References of "Voos, Holger 50003283"
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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 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 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 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 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 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 ▲]

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See detailNonlinear protocols for distributed consensus in directed networks of dynamic agents
Li, Yumei UL; Voos, Holger UL; Darouach, Mohamed

in Journal of the Franklin Institute (2015), 352(9), 3645-3669

This paper deals with the distributed consensus problem of multi-agent systems. While existing work mainly considers the design of linear protocols, we derive nonlinear protocols for directed networks of ... [more ▼]

This paper deals with the distributed consensus problem of multi-agent systems. While existing work mainly considers the design of linear protocols, we derive nonlinear protocols for directed networks of dynamic agents with fi xed and switched topologies, respectively. The obtained nonlinear protocols have the same effectiveness as the existing linear protocols, however they can satisfy the input constraints of real world physical systems, as well as the state value restrictions of agents, which ensure the smooth communication of the whole network and the correct data transmission among agents under the limited bandwidth. In contrast to most existing approaches that commonly use the Lyapunov function theory in order to prove the consensus problem, simple and effective mathematical methods are developed here for this purpose. Based on the equivalent in fi nitesimal functions and differentials as well as linear approximations as comparatively simple mathematical tools, we prove that the distributed consensus is asymptotically reachable and derive the group decision values. For balanced topology structures, these nonlinear protocols in particular guarantee that the agents asymptotically reach an average-consensus. Furthermore, the obtained protocols relax the constraints on the communication links among the agents. Finally, simulations comprising the vertical alignment maneuver of a team of unmanned aerial vehicles (UAVs) and the phase synchronization of three oscillators are studied, respectively. The simulation results underline that the developed nonlinear protocols are effective and feasible for distributed consensus in directed networks of dynamic multi-agent systems. [less ▲]

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See detailDecentralized Dynamic Observer-Based Control for Large Scale Nonlinear Uncertain Systems
Gao, Nan; Darouach, Mohamed; Alma, Marouane et al

in American Control Conference ACC 2015, Chicago, USA (2015)

The objective of this paper is to propose a decentralized control for a class of large scale uncertain systems. These systems consist of interconnected subsystems where the nonlinear interconnections are ... [more ▼]

The objective of this paper is to propose a decentralized control for a class of large scale uncertain systems. These systems consist of interconnected subsystems where the nonlinear interconnections are quadratic bounded. The proposed control is based on a new form of dynamic observer (DO) and the popular used proportional observer (PO) and proportional integral observer (PIO) are only particular cases of it. The control method is derived from the solution of linear matrix inequalities (LMIs), on the basis of the algebraic constraints obtained from the analysis of estimation error. A numerical example is provided to illustrate the effectiveness of the proposed method. [less ▲]

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See detailAn Approach for a Distributed World Model with QoS-Based Perception Algorithm Adaptation
Blumenthal, Sebastian; Hochgeschwender, Nico; Prassler, Erwin et al

in 2015 IEEE/RSJ International Conference on Intelligent Robots and Systems IROS, Hamburg, Germany, 2015 (2015)

This paper presents a distributed world model that is able to adapt to changes in the Quality of Service (QoS) of the communication layer by online reconfiguration of perception algorithms. The approach ... [more ▼]

This paper presents a distributed world model that is able to adapt to changes in the Quality of Service (QoS) of the communication layer by online reconfiguration of perception algorithms. The approach consists of (a) a mechanism for storage, exchange and processing of world model data and (b) a feedback loop that incorporates reasoning techniques to adapt to QoS changes immediately. The latter introduces a Level of Detail (LoD) metric based on a spatial resolution in order to infer an upper bound for the amount of data that can be transmitted without violating an application specific transmission delay. [less ▲]

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See detailAdaptive sliding mode fuzzy control for unknown robots with arbitrarily-switched constraints
Jasim, Ibrahim UL; Plapper, Peter UL; Voos, Holger UL

in Mechatronics (2015), 30C

This article addresses the control problem of robots with unknown dynamics and arbitrarily-switched unknown constraints. Such kind of robots will be shown to be unknown hybrid systems with arbitrary ... [more ▼]

This article addresses the control problem of robots with unknown dynamics and arbitrarily-switched unknown constraints. Such kind of robots will be shown to be unknown hybrid systems with arbitrary switching and an Adaptive Sliding Mode Fuzzy Control (ASMFC) strategy is proposed that handles the unknown dynamics of the robot along with the unknown constraints arbitrary switching. The ASMFC is a synergy of finding a Common Lyapunov Function (CLF) between the resulted switched subsystems of the considered robots, employing the Fuzzy Logic Systems (FLS), and the use of the Sliding Mode Control (SMC). The CLF accommodates the constraints arbitrary switching, the SMC adds robustness against possible parameters drift, and the FLS approximates the unknown robot dynamics. All unknown parameters are adapted online and all closed loop signals are guaranteed to be bounded. The proposed strategy is validated by conducting an experiment on a KUKA Lightweight Robot (LWR) doing a typical force-guided peg-in-hole assembly task that falls in the category of robot systems under consideration. Excellent tracking performance is obtained when using the ASMFC strategy. Comparison is conducted with the performance of a PD controller that is widely used in commanding industrial robots and the superiority of the proposed strategy is shown. [less ▲]

