Almost fault‐tolerant tracking

Abstract

SummaryA new formulation of the problem of almost fault‐tolerant perfect tracking in presence of disturbances is presented, and necessary and sufficient existence conditions are found, as well as a controller, which consists of a feedback block and two feedforward blocks. The feedback block is aimed for almost disturbance and fault decoupling, and the feedforward blocks are aimed for almost perfect tracking. A two‐step control design procedure such that the feedback block is designed independently of the feedforward blocks is presented. In order to simplify the necessary and sufficient existence conditions, as well as to present a physical interpretation of the existence conditions, the dimension of disturbance and fault vectors is reduced. In order to find a feedback controller, the physical interpretation of the existence conditions is used so that the four‐block‐type problem is transformed to a two‐block‐type problem. Examples are given, which illustrate that the controller of the article is practically realizable.