Development of Flexible Spherical Actuator with 3D Coordinate Measuring Device

Rehabilitation devices help to recover the physical abilities of patients. This study aims to develop a portable rehabilitation device that is safe to use when?patients are holding it by hands. In a previous study, to realize a home rehabilitation device, a flexible spherical actuator that can provide motion to patients was developed. In this study, to measure the relative position between both handling stages, a 3D coordinate measuring device using three wire-type linear potentiometers and an embedded controller was proposed and tested. In this paper, the spherical actuator with built-in 3D coordinate measuring device is described. The measuring method and experimental results obtained are also presented. The tracking position control of the actuator using the measuring device was carried out. As a result, the position of the handling stages can be successfully controlled using the feedback signal from the tested?measuring device.

THEORETICAL ANALYSIS OF COORDINATES MEASUREMENT BY FLEXIBLE 3D MEASURING SYSTEM

The system mathematical model of flexible 3D measuring system is built by theoretical analysis, and the theoretical formula for measuring space point coordinate is also derived. Frog-jumping based coordinate transform method is put forward in order to solve measuring problem for large size parts. The frog-jumping method is discussed, and the coordinate transform mathematical model is method of the space point coordinate compared to original value, and an advanced method is provided, Form the space point coordinate transform formula can derive the calculation measuring method for measuring large size parts.

Auto-measuring System of 3-Dimensional Human Body

To realize the automation of fashion industry measuring,designing and manufacturing, the auto-measurement of 3D size of human body is of great importance. The auto measurement system of 3D human body based on Charge Coupled Devices (CCD) and infrared sensors is presented in this paper. The system can measure the bare size of human body that excludes the effect of clothing quickly and accurately.

A Novel Gd Coordination Polymer Based on 2-(Pyridin-3-yl)-1H-imidazole-4,5-dicarboxylate: Synthesis, Structure and Dielectric Properties

A new Gd coordination polymer based on 2-（pyridin-3-yl）-lH-imidazole-4,5-dicar- boxylate, formulated as {[Gd2（HPyIDC）2（H2O）5]·（bpy）·（NO3）2·3H2O}n （1, bpy = 4,4＇-bipyridine） has been synthesized under hydrothermal conditions. The compound crystallizes in triclinic, space group Pi with a = 11.451（2）, b = 11.596（2）, c = 15.7333（3） A, β = 79.47（3）°, Z = 2, V= 1948.6（7） A^3, C30H34Gd2N10O22, Dc = 2.047 g/cm^3, Mr= 1201.17, 2（MoKa） = 0.71073 A,μ = 3.477 mml, F（000） = 1176, the final R = 0.0554 and wR = 0.1181. Polymer 1 is a 2D network built up from 4-connected HPylDC2- anion and 4-connected Gd ions. Dielectric constant of complex 1 was measured at different frequencies with temperature variation.

Robot Vision System for Coordinate Measurement of Feature Points on Large Scale Automobile Part

In this paper,we present a robot vision based system for coordinate measurement of feature points on large scale automobile parts.Our system consists of an industrial 6-DOF robot mounted with a CCD camera and a PC.The system controls the robot into the area of feature points.The images of measuring feature points are acquired by the camera mounted on the robot.3D positions of the feature points are obtained from a model based pose estimation that applies to the images.The measured positions of all feature points are then transformed to the reference coordinate of feature points whose positions are obtained from the coordinate measuring machine（CMM）.Finally,the point-to-point distances between the measured feature points and the reference feature points are calculated and reported.The results show that the root mean square error（RMSE） of measure values obtained by our system is less than 0.5 mm.Our system is adequate for automobile assembly and can perform faster than conventional methods.

Synthesis and Crystal Structure of a 2D Sm(Ⅲ) Coordination Polymer: {[Sm_2L_3(H_2O)_4]·(4,4?-bpy)·3H_2O}_n

A new compound, {[Sm^2L3（H2O）4]·（4,4＇-bpy）·3H2O}n（1, H2 L = 5-（3-pyridyl methoxy） isophthalic acid, 4,4＇-bpy = 4,4A-dipyridyl）, has been hydrothermally synthesized and characterized by single-crystal X-ray diffraction. It crystallizes in triclinic, space group P1 with a = 11.266（2）, b = 15.530（3）, c = 16.711（3） A, α = 112.803（3）, β = 90.526（1）, γ = 94.006（3）°, V = 2686.6（9） A3, Z = 2, Dc = 1.727 g/cm^3, μ = 2.251 mm-1, F（000） = 1392, S = 0.999, the final R = 0.0296 and wR = 0.1058. In the title compound, two crystallographically independent Sm^3＋ cations are bridged by the carboxyl group of L2- ligands to form two different {Sm^2} binuclear subunits which are further connected by two distinct L2- ligands to shape a 1D chain, and such 1D chains are linked up to generate a 2D coordination polymer by another crystallographically unique L2- ligand. The thermogravimetric analysis and luminescent property of the title compound were also investigated.

