Study And Implementation Of Interpolation Algorithm Based On NURBS Curve

The technology of numerical control is a kind of modern automatic control technology, it is one of the most crucial link in modern production technology. The interpolation technology of NC (Numerical Control) is the crucial technology in NC system, its interpolation algorithm will directly affect the working speed and accuracy of CNC (Computer Numerical Control) system. The interpolation with free-formed curves has many advantages. It can get higher speed, efficiency and smoother surfaces. So it is significant in studding interpolation with free-formed curve of CNC.NURBS (Non-Uniform Rational B-Spline) provides a uniform expression of all curves. NURBS interpolation has been a hot research spot and a trend in numerical control filed. This paper study NURBS curve's development, nature and calculation method of parameter deeply. The existing NURBS curve interpolation arithmetic directly has questions which was difficult to eliminate chord error, speed and acceleration control. In order to solve the problem above, the paper put forward feed rate self-adapting interpolation arithmetic, it calculate the parameter by adams and difference equation, at the same time the prediction-correction method is adopted to control error of parameter calculation. On the aspect of Ace.(acceleration) and Dec.(deceleration) control, the paper put forward a segmental control method of Acc. and Dec., which control the alteration of speed and limit jerk, it also solve the problem of judging Acc. and Dec. point by Acc. and Dec. slot.To prove the interpolation arithmetic above, make experiment on the triaxial precision positioning servosysterm. From the experiment result, we can get the error with interpolation arithmetic above satisfy systematic requirement. At the same time, it control speed and Ace. and Dec. validity, realize the optimization of interpolation accuracy and speed, increase quality and efficiency of working.