Decoupling Control of Linear and Rotary Permanent Magnet Actuator Using Two-Directional $d\hbox{-}q$ Transformation

This paper presents a study on decoupling control of a linear and rotary permanent magnet actuator (LRPMA) with linear, rotary and helical movements. Since both linear and rotary motions of the actuator are dependent on both current and voltage, a novel two-directional d-q transformation is proposed to decouple the inter-relationship between the current and voltage in each coil. The expressions of input power, magnetic field energy, rotary torque, linear force and copper loss are all derived. A MATLAB/Simulink model for helical movement is then setup with hysteresis current control. A practical LRPMA prototype is manufactured and its control system is implemented with a dual digital signal processor. Simulations and experimental measures on the LRPMA prototype are reported to showcase the effectiveness of the control strategy.