High Speed Laser 3D Measurement System

Using the method of line structure light produced by a laser diode,three dimensional profile measurement is deeply researched.A hardware circuit developed is used to get the center position of light section for the improvement of the measurement speed.A double CCD compensation technology is used to improve the measurement precision. An easy and effective calibration method of the least squares to fit the parameter of system structure is used to get the relative coordinate relationship of objects and images of light section in the directions of height and axis. Sensor scanning segment by segment and layer by layer makes the measurement range expand greatly.

Measurement and Compensation of Deviations of Real Tooth Surface of Spiral Bevel Gear

This paper presents a method for measurement of deviation of the real gear tooth surface from the theoretical one with a coordinate measurement machine and compensation of repeatable parts. By investigation of characteristics of distortion of the gear tooth surface along the circle direction, the deviation is derived from distortion, and the definition of deviation with the geometrical invariability is proposed. Then the approach for determination of the location and orientation of the gear with respect to the coordinate measurement machine and the measurement way are developed. The deviation is represented with a difference surface, and an algorithm for derivation of parameters of global form deviations from the discrete points has been provided. Finally, the compensation approach is discussed.

Tides and short-term variabilities in the Kuroshio west of Yonakuni-jima

Direct current measurements at the mooring station M southwest of Yonakuni-jima are carried out from May 18 to June 1, 1996. The Observed Kuroshio Current at 290 and 594 m depths of the mooring station M is quite steady ddring the pened of Observation. The rotary spectral estimates of the current data by the maximum entropy method show that there are prominent diurnal and semidiurnal spectral peaks. The semidiurnal tide is predominant at 290 m depth while there is the current fluctuation with the inertial period except for the tidal oscillation at 594 m depth. There are also peaks at the pened of 4-7 d. There is a significant coherence between two time series of currents at 290 and 594 m depths in the pened range of 3 - 5 d. The Japan Meteorological Agency (JMA) wind data during the same period as the oceanic measurement are used in comparison with the current meter data. Rotary spectral estimates for the wind data show significant peaks at the period of 3 - 5 d. It is concluded from the cross spectra between the wind and the current that the current fluctuation of 3 - 5 d period at 290 m depth response to the wind fluctuation of the same periods with time lags smaller than 1 d.

Investigation on 3Dt wake flow structures of swimming bionic fish

A bionic experimental platform was designed for the purpose of investigating time accurate three-dimensional flow field, using digital particle image velocimetry （DSPIV）. The wake behind the flapping trail of a robotic fish model was studied at high spatial resolution. The study was performed in a water channel. A robot fish model was designed and built. The model was fixed onto a rigid support frame- work using a cable-supporting method, with twelve stretched wires. The entire tail of the model can perform prescribed motions in two degrees of freedom, mainly in carangiform mode, by driving its afterbody and lunate caudal fin respectively. The DSPIV system was set up to operate in a trans- lational manner, measuring velocity field in a series of parallel slices. Phase locked measurements were repeated for a number of runs, allowing reconstruction of phase average flow field. Vortex structures with phase history of the wake were obtained. The study reveals some new and complex three-dimensional flow structures in the wake of the fish, including ＂reverse hairpin vortex＂ and ＂reverse Karman S-H vortex rings＂, allowing insight into physics of this complex flow.

Experimental Study on Full-Surface Buckling of Variable Curvature Cylindrical Shell Using Multi-camera 3D-DIC System

To achieve full-surface strain measurement of variable curvature objects,a 360°3D digital image correlation(DIC)system is proposed.The measurement system consists of four double-camera systems,which capture the object’s entire surface from multiple angles,enabling comprehensive full-surface measurement.To increase the stitching quality,a hierarchical coordinate matching method is proposed.Initially,a 3D rigid body calibration auxiliary block is employed to track motion trajectory,which enables preliminary matching of four 3D-DIC sub-systems.Subsequently,secondary precise matching is performed based on feature points on the test specimen’s surface.Through the hierarchical coordinate matching method,the local 3D coordinate systems of each double-camera system are unified into a global coordinate system,achieving 3D surface reconstruction of the variable curvature cylindrical shell,and error analysis is conducted on the results.Furthermore,axial compression buckling experiment is conducted to measure the displacement and strain fields on the cylindrical shell’s surface.The experimental results are compared with the finite element analysis,validating the accuracy and effectiveness of the proposed multi-camera 3D-DIC measuring system.

