A method of fractional order sliding mode control is proposed for the typical nonlinearity and uncertainty of magnetic levitation ball system. In order to overcome the chattering effect in traditional sliding mode control, design method of the fractional order sliding mode control is given by using fractional order PDμ structure design in the sliding surfaces function of the traditional sliding mode controller in combination with constant speed reaching law. The stability of the control method is proved by Lyapunov stability theory,and using the Tustin algorithm and continued fraction expansion method,the fractional order sliding mode controller is discretized. The results of the simulation and ex-periment show that fractional sliding mode controller makes the magnetic levitation ball system have good tracking performance and strong robustness to external disturbance.
magnetic levitation ball systemsfractional-order sliding mode controlreal-time controlrobustness