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With the increase of the weight and volume of the processed parts, large CNC vertical lathe has become the ideal equipment for large parts. The main factor that influences the processing efficiency of CNC vertical lathe is hydrostatic thrust bearing speed. The thrust ball bearing with DVT500 CNC vertical lathe was adapted as the research object to research on motion characteristics of CNC vertical lathe hydrostatic thrust bearing, and the three-dimensional flow mathematical model and boundary condition of hydrostatic thrust bearing system were built up. Then the hydrostatic thrust bearing temperature field distribution and lubricating properties were obtained with the use of computational fluid dynamics (CFD) theory and the finite volume method combined with the segregated solver of FLUENT. The simulation results show that, using oil feedback can improve the bearing capacity and stability of thrust bearing, structure of large hydrostatic thrust bearing design and has a guiding significance to the operation reliability.

The oxidation kinetic curves of four kinds of austenitic stainless steel at 700°C was measured by weighting method. It is showed that the oxidation curves of those austenitic stainless steels follow the parabolic law. The mass gain of 800Al steel. is the least of all. The surfacemorphology and structure of the oxide scale were studied by scanning electron microscopy and X-ray diffraction methods. It is found that adense oxide scale formed at 700°C in all four austenitic stainless steels. In austenitic stainless steel with high Mn content, scales are mainly composed of Mn2O3 and the spinel MnFe2O4. Scales of austenitic stainless steel with high Cr content but without element Al are composed by Cr2O3 and the small amount of spinel FeCr2O4 . Scales of austenitic stainless steel with element Al and Cr are composed of (Fe0.6Cr0.4)2O3 and Al oxide, showing the excellent oxidation resistance property.

A picking and steering adjustment system for blueberry harvesters has been developed. In this paper, the main hardware and working principles of the system is introduced first, then the application of an ant colony simplification algorithm in the system development is presented. Information of virtual modeling the blueberry plant images and fruit distributions is obtained through the control system which is used as input for the ant colony simplification algorithm calculation. Then results are translated into real-time travelling path planning instructions for the blueberry harvester. The research provided technological and new knowledge support for future investigations into intelligent travelling path selection, thus playing an important role in mechanization and intelligent harvesting processes for blueberry harvesters.

The color of blueberries is not only an important appearance quality for mature blueberries, but a standard for blueberry harvesting. In this paper, through blueberry detection hardware system, blueberry color parameters in RGB image space are figured out. Then, in order to input the parameters into the harvesting system, Hue in HLS image space is carried out by neural networks.

A novel sensor placement criterion is proposed for structural health monitoring after five influencing criteria are critically reviewed. The objective of the proposed criterion is to achieve best identification of modal frequencies and mode shapes through almost unbiased estimation of modal coordinates. The proposed criterion derived by the Representative Least Squares method depends on both the characteristics and the actual loading situations of a structure. It selects sensor positions with the best subspace approximation of the vibration responses from the linear space spanned by the mode shapes. Furthermore, the connection between the Effective Independence and the approximate Representative Least Squares estimator is obtained through matrix perturbation analysis. It is found that the Effective Independence is a step-by-step approximation to that of the Representative Least Squares criterion.