ABSTRACT Magnetic screw motors (MSMs) facilitate the conversion of rotary motion into linear motion through magnetic coupling. Nevertheless, relative motion errors are inherently present within the magnetic transmission process. To acquire the relative motion error in real time during the operation of the MSM, this article proposes a relative motion error observer based on the MSM transmission structure. The rotary component can be calculated by the magnetic transmission ratio of the MSM and the reference linear component of the mover. Then the calculated rotary component is compared with the actual rotary component obtained from sensors, thereby the real‐time determination of the relative motion error can be realized. To observe relative motion errors, the rotor position, linear speed, and force of the mover are respectively designated as control targets, and the corresponding closed‐loop control systems are established. The observation of relative motion error facilitates the analysis of the MSM transmission characteristics and the implementation of various control strategies. For instance, relative speed compensation can provide a foundational approach for sensorless control of linear position. Furthermore, to improve the dynamic performance of the closed‐loop system without increasing the complexity of the system, the adaptive fuzzy PI controller is implemented in the control system.
Zhang et al. (Thu,) studied this question.