The look-ahead function-based interpolation algorithm for continuous micro-line trajectories

Continuous micro-line segments having micron magnitude are also used to approach complicated trajectories in computer numerical control (CNC) machining. Traditional linear interpolation processes micro-line segments separately. The rather small lengths of the segments result in low machining efficiency, and the frequent acceleration and deceleration also reduce the lifetime of the motor. To solve the problems, in this paper, we present an interpolation algorithm that is based on the look-ahead function. The look-ahead-based feedrate planning is elaborated from the aspects of trajectory feedrate description, feedrate preplanning, and feedrate planning. With the function of feedrate planning, CNC systems can predict the variation of the curvature of the coming trajectory so that adaptively determining whether accelerates interpolation feedrate to enhance machining efficiency or decelerates the feedrate to guarantee the machining precision. In addition, the trajectory interpolation for micro-line segment trajectories is analyzed as well, which realizes the generalization of the coordinates for each interpolation step. The implementation of the proposed algorithm in our CNC system is also studied. Finally, two machining experiments are provided to verify the accuracy and efficiency of the proposed interpolation algorithm.