International Journal of Digital Signals and Smart Systems (12 papers in press)
Third order sliding mode control of a medical robot for tele-echography
by Amina Jribi
Abstract: This paper deals with the control problem of robotic manipulators, which are always subject to nonlinear uncertainties. In particular, a dynamic system with fast actuators is exposed to many disrupting risks, generally induced by the presence of parametric uncertainties and unmoderated dynamics. So the dynamic model becomes highly nonlinear, which requires the use of a robust stabilizing control. In this context, we propose a solution based on the third order Sliding Mode Control (SMC) approach, in order to ensure a performant trajectory tracking motion control for a medical task. The proposed controller is expected to remove the standard sliding mode restrictions, to provide for a higher accuracy and robustness in realization with respect to the current existence of imperfections. Simulation results confirm the effectiveness of the proposed third order SMC design with respect to disturbances, mainly affecting control systems.
Keywords: Trajectory tracking; third order sliding mode controller; manipulator robots; medical task; disturbances.
Robust Fault Detection and Accommodation for Stochastic Systems based on Adaptive Threshold
by Marwa Houiji, Rim Hamdaoui, Mohamed Aoun
Abstract: This paper treats the problem of sensor and actuator fault detection and accommodation for a linear stochastic systems subjected to unknown disturbances. A bank of Augmented Robust Three stage Kalman filters (ARThSKF) is adapted to estimate both the state and the fault as well as to generate the residuals. Besides this paper presents the evaluation of the residuals with Bayes test of binary hypothesis test for fault detection to adaptive threshold compared with fixed threshold. This test allows the detection of low magnitude faults as fast as possible with a minimum risk of errors, which reduces the probability of non detection and false alarm probability. Moreover, the result given by the fault detection and diagnosis part are then used by the Fault Accommodation (FA) that tolerates the faults and compensates its effects on the system behaviour.
Keywords: Fault Detection; Sensor and actuator failures; Stochastic Systems; Detection delay,
Adaptive Threshold; Fault accommodation.
Robust Fault Detection Based on Bond Graph UIO Observer
by Ghada Saoudi
Abstract: Motivated by recent concerns in building a totally graphical unknown
input observer (UIO), a bond graph approach to design an UIO observer for
linear systems with unknown inputs is reevaluated in this paper. By using the
Bond graph methodology and the geometric theory as the main tools, a simple
and systematic design procedure is depicted. Compared with the classical UIO
design, the built observer is a none other than the famous Luenberger observer
but with higher freedom degree that ensures the decoupling of the disturbance
and the estimation error. In the past, it was believed that the method is valid for
control purpose. Here, a new result is obtained, namely that the method is valid
also for robust fault detection purpose. On the other hand, the method is found
with no previous simulation results. In this paper, a proof with simulations results
on an electromechanical system will show the performance of the approach.
Keywords: Unknown Input Observer; Bond Graph; Geometric Approach; Robust Fault detection.
A Speed Sensor Fault Tolerant Control for Electrical Vehicle System
by Moussa Boukhnifer
Abstract: In this paper, we propose an experimental study for hybrid voting algorithm based on observer and robust control design for two mechanical sensor faults. The proposed strategy is applied for the induction motor speed drive of electrical vehicle powertrain. To adopt the best performance method for electrical vehicle application, we illustrate the effectiveness of the hybrid voting algorithm approach with the New European Driving Cycle (NEDC) speed profile. The experimental results demonstrate the effectiveness of the proposed Input/Output FTC architecture.
Keywords: Fault Tolerant Control; Induction Motor; Electric Vehicle; Sliding Mode; Voting Algorithm.
Sensor fault detection in nonlinear system using threshold estimation
by NORA KACIMI
Abstract: In this paper, an advanced study of fault diagnosis by using real data signal system. This study is online and fast application for fault diagnosis sensors. The diagnosis involves respectively two steps: fault detection and fault localization. An online fault detection approach for an experimental three tanks system is developed. This approach is based on real time signal and statistical analysis. We used the standard deviation and the mean value of several independent experimental repeated in the normal state and under the same conditions for estimating threshold of fault detection. Then, the acquisition of signal data test in real time is used to validate this threshold estimation. Also, in this research work, a proposed technique of fault detection is implemented and validated experimentally in prototype of three tanks laboratory.
Keywords: Fault detection,statistical analysis,adaptive threshold,fault sensor,three tanks system.
Adaptive Neural Super Twisting Controller Based on Terminal Sliding Mode and Time Delay Estimation Method for Robotic Manipulator.
by Amar Rezoug, Mustapha Hamerlain
Abstract: In this paper a robust control approach based on sliding mode theory and artificial neural network technique was proposed for trajectory tracking mode of n-DOF robot manipulator. Time delay estimation method and Nonsingular terminal sliding mode control were used to design the nominal control part of the sliding mode control without any knowledge about the robot model. Super twisting algorithm was designed using radial based function neural networks to replace the discontinuous control part. In order to test the effectiveness of the proposed approach, it was applied to 2-DOF robotic manipulator and compared with a classical approach.
Keywords: Terminal Sliding Mode; neural networks; Super Twisting; Time Delay Estimation.
