Adaptive Fuzzy Fault Tolerant Control Using Dynamic Sliding Mode

Abstract

In this paper, an actuator fault tolerant control (FTC) has been designed using dynamic sliding mode control (DSMC) for single input nonlinear systems which are affected from uncertainty. In DSMC the switching of input control signal is removed due to the integrator which is placed before the input control signal of the plant hence, its result is reducing of chattering. However, in DSMC the augmented system (the system plus the integrator) is one dimension bigger than the actual system and then, the plant model should be completely known. To overcome on this problem, an adaptive fuzzy observer (AFO) has been proposed. Finally, we show the combination result of DSMC and AFO is the compensation of the fault by input control signal of the plant, while the performance and robustness of the closed loop system are reserved. The main property of the proposed approach is its simplicity and we only use system output for FTC and moreover, the fault diagnosis (detection, isolation and reconstruction) is done at the same time. The upper bound of the uncertainty is not used in DSMC and AFO, which is important in practical implementation. Simulation results show the advantages of the proposed approach.