双摇杆假肢膝关节的运动学与动力学分析

膝关节是人体正常运动的重要部位。为了满足下肢截肢患者恢复正常运动功能的需求,设计了一款双摇杆机构的假肢膝关节。首先,建立了下假肢的简化模型,通过对模型的运动学分析,获得了相关关节角度、角速度、角加速度等参数。通过动态静力分析法对双摇杆的各个杆件进行动力学分析,最终得到输出阻尼力与驱动力矩之间的平衡方程。通过Adams仿真分析,得到了高度相似的膝关节瞬心轨迹和踝关节轨迹运动曲线对比图。结果表明,设计的双摇杆假肢膝关节具有良好的稳定性与仿生性,能够满足截肢患者的运动需求。研究为双摇杆假肢膝关节整体的结构设计、加工和实时控制提供了理论依据。     

A method for the reduction of skin marker artifacts during walking : Application to the knee

Previous studies have demonstrated the importance of joint angle errors mainly due to skin artifact and measurement errors during gait analysis. Joint angle errors lead to unreliable kinematics and kinetic analyses in the investigation of human motion. The purpose of this paper is to present the Joint Averaging Coordinate System (JACS) method for human gait analysis. The JACS method is based on the concept of statistical data reduction of anatomically referenced marker data. Since markers are not attached to rigid bodies, different marker combinations lead to slightly different predictions of joint angles. These different combinations can be averaged in order to provide a “best” estimate of joint angle. Results of a gait analysis are presented using clinically meaningful terminology to provide better communication with clinical personal. In order to verify the developed JACS method, a simple three-dimensional knee joint contact model was developed, employing an absolute coordinate system without using any kinematics constraint in which thigh and shank segments can be derived independently. In the experimental data recovery, the separation and penetration distance of the knee joint is supposed to be zero during one gait cycle if there are no errors in the experimental data. Using the JACS method, the separation and penetration error was reduced compared to well-developed existing methods such as ACRS and Spoor & Veldpaus method. The separation and penetration distance ranged up to 15 mm and 12 mm using the Spoor & Veldpaus and ACRS method, respectively, compared to 9 mm using JACS method. Statistical methods like the JACS can be applied in conjunction with existing techniques that reduce systematic errors in marker location, leading to an improved assessment of human gait.     

Motion error compensation of multi-legged walking robots

Existing errors in the structure and kinematic parameters of multi-legged walking robots,the motion trajectory of robot will diverge from the ideal sports requirements in movement.Since the existing error compensation is usually used for control compensation of manipulator arm,the error compensation of multi-legged robots has seldom been explored.In order to reduce the kinematic error of robots,a motion error compensation method based on the feedforward for multi-legged mobile robots is proposed to improve motion precision of a mobile robot.The locus error of a robot body is measured,when robot moves along a given track.Error of driven joint variables is obtained by error calculation model in terms of the locus error of robot body.Error value is used to compensate driven joint variables and modify control model of robot,which can drive the robots following control model modified.The model of the relation between robot’s locus errors and kinematic variables errors is set up to achieve the kinematic error compensation.On the basis of the inverse kinematics of a multi-legged walking robot,the relation between error of the motion trajectory and driven joint variables of robots is discussed.Moreover,the equation set is obtained,which expresses relation among error of driven joint variables,structure parameters and error of robot’s locus.Take MiniQuad as an example,when the robot MiniQuad moves following beeline tread,motion error compensation is studied.The actual locus errors of the robot body are measured before and after compensation in the test.According to the test,variations of the actual coordinate value of the robot centroid in x-direction and z-direction are reduced more than one time.The kinematic errors of robot body are reduced effectively by the use of the motion error compensation method based on the feedforward.     

较小样本动态声发射信号多元统计分析技术

利用多传感信息集成系统,以两组平均年龄对应的受试对象往复运动过程中获取的动态声发射信号和角度信号为对象,研究了适用于较小样本的动态声发射信号多元统计分析技术.通过同步记录的角度信号,将往复运动分解为若干个独立运动周期和运动过程;利用累计概率分布,选取具备较显著差异的特征;结合多元统计技术,减小数据量,建立动态声发射信号的可视化模型,证实了使用较小样本声发射信号实现膝盖骨关节诊断的可行性.     

