虚拟维修中表面间碰撞检测问题研究

Research on Collision Detection between Surfaces for Virtual Maintenance

基于几何约束的虚拟样机中,表面间的碰撞检测是实现维修操作的必要条件。目前有一些公用的碰撞检测工具包,但这些碰撞检测工具包一般支持多面片模型,并没有利用CAD模型中的表面信息,无法确定发生碰撞的表面。该文针对虚拟维修操作的特点,提出了一种新的场景图数据结构。在该场景图下采用表面-三角面片映射和表面-对象映射,在通用的碰撞检测工具包的基础上实现表面间的碰撞检测。最后,描述了约束管理系统的结构,利用该系统可对碰撞检测系统中发生碰撞的表面进行约束识别和求解,从而有效地支持虚拟维修中的装配和拆卸操作。

Detecting collision between surfaces is important and necessary for supporting interactive maintenance operations based on the geometric constraint - based simulation. The current collision detection toolkits are used for supporting polygonal models and are effective in determining exactly the intersecting polygons. However, they disregard all the surface data of the CAD model and do not provide information about intersecting surfaces. Therefore, an effective scene graph data representation of virtual maintenance training system is presented in this paper. The surface based collision detection is implemented by surface - polygon mapping algorithm and surface - object algorithm on top of current collision detection toolkits. Final, the system of restriction management is built up, which can use colliding surfaces to simulate realistic maintenance behavior interactively.