Design of second-order sliding mode controller for Electromagnetic Levitation Grip used in CNC

A novel second-order sliding model controller aiming at the inherent chattering of classical sliding mode control for high-precision air gap control of Electromagnetic Levitation Grip used in CNC(Computerized Numerical Control) was proposed, and the control strategies based on super-twisting algorithm was designed. Electromagnetic Levitation Grip is a very complex system with real parameter uncertainties and external disturbances in the process of air gap control. This method can eliminate the chattering which may excite high frequency chattering, keep the robustness of system, and effectively improve the dynamic response of system. Simulation results demonstrate that the design of Second-order sliding mode controller can achieve the better stability of suspension, strong immunity and high stiffness.