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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 detailLuxembourg United Qualification Document for RoboCup 2017
Caire, Patrice; Voos, Holger UL; Medernach, Yan et al

Report (2017)

This is the qualification document for the new team, and first team of Luxembourg, called “Luxembourg United”. This is also the team’s first attempt to qualify for a RoboCup competition. First, a general ... [more ▼]

This is the qualification document for the new team, and first team of Luxembourg, called “Luxembourg United”. This is also the team’s first attempt to qualify for a RoboCup competition. First, a general description of the Luxembourg United team is presented, along with its members and the equipment owned by the team. Second, the mixed team option is considered and potential eventualities suggested. Third, the Luxembourg United team thankfully acknowledges its use of the B-Human code, and lists its original contributions to this code as well as to RoboCup 2017. Fourth, The activities of the team that contribute to Luxembourg United are outlined. Fifth, the impact of the team’s participation and research in RoboCup is described as it applies to the SPL community, to Luxembourg University and SnT Research Center, and to the whole country of Luxembourg. We conclude this document with considerations pertaining to the path that brought us to RoboCup, and present futur perspectives. [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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See detailStates and unknown input estimation via non-linear sliding mode high-gain observers for a glucose-insulin system
Aguilera Gonzalez, Adriana UL; Voos, Holger UL; Darouach, Mohamed

in IEEE EMBS Conference on Biomedical Engineering and Sciences (IECBES), Kuala Lumpur, Malaysia, 2016 (2016, December 04)

A meal-estimation algorithm is developed based on an extended mathematical model of the glucose-insulin system. The proposed model describes the dynamics of glucose levels in blood and in subcutaneous ... [more ▼]

A meal-estimation algorithm is developed based on an extended mathematical model of the glucose-insulin system. The proposed model describes the dynamics of glucose levels in blood and in subcutaneous layer, as well as the meal intake which is considered an unknown input of the system. This model seeks to represent in a more realistic manner, the pancreas malfunction in patients with Type 1 Diabetes Mellitus. Based on model, a non-linear high gain observer (NHGO) with a sliding mode is designed in order to estimate the unmeasured states and the external disturbances of the system. This scheme is useful to maintain frequent monitoring of glucose levels and any changes in its behaviour. The unknown input or disturbance is estimated through the sliding mode based only the estimation error. Data from a real patient is used to evaluate the effectiveness of the proposed estimation scheme. [less ▲]

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See detailGraph-based Software Knowledge: Storage and Semantic Querying of Domain Models for Run-Time Adaptation
Hochgeschwender, Nico UL; Schneider, Sven; Voos, Holger UL et al

in IEEE International Conference on Simulation, Modeling, and Programming for Autonomous Robots SIMPAR, San Francisco, Dec 2016 (2016, December)

Software development for robots is a knowledge intensive exercise. To capture this knowledge explicitly and formally in the form of various domain models, roboticists have recently employed model-driven ... [more ▼]

Software development for robots is a knowledge intensive exercise. To capture this knowledge explicitly and formally in the form of various domain models, roboticists have recently employed model-driven engineering (MDE) approaches. However, these models are merely seen as a way to support humans during the robot's software design process. We argue that the robots themselves should be first-class consumers of this knowledge to autonomously adapt their software to the various and changing run-time requirements induced, for instance, by the robot's tasks or environment. Motivated by knowledge-enabled approaches, we address this problem by employing a graph-based knowledge representation that allows us not only to persistently store domain models, but also to formulate powerful queries for the sake of run time adaptation. We have evaluated our approach in an integrated, real-world system using the neo4j graph database and we report some lessons learned. Further, we show that the graph database imposes only little overhead on the system's overall performance. [less ▲]

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See detailA real-time model predictive position control with collision avoidance for commercial low-cost quadrotors
Dentler, Jan Eric UL; Kannan, Somasundar UL; Olivares Mendez, Miguel Angel UL et al

in IEEE Multi-Conference on Systems and Control (MSC 2016), Buenos Aires, Argentina, 2016 (2016, September 20)

Unmanned aerial vehicles (UAVs) are the future technology for autonomous fast transportation of individual goods. They have the advantage of being small, fast and not to be limited to the local ... [more ▼]

Unmanned aerial vehicles (UAVs) are the future technology for autonomous fast transportation of individual goods. They have the advantage of being small, fast and not to be limited to the local infrastructure. This is not only interesting for delivery of private consumption goods up to the doorstep, but also particularly for smart factories. One drawback of autonomous drone technology is the high development costs, that limit research and development to a small audience. This work is introducing a position control with collision avoidance as a first step to make low-cost drones more accessible to the execution of autonomous tasks. The paper introduces a semilinear state-space model for a commercial quadrotor and its adaptation to the commercially available AR.Drone 2 system. The position control introduced in this paper is a model predictive control (MPC) based on a condensed multiple-shooting continuation generalized minimal residual method (CMSCGMRES). The collision avoidance is implemented in the MPC based on a sigmoid function. The real-time applicability of the proposed methods is demonstrated in two experiments with a real AR.Drone quadrotor, adressing position tracking and collision avoidance. The experiments show the computational efficiency of the proposed control design with a measured maximum computation time of less than 2ms. [less ▲]

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See detailUAV degradation identification for pilot notification using machine learning techniques
Manukyan, Anush UL; Olivares Mendez, Miguel Angel UL; Bissyande, Tegawendé François D Assise UL et al

in Proceedings of 21st IEEE International Conference on Emerging Technologies and Factory Automation ETFA 2016 (2016, September 06)

