Dynamic compensation of machine tool feed error  based on reference trajectory correction

YAN Tao1，ZHANG Hong2，SUN Li-jun3
(1. Department of Information Engineering, Yantai Vocational College, Yantai 264670, China; 2. Department of
 Mechanical Engineering, Jiangnan University, Wuxi 214122， China; 3. Department of
Mechanical Engineering, Yantai Vocational College, Yantai 264670, China)

Abstract: Aiming at the tracking accuracy of machine tool servo feed system, the linear servo dynamic compensator and closed-loop servo control system were studied, and a new dynamic error compensation scheme was proposed. The position error caused by servo dynamics and friction interference was pre-compensated by modifying the reference trajectory. Firstly, the velocity and acceleration curves of the reference track were modulated to achieve accurate tracking. Then, the reference position curve was modified according to the state of prefilter to eliminate the quadrant burr. Finally, the optimal error compensation was obtained by digital trajectory prefilter, and its parameters were automatically adjusted by iterative learning. Tests were carried out in a multi-axis feed system with different processing parameters. The results indicate that by combining two compensation filters, the compensation scheme can simply and effectively reduce the contour error from 10 μm to 1 μm without complicated professional knowledge, and is suitable for any tool path.
Key words: machine tool servo feed; dynamic error; reference trajectory; pre-compensation; prefilter