Near Optimal Measuring Sequence Planning and Collision-Free Path Planning with a Dynamic Programming Method

A near optimal measuring sequence was introduced to complete the entire measuring process and reduce the measuring time of a coordinate measuring machine (CMM) for a workpiece whose shape consists of several geometric elements. The number and positions of the measuring points of the workpiece were planned by a CAD/CAM software system. A weight matrix of the number of probe spins and the concept of the angle difference matrix were proposed for the measured feature face using the assumptions in this paper, for the purpose of dynamic programming. First, a dynamic programming method was carried out to plan the optimal measuring sequence of the feature face of the geometric elements. Then, a measuring point distance difference matrix was established for an individual feature face. Then, a dynamic programming method was used to plan the measuring path of the measuring points for solving the approximated shortest path. A collision-free interference inspection method established in this paper was also used to include a collision-free path for paths with interference. The entire measuring path planning was thus completed. With the help of CAD/CAM software and the powerful computation and analytical capability of computers, the system was able to achieve an appropriate measuring sequence in a short time.