Sliding mode-H∞ control of crossbeam magnetic levitation system in moving numerical control machining tool

The parameter perturbation and unmodeled dynamic parameters would affect the system performance during the operation of gantry moving numerical control machine tool. An adaptive integral sliding mode controller combining with robust H∞ control theory was designed to ensure the stability and accuracy of the system. The integral sliding mode controller was used for the robust control of whole system in order to decrease the chattering of sliding mode controller. And the adaptive control was adopted to estimate the uncertain parameters in control law. With considering the effect of quality changed by cutting parts and the external disturbances, H∞ control theory was combined to enhance the robust of the system. The simulation results show that the present controller has the powerful disturbance suppressing ability and can realize the steady levitation.