CONTROLLING SCHEMES IN DIGITAL LOAD SIDE TRANSMISSION SYSTEM FOR INTELLIGENT LIGHTING
by T. Yuvaraja, K. Ramya, Mathudevan V
Abstract: This manuscript deals with the DLT compatible control devices in intelligent lighting systems with high output power in the designed converter. The presented methodology deals with two-wire bound power line communication. The presented topology works without a neutral wire connection and is hence applicable to all typical house installations lacking a neutral wire at the light switch lead-out and is an excellent solution for providing continuous operation of a DLT control device with WiFi, even if half waves of mains are missing or short blackouts of several half waves. DLT control devices can be embedded in a smart home environment, which is a unique feature enabled by the proposed power supply concept.
Keywords: Light Emitting Diode; Digital Load Transmission; Low Current.
Fast detection control for fault-tolerant converter back-to-back with redundancy leg supplying an induction motor drives
by Khaled Sahraoui, Bachir GAOUI, Lakhdar MOKRANI, Kelthoum BELARBI
Abstract: The purpose of this paper is the study of fault tolerant control with pulse large modulation (PWM) AC-DC-AC converter for supplying a three-phase rotor field oriented induction motor. The back to back converter is supplied with three-phase network and composed of a PWM rectifier and a voltage source inverter. Fault tolerant topology of AC-DC-AC converter with redundancy have been studied and associated with affective and fast method of fault detection and compensation to guarantee the continuity of service, in the presence of an open circuit failure possibility on the level of one of their legs. Although of the presence of open circuit on the level of the converter legs, the obtained simulation results show that the proposed method has the ability to maintain the good performance of the drive.
Keywords: Asynchrouns machine; Converter with redundant leg; Field oriented control; Service Continuity; sigma-delta PWM; Three-phase AC-DC-AC converter.
Iris recognition: using a Statistical Models of Shape and Spatial Relation for effective segmentation
by Houda Khmila
Abstract: This paper presents a new segmentation method based both on Active Shape Model (ASM) and spatial distance model to segment iris structures. The extracted iris is normalized by Daugmans Rubber Sheet model. Then the feature are extracted by the 1D Log Gabor Filter, afterwards The Hamming distance is used to compare the binary codes stored previously. The evaluation experiments are performed on a set of 300 right iris images from 41 persons of CASIA-IrisV4 database. We obtain a correct recognition rate of 100%. The experimental results have shown that the performance of the proposed approach is encouraging
Keywords: Biometrics; iris recognition; segmentation; ASM+D; identification.
Control Design and Sensors Fault Tolerant for Vehicle Dynamics
by Naoufal El Youssfi, Mohammed Oudghiri, Rachid El Bachtiri
Abstract: This paper presents a control approach based on the state feedback estimated by the observer. It also offers a method of detection and isolation of sensor defects (FDI), which is based on a bank of observers in order to apply a fault tolerant control strategy (FTC) to the lateral and roll dynamics of the vehicle represented by the fuzzy model of Takagi-Sugeno (TS). This approach makes it possible to preserve the stability of the vehicle despite the presence of sensor defects; based on the Lyapunov approach, the observer and controller designs were formulated as linear matrix inequalities (LMI); the simulation results clearly show the importance and effectiveness of the proposed strategy.
Keywords: Takagi Sugeno (TS) Fuzzy model; observer bank; controller; LMI; FTC; FDI; vehicle lateral dynamics.
Massively Parallel Hybrid Algorithm on Embedded Graphics Processing Unit for Unmanned Aerial Vehicle Path Planning
by Vincent Roberge
Abstract: To operate autonomously, military unmanned aerial vehicles (UAVs) must be equipped with a path planning module capable of calculating feasible trajectories. This is a highly complex and non-linear optimization problem that challenges state of the art methods. In this paper, we present a massively parallel hybrid algorithm to solve the path planning problem for fixed-wing military UAVs. The proposed solution combines the strengths of the genetic algorithm and the particle swarm optimization and allows for the calculation of quasi-optimal paths in realistic 3D environments. To reduce the execution time, the proposed algorithm is parallelized on the NVIDIA Jetson TX1 embedded graphics processing unit (GPU). By exploiting the parallel architecture of the GPU, the runtime is reduced by a factor of 23.6x to just 4.3 seconds while requiring only 10 Watts, making it an excellent solution for on-board path planning. The proposed system is tested in a simulation using 18 scenarios on 6 different terrains.
Keywords: hybrid metaheuristic; genetic algorithm; graphics processing units; NVIDIA Jetson TX1; particle swarm optimization; path planning; parallel computing; unmanned aerial vehicle.
Fractional PID Controller design for Nonlinear Systems based on Singular Perturbation Technique.
by Mohamed Lazhar WARDI, Messaoud AMAIRI, Mohamed Naceur ABDELKRIM
Abstract: This paper deals with the output regulation of nonlinear control systems in order to guarantee desired performances in the presence of plant parameters variations and external disturbances. The proposed control law structures are based on the fractional order PI (FOPI) and PID (FOPID) control schemes. By introducing the two-time-scale notions in the closed-loop system, the presented design methodology of fractional PID control guarantees desired transients. Then, the singular perturbations technique is used to analyze the closed-loop system properties and to get explicit expressions for evaluation of the controller parameters. The tuning of the controller parameters is based on a constrained optimization algorithm. Simulation examples are presented to show the effectiveness of the proposed method.
Keywords: Fractional order controller; Nonlinear Systems; Singular Perturbations Technique; Robustness.