References of "Voos, Holger 50003283"
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See detailA Class of Improved Wake Interaction Model for the Coordinated Control of Wind Farms
Pan, Lin UL; Voos, Holger UL; Darouach, Mohamed

in IEEE Conference Publications (Ed.) IEEE International Chinese Automation Congress (CAC), 2015 (2015, December 01)

This paper is focused on the Wind Energy (WE) systems and Wind Farms (WFs) optimization in Luxembourg. It describes the overview of the wind resources in all the WFs and presents a class of Improved Wake ... [more ▼]

This paper is focused on the Wind Energy (WE) systems and Wind Farms (WFs) optimization in Luxembourg. It describes the overview of the wind resources in all the WFs and presents a class of Improved Wake Interaction Model (IWIM) for Coordination and Optimization Control (CnOC) of WFs. Based on Wind Power (WP) assessment of WFs, the statistical method is used to model the distribution of Wind Speed (WS) and Wind Direction (WD). Some simulation figures about the Wind Rose (WR) and WF optimization demonstrate the description and assessment of WP in detail. These assessments are expected to enhance the effectiveness of exploitation and utilization of WP in WFs of Luxembourg. [less ▲]

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See detailRetalis Language for Information Engineering in Autonomous Robot Software
Ziafati, Pouyan UL; dastani, mehdi; meyer, john-jules et al

in IfCoLog Journal of Logics and their Applications (2015), 2(2), 85

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See detailA Wake Interaction Model for the Coordinated Control of Wind Farms
Pan, Lin UL; Voos, Holger UL; Li, Yumei et al

in Emerging Technologies & Factory Automation (ETFA), 2015 IEEE 20th Conference on (2015, September 08)

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See detailGaussian Filtering for Enhanced Impedance Parameters Identification in Robotic Assembly Processes
Jasim, Ibrahim UL; Plapper, Peter UL; Voos, Holger UL

in 20th IEEE International Conference on Emerging Technologies and Factory Automation (ETFA 2015), Luxembourg 8-11 September 2015 (2015, September 08)

Robot interaction with the environment is normally described as a mass-spring-damping impedance model and the estimation of such interaction impedance parameters requires the computation of the joint (or ... [more ▼]

Robot interaction with the environment is normally described as a mass-spring-damping impedance model and the estimation of such interaction impedance parameters requires the computation of the joint (or task) space velocity and acceleration. In many cases, the velocity and acceleration are computed by numerically computing the first and second derivatives of the sensed position signal. The numerical differentiation results in approximation errors when computing the velocity and acceleration signals that would have a direct impact on the estimation of the impedance parameters. This article proposes enhancing the estimation of the impedance parameters by smoothing the velocity and acceleration signals prior to the considered estimation process. Gaussian Smoothing Filter (GSF) is employed in smoothing the considered signals. After the smoothing process, impedance parameters estimation becomes more feasible using the available strategies like the Least Mean Square (LMS) or any other estimation approach. Experiments are conducted on a KUKA Lightweight Robot (LWR) doing the assembly of the air-intake manifold of an automotive powertrain. The impedance parameters are estimated for the smoothed and unsmoothed cases in order to show the enhancement in the estimation process. [less ▲]

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See detailModel-Free Robust Adaptive Control for Flexible Rubber Objects Manipulation
Jasim, Ibrahim UL; Plapper, Peter UL; Voos, Holger UL

in 20th IEEE International Conference on Emerging Technologies and Factory Automation (ETFA 2015), Luxembourg 8-11 September 2015 (2015, September 08)

This article addresses the control problem of robots with unknown dynamics and manipulating flexible rubber objects of unknown elasticity. The manipulated rubber object is considered to be interacting ... [more ▼]

