Open Numerical Control System

Open architecture CNC system is a prevailing CNC system. Its open architecture is based on extensible software and hardware platform. This thesis gives detailed description of the system from the following three aspects: real time control, cutting compensation algorithm and interpolation techniques.The system employs WDM (Windows Driver Model) - an efficient driver programming methods based on the concept of standard and layered driver - to develop device drivers. It enables the system to accomplish real time tasks on multi-task operation systems with the help of the efficient and effective "soft" real time approach. The system gives real time response to interrupts and controls the machine precisely. Then, the thesis introduces C style cutting - compensation algorithm to perform smooth transition among various angle patterns. Here, three methods are presented: shortening compensation, extending compensation and insertion compensation. This thesis also puts forward an improved DDA arc interpolation algorithm, which decreases the radial deviation of the traditional algorithm without losing the original advantages. Another algorithm is employed to simplify the process of judging the end of interpolation.The thesis describes the course of trial and analyzes the results. Finally, the characteristics and development trends of the CNC systems are briefly discussed.