Modeling and Control of Feed Drive System for a Micro-Machining Platform With Nano-Resolution

The feed drive system plays a key role of increasing processing efficiency and improving machining quality of parts. The external disturbances, such as cutting forces and frictional nonlinearities seriously affect the machining quality. The feed drive system should be capable of rejecting such disturbances. In this paper, the feed drive system of a micro-machining platform with nano-resolution was modeled and controlled. A decoupled algorithm was implemented to linearly regulate flux-producing and force-producing currents of motor. The current controller was designed based on the electrical model of motor employing pole-zero cancellation method. The speed controllers, i.e., proportional-integral (PI) and sliding mode control (SMC) were designed and compared. The SMC exhibits the better property of rejecting the external disturbance compared to PI controller. The electromagnetic force produced by Linear Permanent Magnet Synchronous Machine (LPMSM) under SMC expresses the quicker response to external variations. The models will be further applied for the design of cross-coupling servo control for this five-axis reconfigurable micro-machining platform.