Adaptive fault-tolerant output-feedback H∞ controller design for systems with saturation nonlinear

This paper is concerned with the adaptive reliable H_∞ output-feedback controlling problem against actuator failures for linear time-invariant systems with actuator saturation. The disturbance tolerance ability of the closed-loop system is measured by an optimal index. A notion of adaptive H_∞ performance index is proposed to describe the disturbance attenuation performances of closed-loop systems. By combining the linear matrix inequality (LMI) approach for output-feedback controllers design and adaptive method, a method of designing adaptive reliable output-feedback controllers is proposed, where the controller parameter matrices are updated automatically to compensate the controller failures effects on systems based on the online estimations of eventual faults. The designs are developed in the framework of LMI approach, which can guarantee the disturbance tolerance ability and adaptive H_∞ performances of closed-loop systems in the cases of actuator saturation and actuator failures. An example is given to illustrate the efficiency of the design method.