The Research Of Embedded Three Coordinates CNC Based On PC104-bus

In recent years, numerical control system is mostly based on computer. Incontrast to the research pattern based on computer, the embedded model system to design embedded CNC system is a new attempt. Agility, module and reconstruction are the new trends of opening CNC. By Analyzing processing character and embedded opening frame, the framework of numerical control system is built on base of the pc104-bus, it can effectively satisfy the requirement.This paper includes the several following parts:1. Analyse the total structure design of the system, introduce the pc104-bus and the primary signification of this thesis is proposed. The design of the system's hardware: a PC104-bus card which has the functions of timer, digital input, digital output, D/A convertion is designed, and the design of the print circuit in details is illustrated.2. The Interpolation algorithm of intersection curves of curved surfaces and intersection curves of curved surface and plane is made research in this paper. For the intersection curves of curved surfaces, the paper proposes a new method. Firstly, a new coordinate is built by rotating the original coordinate systerm. In the new coordinate systerm, the original plane is transformed into a plane of the same height. Secondly, the interpolation algorithm is deduced from the intersection curve equation of the new plane. The intersection curves of curved surface and plane are interpolated according to the interpolation algorithm rule of direction and error which cuts down the computational complexity and guarantees a position error of at most one step.3. Combining the interpolation algorithm, the paper presents a new a radius compensation algorithm for tool motion generation along planar offset polynomial curves, which is different from traditional methods,4. In RTOS, Most of the practicable methods put forward to realize real-time control on the PC and the structure of Windows operating system are analyzed .The problem that it is hard to apply real-time control to Windows Operating system is also solved, which depends on the outside Timer-interruption hardware interface joined with VxD device driver.