Time Nonlinear State Observer for an Anaerobic Digestion Model
Chaib Draa, Khadidja UL; Voos, Holger UL; Alma, Marouane et al

in IEEE International Conference on Systems and Control, Batna 7-9 May 2017 (2017, May)

This paper deals with the design of a discrete time nonlinear observer for an anaerobic digestion process. The designed observer is devoted to a general class of systems, precisely linear systems, LPV ... [more ▼]

This paper deals with the design of a discrete time nonlinear observer for an anaerobic digestion process. The designed observer is devoted to a general class of systems, precisely linear systems, LPV systems with known and bounded parameters, and nonlinear Lipschitz systems. In order to ensure stability of the estimation error, a new LMI condition is proposed. In this LMI, additional decision variables are included to enhance its feasibility. Indeed, this was possible due to the use of a suitable reformulation of the Young’s inequality. Numerical simulations using the investigated two-step anaerobic digestion model show the effectiveness of the proposed LMI methodology. [less ▲]

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See detailA New Polytopic Approach for the Unknown Input Functional Observer Design
Bezzaoucha, Souad UL; Voos, Holger UL; Darouach, Mohamed

in International Journal of Control (2017)

In this paper, a constructive procedure to design Functional Unknown Input Observers for nonlin ear continuous time systems is proposed under the Polytopic Takagi-Sugeno framework. An equivalent ... [more ▼]

In this paper, a constructive procedure to design Functional Unknown Input Observers for nonlin ear continuous time systems is proposed under the Polytopic Takagi-Sugeno framework. An equivalent representation for the nonlinear model is achieved using the Sector Nonlinearity Transformation (SNT). Applying the Lyapunov theory and the L2 attenuation, Linear Matrix Inequalities (LMI)s conditions are deduced which are solved for feasibility to obtain the observer design matrices. To cope with the e ffect of unknown inputs, classical approach of decoupling the unknown input for the linear case is used. Both algebraic and solver based solutions are proposed (relaxed conditions). Necessary and su fficient conditions for the existence of the functional polytopic observer are given. For both approaches, the general and particular cases (measurable premise variables, full state estimation with full and reduced order cases) are considered and it is shown that the proposed conditions correspond to the one presented for standard linear case. To illustrate the proposed theoretical results, detailed numerical simulations are presented for a Quadrotor Aerial Robots Landing and a Waste Water Treatment Plant (WWTP). Both systems are highly nonlinear and represented in a T-S polytopic form with unmeasurable premise variables and unknown inputs. [less ▲]

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See detailModel predictive control for cooperative control of space robots
Kannan, Somasundar UL; Sajadi Alamdari, Seyed Amin UL; Dentler, Jan Eric UL et al

in Model predictive control for cooperative control of space robots (2017, January)

The problem of Orbital Manipulation of Passive body is discussed here. Two scenarios including passive object rigidly attached to robotic servicers and passive body attached to servicers through ... [more ▼]

The problem of Orbital Manipulation of Passive body is discussed here. Two scenarios including passive object rigidly attached to robotic servicers and passive body attached to servicers through manipulators are discussed. The Model Predictive Control (MPC) technique is briefly presented and successfully tested through simulations on two cases of position control of passive body in the orbit. [less ▲]

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See detailReal-time graph-based SLAM in unknown environments using a small UAV
Annaiyan, Arun UL; Olivares Mendez, Miguel Angel UL; Voos, Holger UL

in 2017 International Conference on Unmanned Aircraft Systems (ICUAS); Miami 13-16 June 2017 (2017)

Autonomous navigation of small Unmanned Aerial Vehicles (UAVs) in cluttered environments is still a challenging problem. In this work, we present an approach based on graph slam and loop closure detection ... [more ▼]

Autonomous navigation of small Unmanned Aerial Vehicles (UAVs) in cluttered environments is still a challenging problem. In this work, we present an approach based on graph slam and loop closure detection for online mapping of unknown outdoor environments using a small UAV. Here, we used an onboard front facing stereo camera as the primary sensor. The data extracted by the cameras are used by the graph-based slam algorithm to estimate the position and create the graph-nodes and construct the map. To avoid multiple detections of one object as different objects and to identify re-visited locations, a loop closure detection is applied with optimization algorithm using the g2o toolbox to minimize the error. Furthermore, 3D occupancy map is used to represent the environment. This technique is used to save memory and computational time for the online processing. Real experiments are conducted in outdoor cluttered and open field environments.The experiment results show that our presented approach works under real time constraints, with an average time to process the nodes of the 3D map is 17.79ms. [less ▲]

