Two-degree-of-freedom control of a dual-stage actuator positioning system for short-span tracking

This paper presents a new two-degree-of-freedom (2DOF) control design method for a dual-stage actuator (DSA) positioning system consisting of a linear motor (LM) and a piezo actuator (PA). The 2DOF controller is proposed to achieve disturbance rejection and short-span tracking in the PA range and is designed using the doubly coprime factorization (DCF) approach, with which the closed-loop transfer function is expressed explicitly in terms of design parameters. This greatly simplifies the optimization of design parameters in meeting desired specifications. We further study how to use the design parameters to deal with specific problems in the DSA, i.e., control allocation and trajectory planning. Experimental results demonstrate the practical implementation of the DSA control system and verify its effectiveness for step tracking and disturbance rejection.