Research on mechatronic coupling facts of linear motor feed drive system based on spectrum characteristics

In this paper, the servo thrust and mechanical structure are analyzed in frequency domain using Maxwell Tensor and Dale Bert's principle, respectively. Three modes of mechatronic coupling are found as follows. 1) The thrust spectrum varies with velocity, which leading to a worse dynamic precision and even instability when the coupling occurs at a certain resonance frequency between the thrust and the mechanical structure; 2) The coupling occurs between mechanical structure and servo system when adjusting the gain in speed control loop or current control loop. 3) The output of linear encoder will fluctuate due to the variation of normal force between the mover and stator, which leading to the variation of the servo thrust spectrum and a re-coupling between servo drive and mechanical structure. In addition, the mechanism and influence factors of the three types of coupling are studied, respectively. The results show that the spectrums of servo drive system and mechanical structure evolve under different control parameters and operational condition, and happen to interaction once at the same natural frequency. Finally, the associated experiments are performed to verify the previous analysis.