This article addresses the control problem of robots with unknown dynamics and manipulating flexible rubber objects of unknown elasticity. The manipulated rubber object is considered to be interacting with arbitrarily-switched constraints. Such a kind of robot system is shown to have switched impedance parameters during a task execution that results in an unknown hybrid nonlinear system with arbitrarily switched signal. A Model-Free Robust Adaptive Control (MFRAC) strategy is proposed for such a robot system that is proved to guarantee global stable performance with all closed loop signals are assured to be bounded. The suggested MFRAC strategy relies on the synergy of the Adaptive Fuzzy System (AFS), the Sliding Mode Control (SMC), and the notion of Common Lyapunov Functions (CLF). The AFS relaxes the need for knowing the precise robot dynamics, the SMC adds robustness against the drift of the dynamics parameters, and the CLF accommodates the arbitrary switching of the impedance parameters. The bounds of the impedance parameters are adapted online and incorporated in the MFRAC design such that a convergent performance is achieved. Experiment is conducted on a KUKA Lightweight Robot (LWR) doing flexible rubber peg-in-hole assembly process that falls in the category of systems considered in this article. From the experimental results, excellent tracking performance is reported when using the proposed MFRAC strategy for the considered robotic system despite the dynamics anonymity and the unknown impedance parameters arbitrary switching. [less ▲]

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See detailLinearizing Control of Biogas Flow Rate and Quality
Chaib Draa, Khadidja UL; Voos, Holger UL; Alma, Marouane et al

in 20th IEEE Int. Conference on Emerging Tecnologies and Factory Automation ETFA 2015, Luxembourg, 8-11 Sept. 2015 (2015, September)

In this paper, we propose to control the quantity and quality of the produced biogas from the anaerobic digestion of organic matter, digested in either a continuous stirred tank reactor or a fixed bed ... [more ▼]

In this paper, we propose to control the quantity and quality of the produced biogas from the anaerobic digestion of organic matter, digested in either a continuous stirred tank reactor or a fixed bed digester. This is motivated by the aim of providing the power grid with a stable amount of energy despite fluctuations in the treated waste concentration and composition. Therefore, we apply the linearizing control principe to a two step (acidogenesis-methanogenesis) mass balance non linear model, all with the introduction of two new control inputs reflecting the addition of stimulating substrates (acetate and alkalinity). To show the performance of the synthesized control laws we simulate the process under an organic shock load feeding. [less ▲]

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See detailContext-based Selection and Execution of Robot Perception Graphs
Hochgeschwender, Nico UL; Olivares Mendez, Miguel Angel UL; Voos, Holger UL et al

in 20th IEEE International Conference on Emerging Technologies and Factory Automation (ETFA'15) (2015, September)

To perform a wide range of tasks service robots need to robustly extract knowledge about the world from the data perceived through the robot’s sensors even in the presence of varying context-conditions ... [more ▼]

To perform a wide range of tasks service robots need to robustly extract knowledge about the world from the data perceived through the robot’s sensors even in the presence of varying context-conditions. This makes the design and devel- opment of robot perception architectures a challenging exercise. In this paper we propose a robot perception architecture which enables to select and execute at runtime different perception graphs based on monitored context changes. To achieve this the architecture is structured as a feedback loop and contains a repository of different perception graph configurations suitable for various context conditions. [less ▲]

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See detailStatic Output Feedback H-infinity Control for a Fractional-Order Glucose-Insulin System
N'Doye, Ibrahima; Voos, Holger UL; Darouach, Mohamed et al

in International Journal of Control, Automation, and Systems (2015), 13(4), 798-807

This paper presents the H∞ static output feedback control of nonlinear fractional-order systems. Based on the extended bounded real lemma, the H∞ control is formulated and sufficient conditions are ... [more ▼]

This paper presents the H∞ static output feedback control of nonlinear fractional-order systems. Based on the extended bounded real lemma, the H∞ control is formulated and sufficient conditions are derived in terms of linear matrix inequalities (LMIs) formulation by using the fractional Lyapunov direct method where the fractional-order α belongs to 0 < α < 1. The control approach is finally applied to the regulation of the glucose level in diabetes type 1 treatment. Therefore, it is attempted to incorporate fractional-order into the mathematical minimal model of glucose-insulin system dynamics and it is still an interesting challenge to show, how the order of a fractional differential system affects the dynamics of the system in the presence of meal disturbance. Numerical simulations are carried out to illustrate our proposed results and show that the nonlinear fractional-order glucose-insulin systems are, at least, as stable as their integer-order counterpart in the presence of exogenous glucose infusion or meal disturbance. [less ▲]

