Research on Digital Dynamic Testing Technique for Electrohydraulic Servovalve

The digital testing technique based on computers for dynamic characteristics of electrohydraulic servovalves via frequency scan method is researched. The no-load piston which measures the servo‘ s transient output flow is designed properly. The velocity testing method by which the speed signal can be obtained indirectly by means of a piezoelectral accelerometer is given. High speed sampling has been realized in Windows OS. Wavelet denoising and Fourier transform are adopted in data processing and analyses. The testing technique discussed has been applied to actual testing systems and the experimental results have proved it to be correct.     

MTF Measurement of EBCCD Imaging System by Using Super Resolution Technique

Existing methods of measurement MTF for discrete imaging system are analysed. A slit target is fre-quently used to measure the MTF for an imaging system. Usually there are four methods to measure the MTF for a discrete imaging system by using a slit. These methods have something imperfect respectively. But for the dis-crete imaging systems of under sampling it is difficult to reproduce this type of target properly since frequencies above Nyquist are folded into those below Nyquist, resulting in aliasing effect. To tackle the aliasing problem, a super resolution technique is introduced into our measurement, which gives MTF values both above and below Nyquist more accurately.     

Dynamic Factor Method of Computing Dynamic Mathematical Model for System Simulation

The computational methods of a typical dynamic mathematical model that can describe the differential element and the inertial element for the system simulation are researched. The stability of numerical solutions of the dynamic mathematical model is researched. By means of theoretical analysis, the error formulas, the error sign criteria and the error relationship criterion of the implicit Euler method and the trapezoidal method are given,the dynamic factor affecting the computational accuracy has been found, the formula and the methods of comput-ing the dynamic factor are given. The computational accuracy of the dynamic mathematical model like this can be improved by use of the dynamic factor.     

A Fast RLE-based Reconstruction Technique for Real-time Robot Tracking

Wheeled Mobile Robots (WMRs) are more and more widely used in advanced manufacturing.For real time tracking of WMRs,a novel way for real-time color image reconstruction based on Run Length Encoding (RLE) is present.In- dexed from a fast look up table (FLUT),color image can be encoded into multiple llne structures with different specified colors. Through object-oriented method,the RLE elements reconstruct the image features.Successful application of this technique for mo- bile robots identification is reported.     

Error Analysis for High-precision 7m Laser Measuring Machine

This paper introduces a high precision 7m laser measuring instrument developedby the anthors and its operating principle,and systematically analyses the errors havinginfluence on the performance of the measuring instrument.Error analysis and actualverification indicate that all the characteristics reached or exceeded the original designspecifications.     

On Concept of Dynamic Economic System With After－Effects─Research on Dynamic Economic System with After－Effects （Ⅰ）

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Method of Precision Control of 3－D Solid Discretization Based on the Second－Order Osculating Surface

A discretization precision control method based on the second-order osculating surface is proposed. The discretization precision of 3-D solid is controlled according to the error between the discrete solid surface and its second-order osculating surface. The global maximal error has been gotten after analyzing all the extremums of the error function. It can be used in controlling and optimizing the discretization precision of 3-D solid in computer 3-D modeling and NC milling path generation.     

Dynamic modeling and simulation for nonholonomic welding mobile robot

Based on the Newton-Euler method, the dynamic behaviors of the left and right driving wheels and the robot body for the welding mobile robot were derived. In order to realize the combination control of body turning and slider adjustment, the dynamic behaviors of sliders were also investigated. As a result, a systematic and complete dynamic model for the welding mobile robot was constructed. In order to verify the effectiveness of the above model, a sliding mode tracking control method was proposed and simulated, the lateral error stabilizes between ?0.2 mm and 0.2 mm, and the total distance of travel for the slider is consistently within ±2 mm. The simulation results verify the effectiveness of the established dynamic model and also show that the seam tracking controller based on the dynamic model has excellent performance in terms of stability and robustness. Furthermore, the model is found to be very suitable for practical applications of the welding mobile robot.     

