Application of passivity and cascade structure to robust control against loss of actuator effectiveness (original) (raw)

Stability of fault tolerant control systems driven by actuators with saturation

A Fault Tolerant Control System (FTCS) model subject to random faults and saturation in actuators is developed. Actuators are assumed to have non-linear saturation characteristics, they operate linearly within their limits and saturate to fixed levels if any limit is exceeded. This paper derives sufficient conditions for the exponential stability in the mean square for a FTCS with saturated actuators using Lyapunov's second method. Sufficient conditions involve the solution of Riccati-like matrix equations. An algorithm to investigate the stability of the FTCS is constructed. Stability of other control models driven by actuators with saturation can be established as interesting special cases of this work. Theoretical results are illustrated by a numerical example.

A novel active fault tolerant control design with respect to actuators reliability

IEEE Conference on Decision and Control and European Control Conference, 2011

In this paper, actuators reliability analysis is considered in the design of active fault tolerant control system. The main objective consists on the synthesis of a fault tolerant controller gain which guarantees a highest overall system reliability. Benefit of incorporating reliability indicators on the controller gain design is to manage effectively the control inputs in order to increase the remaining life time of a system in the presence of faults. A reliability analysis of system modeled by a state space representation is proposed. A controller gain design is reformulated as an Linear Matrix Inequality (LMI) problem and synthesized through an effective admissible model matching approach.

Active fault tolerant control for nonlinear systems with simultaneous actuator and sensor faults

International Journal of Control, Automation and Systems, 2013

The goal of this paper is to describe a novel fault tolerant tracking control (FTTC) strategy based on robust fault estimation and compensation of simultaneous actuator and sensor faults. Within the framework of fault tolerant control (FTC) the challenge is to develop an FTTC design strategy for nonlinear systems to tolerate simultaneous actuator and sensor faults that have bounded first time derivatives. The main contribution of this paper is the proposal of a new architecture based on a combination of actuator and sensor Takagi-Sugeno (T-S) proportional state estimators augmented with proportional and integral feedback (PPI) fault estimators together with a T-S dynamic output feedback control (TSDOFC) capable of time-varying reference tracking. Within this architecture the design freedom for each of the T-S estimators and the control system are available separately with an important consequence on robust L 2 norm fault estimation and robust L 2 norm closed-loop tracking performance. The FTTC strategy is illustrated using a nonlinear inverted pendulum example with time-varying tracking of a moving linear position reference.

A simultaneous stabilization approach to (Passive) fault tolerant control

Proceedings of the American Control Conference, 2004

Absfracf-This paper discusses the problem of designing fault tolerant compensators that stabilize a given system both in the nominal situation, as well as in the situation where one of the sensors or one of the actuators has failed. It is shown that such compensators always exist, provided that the system is detectable from each output and that it is stabilizable. The proof of this result is constructive. A family of second order systems is described that requires fault tolerant compensators of arbitrarily high order.

Application of absolute stability theory to robust control against loss of actuator effectiveness

IET Control Theory & Applications, 2009

The problem studied here is passive fault tolerant control (FTC) for actuator faults as a result of loss of effectiveness. This FTC problem is formulated in the 'absolute stability theory framework'. Based on this formulation, different tools from absolute stability theory are applied. Four controllers are proposed for four problem settings: (a) LTI certain plants, (b) uncertain LTI plants, (c) LTI models with input saturations and (d) non-linear affine single-input plants. The proposed controllers are tested on the hovercraft numerical example.

Fault tolerant control for nonlinear systems described by Takagi-Sugeno models

2010

ABSTRACT: In this paper the problem of active fault tolerant control (FTC) in noisy systems is studied. The proposed FTC strategy is based on the known of the fault estimate and the error between the faulty system state and a reference system state. A proportional integral observer is used in order to estimate the state and the actuator faults. The obtained results are then extended to nonlinear systems described by nonlinear Takagi-Sugeno models.

Fault-Tolerant Control System Design for Nonlinear System with Actuator Faults

Proceedings of International Conference on Artificial Life and Robotics, 2022

This article deals with observer-based integrated robust fault estimation and accommodation design problems for nonlinear system. The environmental disturbance torque, actuator faults, sensor faults and model uncertainties are considered. Firstly, we propose the augmented fault estimation observer (AFEO) to guarantee the convergence of H∞ performance index of fault estimation and to restrict the influence of uncertainties with respect to the fault estimation error as well. We then design the fault accommodation which is based on the dynamic output feedback to keep the stability of the closed-loop system while malfunctioning. AFEO and dynamic output feedback fault tolerant controller (DOFFTC) are separately designed. Their performances are separately considered. Finally, we propose a simulation result of the micro-satellite attitude control system to demonstrate the effectiveness of the presenting method.

Design of passive fault-tolerant flight controller against actuator failures

Chinese Journal of Aeronautics, 2015

The problem of designing passive fault-tolerant flight controller is addressed when the normal and faulty cases are prescribed. First of all, the considered fault and fault-free cases are formed by polytopes. As considering that the safety of a post-fault system is directly related to the maximum values of physical variables in the system, peak-to-peak gain is selected to represent the relationships among the amplitudes of actuator outputs, system outputs, and reference commands. Based on the parameter dependent Lyapunov and slack methods, the passive fault-tolerant flight controllers in the absence/presence of system uncertainty for actuator failure cases are designed, respectively. Case studies of an airplane under actuator failures are carried out to validate the effectiveness of the proposed approach.

A design method for fault adaptation with actuators saturations avoidance

issi.uz.zgora.pl

In this paper, a new approach of reconfigured system is proposed to improve the performance of an active fault tolerant control system. The method is based on model predictive control and reference trajectory adjustment techniques. When an actuator fault occurs in the system, the controller balances to the nearest degraded reference trajectory. A constraint set and cost function are established to avoid actuators saturation and reduce control energy spent in closed loop dynamics. The effectiveness of the proposed method has been illustrated using a hydrothermal system subject to actuator failure and constraints on the actuator dynamic ranges. Satisfactory results have been obtained.

New fault tolerant control strategy for nonlinear systems with multiple model approach

2010

Abstract—This paper addresses a new methodology to con-struct a fault tolerant control (FTC) in order to compensate actuator faults in nonlinear systems. This approach is based on the representation of the nonlinear model with a multiple model under Takagi-Sugeno's form. The proposed control requires a simultaneous estimation of the system states and of the occurring actuator faults.