A two-stage collision detection method of a multi-axis CNC machine tool based on bounding box and basic primitive

Abstract

A fast and accurate two-stage collision detection method is proposed to ensure the normal processing of multi-axis CNC machine tools (MACMT) and avoid collision between the tool and the workpiece. Taking the machining of complex curved parts using a large gantry milling machine as an example, the motion relationship between the key components of the machine tool and the collision detection model are described in detail. Then, collision detection is performed on CNC machining through grading. In the first stage, the repeated projection method quickly eliminates long-distance non-intersecting collision detection. In the second stage, in order to further accurately detect, a hierarchical bounding box tree is constructed to divide the bounding boxes into layers and traverse the intersection states of each node layer by layer. A point set determination method is proposed for the basic primitive of leaf nodes to perform the most accurate collision detection. Finally, accuracy testing and real-time experimental verification are conducted in the self-developed MACMT virtual simulation system. The experimental results show that the proposed method can meet the requirements of accuracy and real-time performance. The lowest running frame rate of the proposed method is 89.1 FPS, and the average frame rate is 117.3 FPS. The detection efficiency is improved by 28.3 %, 12.9 %, 10.6 % and 9.8 % compared to traditional methods and other reference methods, respectively. Therefore, the method proposed in this paper can perform collision detection faster and more accurately, avoiding economic losses and ensuring personal safety.