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See detailAttack-tolerant Control and Observer-based Trajectory Tracking for Cyber-Physical Systems
Bezzaoucha, Souad UL; Voos, Holger UL; Darouach, Mohamed

in European Journal of Control (in press)

In the present paper, a model-based fault/attack tolerant scheme is proposed to cope with cyber-threats on Cyber-Physicals Systems. A common scheme based on observers is designed and a state feedback ... [more ▼]

In the present paper, a model-based fault/attack tolerant scheme is proposed to cope with cyber-threats on Cyber-Physicals Systems. A common scheme based on observers is designed and a state feedback control based on an aperiodic event-triggered framework is given with control synthesis and condition on the switching time. Classical fault tolerant control with Bi-linear Matrix Inequality () approaches are used to achieve novel and better security strategy based on an event-triggered control implementation. The purpose of using the event-based implementation would be to reduce (limit) the total number of transmissions to only instances when the networked control system (NCS) needs attention. Simulation results on a real-time laboratory three tank system are given to show the attack-tolerant control ability despite data deception attacks on both actuators and sensors. A detection/isolation scheme based on residual observers bank is also proposed. [less ▲]

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See detailAn Effective Hybrid Imperialist Competitive Algorithm and Tabu Search for an Extended Flexible Job Shop Scheduling Problem
Tessaro Lunardi, Willian UL; Voos, Holger UL; Cherri, Luiz Henrique

in 34th ACM/SIGAPP Symposium On Applied Computing, Limassol, Cyprus April 8-12, 2019 (2019, April 08)

An extended version of the flexible job shop problem is tackled in this work. The investigated extension of the classical flexible job shop problem allows the precedences between the operations to be ... [more ▼]

An extended version of the flexible job shop problem is tackled in this work. The investigated extension of the classical flexible job shop problem allows the precedences between the operations to be given by an arbitrary directed acyclic graph instead of a linear order. The problem consists of designating the operations to the machines and sequencing them in compliance with the supplied precedences. The goal in the present work is the minimization of the makespan. In order to produce reasonable outcomes in acceptable time, a hybrid imperialist competitive algorithm and tabu search is proposed to solve the problem. Numerical experiments assess the efficiency of the proposed method and compare it with well-known scheduling algorithms. [less ▲]

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See detailEvaluation of End-To-End Learning for Autonomous Driving: The Good, the Bad and the Ugly
Varisteas, Georgios UL; Frank, Raphaël UL; Sajadi Alamdari, Seyed Amin UL et al

in 2nd International Conference on Intelligent Autonomous Systems, Singapore, Feb. 28 to Mar. 2, 2019 (2019, March 01)

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See detailNew Trends in Observer-based Control: An Introduction to Design Approaches and Engineering Applications, Chapter 13: Observer-based Event-triggered Attack-Tolerant Control Design for Cyber-physical Systems
Bezzaoucha, Souad UL; Voos, Holger UL

in New Trends in Observer-based Control: An Introduction to Design Approaches and Engineering Applications, Chapter 13: Observer-based Event-triggered Attack-Tolerant Control Design for Cyber-physical Systems (2019)

In the following chapter, we first introduce an appropriate model associating paradigms from control theory and computer science (system subject to both physical attacks and sensors/actuators attacks via ... [more ▼]

In the following chapter, we first introduce an appropriate model associating paradigms from control theory and computer science (system subject to both physical attacks and sensors/actuators attacks via the connected network, i.e., false-data injection attacks on actuators/sensors). Then, inspired by a combination between the classical fault-tolerant control (FTC) approach and the event-triggered control, an observer-based attack-tolerant control solution is proposed. The aim of our work is, first, to establish theoretical foundations for the development of model-based monitoring and attack-tolerant control for reliable deployment of a large number of advanced Cyber-Physical Systems. [less ▲]

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See detailNonlinear Model Predictive Control for Ecological Driver Assistance Systems in Electric Vehicles
Sajadi Alamdari, Seyed Amin UL; Voos, Holger UL; Darouach, Mohamed

in Robotics and Autonomous Systems (2018)

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See detailEcological Advanced Driver Assistance System for Optimal Energy Management in Electric Vehicles
Sajadi Alamdari, Seyed Amin UL; Voos, Holger UL; Darouach, Mohamed

in IEEE Intelligent Transportation Systems Magazine (2018)

Battery Electric Vehicles have a high potential in modern transportation, however, they are facing limited cruising range. The driving style, the road geometries including slopes, curves, the static and ... [more ▼]

