Minimum time feed-rate optimization along predefined toolpath with acceleration constraints on each axis

A feed-rate optimization approach is proposed in this paper for generating minimum time feed-rate along predefined toolpath for Cartesian computer numerical control (CNC) machines with acceleration constraints on each axis. By properly defining new states, the original minimum time feed-rate optimization (MTFO) problem is formulated as a general time-independent optimal control problem. A control vector parameterization (CVP) method is applied to convert the optimal control problem into a nonlinear programming (NLP) problem which can be solved conveniently and effectively. The second derivatives of the path parameter with respect to time (pseudo-acceleration) act as optimization variables. The sequential quadratic programming (SQP) method is used to solve the NLP problem and obtain the numerical solution. A simple example and a real manufacturing test are performed to verify the effectiveness of the approach.