The comparison of joint kinematic error using the absolute and relative coordinate systems for human gait

Minimizing artifacts from skin movement is vital for acquiring more accurate kinematic data in human movement analysis. There are several stages that cause skin movement artifacts and these stages depend on the selection of the reference system, the error reduction method and the coordinate system in clinical gait analysis. Due to residual errors, which are applied to the Euler and Bryant angle methods in each stage, significant cumulative errors are generated in the motion analysis procedure. Thus, there is currently a great deal of research focusing on reducing kinematic errors through error reduction methods and kinematic error estimations in relation to the reference system. However, there have been no studies that have systematically examined the effects of the selected coordinate system on the estimation of kinematic errors, because most of these previous studies have been mainly concerned with the analysis of human movement using only the human models that are provided in the commercial 3D motion capture systems. Therefore, we have estimated the differences between the results of human movement analyses using an absolute coordinate system and a relative coordinate system during a gait, in order to establish which system provides a more accurate kinematic analysis at the ankle joint. Six normal adult subjects with no neurological or orthopedic conditions, lower extremity injuries, or recent history of lower extremity surgery were used in this study. The analysis was conducted at a walking speed of 1.35m/s. For the clinical estimation, we used a cardinal plane based on the segmental reference system and the differences were plotted on the planes. From this analysis, when a relative coordinate system was in the gait analysis, the average kinematic error occurring during the gait was determined to be 13.58mm, which was significantly higher than the error generated with an absolute coordinate system. Therefore, although the relative coordinate system can also be used to calculate the ankle joint center during the clinical gait analysis, the absolute coordinate system should be employed in order to obtain more accurate joint kinematic data. In addition, the results from this study can be used as a basis to select an appropriate coordinate system with regards to the diagnostic accuracy level required for various kinds of gait disorders. This paper was recommended for publication in revised form by Associate Editor Hong Hee Yoo Yong Hoon Rim received his B.S. and M.S degrees in Bio-Mechatronic engineering from Sungkyunkwan University in 2002 and 2004, respectively. Yong Hoon Rim is currently a Researcher at the Bio-Mechatronics center and also a candidate in the biomedical Ph.D. program at Sungkyunkwan University, Korea. His research interests are in the area of digital human modeling, workspace optimization and ergonomics in digital factory. Ahn Ryul Choi received his B.S. and M.S. degrees in Bio-Mechatronic engineering from Sungkyunkwan Univer-sity in 2005 and 2007, respectively. Ahn-Ryul Choi is curr-ently a Researcher at the Bio-Mechatronics center and also a candidate in the biomedical Ph.D. program at Sungkyunkwan University, Korea. His research interests are in the area of digital human modeling and simulation. Sang Sik Lee received his Ph.D. degree from Sungkyun-kwan Universi-ty in 2000. He is currently serving as a research professor at the Bio-Mechatronics center in Sungkyunkwan University. His research interests are in the area of digital human modeling and industrial ergonomics. Kyoung Kee Min received his Ph.D degree Sungkyunkwan University in 2008. Dr. Min is currently a researcher at the Bio-Mechatronics Center in Sungkyunkwan University. Dr. Min’s research interests are in the area of disease classification using artificial neural network, digital human modeling & control. Dong Hyuk Keum received his Ph.D. degree from Seoul National University in 1979. Dr. Keum is currently a Professor at the Department of Bio-Mechat- ronic engineering at Sungkyun-kwan University, Korea. He is currently serving as the chief of an evaluation committee of the Rural Development Administrator. Dr. Keum’s research interests are in the area of simulation of post-harvest systems, quality evaluation of food materials and the processing technology. Chang Hyun Choi received his Ph.D. degree from Iowa State University in 1988. Dr. Choi is currently a Professor at the Department of Bio-Mechatronic Engineering at Sungkyunkwan University, Korea. He is currently serving as an evaluation committee of the Rural Development Administration, Korea and Korea Industrial Technology Foundation. Dr. Choi’s research interests are in the area of nondestructive quality evaluation of foods, and automatic control of off-road machinery. Joung Hwan Mun received his Ph.D. degree majoring in mechanical engineering from the University of Iowa in 1998. Dr. Mun is currently a Professor at the Department of Bio-Mechat-ronic engineering at Sungkyun-kwan University in Suwon, Korea. He is currently serving as a director of the Bio-Mechatronics center with regard to an international IMS project. Dr. Mun’s research interests are in the area of digital human modeling, sports biomechanics, bio-electronics and digital factory for human oriented production system.     

