Research On Applying DSP Into Open CNC System

This contribution focuses on applying Digital Sigal Prossesor (DSP) to the open CNC system. An open CNC system has been developed and then tested and verified.The hardware system is made up of host computer and slave computer. The host realizes a user interface,including converting the STEP-NC code to G-M code, transfering machining code and displaying, by using a PC based on Windows2000 operating system; The slave realizes interpolation and position controlling by using F2812 which is a 32-bit fixed-point, 150MHz Digital Signal Processor with abundant peripheral interface, including CPU timer, Event Management unit, designed by TI corporation. The host communicates with the slave by using USB2.0 interface.The software module of this system includes three parts: host computer software, slave computer software and the communication protocol software. The host computer software is developed by VC++6.0 development tool using multithread technologies, Windows Driver Module. As a user interface, the host computer realizes friendly man-machine interface through two main functions: first, receiving the user request and transferring it to the slave computer; second, receiving the feedback data from slave computer and displaying the current postion of each axis, μC/OS-Ⅱ, a real-time multitask operating system, is ported to the slave computer, which simplifies the system design and improves the system expansibility. The slave computer realizes interpolation and position controlling functions, receives the request from host computer. Also a communication protocol is realized to ensure the security of data transferring.At last, by adopting Siemens AC servo motors and amplifiers, a milling machine is retrofitted and then experiments are conducted. The experimental results have demonstrated the feasibility of the open CNC system developed in this paper.