Computer simulation study on optimization of linear servo motor used in CNC machines

For computer numerical control (CNC) machine tools, the double side air-cored permanent magnet linear servo motor (DAPMLSM) is suitable for high-speed and high-precision servo feed systems. But it also has thrust ripple caused by non-sinusoidal magnetic field distribution. Finite element analysis (FEA) was used to study motor characteristics, and the computer simulation results match well with the prototype data. It indicates FEA method is accurate. Based on that, the influences of DAPMLSM main structure dimensions were analyzed. The air-gap and magnet thickness mainly affect the amplitude, and the pole-arc coefficient affects both amplitude and its distribution. The distribution condition of the magnetic field in the air-gap could be improved effectively by optimal design of the pole-arc coefficient, furthermore the thrust fluctuations is reduced.