GA-Assisted Output-Feedback Sliding Mode Control of Fuzzy Systems via Improved Static Time-Delayed Feedback

In this paper, we put forward an improved delayed output-feedback sliding mode control of fuzzy systems with arbitrary order. A new type of time-delay estimators is proposed for approximating the output derivatives in sliding surface, which has appealing noise attenuation capability. Such estimator is deliberately embedded in the feedback loops, which results in an improved delayed sliding surface. On this basis, static output feedback sliding mode control design via stabilizing delays is proposed to stabilize the fuzzy system in the presence of estimation biases and measurement noises. Differently, the estimator and controller parameters are co-designed by genetic algorithm to makes a trade-off among multiple objectives: the closed-loop stability, noise attenuation and estimation accuracy. The resulting design method is demonstrated by two examples: a mass-spring-damper system and a single-link rigid robot system.