Development Of Embedded Controller For Integrated Error Compensation Of CNC Machine Tools

In order to realize the effective compensation of the complex error of geometric and thermal of the numerical control system, this paper is aimed at the FANUC numerical control system, designed a comprehensive error compensation controller for CNC system based on single chip microcomputer using the origin coordinate translation method.We analyzed the characteristics of error compensation method of three kinds of NC machine tools. For FANUC numerical control system, we determined the comprehensive error compensation method and compensation implementation method. After that, we designed the overall structure of the NC machine tools integrated error compensation embedded controller, and hardware system based on the core microprocessor STM32F103ZET6. In order to ensure the storage of comprehensive error model, we extended the EEPROM. To meet the needs of human-computer interaction, the keyboard and LCD 12864 are adopted as input and output devices. In addition, in order to input comprehensive error model by the more humanized upper computer interface, we developed the RS232 circuit to communicate with the host computer. In the software part, Keil MDK software platform is used to develop the microcontroller program, and STM32 firmware library is used to compile programs of single chip microcomputer, including single chip microcomputer main program, interrupt configuration programming, man-machine interactive program, USART serial communication program, comprehensive error validity judgement program and EEPROM storage program. The upper monitor program is developed by VS2008+Qt, including user interface design and application design, using multi thread to ensure the smooth and real-time data transmission of the interface.Finally, for the development of comprehensive error compensation embedded controller of NC machine tool, we took debugs and the experimental verification. The experimental results show that the embedded controller can realize geometric error and thermal error compensation, as well as the CNC positioning accuracy improvement effectively.