The Control Method Research Of Three Coordinates CNC Based On Windows

Numerically controlled machines play an important role in the economic development. In recent years, one mainstream of CNC technology researches is to design the open-architecture CNC system based on PC.Researchs on how to design the CNC system of open-architecture based on PC are made in the paper, and difficulties to develop the CNC system based on Windows system are analyzed. It is difficult to realize the real-time control based on Windows system because it shields the operation to basic equipment. By the design of regular interruption on the hardware interface and the development of Windows device driver in the core, the dissertation achieves the request of visiting the hardware and meets the requirement of real-time control at hardware level of the CNC system.Interpolation and radius compensation are two important functions of the CNC system.They determine the property of the CNC system. In the paper, the author studies them and proposes an efficient and accurate method for developing a class of precise interpolation algorithms which can drive the cutter of a CNC machine along three-dimensional (3D) trajectories. There are two kinds of the curve definitions: implicit and parametric. The method uses the implicit definition to interpolate the intersection curve on the basis of step selection rules. This method guarantees a position error of at most one step. For the parametric curve ,the method is using straight-line segments to approximate the desired path. This linearization has obvious advantage of high efficient.Quadric curve's C-tool compensation on the basis of difference interpolation of the CNC system is also studied in this paper. The method of vector is used in calculating the intersection-point of quadric equidistance curves, it greatly reduces the complexity of calculating; With the synthetic interpolation theory , any straight line and qudric curve's(circle,cllipse,parabold,hyperbold) equidistance curve can be interpolated indirectly, equidistance curve's traditional calculating errors are avoided and controlled precision is improved. Finally, the author concludes the research work and points out the questions which needed to be resolved in the further reseach.