Contour error vector model and its application to CNC systems

To realize the Cross-Coupled Control (CCC) of complicated curve in three dimensions and improve the contour error compensation precision, a new contour error estimation model was proposed. By the model, the contour error vectors were computed with tool position points from the interpolator of Computer Numerical Control (CNC) and position tracking errors of servo systems. Based on the model, a collaborative motion control system composed of contour control loop and position control loop was put forward, the system implemented position tracking control and contour compensation control simultaneously. Simulation and experiments proved that the system with double closed loops could remarkably improve the contour machining precision of CNC system.