Hysteresis and magnetic flux leakage of long stroke micro/nanopositioning electromagnetic actuator based on Maxwell normal stress

Abstract

In order to compensate for the inherent hysteresis and magnetic flux leakage of large stroke Maxwell electromagnetic actuators, a hysteresis modeling method including a magnetic flux leakage effect is proposed. Firstly, the working principle and mechanical structure of a Maxwell electromagnetic actuator are briefly described. The physical model of the actuator is established via Ampere's loop law, the continuity principle of magnetic flux, and Ohm's law of magnetic circuits. Subsequently, a parametric hysteresis operator, together with a shaping function is proposed, and a hysteresis operator parameter identification method is also presented. In order to enhance hysteresis model accuracy, the magnetic flux leakage coefficients of the actuator with different positions are obtained and considered. To compare the compensation effects of the hysteresis operator before and after optimization, a compound control method of inverse hysteresis feedforward is proposed to conduct the trajectory tracking experiments. The experimental results demonstrate that the trajectory tracking errors compared with the feedback control and the unoptimized hysteresis model feedforward control, the feedforward control of the optimized hysteresis reduced to 14.7% and 48.2%, respectively.