A long-stroke planar linear actuator equipped with magnetic guide

Abstract

This paper introduces the design, fabrication and characterization of a micro electromagnetic linear actuator integrated with magnetic guide. The actuator consists of a slider, a stator and a magnetic guide. A magnetic guide is used to replace the mechanical rail of conventional linear actuator to ensure the linear motion and to avoid friction. The purpose of this paper is to study the influence of magnetic guide on the dynamic characteristics of electromagnetic linear actuator and measuring techniques for micro-actuators. To test the resistance to motion and output thrust force of the actuator, a cantilever type force sensor is proposed, which can measure the small force in ~mN order, and the measurement error is less than 3%. Using this sensor, the output thrust measured is higher than 10mN when 1A current is applied, and the friction force of the actuator measured is about 7.73mN. Two-phase square wave and sine wave current are used to drive the actuator, the minimum driving current and frequency of the actuator are less than 0.1A and 1Hz respectively. The actuator attains a maximum stable moving speed of 0.15m/s with the input signal frequency of below 250Hz. In addition, the anti-interference capability of the actuator is evaluated through simulations and experiments. These results show that the actuator can bear an interference 45 times its own gravity in the directions that are perpendicular to the moving freedom, and can adjust the direction of motion automatically when the rotation angle in three orthogonal directions is less than 6 °.