Controller Design Robust to Nonlinear Elements based on Fractional Order Control System

Abstract

Most controller design methods to deal with nonlinear elements are not general. For example, anti-windup controller is effective only for saturation. Fractional order control system (FOCS) is proposed as a general method to design controllers robust against nonlinear elements, which always exist in motion control system. FOCS is described by fractional integrals. Some practical design rules of FOCS are developed and applied to motor speed control systems containing saturation and gear-backlash. Simulation and experimental results show the effectiveness of FOCS based design method.