Generation of velocity profiles with speed limit of each axis for high-speed machining using look-ahead buffer

Abstract

An efficient look-ahead algorithm to generate velocity profiles is presented in this paper. Algorithm allows for a nonzero starting point velocity and end point velocity of every line segment to increase machining productivity. The paper considers the intelligence of look-ahead to achieve faster machining speed, along with required accuracy. Speed limitation of a specific axis and the direction change of an axis are newly added to the constraints of the velocity profile problem. This paper solves graphically the problem of generating velocity profiles and derives the equations for representing the velocity profile. A method to manage the look-ahead buffer is also proposed. To generate velocity profiles using the look-ahead buffer, three phases are proposed. Phase 1 determines the velocity conditions such as the maximum velocity, starting point velocity and end point velocity. In phase 2, velocity profiles are generated independently. Phase 3 handles the change of the start or end point velocity. This phase 3 is repeated until all adjacent point velocities are the same. The proposed method was utilized in the manufacturing field to engrave aluminum tire molds. It was demonstrated that this method contributes to an increase of the machining accuracy and a reduction of the production time.