Applied Mechanics and Materials Vol. 192

Abstract: This article is in view of the model data storage the problems in the process of interaction, through the XML data intermediate storage method, of the hydraulic press for each model will be stored in the characteristic dimensions in the XML document, according to the predetermined XML Schema (XML Schema Definition, XSD), more articulate products of various kinds of CAD model design information. In this way the data exchange, this model of data kept the way to avoid inconsistencies, transfer of data volume is small, and not in the different between platform to transmit documents appear data loss, data distortion phenomenon, for the follow-up of CAE/CAM analysis with good books.

Abstract: Based on the structured light measurement principle, digital fringes projection technology and phase-shifting measuring technology, specific to the 3D profile of some tiny objects like teeth, in this paper we proposes a 3D scanning system which was directly used for intraoral dental measurement utilizing the merits of flexible and long distance signal transmission of the fiber image bundle. The structured light is projected out from DLP LightCommander produced by Texas Instruments Company, shrunk via telecentric imaging lens, conveyed in fiber image bundle. Utilizing the transformational relation between single-camera and projector, afterwards, the 3D profile of teeth is obtained by reconstructing the acquisition images in electronic endoscope. The feasibility of this system has been testified in our experiments. It satisfies the requirements of miniaturization, directness and flexibility; expands the scope of application of micro-3D measurement with structured light in dental clinical practice.

Abstract: In this paper, the application of a FPGA-based large-screen and high-resolution display accelerator technology in full-automatic textile machinery (computerized flat knitting machine) is studied. The design of traditional computerized knitting machine system is difficult to support the display of large screen and high resolution operating interface. Therefore, a displaying accelerator is designed in this paper. It comprises of FPGA, configuration chip, SDRAM and LVDS transmitter chip, is located between the embedded main processor and high resolution TFT LCD screen of computerized flat knitting machine, and implements the modules such as display acceleration logic and SDRAM controller relying on Verilog HDL programming in FPGA. The computerized flat knitting machine, applying displaying acceleration technology, can present its dynamic color interface on an 800 x 600 resolution TFT LCD (10.4") on the condition that real time, reliability and cost can be ensured.

Abstract: Aim at the need of excessive freedom jointing robot real time measuring joint angle positions during work process, The engineer is an measure system of excessive freedom jointing robot, which are base on absoluteness type photo-electricity coder and TMS320F2812. The system have more group sixteen bits IO and SCI communicate interface, which can make jointing robot real time measuring, and implement the visual interface of the upper machine .The system has well real time and friendly human-machine interface, which is the same with minutely machining appliance extensive.

Abstract: This paper analysis the formation conditions of isolated power system, its influencing factors, revealing the operation mode, automatic safety device, generator protection regulation characteristics and these factors to stable operation of isolated power system. The dynamic models for isolated power system with generating unit of medium and small capacity are proposed in the paper to meet the need of the applicable ones to study their dynamic characteristics. The differences between isolated and the interconnected power system in the frequency characteristics are proposed and consider into low-frequency load shedding scheme and optimization methods that can meet both isolated and the interconnected power system frequency stability requirements. Not only more proper control strategy of units but their evaluation indexes are suggested to improve performance and achieve stability in islanded power system.

Abstract: Complex resistivity of soil must be measured using low-frequency power supply to overcome the skin effect, but, because of using higher frequency, the existing conventional complex resistivity meter is not suitable for soil. To this end, with the discrete Fourier transform and spectrum analysis, a measurement system for soil complex resistivity based on LabVIEW virtual instrumentation development platform and PXI data acquisition card was designed and developed. The system can measure the complex resistivity of the soil under low frequency, track the fluctuations of supply frequency automatically using of software synchronization technology, and then automatic adjust the sampling rate to reduce measurement error. The measurements results of the Cole-Cole circuit model of complex resistivity show that the system has a high accuracy.

Abstract: At present, the analog signal source in a traditional sense is far away from being sufficient to meet the needs of the modern development. Besides, the emergence of the direct digital synthesis (DDS) technology brings about a new vitality to the electronics technology of the modern times. However, because of the characteristics of the digitization, the direct digital synthesis still has the problems (the limited the output frequency range and the large spurious output). For this reason, it is particularly important to solve these problems currently. In this paper, the author carries out an analysis on the circuit characteristics of the DDS system and the analog modulation signal source system, studies their performances and characteristics, and also makes a design on both software and hardware that are based on the analog circuit and AT89C51 microcontroller system. This system is mainly composed of the microcontroller control module, the frequency synthesis module and the multiplier module. The DDS frequency synthesizer can work stably and is easy to realize. Also, the high resolution of its output frequency can meet the requirements of people in the modern times.

Abstract: The paper discusses the pth moment stability of neutral stochastic differential equation with multiple variable delays. The stability is more general and representative than the exponential stability. This investigation uses a specific Lyapunov function based on usual methods. And it discusses the neutral stochastic differential equations with multiple variable delays which is much more general form. Finally a two dimensional half-linear example is discussed to illustrate the theory.

Abstract: The performance of MEMS gyroscope is crucial to its application, and the zero-bias stability is the main characteristic parameter of gyroscope performance. When fusing several outputs of similar MEMS gyroscope, we often use the weighted mean method. The weight has great influence on the fusing result. In this paper, the optimal weight choice used in the fusion of Multi-MEMS gyroscope data is derived based on multivariate numerical theory. Experimental results show that after simulating multi-MEMS gyroscope data fusion on the measurement result of several gyroscopes, the zero-bias stability will effectively improve.

Abstract: The majority of MEMS based gyroscopes currently under development operates in a vibratory mode and measures the angular rate instead of the absolute angle. The paper aims to establish the system dynamics models of the typical MEMS Gyro: Vibration Micro-gyroscope and analyzes the dynamic features. With different precision MEMS Gyros as the example, the detailed Times-series analysis are made of AR (6) and ARMA (2, 1) models, the impact of considering the estimation effective and the precision improved