进给系统定位误差解耦补偿及热误差建模研究

Secondly, the constituent elements and coupling principles of the comprehensive positioning error of the feed system were analyzed, and a complete scheme for decoupling and compensating the positioning error was proposed. The thermal error and geometric error were separated from the measured positioning error data using linear fitting method, and the geometric error was compensated through the pitch error compensation function of SIEMENS 828D numerical control system, reducing the geometric error from -1.4μm~1.6μm to -0.2μm~0.2μm. The effectiveness of the error separation method was verified.

Thirdly, the effects of different influencing factors on the thermal error of the feed system were studied. The influence of electric spindle heating on the measurement of positioning error in the X and Z directions of the feed system was investigated. The effects of non-motion heating, motion heating, and comprehensive heating on the error of the feed system were revealed by experiments at different feed rates, and it was proved that the thermal error of the X-axis feed system was caused by the superposition of non-motion heating and motion heating. The effect of feed rate on the thermal error of the Z-axis feed system was obtained through experiments at different feed rates.

Finally, the modeling and compensation techniques for the thermal error of the feed system were developed. Based on the mechanism and influencing factors of the thermal error of the feed system, the temperature points for modeling were selected, and the models for the origin drift error and thermal expansion error of the X and Z axis feed systems were established using a multiple linear regression model. The thermal error compensation of the lathe feed system was realized through the compensation interface of the SIEMENS 828D numerical control system. The effectiveness of the error separation, modeling and compensation methods was verified through experiments under different working conditions, including different feed rates and idle travel. The results showed that the positioning accuracy of the X and Z axis feed systems was significantly improved, with the positioning error reduced from 30.9μm to within 3.6μm and from 50.3μm to within 3.7μm, respectively.