Unmanned Aerial Vehicles are currently investigated as an important sub-domain of robotics, a fast growing and truly multidisciplinary research field. UAVs are increasingly deployed in real-world settings ... [more ▼]

Unmanned Aerial Vehicles are currently investigated as an important sub-domain of robotics, a fast growing and truly multidisciplinary research field. UAVs are increasingly deployed in real-world settings for missions in dangerous environments or in environments which are challenging to access. Combined with autonomous flying capabilities, many new possibilities, but also challenges, open up. To overcome the challenge of early identification of degradation, machine learning based on flight features is a promising direction. Existing approaches build classifiers that consider their features to be correlated. This prevents a fine-grained detection of degradation for the different hardware components. This work presents an approach where the data is considered uncorrelated and, using machine learning <br />techniques, allows the precise identification of UAV’s damages. [less ▲]

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See detailOperational Space Control of a Lightweight Robotic Arm Actuated By Shape Memory Alloy (SMA) Wires
Quintanar Guzman, Serket UL; Kannan, Somasundar UL; Olivares Mendez, Miguel Angel UL et al

in ASME 2016 Conferences on Smart Materials, Adaptive Structures and Intelligent Systems, Vermont 28-30 September 2016 (2016, September)

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See detailA Fast Model-Predictive Speed Controller for Minimised Charge Consumption of Electric Vehicles
Schwickart, Tim Klemens UL; Voos, Holger UL; Hadji-Minaglou, Jean-Régis UL et al

in Asian Journal of Control (2016), 18(5),

This paper presents the design of a real-time implementable energy-efficient model-predictive cruise controller for electric vehicles including the driving speed reference generation. The controller is ... [more ▼]

This paper presents the design of a real-time implementable energy-efficient model-predictive cruise controller for electric vehicles including the driving speed reference generation. The controller is designed to meet the properties of a series-production electric vehicle whose characteristics are identified and validated by measurements. The predictive eco-cruise controller aims at finding the best compromise between speed-reference tracking and energy consumption of the vehicle using an underlying dynamic model of the vehicle motion and charge consumption. The originally non-linear motion model is transformed into a linear model mainly by using a coordinate transform. To obtain a piecewise linear approximation of the charge consumption map, the measured characteristics are approximated by a convex piecewise linear function represented as the maximum of a set of linear constraint functions. The reformulations finally lead to a model-predictive control approach with quadratic cost function, linear prediction model and linear constraints that corresponds to a piecewise linear system behaviour and allows a fast real-time implementation with guaranteed convergence. Simulation results of the closed-loop operation finally illustrate the effectiveness of the approach. [less ▲]

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See detailInvariant Observer Applied to Anaerobic Digestion Model
Chaib Draa, Khadidja UL; Voos, Holger UL; Alma, Marouane et al

in IEEE 21st International Conference on Emerging Technologies and Factory Automation (ETFA), Berlin, Germany, 2016 (2016, September)

In this note, we design an invariant observer for a two step (acidogenesis-methanogenesis) mass balance nonlinear model, in order to estimate simultaneously all bacteria and substrate concentrations found ... [more ▼]

In this note, we design an invariant observer for a two step (acidogenesis-methanogenesis) mass balance nonlinear model, in order to estimate simultaneously all bacteria and substrate concentrations found in the anaerobic digestion process. The particularity of the designed observer is the use of only the methane flow rate which is cheap to measure and commonly measured online even at industrial scale. [less ▲]

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See detailAutomated Decision Support IoT Framework
Tessaro Lunardi, Willian UL; Amaral, Leonardo; Marczak, Sabrina et al

in IEEE 21st International Conference on Emerging Technologies and Factory Automation (ETFA), Berlin, Germany, 2016 (2016, September)

During the past few years, with the fast development and proliferation of the Internet of Things (IoT), many application areas have started to exploit this new computing paradigm. The number of active ... [more ▼]

During the past few years, with the fast development and proliferation of the Internet of Things (IoT), many application areas have started to exploit this new computing paradigm. The number of active computing devices has been growing at a rapid pace in IoT environments around the world. Consequently, a mechanism to deal with this different devices has become necessary. Middleware systems solutions for IoT have been developed in both research and industrial environments to supply this need. However, decision analytics remain a critical challenge. In this work we present the Decision Support IoT Framework composed of COBASEN, an IoT search engine to address the research challenge regarding the discovery and selection of IoT devices when large number of devices with overlapping and sometimes redundant functionality are available in IoT middleware systems, and DMS, a rule-based reasoner engine allowing to set up computational analytics on device data when it is still in motion, extracting valuable information from it for automated decision making. DMS uses Complex Event Processing to analyze and react over streaming data, allowing for example, to trigger an actuator when a specific error or condition appears in the stream. The main goal of this work is to highlight the importance of a decision support system for decision analytics in the IoT paradigm. We developed a system which implements DMS concepts. However, for preliminarily tests, we made a functional evaluation of both systems in terms of performance. Our initial findings suggest that the Decision Support IoT Framework provides important approaches that facilitate the development of IoT applications, and provides a new way to see how the business rules and decision-making will be made towards the Internet of Things. [less ▲]

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See detailA Generalized Interaction Wake Model with Its Variation for Control in Wind Farms
Pan, Lin UL; Voos, Holger UL; Darouach, Mohamed

in 35th Chinese Control Conference, Chengdu. China, 2016 (2016, July 28)

Detailed reference viewed: 177 (8 UL)