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See detailChapter 4:A Survey on The Polytopic Takagi-Sugeno Approach: Application to the Inverted Pendulum
Bezzaoucha, Souad UL; Voos, Holger UL; Darouach, Mohamed

in The Inverted Pendulum: From Theory to New Innovations in Control and Robotics (2017)

This book chapter gives a general scope, states the main results obtained and methods used for the Polytopic Takagi-Sugeno approach with a detailed application to the inverted pendulum. Modeling, observer ... [more ▼]

This book chapter gives a general scope, states the main results obtained and methods used for the Polytopic Takagi-Sugeno approach with a detailed application to the inverted pendulum. Modeling, observer and controller design will be considered. [less ▲]

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See detailCooperative localization of unmanned aerial vehicles in ROS - The Atlas node
Kremer, Paul; Dentler, Jan Eric UL; Kannan, Somasundar UL et al

in 2017 IEEE 15th International Conference on Industrial Informatics (INDIN) (2017)

This paper is presenting the implementation and experimental validation of the cooperative robot localization framework “Atlas”. For ease of application, Atlas is implemented as a package for the Robot ... [more ▼]

This paper is presenting the implementation and experimental validation of the cooperative robot localization framework “Atlas”. For ease of application, Atlas is implemented as a package for the Robot Operating System (ROS). ATLAS is based on dynamic cooperative sensor fusion which optimizes the estimated pose with respect to noise, respective variance. This paper validates the applicability of Atlas by cooperatively localizing multiple real quadrotors using cameras and fiduciary markers. [less ▲]

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See detailObserver design for Lightweight Robotic arm actuated by Shape Memory Alloy (SMA) wire
Quintanar Guzman, Serket UL; Kannan, Somasundar UL; Voos, Holger UL et al

in Quintanar Guzman, Serket; Kannan, Somasundar; Voos, Holger (Eds.) et al 14th International Workshop on Advanced Control and Diagnosis, Bucharest, Romania, 16-17 November 2017 (2017)

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See detailHierarchical control of aerial manipulation vehicle
Kannan, Somasundar UL; Bezzaoucha, Souad UL; Quintanar Guzman, Serket UL et al

in AIP Conference Proceedings (2017), 1798(1), 020069

Hierarchical Control of the Aerial Manipulator is treated here. The modelling aspect of the highly coupled Aerial Vehicle which includes Quadrotor and manipulator is discussed. The control design to ... [more ▼]

Hierarchical Control of the Aerial Manipulator is treated here. The modelling aspect of the highly coupled Aerial Vehicle which includes Quadrotor and manipulator is discussed. The control design to perform tasks in operational space is addressed along with stability discussion. The simulation studies are successfully performed to validate the design methodology. [less ▲]

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See detailAdaptive Control of Hysteretic Robotic arm in Operational Space
Kannan, Somasundar UL; Quintanar Guzman, Serket UL; Bezzaoucha, Souad UL et al

in 5th International Conference on Mechatronics and Control Engineering ICMCE, venice, Italy, 2016 (2016, December 14)

The focus of the current article is on Operational Space Control of a single degree of freedom robotic arm with hysteretic joint behaviour due to actuation by a single Shape Memory Alloy (SMA) wire. A ... [more ▼]

The focus of the current article is on Operational Space Control of a single degree of freedom robotic arm with hysteretic joint behaviour due to actuation by a single Shape Memory Alloy (SMA) wire. A Closed Loop Inverse Kinematics Algorithm is used in the outer loop with Adaptive joint control in the inner loop. A composite stability analysis is used to analyse the stability of the closed loop system and finally successfully validated through simulation study. [less ▲]

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See detailA tracking error control approach for model predictive position control of a quadrotor with time varying reference
Dentler, Jan Eric UL; Kannan, Somasundar UL; Olivares Mendez, Miguel Angel UL et al

in IEEE International Conference on Robotics and Biomimetics ROBIO, Qingdao, China, 2016 (2016, December 06)

In mobile robotic applications, a common problem is the following of a given trajectory with a constant velocity. Using standard model predictive control (MPC) for tracking of time varying trajectories ... [more ▼]

In mobile robotic applications, a common problem is the following of a given trajectory with a constant velocity. Using standard model predictive control (MPC) for tracking of time varying trajectories leads to a constant tracking error. This problem is modelled in this paper as quadrotor position tracking problem. The presented solution is a computationally light-weight target position control (T PC), that controls the tracking error of MPCs for constantly moving targets. The proposed technique is assessed mathematically in the Laplace domain, in simulation, as well as experimentally on a real quadrotor system. [less ▲]

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