Interference Detection And Processing Algorithm Based On Multi-information Voxel Model

In the process of tool-interference detection and processing in the area of additive manufacturing and multi-axis machining for triangular mesh models,there are efficient problems in the detection and processing of interference due to the low efficiency of the intersection of Boolean operation in the triangular mesh model.To handle these questions,study on the characteristics of the triangular mesh model,voxel model and voxel model Boolean operation process was carried out,and a new two-level voxel model with multi information was build.A brand new method for the detection and processing of tool-interference with triangle mesh model was designed.The multi-information two-level voxel model designed in this paper is a two-level voxel model based on triangle mesh original data and topological relations.At the basement of this voxel model,two attribute-value 3-dimensional arrays were built as the mapping of the first and the second voxel space.And the attribute value of each voxel element was recorded in the corresponding element in these arrays.In addition,another surface information three-dimensional array was used to record the seed triangle mesh ID in each boundary voxel of the second-level voxel space.In the process of establishing the multi-information two-level voxel model,the seed triangle mesh was firstly recorded in the second-level voxel space and the boundary voxels were identified.Then,the boundary voxels were coded in a plane and the solid voxels were found.And finally establish a first-level voxel model based on the second-level voxel model,so as to complete the establishment of the data structure.Based on the multi-information two-level voxel model,this paper designed the interference detection and processing algorithms for global interference and local interference.For the global interference problem,this paper firstly classified the global interference phenomenon into two types: tangential and penetrating.Then a global interference detection algorithm was designed.The algorithm scanned from the tool location point along the axis of the knife and the intersecting voxels were detected for the intersection.From the intervening voxels,the local model's surface mesh is indexed to make a fine judgment.For "tangential" global interference,this paper designed a tool orientation adjustment algorithm based on bounding box.For the "penetrating" global interference,firstly the "adjust hemisphere" at the knife site should be built and the voxels inside this hemisphere could be found.Then the attitude of the tool could be adjusted based on the triangular mesh neighbor area in these boundary voxels.For the local interference phenomenon,this paper adopted the method of “knife raising” to deal with the problem of over-cutting.Firstly,the voxel elements that intersect with the cutter head were fount out,and indexed out the local triangular mesh neighbor area,and then the "lifting knife" distance was calculated according to each three triangular grids and finally achieved the removal of local interference.The multi-information two-level voxel model described in this paper can provide “relative position information” at any point in space relative to the surface of the original model as well as the “local topographic information” at the surface.The interference detection and processing algorithm designed based on this data structure has the advantages of high efficiency and accuracy.It can effectively deal with the global interference and local interference problems at any position on the triangular mesh model,and provides a set of feasible solutions for interference-free tool attitude.