Papers by Keyword: Virtual Measurement

Abstract: This paper analyzed the adjustment principle and calculation method of parameters for CNC spiral bevel gear milling machine, and establish the models of NC machining of spiral bevel gear milling machine. Through the calculation of examples, we acquire the machine tool axes of the instantaneous position when CNC spiral bevel gear milling machine process. The paper establish simulation machine model of spiral bevel gear milling machine and the simulation processing. The simulation results meet the spiral bevel gear milling machine functional verification requirements.

Abstract: Based on machining principles of spiral bevel gear and coordinate transformation matrix, the formate-cut wheel model was built. The gear tooth surface of the model has controllable error and can be imported into the Virtual Gear Measuring Center (VGMC) to be virtually measured. The various factors that affect the gear model accuracy were analyzed and the error control strategy was proposed, which lays a solid foundation for the realization of the gear tooth surface measurement and error analysis of spiral bevel gears.

Abstract: Virtual surface measurement is necessary to assist the actual measurement of large deployable space antenna structure. To realize a virtual surface measurement on this kind of structures, we take several steps to get the virtual measurement images. A virtual 3D model of the antenna structure and virtual hung system are constructed; virtual measure rules, coded marks and uncoded marks are also built up. The pinhole camera model is used to simulate the actual photogrammetric measurement tools. Through examples with OpenCV tools, the virtual measurement method is verified to be reasonable. Then different resolution images of perspective projections of the virtual measurement in virtual camera positions and orientations are obtained. Proper selections of the camera resolution and proper positions and orientations of the camera are found through virtual measurement experiments. Such results can be used in an actual photogrammetric measurement. The virtual measurement method can be used to reduce the attempt times and to assist the actual measurement with available photogrammetric measurement tools.

Abstract: The architecture of VGMC was introduced, a virtual workpiece modeling methods and procedures was proposed, also the workpiece drawing in professional graphics software was transformed successfully into VGMC. It proves that the virtual wokpiece can be used in the virtual measurement, and the measurement software will be detected by virtual measurement using virtual wokpiece.

Abstract: A virtual measurement system for geometric surfaces of some specific mechanical components was created with Cage Method and Virtual Probe technique based on Three Model Method. The fundamental constituents of the system, the key part of the Three model Method, measured model, were presented in detail with weighed random number technique. Measuring accuracy may properly be controlled by alteration of the number of sampling points of the measured model. Principle of the measuring system, with extendable function, was put forward and explained. The system was operated by VC++ and OpenGL with characteristics of lifelike, function-extension, and immersion. Virtual measurement on a bar-shaft for cylindricalness is given as an example, and it has been shown that the results have much good agreement with those of experiments and that the system worked stably.

Abstract: Wavelet analysis was applied to detect the greatest deviation from the perfect circle for the roundness and cylindricalness of shaft-like components in the virtual manufacturing engineering. Based on the concepts of the roundness and cylindricalness, the least square method was adopted into the determination of the reference—the least square circle from which the deviation was calculated. In order to obtain the extremum of the errors, wavelet transform was carried out with binary wavelet from the time domain to frequency domain. A virtual probe was used to have the signals for the measured point by using WTnode_gettranslation() function. The accuracy of the measurement depends, to a large extent, on the length of individual step along the axis and the density of the measured points on the sections. Experiments have shown that the measuring processing was time-saving and the results from the wavelet analysis were much reliable.