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See detailAn algebraic detection approach for control systems under multiple stochastic cyber-attacks
Li, Yumei UL; Voos, Holger UL; Darouach, Mohamed et al

in IEEE/CAA Journal of Automatica Sinica (2015), 2(3), 258-266

In order to compromise a target control system successfully, hackers possibly attempt to launch multiple cyberattacks aiming at multiple communication channels of the control system. However, the problem ... [more ▼]

In order to compromise a target control system successfully, hackers possibly attempt to launch multiple cyberattacks aiming at multiple communication channels of the control system. However, the problem of detecting multiple cyber-attacks has been hardly investigated so far. Therefore, this paper deals with the detection of multiple stochastic cyber-attacks aiming at multiple communication channels of a control system. Our goal is to design a detector for the control system under multiple cyberattacks. Based on frequency-domain transformation technique and auxiliary detection tools, an algebraic detection approach is proposed. By applying the presented approach, residual information caused by different attacks is obtained respectively and anomalies in the control system are detected. Sufficient and necessary conditions guaranteeing the detectability of the multiple stochastic cyber-attacks are obtained. The presented detection approach is simple and straightforward. Finally, two simulation examples are provided, and the simulation results show that the detection approach is effective and feasible. [less ▲]

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See detailEffects of Permanent Bounded Cyber-Attacks on Networked Control Systems
Gerard, Benjamin UL; Voos, Holger UL; Li, Yumei UL et al

in 23rd Mediterranean Conference on Control and Automation (MED) (2015, June 16)

In this paper, the problem of permanent bounded cyber-attacks on networked control systems is treated. After a characterisation of malicious cyber attacks, the danger of permanent bounded cyber-attacks of ... [more ▼]

In this paper, the problem of permanent bounded cyber-attacks on networked control systems is treated. After a characterisation of malicious cyber attacks, the danger of permanent bounded cyber-attacks of two types is proved, the step attacks on system with invariant zero with zero real part and the free attacks. Simulation examples demonstrate the obtained results. [less ▲]

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See detailAn application of linear algebra theory in networked control systems: stochastic cyber-attacks detection approach
Li, Yumei UL; Voos, Holger UL; Darouach, Mohamed et al

in IMA Journal of Mathematical Control and Information (2015)

Based on the traditional linear algebra theory, this paper propose the attack detection schemes for networked control systems (NCSs) under single stochastic cyber-attack and multiple stochastic cyber ... [more ▼]

Based on the traditional linear algebra theory, this paper propose the attack detection schemes for networked control systems (NCSs) under single stochastic cyber-attack and multiple stochastic cyber-attacks aiming at multiple communication channels of NCSs, respectively. The focus is on designing an anomaly detector for NCSs under cyber-attacks. First, we construct a model of stochastic NCSs with stochastic cyber-attacks which satisfy the Markovian stochastic process. And we also introduced the stochastic attack models that NCSs are possibly exposed to. Next, based on the frequency-domain transformation technique and linear algebra theory, we propose the algebraic detection schemes for possible stochastic cyber-attacks. We transform the detector error dynamics into algebraic equations. By applying the presented approaches, residual information that is caused by different attacks is, respectively, obtained and anomalies on the control system are detected. In addition, sufficient and necessary conditions guaranteeing the detectability of the stochastic cyber-attacks are obtained. The presented detection approaches in this paper are simple, straightforward and easy to implement. The aim of this work is to use traditional mathematics tools to solve new problems that arise from the complex NCSs. Finally, two simulation examples are provided. The simulation results underline that the detection approaches are effective and feasible in practical application. [less ▲]

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See detailVision Based Fuzzy Control Autonomous Landing with UAVs: From V-REP to Real Experiments
Olivares Mendez, Miguel Angel UL; Kannan, Somasundar UL; Voos, Holger UL

in 23nd IEEE Mediterranean Conference of Control and Automation (MED), 2015, Torremolinos 2015, Spain (2015, June)

This paper is focused on the design of a vision based control approach for the autonomous landing task of Vertical Take-off and Landing (VTOL) Unmanned Aerial Vehicles (UAVs). Here is presented the setup ... [more ▼]