A Novel Method for Measuring Electro-optic Coefficient of Poled Polymer Waveguide

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圆柱度仪测量基准反向法误差分离技术

对大尺寸试件的圆柱度误差的超精测量,仪器的测量基准误差不能忽略,如何分离出基准本身的形状误差及基准之间的位置误差产长期存在的难题。本文首次提出一种可分离出基准间的平行度误差以及直行基准的形状误差的方法,即反向法,从而较圆满地解决了这一问题。利用该方法建立的模型可用于重要试件圆柱度误差的超精测量中,该技术对超精密车床的研制提供了依据。     

数字式测高仪的动态特性测试分析

数字式测高仪的测量速度、定位精度和测量力是表征其动态特性的3个主要方面.为此,论述了它们的具体测量方法,以某数字式测高仪为对象,采用微平面镜激光干涉仪、精密测力计等器具进行动态特性测试,给出了测试结果,分析了误差来源及其变化规律,其中,对测高仪定位误差的测试与分析是新的尝试.测试结论对改进测高仪的设计、提高测量精度具有实际价值.     

常用测量仪器的使用及测量误差的计算

介绍了测量误差的来源，以电压表和电流表测量电路中的电压和电流为例，提出了减小仪表测量误差的方法，包括采用电压表、电流表在不同量程下进行2次测量的计算法，合理选择电阻挡的量程，减少示波器的测量误差，合理选择仪表的准确度等．实验结果表明，采用这些方法可以有效减少测量误差．     

常用测量仪器的使用及测量误差的计算

介绍了测量误差的来源,以电压表和电流表测量电路中的电压和电流为例,提出了减小仪表测量误差的方法,包括采用电压表、电流表在不同量程下进行2次测量的计算法,合理选择电阻挡的量程,减少示波器的测量误差,合理选择仪表的准确度等.实验结果表明,采用这些方法可以有效减少测量误差.     

现场照相测量的相机标定研究

照相机标定是利用计算机视觉技术进行测量的基础工作.根据相机成像的几何原理,分析了照相机的一般性标定原理、方法和过程,并根据在交通事故现场使用照相测量技术时标定的特点,结出了实验研究的解决方法.     

基于虚拟仪器技术的轮荷测量仪电测系统开发

依据电阻应变测量原理,应用机电一体化技术,开发测量汽车轮荷的测量仪电测系统.该系统由数采硬件电路和上位机车辆轮荷测量系统软件组成.应变传感器测得的电压信号,先后经过调理电路、A/D转换电路和光电隔离电路,传输给MCU.通过串口通信协议,MCU与上位机轮荷测量系统间进行指令和数据的传输,数据经过存储和运算处理后,通过上位机系统面板把轮荷值传达给用户,并将结果储存到PC机中.采用砝码加载,在可倾斜卡具上对测量仪进行了实验标定.根据实验数据算得测量仪的非线性误差为±0.72%,重复性误差为±1.37%,迟滞性误差为±1.47%,灵敏度误差为±1.67%,最终得到综合误差为±2.71%,满足轮荷测量仪预期设计的测量精度和功能要求.     

LabVIEW与圆度误差虚拟测量仪

简要介绍了虚拟仪器的系统构成，利用LabVIEW作为软件开发平台，以PCL818L数据采集卡作为前向通道硬件设计基础，设计了可视化圆度误差虚拟测量仪。     

A New Study to Compensate Dynamic Measuring Error of Serial Multiple Degree of Freedom（DOF） Strain Gauge Force Sensor

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Investigation of the Dynamic Characteristics of a Rotor Bearing Assembly

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关于平直度测量仪精度的探讨

本文从原理、结构、制造及使用等方面来分析平直度测量仪的误差。试图找出各因素对仪器的影响程度,以便提高产品的精度。