Research On Control Software In Embedded Open CNC System

With the development of manufacturing technique, modern NC machine tools which are material carriers of Advanced Manufacturing Technology are developing forward high speed, high precision and functional completeness. Embedded Open CNC System based on microcontroller has the merits of small, specialized, integrated and economic. In this foundation, CNC control software development should possess excellent performance. As the core module of the CNC control software, the precision and speed of interpolation module as well as interpolation pretreatment module are important indicators of CNC system and decide its character. In order to research and develop embedded open stepper system, the methods of interpolation module and interpolation pretreatment module including decoding and interpolation are studied deeply in the paper.Based on the traditional decoding methods, the paper puts forward a method of combination of translation and interpretation decoding, which takes two scans to separates error inspection task with interpretation decoding task. Error inspecting takes layer scanning mode to ensure that NC program be checked comprehensive and rapidly. Taking into consideration the real-time requirements of following interpretation, collation and storage of NC program according to the standard format join the decoding module in order to enhance the speed and save the memory.Minimum deviation interpolator is the core of the interpolation module. On the basis of improvement, the process of interpolation is simplified and the interpolator formula in the different quadrants is uniformed, which give full play to advantages of high accuracy and benefit for multiaxial feed. Compared with point-by-point compared interpolator, a new discrimination method called the longest axis end-point discrimination based on minimum deviation interpolation is adopted, which improve the accuracy, real-time requirement and reliability of the interpolation.Combined with minimum deviation interpolator and the direct method, the linear-exponential acceleration and deceleration control method of stepper motor is put forward. The method improves the accelerated and decelerated process, simplifies the judgment of quadrants and solves the problem that real-time calculation is slower, thereby increasing the speed of interpolation.The minimum deviation interpolator and feed-control method showed above, which meet the needs of embedded open stepper CNC system, have been applied to the independent researched CNC system and benefit for the industrialization.