The Research And Implementation About The Nonlinear Motion Control Interpolation Algorithm For The CNC System

CNC machining accuracy is related to speed control and interpolation algorithm,interpolation algorithm directly affects the CNC controller's performance. During NURBS curve machining process, with a small line segments approximating curve processing, linear distance is short, which caused great speed fluctuations and the processing error is difficult to control. So the spline curve interpolation technology is the key factor to realize high speed and high precision CNC machining. At the same time, with the development of microelectronics technology in recent years, embedded CNC system due to the advantages of small volume and high operation speed, stability, it has wide application prospect. This paper to HUST-6A embedded CNC controller as the basic development platform, developed a high-performance spline curve interpolation algorithm, which has important application value.First, this paper studied the mathematical model of the spline curve, based on the research of the mathematical model, it presents spline interpolation method is used for sampling curve formula. In order to better applied to embedded systems and easy programming, this paper also gives a NURBS curve to calculate the matrix representation. In order to verify the correct of the algorithm, this paper using Qt Creator developed graphic display components, and the interpolation simulation.Secondly, this paper is cutter location point processing, the cutter location points directly produced by CAM is isolated and have no connection. By identifying and eliminating categorizing cutter location points, retained within the scope of the setting accuracy, spline curve fitting to the basic data points, in addition to the unnecessary error points and redundant points, simplifies the calculating conditions. At the same time, considering the real time calculation of CNC control system and the biggest bear ability, it also gives the method of spline curve section, to ensure the piecewise spline curve graphics consistent. Using the above algorithm, the simulation analysis was carried out on the spline curve, verify the feasibility of the algorithm.Third, this paper was given by using Taylor incremental implementation technology principle to calculate the node spline curve real-time interpolation method on the above techniques. By comparing homogeneous coordinates and coefficient matrix interpolation method, homogeneous coordinate interpolation algorithm is given and gives the expressions of homogeneous coordinates. According to the requirements of speed, acceleration and machining precision, it is given bow high error calculation and control factors. By designing the linear introduce a simplified method is to finally reach the designated position detection. Finally the above algorithm is transplanted to HUST-A6 controller to set up the test platform. Under the same test conditions, by comparing the linear interpolation and circular arc with the spline curve interpolation speed graphics, demonstrate the efficiency and stability of the algorithm.