A Design of Fault-tolerant Adaptive Control with External Signal Injection for Input-redundant Linear Plant

Abstract

In this paper, we propose a design of the fault tolerant adaptive control system for the input redundant linear plants which has m input channels with model reference adaptive control scheme. A feature of the proposed control system is to introduce the adaptive allocator which distributes and injects external signals into the plant. We derive adaptive law which ensures stability of output of the plant which has up to (m − 1) faults, using a suitable Lyapunov function. Through a numerical simulation, we show the stability and fault-tolerance of the designed MRAC.

Active fault-diagnosis method using adaptive allocator and fault-tolerant adaptive control system design

“…1. The new approach to the AFD for the input redundant plant which utilizes the adaptive test signal allocator in the control system [29] was proposed. 2.…”

“…In this section, we describe the design of an fault-tolerant adaptive control system with an adaptive allocator for testsignal injection and actuator faults [29]. For the system design, we considered the following assumptions:…”

“…We now define the following 2D vectors, Substituting the elements in (26) by the inner products of these vectors, The Eq. (29) indicates that the coefficients from test signals to the control effort can be represented using 2D allocators ᾱ 1 , ᾱ 2 , and ᾱ 3 .…”

“…We propose a new AFD method with input redundancy in this paper based on the, and design a control system proposed in the literature [29] to implement it in this paper. In the literature [29], we have designed an adaptive control system that guarantees reference model tracking while applying arbitrary bounded test signals for the input redundant system with unknown parameters. A feature of the proposed AFD method is adaptive allocation of the test signals in the control system.…”

“…The proposed control system design for the faulty model is based on the model reference adaptive control (MRAC) technique. In "Fault-tolerant adaptive control design with adaptive allocator" section, we show the derivation of the adaptive law for the controller and allocator using a suitable Lyapunov function [29]. The adaptive laws of the adaptive allocator and controller are derived by using a suitable Lyapunov function, in "Fault-tolerant adaptive control design with adaptive allocator" section.…”