A Dual NURBS Curve Five-Axis Interpolator With Interval Division Under Axial Kinematic Constraints

This article presents an online full real-time dual nonuniform rational B-spline interpolator. Under the constraints of the kinematic parameters of the drive axis, the nonlinear effects of the five-axis CNC are solved on the basis of dual NURBS curve trajectory. Furthermore, smooth interpolation data are generated to realize machining efficiency, balance of quality and machining accuracy. After introducing the idea of ​​interval division, this research divides the tool path into instruction speed, transition speed, and constant speed intervals. In order to prevent the increase of the computational burden of the numerical control system due to the too large sampling data points, the two-step scanning method is adopted to realize the precise expression of the parameter position of the starting point in each interval, and the calculation of the interval speed is studied. Further, in order to meet the real-time requirements of industrial systems and avoid inputting all trajectory segments into the system for calculation, this article proposes a prospective velocity bidirectional scanning planning method based on interval division, which realizes the segmented planning of the full trajectory. The planning result adopts the S-curve acceleration and deceleration control commonly used in the industry to realize the interpolation output. The proposed system interpolation method belongs to the online real-time processing and can be applied to the actual numerical control system. The proposed interpolator is verified by simulation and experimental tests for the cutter shaft to participate in the oblique flow impeller.