Higher-order and Hard-nonlinear Control with Fuzzy Logic

Abstract

With the advances in science and technology, modern systems become more and more complex and difficult to identify. This trend is bound to limit the usage of such control algorithms as model reference adaptive control, which needs to identify the order of the system first. Meanwhile, in a realistic control system the hard nonlinearities, such as saturation, backlash, and hysteresis, always exist. Unfortunately, they usually cause oscillation and tracking error in the system. With the theory of fuzzy logic, the operator's experience can be applied to the control systems. This article proposes a fuzzy controller design procedure by applying the fuzzy logic, the ideas of the phase plane approach, and the sliding mode control. With this fuzzy controller, the higher-order systems with hard nonlinearity can be well controlled.