Battery Electric Vehicles have a high potential in modern transportation, however, they are facing limited cruising range. The driving style, the road geometries including slopes, curves, the static and dynamic traffic conditions such as speed limits and preceding vehicles have their share of energy consumption in the host electric vehicle. Optimal energy management based on a semi-autonomous ecological advanced driver assistance system can improve the longitudinal velocity regulation in a safe and energy-efficient driving strategy. The main contribution of this paper is the design of a real-time risk-sensitive nonlinear model predictive controller to plan the online cost-effective cruising velocity in a stochastic traffic environment. The basic idea is to measure the relevant states of the electric vehicle at runtime, and account for the road slopes, the upcoming curves, and the speed limit zones, as well as uncertainty in the preceding vehicle behavior to determine the energy-efficient velocity profile. Closed-loop Entropic Value-at-Risk as a coherent risk measure is introduced to quantify the risk involved in the system constraints violation. The obtained simulation and field experimental results demonstrate the effectiveness of the proposed method for a semi-autonomous electric vehicle in terms of safe and energy-efficient states regulation and constraints satisfaction. [less ▲]

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See detailAn Imperialist Competitive Algorithm for a Real-World Flexible Job Shop Scheduling Problem
Tessaro Lunardi, Willian UL; Voos, Holger UL; Cherri, Luiz Henrique

in 23rd IEEE International Conference on Emerging Technologies and Factory Automation, Torino, Italy, September 4-7, 2018 (2018, September)

Traditional planning and scheduling techniques still hold important roles in modern smart scheduling systems. Realistic features present in modern manufacturing systems need to be incorporated into these ... [more ▼]

Traditional planning and scheduling techniques still hold important roles in modern smart scheduling systems. Realistic features present in modern manufacturing systems need to be incorporated into these techniques. The real-world problem addressed here is an extension of flexible job shop scheduling problem and is issued from the modern printing and boarding industry. The precedence between operations of each job is given by an arbitrary directed acyclic graph rather than a linear order. In this paper, we extend the traditional FJSP solutions representation to address the parallel operations. We propose an imperialist competitive algorithm for the problem. Several instances are used for the experiments and the results show that, for the considered instances, the proposed algorithm is faster and found better or equal solutions compared to the state-of-the-art algorithms. [less ▲]

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See detailVulnerability Analysis of Cyber Physical Systems under False-Data injection and disturbance attacks
Gerard, Benjamin; Bezzaoucha, Souad UL; Voos, Holger UL et al

in Vulnerability Analysis of Cyber Physical Systems under False-Data injection and disturbance attacks (2018, September)

In the present paper, the problem of attacks on cyber-physical systems via networked control system (NCS) subject to unmeasured disturbances is considered. The geometric approach is used to evaluate the ... [more ▼]

In the present paper, the problem of attacks on cyber-physical systems via networked control system (NCS) subject to unmeasured disturbances is considered. The geometric approach is used to evaluate the security and vulnerability level of the controlled system. The presented work deals with the so-called false data injection attacks and shows how imperfectly known disturbances can be used to perform undetectable, or at least stealthy, attacks that can make the NCS vulnerable to attacks from malicious outsiders. A numerical example is given to illustrate the approach. [less ▲]

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See detailExperimental validation of adaptive control for a Shape Memory Alloy actuated lightweight robotic arm
Quintanar Guzman, Serket UL; Kannan, Somasundar UL; Voos, Holger UL et al

in ASME 2018 Conferences on Smart Materials, Adaptive Structures and Intelligent Systems, San Antonio 10-12 September 2018 (2018, September)

This article presents the experimental validation of a Direct Adaptive Control for angular position regulation of a lightweight robotic arm. The robotic arm is single degree-of-freedom (DOF) system ... [more ▼]

This article presents the experimental validation of a Direct Adaptive Control for angular position regulation of a lightweight robotic arm. The robotic arm is single degree-of-freedom (DOF) system, actuated by two Shape Memory Alloy (SMA) wires. The proposed adaptive control is capable of adapting itself to the hysteretic behavior of SMA wires and update its behavior to deal with the changing parameters of the material over time. The closed-loop approach is tested experimentally showing its effectiveness to deal with the highly nonlinear dynamics of the SMA wires. These results are discussed and compared with a classical control approach. The updated design and hardware development and modeling of the robotic arm are shown. [less ▲]

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See detailA Contribution to Cyber-Physical Systems Security: an Event-based Attack-tolerant Control Approach
Bezzaoucha, Souad UL; Voos, Holger UL

in Proceedings of 10th IFAC Symposium on Fault Detection, Supervision and Safety for Technical Processes, SAFEPROCESS 2018 (2018, August 29)

