Study On The Turret Feed Servo System Of Precision CNC Lathe

CNC lathe is one of the important equipment of engineering machinery, which combines machinery, electron, automatic control, precise detection and other high technology. With the diverse needs of society and the continue advances of related technologies, CNC lathes are developed towards high precision and high-speed fields. The feed servo system as the connecting loop between the CNC lathe and the mechanically-driven parts, its dynamic performance and static performance decide velocity, positioning accuracy, functional reliability and other technical indicators of the CNC lathe turret. Therefore, studying and improving the technical performances and the reliability of the servo system is the key technology to realize high precision CNC lathe, which has great practical significance for CNC lathe.This subject belongs to the National Major Machine Projects (HTC325un) of the Eleventh Five-year Plan, which mainly designs a turret feed servo system of the precise CNC lathe, and the primary research had been done are as follows:(1) On the base of analyzing the working characteristics of the turret feed servo system and the electrical drive automatic control, a design proposal of closed loop position servo control has been adapted to control the precise CNC lathe turret feed servo control system.(2) Has designed and modeled the drive loop, speed loop, mechanical drive loop and feed loop for the PMSM feed servo system.(3) Has actually selected the main components for the PMSM feed servo system.(4) After setting the parameters of the PMSM feed servo system and simulating the system with Simulink, has analyzed the system performances through time domain and frequency domain.(5) Adapted the fuzzy adaptive PID control, the hybrid fuzzy-PID control and traditional PID control respectively to intelligently control the PMSM feed servo system, and then analyzed and compared the three control strategies.The study results show that: the PMSM servo system meets the feed requirements of the precise CNC lathe turret; further more, the three-loop structure greatly improves the positioning accuracy of the feed system; and the closed-loop control effectively reduces the system error caused by the mechanical transmission.