High-Precision Coordinated Position Control of Integrated Permanent Magnet Synchronous Linear Motor Stations

In multi-station linear reciprocating processing systems, the positioning accuracy and the cooperative precision of the motion stations directly affect the production quality of products. This paper aims to enhance both the positioning and the coordination accuracy of the motion stations from the integrated permanent magnet synchronous linear motor (IPMSLM) stations during the reciprocating motions, especially in the presence of load disturbance. Firstly, the adaptive control strategy based on pole placement principle with online parameter identification is proposed for single IPMSLM station. The least squares identification algorithm with forgetting factor is employed to calculate the mathematic model online, so as to solve the problem that the IPMSLM stations cannot be accurately modeled with the existence of parameter perturbation and load disturbance. Secondly, in order to improve the coordination performance of the IPMSLM stations, the cooperative error equation is proposed, and a ring coupling cooperative (RCC) control strategy based on Lyapunov stability theorem is designed. The accuracy and effectiveness of this proposed collaborative control strategy is verified by experiments under no-load and spring-load conditions. Experimental results show that for the proposed adaptive and coordinate control strategy, the positioning error and the coordination error during the reciprocating motion can be guaranteed uniformly within $\pm 8~\mu \text{m}$ and $\pm 10~\mu \text{m}$ , respectively.