Accurate interpolation and contouring control algorithm based on FIR filters for the corner transition

In the process of high-speed machining, there are sharp corners at the joint of short lines. The vibration of cutting tools at the sharp corners will be severe, which will reduce the quality of machining surface and machining efficiency. For this problem, impulse response technology is proposed and applied. However, there is inevitable time delay in impulse response technology, which leads to the uncertainty of the maximum contour error of the corner. In order to further generate accurate reference motion trajectories, an accurate interpolation and contouring control algorithm based on FIR filters for the corner transition is proposed in this paper. According to the continuous short lines information in the CNC system, the rectangular velocity pulse signal of the short line is obtained. Initial rectangular velocity pulse is filtered to obtain third-order trajectory. In order to realize the continuous feed motion of short lines, the maximum feed velocity of short lines is constrained. Under the constraint of the maximum velocity limited, the maximum contour error of the corner is controlled by changing the overlapping time, and the accurate mathematical expression of the maximum contour error is reached. By using the FIR filters, the acceleration and jerk curves are generated from velocity pulse profiles. Through the experiment and simulation analysis, the algorithm proposed in this paper can determine the maximum contour error of the corner to realize smooth transition and reduce the machining path time by 7–10%. The proposed algorithm is proposed to achieve G1 continuous acceleration and effectively improve the processing quality.