The validity of using a video-based motion analysis system for measuring maximal area of fingertip motion and angular variation

The aim of the study was to verify the application of a three-dimensional video motion analysis system to evaluate maximal fingertip motion area and angular variation of the hand by comparison and correlation with videofluoroscopic analysis. Eight normal subjects were recruited in this study. The maximal motion area of the fingertip and the angles of the metacarpal phalangeal (MP), proximal interphalangeal (PIP) and distal interphalangeal (DIP) joints in performing five sequential postures for functional evaluation of the hand were measured using a video motion analysis system and a fluoroscopy system respectively. The results indicated that the intraclass correlation coefficient (ICC) of the calculated maximal fingertip motion area between the two methods was 0.9597. The ICC for total active motion (TAM) measurements of three finger joints was 0.940 between the surface and bony landmarks by fluoroscopy, 0.952 between the surface landmarks from fluoroscopy and motion analysis, and 0.927 between the bony landmark from fluoroscopy and surface markers from motion analysis. The ICC for angular measurements between three different paired assessments was 0.9650, 0.8896 and 0.8799 for the MP, PIP and DIP joints respectively. The results indicate that motion analysis is a practical method for assessing impairment of the hand.     

激光制导测量机器人运动系统设计

激光跟踪测量系统是目前最新型的便携式空间大尺寸坐标测量系统,但在测量大型被测对象时,人工布点及测量过程繁杂,测量效率低,并造成被测对象几何形状变形,严重影响其测量精度。为解决以上问题,提出了新型的“光束运动—光靶跟踪”激光跟踪测量方法,建立了新型激光跟踪测量方法论,并在此理论基础上,研制开发了一种能够在水平和垂直被测对象表面上运动小型轮臂复合式激光制导测量机器人。该机器人机构融合轮式机构、爬行臂式结构和真空吸附式机构优点,并且具有重量轻、体积小、运动灵活和反应快速等特点,可以根据不同的被测对象表面特征变换测量模式,利用轮式结构实现机器人在水平被测表面上高速远距离运动,利用爬行臂式和真空吸附式机构实现机器人在倾斜光滑表面上灵活地爬行和转向。对其运动特性进行了详细的分析。最后利用激光跟踪仪和三坐标测量机对研制激光制导测量机器人进行了性能测试,试验结果证明了该机器人能跟踪激光束自动高效地完成被测对象实体测量。     

冲击载荷下载人飞行器乘员颈椎力学行为研究

利用生物力学仿真软件LifeMOD,根据关节力矩模型和肌肉力学模型,建立了用于多刚体分析的三维人体动力学模型。采用载人飞行器在着陆过程中的边界条件,模拟了乘员坐姿承受水平方向冲击作用时头颈部脊椎的动态响应。对航空航天领域中各种致伤因素下乘员脊椎骨骼损伤的研究有一定的意义,同时也为优化防护结构、保障乘员生命安全提供了一定的参考。     

The performance of a new measuring method for three-dimensional ball motion in a ball-bearing

Recently, a new method for measuring ball motions three dimensionally was developed by one of the present authors and its principle was reported in the previous paper.Before its practical applications were examined, the calibration tests were carried out and the outputs obtained by this new method were compared with the values expected theoretically. By compensating for some undesirable effects, it was confirmed that the outputs were sufficient to analyse actual ball motions within an experimental error of 5%.In order to demonstrate its usefulness, an example of experimental results obtained by this new technique is shown.     

钢管光电测长系统及误差分析

介绍了一种钢管光电测长系统及其测长原理,并对定长钢管重复50次测量所得数据进行了分析.结果证明,此测长方法可使测长精度达到±1 mm.     

Eddy-current measuring system for analysis of alloy defects and weld seams

A measuring system based on an eddy-current transformer permits the detection of defects in plates of duralumin and aluminum–magnesium alloys.     

孔系间距的现场测量方法精度分析

分析孔心间距现场测量的不同方法,并计算各测量方法的误差,选择最优的测量方案加以推荐。     

基于运动微分方程特征值的转子-轴承系统失稳可靠性分析

从转子-轴承系统的运动微分方程入手,应用零部件可靠性分析方法,以运动方程特征值为稳定裕度评估量选定系统的状态方程,对动压润滑的向心滑动轴承进行了可靠性分析。通过数值仿真分析对建立的可靠性模型进行了验证,为工程实际中动压润滑向心滑动轴承的选用和轴系的设计提供一定的理论依据。     

拉力试验机的计算机辅助测试系统

阐述拉力试验机的计算机辅助测试系统的设计方法 ,以及该系统的特性、测量放大及数据采集 ,给出了试验软件的设计实例     

Development of high-precision micro-coordinate measuring machine: Multi-probe measurement system for measuring yaw and straightness motion error of XY linear stage