Analysis of human arm movement during vehicle steering maneuver

The analysis of human arm motion during steering maneuver is carried out for investigation of man-machine interface of driver and steering system Each arm is modeled as interconnection of upper arm, lower arm, and hand by rotational joints that can properly represents permissible joint motion, and both arms are connected to a steering wheel through spring and damper at the contact points The joint motion law during steering motion is determined through the measurement of each arm movement, and subsequent inverse kinematic analysis Combining the joint motion law and inverse dynamic analysis, joint stiffness of arm is estimated Arm dynamic analysis model for steering maneuver is setup, and is validated through the comparison with experimentally measured data, which shows relatively good agreement To demonstrate the usefulness of the arm model, it is applied to study the effect of steering column angle on the steering motion

     

基于三组测量绳结构的软体机械臂运动检测

针对气动软体机械臂运动形状检测问题,设计了一种基于拉线编码器的三组测量绳结构的运动学参数检测装置。依据分段常曲率法,构建了气动模块化软体机械臂的运动检测模型,基于机械臂柔性材料的特点,在建模过程中引入刚度法,使检测模型能准确反映从机械臂驱动气压到形状变化以及运动学参数的映射关系。提出了一种可模块化组装的气动软体机械臂,用于验证检测装置与模型的精度,所提出的机械臂在构型上由硅胶基体、运动气囊和连接板组成,能实现机械臂的模块化组装。通过对所构建的运动检测模型进行推导与仿真,得到了模型的相对误差。最后,通过试验验证了运动检测建模的精度和机械臂驱动、构型以及运动的特征。研究结果表明：相比于传统的视觉追踪方法,所设计的基于三组测量绳结构的检测装置能实现对软体机械臂运动形状的高精度检测。     

Error analysis and auto-calibration for a Cartesian-guided tripod machine tool

This paper focuses on the error analysis and calibration methodologies for a parallel kinematic machine (PKM) called a Cartesian-guided tripod (CGT). The CGT volumetric error due to the geometric error, kinematic parameter error and nonlinear machine stiffness were studied. It is well known that the PKM nonlinear machine stiffness can produce significant volumetric errors from several tens to several hundreds of micrometres depending on the averaged value and deviation range for the machine stiffness. For most PKMs, joint level sensors are used to estimate the virtual Cartesian movements of the cutting tool. The nonlinear stiffness effect is not detected by this indirect metrology method and must be compensated for by a calibration methodology. A solution for the nonlinear stiffness effect implemented on the CGT involves using a passive Cartesian guiding/metrology leg that is independent of the driving legs to directly measure the Cartesian movement of the motion platform. Because the metrology loop of the Cartesian guiding/metrology leg is separated from the kinematic loops of the driving legs, the volumetric accuracy of the CGT is immunised against thermal errors and load deformations on the drive mechanisms. The passive Cartesian guiding/metrology leg is also used for the auto-calibration of the CGT kinematic parameters. The auto-calibration methodology and simulation results were studied and reported.     

A technique for motion capture of the finger using functional joint centres and the effect of calibration range of motion on its accuracy

A method of kinematic analysis of the fingers using stereo-photogrammetry, referred to as the phalanx transformation technique, has been proposed. Functional methods were used to define the joint axes and subsequently each finger segments' anatomical coordinate system. Thirteen subjects were tested and the accuracy of the technique assessed. The average error across the three joints of the finger was found to be 0.6 mm, which translates to a 2.2% error in predicted joint reaction force when using a biomechanical model. The subjects were required to have sufficient movement in their joints to define the joint axes functionally. Some subjects of clinical interest can have a significantly reduced mobility owing to injury or pathology, therefore, the effect of calibration range of motion on accuracy was analysed. It was found that, for a range of motion typical of a subject with rheumatoid arthritis, the errors in predicted joint reaction force were < 7%. The accuracy of this technique compared favourably with others previously proposed and, considering the other errors inherent in modelling, those found in this study were deemed to be acceptable.     

移动蛇形机械臂空间路径跟踪策略研究

移动蛇形机械臂具有结构细长和多自由度的特点,其运动学逆解不唯一且计算量大成为研究的难点之一。针对某14自由度的移动蛇形机械臂,采用几何推导法设计了基于末端跟随算法的运动控制策略,实现了机械臂末端的精确位置跟踪,避免使用复杂的逆运动学算法进行求解。该策略考虑了机械臂关节角度和基座移动距离的约束,保证在无约束时机械臂各关节都处在前一时刻的关节轴线上,从而缩小机械臂的位形偏移量,使机械臂的运动更加平滑。通过三维空间轨迹跟踪数值仿真,验证了算法的有效性。通过计算效率和运动幅度,对比该策略与基于雅可比矩阵的数值优化法、人工智能优化算法的性能,说明了该策略的适用性。     

