Research And Development Of An Embed-ded CNC System Based On ARM And Linux

Embedded CNC system combines traditional NC technology with embedded system technologywell, it has become an important development direction of CNC system technology due tosome ad-vantages such as customized function, low cost, compact size, high reliability and so on. EmbeddedCNC system can promote the development of professional and economical CNC system effectivelyand it has a broad application prospect of industrialization.On the basis of analyzing function requirements, an embedded CNC system based on ARM andLinux is studied and developed. There are some problems with the PC+motion controller architec-ture that mostly used in domestic NC system such as long development cycle, high cost and compli-cated realization. Therefore, in the respect of hardware, an embedded CNC system based on ARM andFPGA architecture is proposed and the corresponding circuit system is designed. In addition, thereal-time interface ability of ARM is greatly enhanced by taking the advantage of the flexibility andhard real-time performance of FPGA. The ARM9based microprocessor S3C2440A works as themaster control unit and it is responsible for handling system control tasks. FPGA is used to expand theinterface of ARM so that the functions of modulation output of motor PWM drive signal andquadruple frequency and direction identification of encoder signal can be realized.In the respect of software, the customization and transplantation of BootLoader、kernel and rootfile system of embedded Linux system is realized. Meanwhile, Xenomai is used to enhance thereal-time performance of Linux and the result of the test shows that the system can satisfy the re-quirement of real-time performance of CNC system.On this basis of that, task modules division for the CNC system is made according to the charac-ter of real-time layer and inner nuclear layer. Furthermore, theory research and practice programmingof some main modules is made, which includes G code interpretation, vector based radius compensa-tion, smooth acceleration and deceleration planning, velocity feedforward position control and graph-ical user interface. All the designed software and hardware are proved by experiments.