Research and Development of the Thermal Error Compensation Embedded in CNC System

Thermally-induced errors are the major contributor to the inaccuracy of the high-precision machine tools. Limited by CNC system´s close-loop structure, the present thermal error compensations are difficult to be embedded in CNC system and only can be as an additional unit out of the CNC system. This paper designed and developed an embedded error compensation module based on the opening CNC system with field bus. The presented embedded error compensation module can exchange data with the CNC system main control module in real time, share the system resources and provide on-line temperature measurement and thermal model calculation. Then the position-dependent thermal error can be compensated by correct the coordinates command during CNC system interpolation progress. An experiment was carried out to verify the performance of the compensation system.