Orientation-point relation based inspection path planning method for 5-axis OMI system

Abstract

Abstract Inspection path planning methods are of great importance to OMI systems. Most researches only optimize the inspection path length. However, the number of probe orientations (NPOs) also has a great influence on inspection efficiency and accuracy, especially for parts with complicated features. To optimize the NPOs and the path length, this paper firstly proposes the concept of orientation-point (O-P) relation schema which includes all valid O-P inspection cases. Then based on the O-P relation schema, two algorithms – the minimum orientation algorithm (MOA) and the shortest path algorithm (SPA), which consider NPOs and path length in different priorities were proposed. MOA was designed to find the minimum orientations that can measure all the inspection points according to the O-P relation schema, then the inspection points were categorized into groups by the selected orientations. The traveling salesman problem (TSP) algorithm was used to plan the inspection path for each group's points, finally the total path was obtained by connecting paths of different groups in sequence. SPA firstly uses the TSP algorithm to obtain the shortest inspection sequence, then minimizes the NPOs by finding orientations that can inspect most consecutive points along the planned inspection sequence according to the O-P relation schema. To avoid possible collisions during the inspection process, a safe box that contains the inspection part was defined before planning the path, which enables the probe to cross obstacles by moving to the safe planes of the safe box. Simulation experiments were conducted on three parts, the results show that both MOA and SPA can obtain a collision-free inspection path. MOA can effectively decrease the NPOs compared with SPA, and the path length can be even shorter than that of SPA in some complicated cases.