| Embeded system is one of the most rapid developing technologies recently. It is a kind of special application-oriented computer system. The application of embedded system can shorten the developing cycle of products and improving the reliability and performance of products. In addition, it has other excellent features such as less system cost, tiny volume and low power consumption of single-chip devices as well as perfect developing environment, abundant resources and supporting operating system of PC platforms. Therefore, embedded system will have a good development future in the field of CNC.Supported by Natural Science Foundation of Jiangsu Province (BK2003005), and based on in-depth study of embedded system and NC system, a novel design of embedded CNC system based on microprocessor ARM is presented in this thesis. The system is designed by module, which includes microprocessor ARM module, memory module, human interface module, communication interface module, CPLD/FPGA module, input and output module. Two-step interpolation method is adopted in system in which microprocessor ARM implements rough-interpolation and FPGA system implements DDA fine-interpolation combined with an excellent accelerate/decelerate control algorithm. It ensures the continuity and stability of the CNC system. The software is developed based onμC/OS–II real-time embedded operating system. The device drivers and API functions is developed. The CNC system can control four axes and has a huge quantity of I/O ports, the spindle and handwheel signal interface. It has a friendly interface to operators. It can be used with lathe or milling machine. The CNC system has implemented and applied successfully on a lathe. The frequency of the axis output signal can reach 1MHz. The maximum feed speed of the axis can reach 60m/min. The whole performance of the CNC system has reached advanced level of CNC. |
