Abstract: With consideration of friction influence, a mathematics model is established for a high-speed high-precision feed servo table under PID control. A two-component mixed friction model is used to express the friction force in servo mechanisms. The friction can be calculated according to the sliding speed, the oil film between the two contact surfaces by using the model. Under various work conditions, the protrusion error occurring at the quadrant boundary in the circular motion is profoundly studied through numerical simulation and experiments and the phenomena that the quadrant protrusion error lags with the rising of the federate is discovered. Comparisons between simulation results and experimental results demonstrate that with the mathematics model considering the friction effects proposed, the dynamics of high-speed high-precision servo feed systems under PID control can be accurately simulated, the friction error and its characteristics in the course of the feeding can be precisely predicted.

Key words: Friction error, High-precision, Numerical control