Optimal design of fuzzy sliding-mode control: A comparative study

The fuzzy logic controller is widely used in many control applications. The advantages of using fuzzy logic controller are that the fuzzy logic controller can extract the control strategy from experts. Also, the linguistic control rules of fuzzy controller are fit for human's thought. However, a primary drawback of the fuzzy logic controller is that the linguistic control rules are hard to generate. It also requires knowledge and experience of human experts. Another drawback is the stability and robustness of the fuzzy control system are hard to check. To achieve the stability and robustness properties of a fuzzy control system, the fuzzy sliding-mode control technique is proposed in the spirit of fuzzy control and sliding-mode control strategy. To simplify the design procedure of fuzzy sliding-mode control rules, two design procedures, that is, Taguchi's method and the genetic algorithms, are applied. The controller design of a third-order nonlinear oscillation system is illustrated as a study case. Comparisons between these two design procedures are also given.