Adaptive Fractional Order Sliding Mode Control for a Nonlinear System

An adaptive fractional order sliding mode controller (AFOSMC) is introduced in this study to control a nonlinear system. This controller includes two units. The primary unit is a fractional order sliding mode control unit which incorporates the sliding mode and the fractional order control features. Second unit is employed for online adjusting the parameters of fractional order sliding mode controller by using a fuzzy logic system. The control performance of FOSMC with various control problems is improved by the tuning of its parameters. In addition, stability analysis of the proposed controller is studied with employing Lyapunov theorem. The efficiency of the developed scheme is investigated by applying it to a van der pol oscillator system. Simulation results indicate the improvements of the developed AFOSMC under disturbances and variation of desired output. Also, the proposed controller has less settling time and rise time compared with another existing controller.