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See detailContact-State Modelling in Force-Controlled Robotic Peg-in-Hole Assembly Processes of Flexible Objects Using Optimised Gaussian Mixtures
Jasim, Ibrahim UL; Plapper, Peter UL; Voos, Holger UL

in Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture (2015)

This article proposes the distribution similarity measure–based Gaussian mixtures model for the contact-state (CS) modelling in force-guided robotic assembly processes of flexible rubber parts. The wrench ... [more ▼]

This article proposes the distribution similarity measure–based Gaussian mixtures model for the contact-state (CS) modelling in force-guided robotic assembly processes of flexible rubber parts. The wrench (Cartesian force and torque) signals of the manipulated object are captured for different states of the given assembly process. The distribution similarity measure–based Gaussian mixtures model CS modelling scheme is employed in modelling the captured wrench signals for different CSs. The proposed distribution similarity measure–based Gaussian mixtures model CS modelling scheme uses the Gaussian mixtures model in modelling the captured signals. The parameters of the Gaussian mixtures models are computed using expectation maximisation. The optimal number of Gaussian mixtures model components for each CS model is determined by considering the classification success rate as an index for the similarity measure between the distribution of the captured signals and the developed models. The optimal number of Gaussian mixtures model components corresponds to the highest classification success rate; hence, object elasticity variation would be accommodated by properly choosing the optimal number of Gaussian mixtures model components. The performance of the proposed distribution similarity measure–based Gaussian mixtures model CS modelling strategy is evaluated by a test stand composed of a KUKA lightweight robot doing peg-in-hole assembly processes for flexible rubber objects. Two rubber objects with different elasticity are considered for two experiments; in the first experiment, an elastic peg of 30 Shore A hardness is considered and that of the second experiment has hardness of 6 Shore A which is even softer than the one used in experiment 1. Employing the proposed distribution similarity measure–based Gaussian mixtures model CS modelling strategy excellent classification success rate was obtained for both experiments. However, more Gaussian mixtures model components are required for the softer one that gives a strong impression of the non-stationarity behaviour increment for softer materials. Comparison is performed with the available CS modelling schemes and the distribution similarity measure–based Gaussian mixtures model is shown to provide the best classification success rate performance with a reduced computational time. [less ▲]

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See detailGlucose-Insulin Minimal Model Augmented: Identification and Validation
Aguilera Gonzalez, Adriana UL; Voos, Holger UL; Darouach, Mohamed

in AMCA Congreso Nacional de Control Automatico 2015, Guernavaca, Mexico, 2015 (2015)

In this paper a new mathematical model of the glucose-insulin system is presented. The proposed model represents Type 1 Diabetes Mellitus patients and seeks to give a suitable model of the malfunction of ... [more ▼]

In this paper a new mathematical model of the glucose-insulin system is presented. The proposed model represents Type 1 Diabetes Mellitus patients and seeks to give a suitable model of the malfunction of the pancreas. Based on the classic minimal model, this new approach takes into account the description of the glucose dynamic in the subcutaneous layer and a meal disturbance term, together with an additional term that represents the insulin injections, which make this proposal a more realistic approach. Virtual data from UVA/Padova T1DMS software are used for rst evaluations of the effectiveness of the proposed model. [less ▲]

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See detailH-infinity dynamic observer design for linear time invariant systems
Gao, Nan; Darouach, Mohamed; Voos, Holger UL et al

in 2014 IEEE 53rd Annual Conference on Decision and Control (CDC), Los Angeles, USA (2014, December)

This paper proposes an H-infinity dynamic observer (DO) for a class of linear time invariant (LTI) systems in the presence of disturbances. It generalizes the existing results on the proportional observer ... [more ▼]

This paper proposes an H-infinity dynamic observer (DO) for a class of linear time invariant (LTI) systems in the presence of disturbances. It generalizes the existing results on the proportional observer (PO), the proportional integral observer (PIO) and the DO. The design method is derived from a new formulation of linear matrix inequality (LMI), based on the solutions of the algebraic constraints obtained from the unbiasedness conditions of the estimation error. A numerical example is provided to show the applicability and performances of our observer. [less ▲]

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See detailH-infinity Adaptive Observer Design and Parameter Identification for a Class of Nonlinear Fractional-Order Systems
N'Doye, Ibrahima; Voos, Holger UL; Laleg-Kirati, Taous-Meriem et al

in 53rd IEEE Conference Decision and Control, CDC’14, Los Angeles, USA, 15-17 Dec. 2014 (2014, December)

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See detailH∞ decentralized dynamic-observer-based control for large-scale uncertain nonlinear systems
Gao, Nan; Darouach, Mohamed; Alma, Marouane et al

in IEEE Int. Conf. on Control, Decision and Information Technologies (CoDIT), Metz, France, 3-5 Nov. 2014 (2014, November)

In this paper an H∞ decentralized observer-based control is proposed for large-scale uncertain nonlinear systems. These systems are coupled by N interconnected subsystems where the interconnections ... [more ▼]

In this paper an H∞ decentralized observer-based control is proposed for large-scale uncertain nonlinear systems. These systems are coupled by N interconnected subsystems where the interconnections satisfy the quadratic constraints. The proposed control is based on a new form of dynamic observer (DO) which generalizes the existing results on the proportional observer (PO) and the proportional integral observer (PIO). The design approach is derived from the solution of matrix inequality and based on the algebraic constraints obtained from the analysis of the estimation error. A numerical example is provided to show the effectiveness of the proposed control. [less ▲]

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