Image-assisted collision detection for calculation of an assembly interference matrix

The assembly interference matrix is a foundational information model for assembly process planning such as assembly sequence and assembly path planning, and supports digital assembly simulation, intelligent assembly, digital twin-based assembly, and so on. The assembly interference matrix represents two parts which are collision or not when they move along specific directions. Traditional assembly interference matrix construction adopts geometric collision detection on the approximate swept volume of parts which are composed by moving step by step. This not only leads to a heavy computational load because of the small moving steps but it is also easy to misjudge the contact as collision as well as missing collision due to discrete spatial movement of the part. To overcome these drawbacks, this work equivalent the collision detection of parts during the establishment of the assembly interference matrix as visibility judgment, and develops an image-assisted calculation method to process the collision between the part’s swept volume as the occlusion of images via computer graphics rendering. This method is implemented on OpenGL to ensure its generalizability, and the implicit calculation is completed in a computer graphics rendering process by setting proper rendering conditions by adopting depth testing and stencil testing. Furthermore, the erosion operation of the image process is employed to distinguish whether contact or collision. Lastly, an example for a gear box assembly confirms the effectiveness of this method.