Virtual Gear Measurement Center Touch Detection

Virtual gear measuring center (VGMC) is a pure software system, which maps and simulates the real mechanical structure, workpieces characteristic and measuring procedure of the real gear measuring center in virtual enviroment. The VGMC plays an important role in the software development and its certification, the separation of measurement error and measurement uncertainty of the real gear measuring center.The touching test is the core of the VGMC. The working performace of the whole system is depending on the arithmetic of the virtual probe and virtual workpieces touch testing. The research on the touching test of VGMC is different from the virtual coordinate mesuring machine (VCMM). In the VCMM, the discrete single point is mainly measured. While in the VGMC, the contiuous scanning touching test of the virtual probe and virtual workpieces is concerned, which mainly relates to the geometrical representation and touching test of the virtual probe and virtual workpieces. In the geometrical representation, the data that is generated by CAD software is imported to the system and then is opened by using OpenGL function. Therefore, in this paper, the DXF and STL are discussed in details, which are two storage formats of the three-dimensional graphics. Meanwhile, the model of the virtual probe and virtual workpieces are generated by using the imported data in the forms of ASCII of STL. In the touching detection, both discrete and continuous collision detection algorithms are studied in this paper. Finally, a kind of contiuous collision detection algorithm is selected, which is composed of Constact and algebra. As the research on the touching detection test of the VGMC is still at the foundation stage, it is mainly carried out in two-dimension space. The touching detection test of virtual probe and virtual workpieces are implemented by using the two methods mentioned above. Experiments result shows that a combination of both collision methods applied to the measurement of the virtual Gear alveolar have a good effect. The concepts of equidistance line and the offset surface in the virtual workpiece are introduced in this paper, which presents a preferable direction to the future researches. The continous scanning touching detection between the virtual probe and virtual workpieces is achieved in the two dimensional space, which lays the foundation for both the three-dimensional space touch detection test and the whole virtual gear measurement center.