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With the highly intelligent development of the manufacturing industry, assembly problems have become one of the reasons for the high cost of products. One of the main challenges in the automatic planning of assembly sequences is the identification of sub-assembly. The sub-assembly identification can effectively realize the parallel development and planning of the assembly. In the paper, the focus is concentrated on a sub-assembly recognition algorithm. It is used to recognize the sub-assemblies in various assemblies in order to simplify assembly sequence and decrease assembly difficulty and costs. Firstly, the principle of sub-assembly recognition algorithm is clarified, and the structural information model of the assembly is defined by the weighted undirected connection graph. It is then converted into an adjacency incidence matrix to judge the membership relations between parts in the assembly. Second, mathematical modeling is performed according to the process and principle of sub-assembly recognition. Thirdly, the sub-assembly recognition algorithm is programmed in Matlab, and the feasibility of the algorithm is verified by an example. Finally, the sub-assembly center initialization, the quantity of sub-assemblies c, and the fuzzy index m among the important factors in the algorithm are selected to analyze the parameters and optimize the parameters. [ABSTRACT FROM AUTHOR]

In this paper, the three-dimensional (3D) reconstruction of target self-calibrating system for the guidance system of air-to-air missile is researched. The basic ideology of self-calibrating theory is studied in depth and also the advantages and disadvantages of traditional calibration method, which is based on active vision and target self-calibrating method, are listed for comparison. The mathematical model of the perspective camera is established, and on this basis, the camera parameters are figured out combining with LM optimization algorithm. The reconstruction is conducted by the method of stratified calibrating. It is proved that the theory of 3D reconstruction of target self-calibrating system in air to air missile is available according to the experimental results. It puts forward a new research approach for the guidance system of air to air missile to identify the target characteristic information in different azimuths. [ABSTRACT FROM AUTHOR]

The Monte Carlo method is suitable to use for the problems of turbomolecular pumps (TMPs). This method has three calculation models, namely, the 2D, ideal 3D, and real 3D models. Theoretically, real 3D models demonstrate the real geometry of TMP and should be more accurate than 2D and ideal 3D models. In this study, a simple modified algorithm of a real 3D model based on that of Amoli et al. is used to calculate the maximum compression ratio K max of a single-stage TMP in both the free molecular and transitional flow regimes. When the upstream and downstream areas are added to the calculation domain and are sufficiently large to ensure that the velocity distribution of incident molecules near the inlet and outlet of the blade area is close to the real condition, calculation results are quite accurate compared with the experiment data reported by Sawada and are much better than those reported by other previous studies. [ABSTRACT FROM AUTHOR]