平面电机的电磁执行器由4组海尔贝克(Halbach)型永磁同步直线电机构成。介绍平面电机的结构和工作原理,给出执行器样机的结构方案和解耦电磁力方程,推导执行器样机的运动控制方程,并提出执行器的电流控制策略,给出电流控制、静态力测量、开环定位、闭环定位的实验步骤和结果,其中,500mA电流阶跃响应的调节时间为2.5ms,稳态误差小于5mA;海尔贝克型执行器的机电常数实测值为17.4N/A,为径向阵列型执行器的1.36倍;开环定位的平均误差为50μm;闭环10mm阶跃响应的调节时间为350ms,稳态误差小于20μm。实验结果表明,海尔贝克型执行器的电磁力模型较准确,电流控制策略可行。
The electromagnetic actuators of the planar motor consist of four Halbach permanent magnet synchronous linear motors. This paper presented the structure and working principle of the planar motor, the structural scheme of the prototype actuator, and the corresponding decoupled electromagnetic force equations. The motion control equation of the prototype was derived and the corresponding current-controlled strategy was proposed. Finally, the experimental procedures and results of current control, static force measurement, open loop positioning, and close loop positioning were presented. The setting time is 2.5 ms and the steady-state error is less than 5 mA in the 500 mA current step response. The measured Halbach actuator electromechanical constant is 17.4 N/A, which is 1.36 times of the radial array actuator's. The average error is 50 μm in open loop positioning. The setting time is 350 ms and the steady-state error is less than 20 μm in 10 mm close loop position step response. The experimental results show that the electromagnetic force model of the Halbach actuator is comparatively accurate and the current-controlled strategy is feasible.