High-speed-high-precision Micro Motion Control Design and Tuning for CNC Servo Systems with the LuGre Friction Model
|關鍵字:||運動控制;啄鑽;卡爾曼濾波器;擾動觀測器;LuGre;CNC;motion control;pecking process;Kalman filter;DOB;LuGre;CNC|
In the pecking machining process for 3C industry electronics board, the major concerns are the servo motor control design, the friction compensation of the machine, and suppression of the external disturbance. Because the micro-motion command of a pecking process is in a high frequency and high-speed repetitive motion, the effect of friction to motion error thus becomes relatively more dominant. This Thesis applies the Kalman filter to suppress the noise of the current feedback in CNC servo motors. Moreover, the disturbance observer (DOB) was applied to the CNC servo motor control to reduce the effect of external disturbance. Then, both the nonlinear static and dynamic friction models will be considered to improve pecking motion precision. By concerning the dynamics of the friction, the LuGre friction model is adopted in this study. However, the three estimated coefficients of the LuGre model are difficult to obtain and an off-line approach is proposed to obtain those coefficients of friction model. Finally, the developed controller including the P, DOB, and LuGre models were integrated on a CNC machine. Experimental results of a pecking process indicate that the RMS of the tracking error is significantly reduced from 90.12um to 2.89um by applying the proposed control structure.
|Appears in Collections:||Thesis|