In the present paper, a model-based fault/attack tolerant scheme is proposed to deal with cyber-threats on Cyber Physicals Systems. A common scheme based on observers is designed and a state feedback ... [more ▼]

In the present paper, a model-based fault/attack tolerant scheme is proposed to deal with cyber-threats on Cyber Physicals Systems. A common scheme based on observers is designed and a state feedback control based on an event-triggered framework is given with control synthesis and condition on the switching time. An event-based implementation is proposed in order to achieve novel security strategy. Observer and controller gains are deduced by solving su cient Bilinear Matrix Inequality (BMI) condition. Simulation results on a real-time laboratory three tank system are given to show the attack-tolerant control ability despite data deception attacks on both actuators and sensors. [less ▲]

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See detailStochastic Optimum Energy Management for Advanced Transportation Network
Sajadi Alamdari, Seyed Amin UL; Voos, Holger UL; Darouach, Mohamed

in 15th IFAC Symposium on Control in Transportation Systems CTS 2018 (2018, July 19)

Smart and optimal energy consumption in electric vehicles has high potential to improve the limited cruising range on a single battery charge. The proposed concept is a semi-autonomous ecological advanced ... [more ▼]

Smart and optimal energy consumption in electric vehicles has high potential to improve the limited cruising range on a single battery charge. The proposed concept is a semi-autonomous ecological advanced driver assistance system which predictively plans for a safe and energy-efficient cruising velocity profile autonomously for battery electric vehicles. However, high entropy in transportation network leads to a challenging task to derive a computationally efficient and tractable model to predict the traffic flow. Stochastic optimal control has been developed to systematically find an optimal decision with the aim of performance improvement. However, most of the developed methods are not real-time algorithms. Moreover, they are mainly risk-neutral for safety-critical systems. This paper investigates on the real-time risk-sensitive nonlinear optimal control design subject to safety and ecological constraints. This system improves the efficiency of the transportation network at the microscopic level. Obtained results demonstrate the effectiveness of the proposed method in terms of states regulation and constraints satisfaction. [less ▲]

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See detailA Decoupling Approach to Design Observers for Polytopic Takagi-Sugeno Models Subject to Unknown Inputs
Bezzaoucha, Souad UL; Voos, Holger UL; Davila, Jorge et al

in Proceedings of the 2018 American Control Conference (2018, June 27)

A decoupling approach for state estimation of nonlinear systems represented in the polytopic Takagi-Sugeno with unmeasurable premise variables subject to unknown inputs is proposed in this paper. The idea ... [more ▼]

A decoupling approach for state estimation of nonlinear systems represented in the polytopic Takagi-Sugeno with unmeasurable premise variables subject to unknown inputs is proposed in this paper. The idea consists in defining a state and unknown input transformations in order to divide the state vector into two parts, a measurable part and an observable one (decoupled from the unknown input). A classical Luenberger observer to estimate the unmeasurable part is then designed and given in terms of Linear Matrix Inequalities (LMIs) conditions. A numerical example is also presented in order to illustrate the proposed approach. [less ▲]

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See detailCyber Security and Vulnerability Analysis of Networked Control System subject to False-Data injection
Gerard, Benjamin; Bezzaoucha, Souad UL; Voos, Holger UL et al

in Proceedings of the 2018 American Control Conference (2018, June 27)

In the present paper, the problem of networked control system (NCS) cyber security is considered. The geometric approach is used to evaluate the security and vulnerability level of the controlled system ... [more ▼]

In the present paper, the problem of networked control system (NCS) cyber security is considered. The geometric approach is used to evaluate the security and vulnerability level of the controlled system. The proposed results are about the so-called false data injection attacks and show how imperfectly known disturbances can be used to perform undetectable, or at least stealthy, attacks that can make the NCS vulnerable to attacks from malicious outsiders. A numerical example is given to illustrate the approach. [less ▲]

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See detailAn Extended Flexible Job Shop Scheduling Problem with Parallel Operations
Tessaro Lunardi, Willian UL; Voos, Holger UL

in ACM SIGAPP Applied Computing Review (2018), 18(2), 46-56

Traditional planning and scheduling techniques still hold important roles in modern smart scheduling systems. Realistic features present in modern manufacturing systems need to be incorporated into these ... [more ▼]

