Design of trigonometric velocity scheduling algorithm based on pre-interpolation and look-ahead interpolation

• A trigonometric velocity scheduling algorithm based on two-time look-ahead interpolation is proposed.
• The velocity scheduling algorithm could provide continuous velocity, acceleration and jerk curves.
• The pre-interpolation explores the path to be machined and classifies the path into three situations.
• The look-ahead interpolation designs and adjusts the feedrate scheduling scheme constantly.
• We adapt the methods of beforehand deceleration and delaying acceleration to guarantee the processing accuracy.

To generate continuous velocity, acceleration and jerk curves of parametric interpolation in high-speed and high-accuracy machining, this paper presents a trigonometric velocity scheduling algorithm based on two-time look-ahead interpolation (pre-interpolation and look-ahead interpolation). The algorithm consists of three modules: pre-interpolation, look-ahead interpolation and real-time interpolation. The pre-interpolation module aims to explore and record the information of the path to be machined. The look-ahead interpolation module firstly calculates the velocity scheduling functions according to the data recorded by pre-interpolation, and then tests and adjusts the feedrate scheduling schemes constantly. The real-time interpolation module adapts the method of beforehand deceleration or delaying acceleration according to the signals received from pre-interpolation and look-ahead interpolation to guarantee the processing accuracy. Simulation and experimental tests demonstrate the availability, effectiveness and advantages of the trigonometric velocity scheduling algorithm. And the proposed trigonometric velocity scheduling algorithm based on pre-interpolation and look-ahead interpolation could realize smooth velocity, acceleration and jerk control with restricted chord error and implement high-quality CNC processing.