Advanced Materials Research Vols. 971-973

Abstract: This paper deals with nonlinear free axisymmetric vibrations of functionally graded thin circular plates whose properties vary through its thickness. The inhomogeneity of the plate is characterized by a power law variation of the Young’s modulus and mass density of the material along the thickness direction, whereas Poisson’s ratio is assumed to be constant. The theoretical model is based on Hamilton’s principle and spectral analysis using a basis of admissible Bessel’s functions to yield the frequencies of the circular plates under clamped boundary conditions on the basis of the classical plate theory. The large vibration amplitudes problem, reduced to a set of non-linear algebraic equations, is solved numerically. The non-linear to linear frequency ratios are presented for various values of the volume fraction index n showing hardening type non-linearity. The distribution of the radial bending stress associated to the non-linear mode shape is also given for various vibration amplitudes, and is compared with those predicted by the linear theory.

Abstract: The design of hardware system for unmanned surface vehicle using IPC is introduced. The hardware system includes shore-based monitoring system, USV carrier and wireless transmission system. The key to USV carrier is IPC and PCI8602 data acquisition card, and PCI8602 is used to control DC motor and other sensors. The differential global positioning system connects with IPC through serial ports of RS232. Shore-based monitoring system mainly includes PC Computers, and wireless transmission system connects with IPC and PC Computer, through serial ports of RS232, so that it achieves wireless data transmission. Then, the experiment results indicate that the hardware system for USV has succeeded to accomplish remote control.

Abstract: Aiming at the complexity of helicopter cable-orientation and high accuracy requirements, a variable universe fuzzy controller combined with ant colony optimization (ACO) is proposed. The ACO is studied and improved to be used in continuous domain. The solution space is decomposed into finite grids then the ACO can be used to optimize the contraction and expansion factors of the universes. The reference cable angle is calculated and the helicopter cable-orientation control system is designed. The adaptive fuzzy controller with variable universe based on ACO is adopted to keep the ground velocity of helicopter at zero. Simulation results indicate that the controller designed in this paper has a better performance than common variable universe fuzzy controller.

Abstract: In the present study, the problem of geometrically nonlinear free vibrations of functionally graded rectangular plates (FGRP) is studied. A homogenization technique has been developed to reduce the FGRP problem under consideration to that of isotropic homogeneous rectangular plate. The material properties of the functionally graded composites examined herein are assumed to be graded in the thickness direction of the plate and estimated through the rule of mixture. The proposed theoretical model is based on the classical plate theory and the Von Karman relationships, and the amplitude equation is derived in the form of a set of non-linear algebraic equation using Hamilton’s principle and a multimode approach. The fundamental nonlinear frequency parameters and the bending stress are then calculated using the iterative and explicit methods of solution to show the effect of the vibration amplitudes and the material distributions. The results obtained in this study are found to be in a good agreement with the published ones dealing with the problem of large vibration of functionally graded plates.

Abstract: Mean Shift algorithm basedon floating point arithmetic calculation is very difficult to be implemented onreal-time systems. Another problem is that the tracking window of Mean Shift isnot adaptive. In order to solve the problems above, an improved Mean Shiftwhich can be implemented on FPGA is presented. Firstly, Hardware/softwarepartitioning based on the complexity of the algorithm is determined theimplementation of SOPC. Secondly, A pipeline structure is employed for MeanShift algorithm to calculate and accumulate kernel function, shift vector andtarget area in a single clock cycle, and accuracy is above 99 percent. Finally,as floating point arithmetic is more time-consuming, custom floating-pointinstruction is added into CPU to improve the algorithm operation speed.Experimental results show that the presented method can adaptively updatetarget windows and track target in 4ms stably, which improve the efficiencyof program by 5 times.

Abstract: This article describes a technique for the use of advanced PLC indexing plate milling machine tools for transformation of the program ; and describes the basic principles of PLC , PLC engineering steps. The system uses Mitsubishi FX2N series PLC as the control center , the entire system using PLC controlled hydraulic valves to achieve the grinding head , under the table up, down , hydraulic cylinders translocation, hydraulic cylinders reset function , enabling Rotary milling machine dedicated automation control system.

Abstract: With the progress of science and technology, people's desire to improve the work efficiency became stronger and stronger. The demand for applied robots is sharply growing. Compared with the traditional rigid robot, the flexible mechanical structure has the advantages of compact and maneuverable. Thusly, this paper follows the direction of low-cost flexible structure, came up with a four-wire flexible manipulator and completed the prototyping research. This manipulator consists of flexible picking paw, flexible picking arm and control system three mainly parts, can be used in various fields.

Abstract: The geometrically non-linear axisymmetric free vibration of functionally graded annular plate (FGAP) having both edges clamped is analyzed in this paper. The material properties of the constituents are assumed to be temperature-independent and the effective properties of FGAP are graded in thickness direction according to a simple power law function in terms of the volume fractions. Based on the classical Plate theory and von Karman type non-linear strain-displacement relationships, the nonlinear governing equations of motion are derived using Hamilton’s principle. The problem is solved by a numerical iterative procedure in order to obtain more accurate results for vibration amplitudes up to twice the plate thickness. The numerical results are given for the first two axisymmetric non-linear mode shapes, for a wide range of vibration amplitudes and they are presented either in a tabular or in a graphical form, to show the significant effects that the large vibration amplitudes and the variation in material properties have on the non-linear frequencies and the associated bending stresses of the FGAP.

Abstract: Accuracy recession is the prime cause which affects the accuracy retentivity of highly-precise Numerically-Controlled Machine Tools, and in recent years a lot of work has been done in this field at home and abroad. The current state and the progress on the research of accuracy recession of numerically-controlled machine tools were comprehensively presented. The effect of friction and wear, the mechanical structure and operation conditions on accuracy recession of numerically-controlled machine tools were described and commented as the key point. And suggestions and developing directions were also put forward aiming at the existed problems.

Abstract: Blade tip losses would reduce lift and power of wind turbine. This paper analyzed the mechanism of tip losses, and according to Prandtl and Glauert tip loss correction factor and blade element - momentum theory derived the blade chord formula with tip losses. Further, lift coefficient calculation formula was obtained by integrating along the blade span. The lift coefficient formula considering tip loss expressed the highest value of lift coefficient of any practical wind turbine with tip losses. The research shows, the impacts of tip losses to chord concentrated in the tip area; tip losses will reduce the lift coefficient about 2 to 6 percent when tip speed ratio changes from 10 to 4.