Traditional planning and scheduling techniques still hold important roles in modern smart scheduling systems. Realistic features present in modern manufacturing systems need to be incorporated into these techniques. Flexible job-shop scheduling problem (FJSP) is one of the most challenging combinatorial optimization problems. FJSP is an extension of the classical job shop scheduling problem where an operation can be processed by several different machines. In this paper, we consider the FJSP with parallel operations (EFJSP) and we propose and compare a discrete firefly algorithm (FA) and a genetic algorithm (GA) for the problem. Several FJSP and EFJSP instances were used to evaluate the performance of the proposed algorithms. Comparisons among our methods and state-of-the-art algorithms are also provided. The experimental results demonstrate that the FA and GA achieved improvements in terms of efficiency and efficacy. Solutions obtained by both algorithms are comparable to those obtained by algorithms with local search. In addition, based on our initial experiments, results show that the proposed discrete firefly algorithm is feasible, more effective and efficient than our proposed genetic algorithm for the considered problem. [less ▲]

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See detailTowards trajectory planning from a given path for multirotor aerial robots trajectory tracking
Sanchez Lopez, Jose Luis UL; Olivares Mendez, Miguel Angel UL; Castillo Lopez, Manuel UL et al

in 2018 International Conference on Unmanned Aircraft Systems (ICUAS), Dallas 12-15 June 2018 (2018, June)

Planning feasible trajectories given desired collision-free paths is an essential capability of multirotor aerial robots that enables the trajectory tracking task, in contrast to path following. This ... [more ▼]

Planning feasible trajectories given desired collision-free paths is an essential capability of multirotor aerial robots that enables the trajectory tracking task, in contrast to path following. This paper presents a trajectory planner for multirotor aerial robots carefully designed considering the requirements of real applications such as aerial inspection or package delivery, unlike other research works that focus on aggressive maneuvering. Our planned trajectory is formed by a set of polynomials of two kinds, acceleration/deceleration and constant velocity. The trajectory planning is carried out by means of an optimization that minimizes the trajectory tracking time, applying some typical constraints as m-continuity or limits on velocity, acceleration and jerk, but also the maximum distance between the trajectory and the given path. Our trajectory planner has been tested in real flights with a big and heavy aerial platform such the one that would be used in a real operation. Our experiments demonstrate that the proposed trajectory planner is suitable for real applications and it is positively influencing the controller for the trajectory tracking task. [less ▲]

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See detailA Mathematical Model and a Firefly Algorithm for an Extended Flexible Job Shop Problem with Availability Constraints
Tessaro Lunardi, Willian UL; Cherri, Luiz Henrique; Voos, Holger UL

in 17th International Conference on Artificial Intelligence and Soft Computing, Zakopane, Poland, June 3-7, 2018 (2018, June)

Manufacturing scheduling strategies have historically ignored the availability of the machines. The more realistic the schedule, more accurate the calculations and predictions. Availability of machines ... [more ▼]

Manufacturing scheduling strategies have historically ignored the availability of the machines. The more realistic the schedule, more accurate the calculations and predictions. Availability of machines will play a crucial role in the Industry 4.0 smart factories. In this paper, a mixed integer linear programming model (MILP) and a discrete firefly algorithm (DFA) are proposed for an extended multi-objective FJSP with availability constraints (FJSP-FCR). Several standard instances of FJSP have been used to evaluate the performance of the model and the algorithm. New FJSP-FCR instances are provided. Comparisons among the proposed methods and other state-of-the-art reported algorithms are also presented. Alongside the proposed MILP model, a Genetic Algorithm is implemented for the experiments with the DFA. Extensive investigations are conducted to test the performance of the proposed model and the DFA. The comparisons between DFA and other recently published algorithms shows that it is a feasible approach for the stated problem. [less ▲]

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See detailModel Predictive Control for Aerial Collision Avoidance in Dynamic Environments
Castillo Lopez, Manuel UL; Sajadi Alamdari, Seyed Amin UL; Sanchez Lopez, Jose Luis UL et al

in 26th Mediterranean Conference on Control and Automation (MED), Zadar, Croatia, 19-22 June 2018 (2018, June)

Autonomous navigation in unknown environments populated by humans and other robots is one of the main challenges when working with mobile robots. In this paper, we present a new approach to dynamic ... [more ▼]

