Automatic Generation of Piecewise Constant Speed Motion with Smooth Transition for Multi-Axis Machines

Abstract

This paper presents a general theory on generating a smooth motion profile for the coordinated motion of five-axes CNC/CMM machines. Motion with constat speed is important and required in many manufacturing processes, such as milling, welding, finishing, and painting. In this paper, a piecewise constant speed profile is constructed by a sequence of Hermite curves to form a composite Hermite curve in parametric domain. Given the continuity of acceleration in our proposed speed profile, it generates relatively better product quality than traditional techniques. We also provide a method for the feasibility study of manufacturing capability in terms of the given machine, the desired path, and the assigned speed. We consider machine dynamics, actuator limitation, path geometry, jerk constraints, and motion kinematics.