Sliding mode for detection and accommodation of computation time delay fault

Computation time delay in digital control systems reduces its robustness as well as degrades its performance. In this paper, the computation time delay is assumed to be constant and smaller than the sampling time and is treated as a fault to be detected, using an appropriate controller to minimize its effects. Thus, a discrete-time sliding mode control that improves the systems' performance when a Computation time delay fault is found is proposed herein. A robust sliding mode observer-based is used to generate the residuals. Using the accumulated residual functions, a new scheme for fault detection and for controller adaptation is proposed. The technique is used to control a Rotary Motion Inverted Pendulum System to illustrate the design procedures and the effectiveness of the method. (C) 2009 IMACS. Published by Elsevier B.V. All rights reserved.