六自由度机械臂运动学分析与仿真

针对安川弧焊工业机器人手臂MOTOMAN-MA1400的构型特点,采用D-H法建立了机械臂的连杆坐标系,得到了以关节角度为变量的正运动学方程,利用Matlab进行正逆运动学计算以及机械臂末端点的轨迹规划。为了验证正逆运动学模型的正确性,直观地观察机械臂各部分运动情况,采用Pro-E建立了机械臂的三维实体模型。将角度变量值导入模型,开发了机械臂运动仿真平台。仿真结果与理论计算一致,从而验证了算法的正确性,并完成了机械臂的运动仿真,为机械臂在矿山领域的实际应用提供了理论参考。     

蛇形机器人的转弯和侧移运动研究

介绍了沈阳自动化研究所研制的蛇形机器人机械结构和控制结构。在分析蛇形曲线的基础上,提出幅值调整法、相位调整法和侧移调整法三种新方法,来处理蛇形机器人侧向滑动带来的方位偏转和完成蛇形机器人自主转弯控制,并给出几种方法的量化关系,建立动力学仿真模型进行了运动仿真。幅值调整法虽然使蛇形机器人转弯角度受到限制但却保证了运动的连续性和稳定性。相位调整法能够使蛇形机器人准确地完成转弯运动。侧移调整法能够实现蛇形机器人前进过程中的侧向位置调整,同时保证运动方向的准确性。将上述方法应用到蛇形机器人的控制中,用仿真和试验验证了以上方法的有效性。     

三叉杆式万向联轴器中有关运动参数的误差分析

在三叉杆式万向联轴器的运动分析的基础上,充分考虑到机构制造和安装的不精确性,运动副轴承的间隙．作用于连杆上力及温度变化引起的连杆变形等因素,进行了三叉杆式万向联轴器运动误差分析。结果表明可通过合理选取各种结构参数,使运动精度控制在允许的范围之内。     

智能假肢膝关节的优化设计及运动学分析

智能假肢膝关节是一种代偿下肢缺失功能的机械电子装置,可以采用双摇杆机构实现对假肢膝关节运动特性的模拟。针对假肢膝关节行走过程中能量消耗过大、稳定性较差的问题,以假肢膝关节机构峰值驱动力矩最小为优化目标,建立了优化模型;在满足性能与结构的约束条件下,运用复合形法对该模型进行优化求解,得到了假肢膝关节机构的最佳结构参数;在此基础上,利用ADAMS软件进行了虚拟运动仿真。结果表明:优化后的智能假肢膝关节具有优良的仿生性能,其峰值驱动力矩相比优化前降低了40%,驱动力矩变化范围缩小36%,大大地提升了智能假肢膝关节的稳定性与续航能力。     

三叉杆式万向联轴器移动副运动参数的误差分析

在三叉杆式万向联轴器有关移动副运动分析的基础上，充分考虑到机构制造和安装的不精确性，以及运动副轴承的间隙等因素，进行了三叉杆式万向联轴器与移动副有关的运动误差分析。结果表明，可通过合理选取各种结构参数，使运动精度在允许的范围之内。     

3-DOF索杆桁架式欠驱动机械手运动控制

索杆桁架式机械手是将绳轮传动系统和平行四边形机构结合而提出的一种新型欠驱动机械手。绳索驱动力同时驱动手指关节耦合运动,而手指关节运动又会直接改变绳拉力在各指节单元的驱动力分布,导致索杆桁架式欠驱动系统具有强非线性和运动耦合特点。针对该问题,利用虚功原理,将绳轮传动系统等效为耦合的关节驱动力矩,并建立3-DOF手指准静态运动学模型。根据手指最大运动空间约束条件,确定关节弹簧配置分布并开展手指准静态运动空间分析。采用拉格朗日方程法建立手指一般动力学方程,并转换为“A-P”型等效动力学模型。在此基础上,开展预变形阶段运动控制研究。通过仿真分析和样机试验验证所提分析方法和运动控制策略的有效性。     

