5 Servo Feed Error Compensation Control of the NC Rotary Table

Feed structure of the NC rotary table was analyzed firstly. The dual worm-gear transmission mechanism was then employed to eliminate the clearance. The transfer function of the servo system was presented. According to the LuGre friction model, the nonlinear fuzzy sliding mode control was presented for the servo system to compensate the friction nonlinearity. Through fuzzy adjusting the switching gain, the sliding mode control compensation system achieved less buffeting characteristics. At last the proposed error compensation approach was employed to control the rotary axis of a NC rotary table. The result shows the effectiveness of method, which has a very important significance to improve the motion precision of the NC rotary table.