基于靶标的三目视觉3维坐标测量系统

为了解决复杂环境中大视场、高精度、非接触3维测量问题,采用三目摄像机结构,通过靶标成像来测量被测点3维坐标的测量系统。测量时摄像机采集测量靶标的图像,计算机通过图像处理的方法获取测量靶标上标志点的3维坐标,并提出基于被测点与标志点间距离方程与直线约束的被测点求解优化方法。测量系统通过高精度光栅位移平台带动测量靶标移动来完成测试。结果表明,测量系统在视场范围、测量精度、使用灵活性等方面有较大的改进,能够测量视场深度从2m～5m范围内的视场,测量精度优于0.2mm。

基于CAD模型在三座标测量机中的应用

本文结合英国LK公司三坐标测量机，从典型孔系零件的模型导入、基准拟合、元素检测、数据评定等几个方面，分析CAD模型在三坐标测量机检测技术中的应用。

单台相机三坐标测量的一种新方法

按照常规摄影测量,如果仅使用一台相机而要获取点的三维坐标则至少需要在两个不同的位置进行摄影。这里则提出了利用单台相机仅拍摄单张像片来获取点的三维坐标的测量方法:借助一根带有3个以上已知标志点的辅助测量棒,利用共线方程和辅助测量棒上3个以上标志点先建立测棒坐标系与摄影测量坐标系的转换关系,再通过坐标转换即可得到辅助测量棒测头(所接触的待测点)在测量坐标系中的坐标。另外,通过试验验证了此单台相机测量原理及所达到的相关精度。

基于激光跟踪仪的关节式坐标测量机参数标定

给出了一种6自由度(degree of freedom,DOF)关节式坐标测量机的总体结构设计,运用Denavit-Hartenberg(D-H)方法建立了该测量机的测量方程,并研究了测量机的误差模型,基于激光跟踪仪建立了基于空间坐标变换原理的测量机参数标定模型.对关节式坐标测量机标定前后的测量精度进行了实验验证,实验结果证明高精度激光跟踪仪可实现对关节式坐标测量机的快速标定.

工件特征点三维坐标视觉测量方法综述

针对工件上特征点的三维坐标视觉测量方法进行了综述 ,其中包括结构光方法、激光自动聚焦法、双目视觉方法、三目视觉方法、单目视觉方法等。对每种方法的特点及其测量精度进行了详细的分析 。

自由型曲面的测量与重建

采用双三次参数 Ｂ 样条和最小二乘法拟合三坐标测量机测头中心轨迹曲面，通过测头半径的三维补偿，生成和重建被测自由曲面。本文方法无需要求采样点有序化和被测面边界的切矢和扭矢为已知，其曲面生成精度高，适用于三坐标测量机上自由曲面的快速、精密测量和重建。

人牙咬痕三维重建与数字化分析

利用五轴三维光栅投影法获取实验性咬痕与待比对牙列的表面点云数据,完成模型三维重建并通过坐标转换建立模拟咬痕。在咬痕和待比对牙列上分别设定标志点后,进行各参数计算,通过运用有关测量学原理计算各个特征量极限误差,确定各个特征量权重值,并进行统计检验,最终得到同一认定结果;经反复检验证明其有效、准确。

主动三维视觉传感技术的研究

主动三维视觉传感技术主要有飞行时间法、点结构光扫描法、线结构光扫描法和编码面结构光法、莫尔法、相位测量轮廓术、傅里叶变换轮廓术等。介绍了上述各种技术的基本原理和优缺点。提出了一种新的技术,即单幅二维图像不标定自适应三维场景重构技术,给出了它的原理并讨论了其特点。

变臂关节式坐标测量机的参数自标定方法研究

为了有效地提高关节式坐标测量机的测量精度,变臂关节式坐标测量机通过锁定坐标测量机的前2个关节,减小前端关节转角误差的引入降低系统传递误差。经D-H方法建模,变臂关节式坐标测量机和关节式坐标测量机具有相同的数学方程,但是两者具有不同的结构参数,主要差别体现在前2个关节转角。提出了一种基于逆运动学分析方法和非线性规划遗传算法的参数自标定方法。首先,采用Robotics Toolbox中的逆运动学分析方法反求到达同一标定点的多组可能位姿;其次,根据这些反求的位姿结合测量模型计算标定点的坐标值;最后,以单点重复误差为目标函数通过遗传算法进行全局搜索并利用非线性规划算法进行局部搜索获取最优标定结果。实验结果表明,所提出的参数自标定方法使得变臂关节式坐标测量机的单点测量精度提高1 000倍,长度测量精度提高8倍。