This paper is focused on the design of a vision based control approach for the autonomous landing task of Vertical Take-off and Landing (VTOL) Unmanned Aerial Vehicles (UAVs). Here is presented the setup of a simulated environment developed in V-REP connected to ROS, and its uses for tuning a vision based control approach. In this work, a Fuzzy control approach was proposed to command the UAV’s vertical, longitudinal, lateral and orientation velocities. The UAV’s pose estimation was done based on a vision algorithm and the knowledge of the landing target. Real experiments with a quadrotor landing in a moving platform are also presented. [less ▲]

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See detailStochastic cyber-attacks estimation for nonlinear control systems based on robust H∞ filtering technique
Yumei, Li UL; Voos, Holger UL; Pan, Lin UL et al

in Control and Decision Conference (CCDC), 2015 27th Chinese (2015, May 23)

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See detailUncertainty Quantification of Exponential Synchronization for a Novel Class of Complex Dynamical Networks with Hybrid TVD Using PIPC
Pan, Lin UL; Voos, Holger UL; Li, Yumei UL et al

in Control and Decision Conference (CCDC), 2015 27th Chinese (2015, May 23)

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See detailOn the robustness of linear and non-linear fractional-order systems with non-linear uncertain parameters
N'Doye, Ibrahima; Darouach, Mohamed; Voos, Holger UL et al

in IMA Journal of Mathematical Control and Information (2015)

This paper presents the robust stabilization problem of linear and non-linear fractional-order systems with non-linear uncertain parameters. The uncertainty in the model appears in the form of the ... [more ▼]

This paper presents the robust stabilization problem of linear and non-linear fractional-order systems with non-linear uncertain parameters. The uncertainty in the model appears in the form of the combination of ‘additive perturbation’ and ‘multiplicative perturbation’. Sufficient conditions for the robust asymptotical stabilization of linear fractional-order systems are presented in terms of linear matrix inequalities (LMIs) with the fractional-order 0<α<1. Sufficient conditions for the robust asymptotical stabilization of non-linear fractional-order systems are then derived using a generalization of the Gronwall–Bellman approach. Finally, a numerical example is given to illustrate the effectiveness of the proposed results. [less ▲]

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See detailAdaptive Control for the Methane Flow rate in Biogas Plants
Chaib Draa, Khadidja UL; Voos, Holger UL; Alma, Marouane et al

in 3rd IEEE Int. Conference on Control, Engineering and Information Technology, Tlemcen, Algeria, 2015 (2015, May)

In this paper we consider the control of the methane flow rate in biogas production using both a continuous stirred tank reactor and a fixed bed digester. The goal is to regulate the methane flow rate in ... [more ▼]

In this paper we consider the control of the methane flow rate in biogas production using both a continuous stirred tank reactor and a fixed bed digester. The goal is to regulate the methane flow rate in order to match an energy demand in spite of variations in the waste concentrations. For this purpose, a two step (acidogenesis-methanogenesis) nonlinear mass balance model is considered. Due to the costs and complexity of the measurements an adaptive observer is designed for the acidogenesis reaction rate. The stability of the observation part is proved and its implementation with the designed adaptive control law for the methane flow rate and the acetate concentration in the reactor are confirmed by simulations. [less ▲]

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See detailGlucose-Insulin System based on Minimal Model: a realisitic approach
Aguilera Gonzalez, Adriana UL; Voos, Holger UL; Darouach, Mohamed

in IEEE UKSim-AMSS Int. Conference on Modelling and Simulation, Cambridge, UK, 2015 (2015, March)

This paper presents a new approach to represent the glucose and insulin levels on patients with diabetes type 1 based on the well known minimal model. In this work it is proposed a new mathematical model ... [more ▼]

This paper presents a new approach to represent the glucose and insulin levels on patients with diabetes type 1 based on the well known minimal model. In this work it is proposed a new mathematical model that attempts modeling properly the exactly malfunction of this system. The model takes into account both: the description of the glucose level in the subcutaneous layer and a meal disturbance term. In silico simulations are used to evaluate the effectiveness of the proposed work. [less ▲]

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See detailA Formal Modeling Framework for Anaerobic Digestion Systems
Chaib Draa, Khadidja UL; Voos, Holger UL; Darouach, Mohamed

in IEEE UKSim-AMSS Int. Conference on Modelling and Simulation, Cambridge, UK, 2015 (2015, March)

