Performance Analysis and Decoupling Control of an Integrated Rotary–Linear Machine With Coupled Magnetic Paths

An integrated rotary-linear machine based on switched reluctance principle is investigated. The characteristics of the motor are analyzed by finite-element methods, with particular emphasis on the coupled magnetic paths. Results from numerical calculation are verified by the hardware experiment. The simple yet effective decoupling algorithm for the independent position control of both rotary and linear axes is proposed. Implemented with the proportional-integral-differential algorithm, the motor is capable of high-precision rotary and linear position tracking with the steady error within 0.3 ° and 10 μm, respectively.