Djamel Boukhetala

Sliding Modes for Fault Tolerant Control

As modern technological systems increase in complexity, their corresponding control systems become more and more sophisticated. In order to increase the reliability, which is crucial topic in industrial applications. The main focus of this chapter will be on the design of fault tolerant control (FTC) strategy. Therefore, FTC has found extensive applications in multiple domains including mechanical engineering, electrical engineering, control engineering, biomedical engineering, and micro-engineering. This chapter gives a brief overview in the field of FTC (definitions, practical requirements and classification). On the other hand, give a brief introduction to the concept of sliding mode control and examine its properties. Sliding surface design and tracking requirements are also discussed. In many ways, this chapter demonstrates the true theoretical and applications depth to which the sliding mode control paradigm has been developed today in the fields of FTC. Also, highlights the benefits and give discussions of some FTC approaches based SMC. At the end, in order to introduce the concept and to prove the effectiveness of the proposed approach a permanent magnet synchronous motor (PMSM) systems case study will be presented.

Sliding mode based fault detection, reconstruction and fault tolerant control scheme for motor systems.

The fault-tolerant control problem belongs to the domain of complex control systems in which inter-control-disciplinary information and expertise are required. This paper proposes an improved faults detection, reconstruction and fault-tolerant control (FTC) scheme for motor systems (MS) with typical faults. For this purpose, a sliding mode controller (SMC) with an integral sliding surface is adopted. This controller can make the output of system to track the desired position reference signal in finite-time and obtain a better dynamic response and anti-disturbance performance. But this controller cannot deal directly with total system failures. However an appropriate combination of the adopted SMC and sliding mode observer (SMO), later it is designed to on-line detect and reconstruct the faults and also to give a sensorless control strategy which can achieve tolerance to a wide class of total additive failures. The closed-loop stability is proved, using the Lyapunov stability theory. Simulation results in healthy and faulty conditions confirm the reliability of the suggested framework.

Particle swarm optimization based fuzzy sliding mode controller for the Twin Rotor MIMO system

In this paper, the application of Particle Swarm Optimization (PSO) on the optimization of the membership functions and the sliding surface constants of the decentralized fuzzy sliding mode controller (FSMC) is presented. This technique is used in order to find an optimal, decentralized, intelligent controller for a nonlinear aerodynamic, Twin Rotor Multi-input, multi-output System (TRMS). Simulation results show the effectiveness of this optimization method. The controller design demonstrates a very good accuracy and a very good response time compared to a PID controller designed using the same method.

PASSIVITY-BASED CONTROLLER– OBSERVER FOR ROBOT MANIPULATORS

This paper deals with the velocity-observer based controller to solve the trajectory tracking problem for rigid robot manipulators, without using the velocity measurement. A remarkable feature of this observer-controller is that it originates from energy reshaping arguments, by analogy with the passivity-based methodology to robot control. Under assumption that the velocities are bounded, it is shown that the whole control system (robot plus controller plus observer) is semi-global asymptotically stable, and an estimate region of attraction is also given. Finally, simulation results on two-link manipulator are provided to illustrate the effectiveness of the controller-observer.

New robust model reference adaptive control for induction motor drives using a hybrid controller

One of the most recent and most intense efforts in control theory deals with handling systems whose behavior of interest is determined by interacting continuous and discrete dynamics. This approach can be applied not only to intrinsic hybrid processes but also to other systems as for example continuous processes with supervisory logic, multi-model control systems, switching control, etc. In this paper we describe a framework for hybrid adaptive control of induction motor which involves logic-based switching among a family of candidate controllers. The importance of the hybrid controller is demonstrated by experimental results. It is shown that the presented hybrid controller for IM drive has fast tracking capability, less steady state error and is robust to load disturbance. The complete speed control scheme of the IM drive incorporating the hybrid control is experimentally implemented and validated for a prototype 1.5 kW IM.

Passivity-based controller-observer for robot manipulators

This paper deals with the velocity-observer based controller to solve the trajectory tracking problem for rigid robot manipulators, without using the velocity measurement. A remarkable feature of this observer-controller is that it originates from energy reshaping arguments, by analogy with the passivity-based methodology to robot control. Under assumption that the velocities are bounded, it is shown that the whole control system (robot plus controller plus observer) is semi-global asymptotically stable, and an estimate region of attraction is also given. Finally, simulation results on two-link manipulator are provided to illustrate the effectiveness of the controller-observer.

Modeling and control of series resonant converter for high voltage applications

Most industrial processes that use electricity as a source of voltage or current, require power circuit for the control of its physical quantities. Power converters are a multi-site privileged in the control of high power systems. In this article we show that the series resonant DC/DC converter, which is a hybrid system. The SRC achieves an output DC voltage equal to n times the input voltage of the converter, the major disadvantage of this type of converter is the the stresses on the power components and Capacitor Charge Time. Furthermore, a control strategy for minimizing the no-load conduction losses is proposed and the transient behavior in case of load steps including output short-circuit is discussed based on digital simulations.

A novel global Harmony Search method based on Ant Colony Optimisation algorithm

The Global-best Harmony Search (GHS) is a stochastic optimisation algorithm recently developed, which hybridises the Harmony Search (HS) method with the concept of swarm intelligence in the particle swarm optimisation (PSO) to enhance its performance. In this article, a new optimisation algorithm called GHSACO is developed by incorporating the GHS with the Ant Colony Optimisation algorithm (ACO). Our method introduces a novel improvisation process, which is different from that of the GHS in the following aspects. (i) A modified harmony memory (HM) representation and conception. (ii) The use of a global random switching mechanism to monitor the choice between the ACO and GHS. (iii) An additional memory consideration selection rule using the ACO random proportional transition rule with a pheromone trail update mechanism. The proposed GHSACO algorithm has been applied to various benchmark functions and constrained optimisation problems. Simulation results demonstrate that it can find significantly better solutions when compared with the original HS and some of its variants.

A geometric approach for fault detection and isolation of stator short circuit failure in a single asynchronous machine

This paper deals with the problem of detection and isolation of stator short-circuit failure in a single asynchronous machine using a geometric approach. After recalling the basis of the geometric approach for fault detection and isolation in nonlinear systems, we will study some structural properties which are fault detectability and isolation fault filter existence. We will then design filters for residual generation. We will consider two approaches: a two-filters structure and a single filter structure, both aiming at generating residuals which are sensitive to one fault and insensitive to the other faults. Some numerical tests will be presented to illustrate the efficiency of the method.

Decoupled sliding mode with type 2 fuzzy-neural network controller for multi-machine power systems

In this paper, we propose a decoupled sliding mode with type 2 fuzzy neural network control scheme that has the ability to enhance the transient stability and achieve voltage regulation of on a two-generator infinite bus power system. The design of this controller involves the direct feedback linearization (DFL) technique and the sliding mode (SM) control theory. In this approach, the whole system is decoupled into two subsystems and the state response of each subsystem can be designed to be governed by a corresponding sliding surface. Then a hierarchical sliding mode control approach is designed. The main drawback of SMC is the calculation of equivalent control. To construct the equivalent control law, an adaptive type 2 fuzzy neural network controller is used to approximate the unknown parts of the system. The stability of the closed-loop system is proved mathematically based on the Lyapunov method. Simulation results illustrate the performance of the developed approach regardless of the system operating conditions.