Failure Compensation for Nonlinear Systems

Abstract

The adaptive actuator failure compensation problem has been addressed so far for linear systems with actuator failures characterized by inputs stuck at some values fixed or variant not influenced by control action. Both the failure patterns and the failure parameters including failure values and failure time are assumed unknown. However, most real-life systems are nonlinear dynamic systems, for example, aircraft flight control systems. Actuator failure compensation for nonlinear systems is an area of major interest. In the following chapters we further our research to several classes of nonlinear systems, whose dynamics can be transformed into some canonical forms that are subject to actuator failures. A key issue of direct adaptive control is the parametrization of the nonlinear system with actuator failures and the applied feedback control scheme for a given control objective under certain matching conditions. Based on a suitable parametrization, an adaptive scheme can be used to update the controller parameters for the case when the plant parameters and actuator failure parameters are both unknown.