Chattering existence and attenuation in fuzzy-based sliding mode control

Chattering is a low amplitude and high-frequency undesired signal which typically appears in relay or switched systems as in variable structure controllers. The chattering phenomenon can be treated as a limit cycle and the describing function (DF) method results in an useful tool for predicting its existence allowing the computation of the amplitude and frequency of such oscillations. In this paper, a sliding mode control based on fuzzy logic is proposed as an alternative to reduce chattering where DF method is used to demonstrate its attenuation level at the output of the plant. Analytical results are complemented with numerical simulations made for a pneumatic linear actuator.