Research On Key Technologies Of The Difference Interpolation CNC Based On Embeded Linux

It is important for CNC system to control the interpolation precision, which decides the characters and functions of CNC system. Traditional NC technology can not adapt development of CNC technology any more because of much deficiency. Most methods are about linear and/or circular interpolation.Though a few research involves in direct interpolation on noncircular curve, result which can be used in practice has not been gained. The real-time character and stability are the most important performances of CNC system. Currently, most CNC systems in the market are based on DOS or Windows/NT. Linux has many advantages, such as true multi-masks, open source codes, good stability, excellent ram management and strong network function, which is a good choice for CNC system. In the thesis, the unified interpolation of conic curves based on Linux is researched. The thesis includes several parts as below:1. This paper firstly introduced situation and history about development of CNC interpolation technology both here and abroad, and then discussed the technology route to develop CNC system based on DOS, Windows and Linux. At last, the key technologies of embedded Linux CNC system is proposed.2. Both the approaches to realize real-time and the RTAI realized fundament control are investigated. The standard Linux kernel is properly reduced to satisfy the demand of embedded CNC system. RTAI is a real-time kernel which is used to develop the innovative modules of the CNC according to its programming characters and features of the CNC system.3. The traditional interpolation of point by point comparison method is discussed. The CNC system is successfully developed, which can directly machining line, circular arc, ellipse, parabola, and hyperbola by uniform algorithm based on difference interpolation.4. As difference interpolation requires special data format, a new NC code interpreter for embedded difference interpolation is introduced. This NC interpreter calculates steps of the curve in its counting direction and transforms NC standard codes to the special format, which can meet the requirements of difference interpolation.