Novel Extended Octrees Method for Collision Detection and Volume Removal in Numerical Control Machining Simulation System

• Main Authors: Ko-JenMei, 梅可人
• Other Authors: Rong-Shean Lee
• Format: Others
• Language: en_US
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/52357278212199492902

博士 === 國立成功大學 === 機械工程學系 === 104 === Multi-axis machine tool acts as an important role in manufacture, such as aerospace and mold industries that need producing surface with high complexity and precision. It requires computer aided analyzing, planning and testing to reach the demands of high efficiency, high precision, steady quality and low cost. Simulation system is important part of intelligence manufacturing. The high precision simulation required massive calculation. Hence the algorithm with high efficiency and the functions integration are important topics. In this study, Wires Extended Octrees method is proposed for volume removal simulation. And Shared Triangles Extended Octrees method is proposed for collision detection. The removed geometry is analyzed for simulating the static cutting force. The smallest unit of Wires Extended Octree is wire. The geometry is divided by Octree and each node contains wire structure. The volume removal is achieved by Boolean operation. The Wires Extended Octree costs the memory space of O(n), where n is the grid number on the edge of geometry. The Wires Extended Octree reduces the quantity of computation and raises the precision. The Shared Triangles Extended Octree applies triangle as the smallest computational unit, and shared triangles under the structure of Octree. Since there is no decomposition of any triangle, the modeling process is fast. The triangles and the leaf nodes of the Octree have links in both directions, so the modeling process can be on-line constructed and removed. The collision detection cooperates with the volume removal for the real-time simulation. The data structures and algorithms integrates the functions of collision detection, volume removal, cutting force estimation and motion simulation to a system for virtual machine tools and virtual robot arms. It is verified by industrial cases of five-axis milling of a turbine blade and free-form surface of a bone bracket. The intelligent functions such as the cutting force model, the geometric error model and the cloud manipulation can be expanded, to achieve a machine tools and robot arms work cell with high adaptivity and high efficiency.