A strategy of continuous sliding mode control for laser beam focus positioning

A high order sliding mode is introduced on the basis of a reaching law method, and a continuous strategy of sliding mode control (SMC) is proposed. Modeling-deviation and unmeasurable external disturbance are compensated by an integral action term. This scheme offers the robust property of conventional variable structure control (VSC) with a continuous control action, so chattering phenomena can be eliminated. Precise and rapid trajectory tracking can be performed by the proposed scheme. Simulation result for a laser beam focus positioning control system is presented