Analysis of Structural Tolerance Influences on Thrust Ripple of U-Shaped Ironless Permanent Magnet Linear Motor

U-shaped ironless permanent magnet linear motors (IL-PMLMs) are widely implemented in precision manufacturing equipment with the advantages of small thrust and high positioning accuracy. However, the structural parameter variations of the motor caused by manufacturing and assembly errors will increase the thrust ripple of the motor and thus cause vibration and reduce the operating accuracy. This paper uses Monte Carlo simulation to analyze the manufacturing tolerances of the motor's primary and secondary structural parameters, including the spacing and position of the winding, the height and width of the permanent magnets, and the thickness of the back iron. Finally, various combinations of parameter tolerances are used for analysis and validation. Assuming all tolerances obey normal distribution, the influence of motor structural parameter tolerances on thrust and thrust ripple is obtained through finite element analysis.