Today, with the development of microsystem technologies, demands for three-dimensional (3D) metrologies for microsystem components have increased. High-accuracy micro-coordinate measuring machines (micro-CMMs) have been developed to satisfy these demands. A high-precision micro-CMM (M-CMM) is currently under development at the National Metrology Institute of Japan in the National Institute of Advanced Industrial Science and Technology (AIST), in collaboration with the University of Tokyo. The moving volume of the M-CMM is 160 mm × 160 mm × 100 mm (XYZ), and our aim is to achieve 50-nm measurement uncertainty with a measuring volume of 30 mm × 30 mm × 10 mm (XYZ). The M-CMM configuration comprises three main parts: a cross XY-axis, a separate Z-axis, and a changeable probe unit. We have designed a multi-probe measurement system to evaluate the motion accuracy of each stage of the M-CMM. In the measurement system, one autocollimator measures the yaw error of the moving stage, while two laser interferometers simultaneously probe the surface of a reference bar mirror that is fixed on top of an XY linear stage. The straightness motion error and the reference bar mirror profile are reconstructed by the application of simultaneous linear equations and least-squares methods. In this paper, we have discussed the simulation results of the uncertainty value of the multi-probe measurement method using different intervals and standard deviations of the laser interferometers. We also conducted pre-experiments of the multi-probe measurement method for evaluating the motion errors of the XY linear stage based on a stepper motor system. The results from the pre-experiment verify that the multi-probe measurement method performs the yaw and straightness motion error measurement extremely well. Comparisons with the simulation results demonstrate that the multi-probe measurement method can also measure the reference bar mirror profile with a small standard deviation of 10 nm.     

影响切削工件表面质量的因素分析及要因的检测系统设计

采用因果分析图等质量分析工具分析了影响切削加工工件表面质量的原因,并找出了影响表面粗糙度的主要因素是切削力、切削温度和机械设备振动.针对切削力和切削温度影响因素,将薄膜热电偶技术引入切削温度检测,设计了一套切削力和切削温度的完整检测系统.试验表明,该检测系统人机交互作用强,操作简单,使用方便.     

Derivation of stiffness matrices for modeling a human cervical spine

Based on the published experimental data under static loading condition, stiffness matrices of the cervical spine were developed. These matrices simulate well the static response of the cervical spine as shown by the authors in an earlier work, while for a dynamic simulation these matrices need some modifications in order to achieve more accurate results. We present a method, in the form of a constrained optimization problem, that facilitates the evaluation of the stiffness matrices to be used in a dynamic simulation. The intervertebral disk and the ligaments are represented by an equivalent stiffness matrix whose elements are assumed to be constant over the entire range of mobility. With a set of new stiffness matrices derived by the proposed method, the dynamic simulation showed a good agreement with the observed motion data.     

A computer method for the dynamic analysis of a system of rigid bodies in plane motion

This paper presents a computer method for the dynamic analysis of a system of rigid bodies in plane motion. The formulation rests upon the idea of replacing a rigid body by a dynamically equivalent constrained system of particles. Newton’s second law is applied to study the motion of the resulting system of particles without introducing any rotational coordinates. A velocity transformation is used to transform the equations of motion to a reduced set. For an open-chain, this process automatically eliminates all of the non-working constraint forces and leads to an efficient integration of the equations of motion. For a closed-chain, suitable joints should be cut and few cut-joints constraint equations should be included. An example of a closed-chain is used to demonstrate the generality and efficiency of the proposed method.     

Recent advances in finite element modeling of the human cervical spine

The human cervical spine is a complex structure that is the most frequently injured site among all spinal injuries. Therefore, understanding of the cervical spine injury and dysfunction, and also biomechanical response to external stimuli is important. Finite element (FE) modeling can help researchers to access the internal stresses and strains in the bones, ligaments and soft tissues more realistically, and it has been widely adopted for spine biomechanics research. Although in recent years numerous techniques have been developed, there are no recent literature reviews on FE models of the cervical spine. Our objective was to present recent advances in FE modeling of the human cervical spine in terms of component modeling, material properties, and validation procedures. Model applications and further development are also discussed. The integration of new technologies will allow us to generate more accurate and comprehensive model of the cervical spine, which can increase efficiency and model applicability. Finally, the FE modeling can help to facilitate diagnosis, treatment, and prevention technologies for cervical spine injuries.     

船舶清刷装置运动系统力学分析

对船舶清刷装置运动系统力学进行了分析。建立了船舶水下清洗设备沿船体表面上下运动时的力学模型,推导了清洗设备抗倾覆、下滑和下滚时的条件,计算了清洗设备正常沿船体上下工作时所需要的最小吸附力和驱动力矩。同时,在设备的后部安装两个弹簧支撑的万向轮,提高了清洗设备的运动性能。数值计算表明,该方案能减少最小吸附力和驱动力矩,达到抗倾的目的。     

漳泽发电分公司煤量计量系统问题分析

分析了山西漳泽发电分公司所使用的皮带秤煤量计量系统在应用中发现的问题,并进行了原因分析,提出了处理方法。     

超声波测厚系统的研究

深孔加工是一种封闭式或半封闭式状态下的加工,其加工过程很不稳定,深孔加工刀具的走偏现象直接影响被加工孔的直线度,造成被加工工件报废,所以在深孔加工过程中的实时检测就显得尤其重要.根据深孔加工系统的特点,将超声波测厚原理用于单管内排屑喷吸钻深孔加工在线监测中,通过检测被加工工件壁厚来判断刀具是否走偏,结果表明,该测试装置较好地解决了深孔钻削加工刀具走偏的监测问题.