一类带冗余支链并联机器的运动学自标定

利用冗余支链测量信息,对一类带冗余支链并联机器的运动学参数进行自标定。通过矢量闭环微分法,建立冗余支链运动学误差模型,并通过多个位姿处误差传递矩阵的组合,得到自标定的辨识雅可比矩阵。针对部分运动学参数误差辨识性差的问题,提出一种基于辨识雅可比矩阵各列线性相关性分析的辨识性分析方法,得到可辨识的运动学参数误差线性耦合式,并简化误差辨识方程使辨识性提高。最后利用冗余支链角度编码器测量信息,完成一个4RRR冗余并联机器的运动学自标定,仿真结果显示,基于冗余支链的运动学自标定能有效提高冗余支链和机构终端运动精度。     

A joint normalcy index to evaluate patients with gait pathologies in the functional aspects of joint mobility

Gait analysis using 3D motion capture systems provides joint kinematic and kinetic analysis results such as joint relative angles and moments that can be use used to evaluate the degrees of pathological gait patterns. However, the complex data produced using these 3D motion capture systems can only analyzed by experts, because the gait analysis is highly coupled to the kinematics of each joint. Therefore, several Several previous studies using gait analysis have relied on the data compression technique to represent gait deviation from the average normal profiles as a single value. Even though it is important to evaluate gait pathologies at the joint level, all these previous studies have just used a single value to evaluate the pathological gait pattern. Using just one variable for evaluation of a gait is limited in terms of determining which joint movement patterns are getting better during rehabilitation. Therefore, in this study, a method suitable for evaluating gait deviation during a gait was developed to provide three indices for the hip, knee and ankle joints. In addition, to validate the proposed method in clinical cases, experimental tests were conducted on thirty thirty-six normal walkers and six patients with cerebral palsy. Furthermore, to validate the proposed method in regards to rehabilitation, experimental tests were conducted on three classified walking groups with imposed ankle equinus constraints. The JNI for the hip joint, knee joint and ankle were 8.78 (±3.70), 2.92 (±3.25) and 8.79 (±4.38), respectively, in the normal walking group. However, these values were significantly different for the pathological walking group with cerebral palsy. The JNI of the hip joint, knee joint and ankle joint were 203.73 (±171.59), 81.23 (±52.13) and 248.39 (±149.99), respectively, for this group. There were also differences between any two of the three classified groups with imposed ankle equinus constraints. In particular, the JNI of the ankle joint was statistically different at the p<0.01 level, and this parameter clearly increased as the degree of the imposed ankle equinus was increased. These results demonstrate that the proposed JNI can be used as a scalar factor to evaluate the angular deviation of each joint in normal and patient groups. In addition, this approach can be adapted to evaluate rehabilitation and pre/post surgery.     

对角修形斜齿轮设计与数控磨齿研究

为了减小齿面振动,降低磨削误差,提出对角修形斜齿轮数控磨齿加工方法：通过设计对角修形曲线,经过3次B样条拟合为对角修形曲面;根据齿条展成渐开线齿面原理,建立平面砂轮磨削斜齿轮6轴联动Free-Form型数控磨齿模型,通过齿条与砂轮位矢等效转换,推导各轴运动关系;建立基于CNC机床各轴运动敏感性分析的齿面修正模型,各轴运动用6阶多项式表示,通过判断砂轮与齿面的接触状态,确定磨削齿面的误差,并分析各系数扰动对齿面误差的影响;以齿面误差平方和最小为目标函数,通过粒子群优化方法,得到机床各轴运动参数,该方法计算结果稳定且精度较高。通过算例表明：沿齿向方向压力角、螺旋角、展成角的微调可分别实现一定的对角修形加工;微调6轴联动机床各轴运动参数,可有效减小对角修形斜齿轮的磨削误差,通过机床运动敏感性分析验证理论和算法的正确性。     

A systematic approach to identify the error motion of anN-degree of freedom manipulator

A generalised calibration technique for identifying the joint geometric parameters of an N-degrees-of-freedom (d.o.f.) robot manipulator model is presented. The technique is analogous to the synthesising calibration method applied in the calibration of coordinate measuring, machines. It describes the state of each joint by six d.o.f. and assumes rigid-body motion. The initial step in the calibration involves locating the axis of motion of each joint; the axes are then used to extract the kinematic parameters, introduced by Denavit-Hartenberg (D-H). In order to derive the generalised manipulator kinematic equation, the robot model is modified to include the six error motion components associated with each axis. The paper also addresses the problem of identifying the error motion components of each joint, on the basis of a set of measurement of three noncollinear points at the robot end-effector at various joint configurations. Because the technique is based on axis-by-axis calibration, other non-geometric errors such as joint backlash and gear transmission error may also be revealed.