The complexity of modeling the anaerobic digestion process meets the difficulty to describe and analyze them mathematically. In this paper, a simplified mathematical model for anaerobic digestion process ... [more ▼]

The complexity of modeling the anaerobic digestion process meets the difficulty to describe and analyze them mathematically. In this paper, a simplified mathematical model for anaerobic digestion process of organic matter, in a continuous stirred tank reactor is proposed. With the aim of upgrading the produced biogas and integrate biogas plants in a virtual power plant, new control inputs reflecting addition of stimulating substrates (acetate and bicarbonate) are added. Based on two step (acedogenesis-methanogenesis) mass balance non linear model, a step-by-step model parameter’s identification procedure is presented in the first step, then in the second step, the yield coefficients and the microbial growth rates are estimated when the later is assumed to be unknown a priori. [less ▲]

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See detailVisual odometry based absolute target geo-location from micro aerial vehicle
Annaiyan, Arun UL; Yadav, Mahadeeswara; Olivares Mendez, Miguel Angel UL et al

in International Conference on Robotics, Automation, Control and Embedded Systems (RACE), 2015 (2015, February 20)

An unmanned aerial system capable of finding world coordinates of a ground target is proposed here. The main focus here was to provide effective methodology to estimate ground target world coordinates ... [more ▼]

An unmanned aerial system capable of finding world coordinates of a ground target is proposed here. The main focus here was to provide effective methodology to estimate ground target world coordinates using aerial images captured by the custom made micro aerial vehicle (MAV) as a part of visual odometery process on real time. The method proposed here for finding target's ground coordinates uses a monocular camera which is placed in MAV belly in forward looking/ Downward looking mode. The Binary Robust Invariant Scalable Key points (BRISK) algorithm was implemented for detecting feature points in the consecutive images. After robust feature point detection, efficiently performing Image Registration between the aerial images captured by MAV and with the Geo referenced images is the prime and core computing operation considered. Precise Image alignment is implemented by accurately estimating Homography matrix. In order to accurately estimate Homography matrix which consists of 9 parameters, this algorithm solves the problem in a Least Square Optimization way. Therefore, this framework can be integrated with visual odometery pipeline; this gives the advantage of reducing the computational burden on the hardware. The system can still perform the task of target geo-localization efficiently based on visual features and geo referenced reference images of the scene which makes this solution to be found as cost effective, easily implementable with robustness in the output. The hardware implementation of MAV along with this dedicated system which can do the proposed work to find the target coordinates is completed. The main application of this work is in search and rescue operations in real time scenario. The methodology was analyzed and executed in MATLAB before implementing real time on the developed platform. Finally, three case studies with different advantages derived from the proposed framework are represented. [less ▲]

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See detailDesign and Simulation of a Real-Time Implementable Energy-Efficient Model-Predictive Cruise Controller for Electric Vehicles
Schwickart, Tim Klemens UL; Voos, Holger UL; Minaglou, Jean-Régis UL et al

in Journal of the Franklin Institute (2015), 352(2), 603-625

This paper presents the design of a novel energy-efficient model-predictive cruise controller for electric vehicles as well a simulation model of the longitudinal vehicle dynamics and its energy ... [more ▼]

This paper presents the design of a novel energy-efficient model-predictive cruise controller for electric vehicles as well a simulation model of the longitudinal vehicle dynamics and its energy consumption. Both, the controller and the dynamic model are designed to meet the properties of a series-production electric vehicle whose characteristics are identified and verified by measurements. A predictive eco-cruise controller involves the minimisation of a compromise between terms related to driving speed and energy consumption which are in general both described by nonlinear differential equations. Considering the nonlinearities is essential for a proper prediction of the system states over the prediction horizon to achieve the desired energy-saving behaviour. In this work, the vehicle motion equation is reformulated in terms of the kinetic energy of the moving vehicle which leads to a linear differential equation without loss of information. The energy consumption is modeled implicitly by exploiting the special form of the optimisation problem. 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 MPC controller and the simulation model in closed-loop operation finally provide a proof of concept. [less ▲]

Detailed reference viewed: 279 (24 UL)