Autonomous navigation in unknown environments populated by humans and other robots is one of the main challenges when working with mobile robots. In this paper, we present a new approach to dynamic collision avoidance for multi-rotor unmanned aerial vehicles (UAVs). A new nonlinear model predictive control (NMPC) approach is proposed to safely navigate in a workspace populated by static and/or moving obstacles. The uniqueness of our approach lies in its ability to anticipate the dynamics of multiple obstacles, avoiding them in real-time. Exploiting active set algorithms, only the obstacles that affect to the UAV during the prediction horizon are considered at each sample time. We also improve the fluency of avoidance maneuvers by reformulating the obstacles as orientable ellipsoids, being less prone to local minima and allowing the definition of a preferred avoidance direction. Finally, we present two real-time implementations based on simulation. The former demonstrates that our approach outperforms its analog static formulation in terms of safety and efficiency. The latter shows its capability to avoid multiple dynamic obstacles. [less ▲]

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See detailAdaptive control for a lightweight robotic arm actuated by a Shape Memory Allow wire
Quintanar Guzman, Serket UL; Kannan, Somasundar UL; Voos, Holger UL et al

in 16th International Conference on New Actuators, Bremen 25-27 June 2018 (2018, June)

This paper presents the design, model and closed-loop control of a single degree-of-freedom (DOF) lightweight robotic arm actuated by a biased Shape Memory Alloy (SMA) wire. The highly non-linear dynamics ... [more ▼]

This paper presents the design, model and closed-loop control of a single degree-of-freedom (DOF) lightweight robotic arm actuated by a biased Shape Memory Alloy (SMA) wire. The highly non-linear dynamics of SMAs represent a challenge for control tasks, due to phenomena as hysteresis or parameters uncertainty. With this in mind, we propose a control capable to adapt itself to the hysteretic behavior and update its behavior to deal with the changing parameters of the material over time. An adaptive control for position regulation is presented. This control includes a set of techniques, providing a systematic way to adjust the control parameters in real time, so maintaining the stability of the system and a desired performance, while dealing with parameter and model uncertainties. The closed-loop approach is tested in experimentally showing its effectiveness to deal with the highly non-linear dynamics of the SMA wire. [less ▲]

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See detailCollision Avoidance Effects on the Mobility of a UAV Swarm Using Chaotic Ant Colony with Model Predictive Control
Dentler, Jan Eric UL; Rosalie, Martin UL; Danoy, Grégoire UL et al

in Journal of Intelligent \& Robotic Systems (2018)

The recent development of compact and economic small Unmanned Aerial Vehicles (UAVs) permits the development of new UAV swarm applications. In order to enhance the area coverage of such UAV swarms, a ... [more ▼]

The recent development of compact and economic small Unmanned Aerial Vehicles (UAVs) permits the development of new UAV swarm applications. In order to enhance the area coverage of such UAV swarms, a novel mobility model has been presented in previous work, combining an Ant Colony algorithm with chaotic dynamics (CACOC). This work is extending CACOC by a Collision Avoidance (CA) mechanism and testing its efficiency in terms of area coverage by the UAV swarm. For this purpose, CACOC is used to compute UAV target waypoints which are tracked by model predictively controlled UAVs. The UAVs are represented by realistic motion models within the virtual robot experimentation platform (V-Rep). This environment is used to evaluate the performance of the proposed CACOC with CA algorithm in an area exploration scenario with 3 UAVs. Finally, its performance is analyzed using metrics. [less ▲]

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See detailA Real-Time 3D Path Planning Solution for Collision-Free Navigation of Multirotor Aerial Robots in Dynamic Environments
Sanchez Lopez, Jose Luis UL; Wang, Min UL; Olivares Mendez, Miguel Angel UL et al

in Journal of Intelligent and Robotic Systems (2018)

Deliberative capabilities are essential for intelligent aerial robotic applications in modern life such as package delivery and surveillance. This paper presents a real-time 3D path planning solution for ... [more ▼]

Deliberative capabilities are essential for intelligent aerial robotic applications in modern life such as package delivery and surveillance. This paper presents a real-time 3D path planning solution for multirotor aerial robots to obtain a feasible, optimal and collision-free path in complex dynamic environments. High-level geometric primitives are employed to compactly represent the situation, which includes self-situation of the robot and situation of the obstacles in the environment. A probabilistic graph is utilized to sample the admissible space without taking into account the existing obstacles. Whenever a planning query is received, the generated probabilistic graph is then explored by an A$^{\star}$ discrete search algorithm with an artificial field map as cost function in order to obtain a raw optimal collision-free path, which is subsequently shortened. Realistic simulations in V-REP simulator have been created to validate the proposed path planning solution, integrating it into a fully autonomous multirotor aerial robotic system. [less ▲]

Detailed reference viewed: 73 (4 UL)