假肢步态实验平台设计

背景：目前对于假肢的评价还停留在主观感受,缺乏一套客观的评价系统,建立模拟人体运动的在线假肢参数检测系统对于假肢性能的评价、假肢研究设计具有重要意义。目的：实现假肢的多种步态运动,并通过运动学、动力学数据的比对,评价其仿真程度。方法：根据仿生学原理,将下肢假肢简化成四杆四轴的力学模型,利用采集得到的多种步态模式,驱动下肢假肢运动,并搭建动态力学测试平台,实时测量假肢运动的地面垂直反力和前后剪力。结果与结论：假肢步态运动,髋膝关节的变化曲线与正常步态数据相一致,而其地面垂直反力与前后剪力也与正常人体相接近。提示假肢步态实验平台模拟了下肢假肢步态运动,并实时采集假肢运动的多项运动学、动力学参数,具备较高的仿真程度。     

小腿假肢穿戴者步态中的脊柱生物力学分析

目的：通过实验证明小腿假肢穿戴者的腰痛与穿戴假肢后行走产生的脊柱生物力学参数改变有关。方法：对小腿假肢穿戴者步态中的脊柱生物力学进行运动学和动力学分析,利用三维动态捕捉系统和地面反力采集设备采集正常人和穿戴者的步态,对比分析了正常步态与穿戴者产生的下肢不等长步态在时空参数、地面反力、脊柱骨盆关节角度和重心高度数据结果。结果：小腿假肢穿戴者步态中的脊柱骨盆倾斜角度与正常人存在很大差异,且在整个步态周期中明显不同。穿戴者脊柱生物力学参数改变是为了弥补截肢后小腿和足部功能损失引起的不稳定,穿戴者的异常步态引起了脊柱相关肌肉和骨骼状态的改变。同时,假脚的设计可能会对穿戴者脊柱生物力学参数产生影响。结论：行走产生的脊柱生物力学参数改变很可能是小腿假肢穿戴者腰痛的发病原因。不同假脚的设计产生的穿戴者脊柱生物力学参数改变有不同影响。     

下肢假肢步态试验机的设计

实验于2008-03在上海理工大学生物力学与康复工程研究所完成。基于仿生学原理,将人体下肢简化为刚体结构,关节简化为单轴结构,设计出一套下肢假肢步态试验装置。整个步态试验机装置系统由模拟腿、动力和传动装置及测控系统组成,主要部件有躯干、大腿、小腿、脚板和髋关节、膝关节、跑步机以及驱动部分。采集健康青年人常速行走的运动步态参数,以其关节角度数据作为输入信号,以步进电机作为动力驱动实现模拟腿的运动,达到正常人行走步态的模拟。结果显示,对模拟后的输出信号进行采集并与输入信号相比,最大相对误差为5.6%,在工程误差允许范围之内。提示下肢假肢步态试验机能基本模拟人的正常步态。     

基于视频图像边缘检测的人体下肢运动步态*☆

背景:步态规律主要应用人体行走的运动学、动力学等参数进行描述.目前在运动医学、康复工程和仿生学等领域,步态分析可为确定疾病诊断、康复和治疗方案提供重要依据. 目的:应用基于人体运动图像的测量装置系统,采集人体在跑步机上行走的下肢运动步态视频,分析人体步态运动规律. 方法:采用基于双摄影机的人体运动图像捕捉系统,在人体的左右髋关节、膝关节、踝关节及脚板设置标识点,对人体在跑步机上行走的下肢运动步态视频进行采集.应用图像边缘检测的原理,对测量数据进行了图像处理和分析,得到人体正常步速行走时,左右大腿与竖直方向夹角、小腿与竖直方向夹角、脚板与竖直方向夹角及膝关节、踝关节标识点的关节角度变化规律. 结果与结论:基于视频图像边缘检测人体下肢的运动步态,成本相对低廉,数据误差较小,精度与进口设备较接近.应用该测量结果初步构建了人体步态行走数据库,为建立步态评定标准、异常步态判别以及进一步的康复治疗提供了依据.     

一种动力型髋离断假肢控制系统研究

目的 探讨一种动力型髋离断假肢控制方法提升佩戴者步态对称性的可行性。 方法 通过九轴姿态传感器采集健康人体下肢步态运动学信息,使用BP神经网络建立穿戴髋离断假肢截肢者健侧-假肢侧运动学映射模型。将截肢者健侧腿的运动学信息实时传入该映射模型,生成髋离断假肢运动的目标轨迹,结合下肢假肢动力学模型,通过PID算法控制髋离断假肢电机运动,实现截肢者的实时步态分析和假肢的实时控制。记录截肢者穿戴动力髋离断假肢行走实验中的步长、步频及最大髋关节角度等数据,并结合步态对称性指标SⅠ、RⅠ、RⅡ对假肢控制效果进行评估。 结果 BP神经网络建立的截肢者健侧和假肢侧的运动学映射模型,综合关联度达到98.7%。相对于传统髋离断假肢,动力髋离断假肢髋关节的最大屈曲角度提升了105.5%,截肢者的步态对称性指标SⅠ和RⅡ分别提升了74.2%和72.2%。 结论 动力型髋离断假肢控制系统能提高假肢穿戴者的步态对称性。     

电动下肢假肢多路况控制策略研究

目的：电动下肢假肢具有较强的非线性和耦合性,针对假肢在不同地形间行走时存在的外部扰动问题,本文提出了积分滑模控制策略。方法：采集人体下肢在平地、上/下斜坡及上/下楼梯五种路况下的运动信息,根据足底压力信息将不同路况的一个完整步态周期划分为支撑期及摆动期两个模态,并分别进行人体下肢运动学分析;利用拉格朗日方程建立假肢支撑期与摆动期的动力学模型;在五种运动模式下,设计积分滑模控制器对假肢进行控制,并进行联合仿真验证。结果：膝踝假肢轨迹跟踪收敛速度加快,误差降低。结论：积分滑模控制器对于外部扰动具有明显的补偿作用,提高了假肢在多路况行走时的控制效果。     

膝上假肢使用者步态对称性分析

在对膝上假肢使用才健侧和残侧的步态进行检测的基础上、对健、则在步态周期内的地面反力、下肢 时相对称性进行了对比和分析，时相对生差异是膝上截肢者步态的主要问题，指同了产生时相不对称的原因并对则对健侧的影响进行了探讨。由于受残侧的影响，健侧的步态与正常步态相差也很大，所得结论对改进假肢性能１假肢装配和患者的训练有重要意义。     

使用下肢假肢者的步态训练

下肢假肢使用者由于受到心理因素影响及假肢假脚的限制,其步态与正常步态有较大区别,影响到使用者的生活和社会活动。如能给予适当的指导和训练则可使患步态较接进正常及缩短适应假肢时间。通过对85例下肢截肢患者安装假肢前后进行针对性的心理治疗及步态训练收到了良好的效果。     

基于有限状态机的智能下肢假肢控制

背景:传统的下肢假肢行走状态改变时膝关节阻尼不能随之改变,假肢跟随性差,变化范围小。目的:基于有限状态机的智能下肢假肢控制方法,实现假肢侧对健肢侧的实时跟踪和步速跟随。方法:智能下肢假肢采用带固定式气缸阻尼器的四连杆机构,采用有限状态机的控制方法,感知当前的步态事件,触发步态状态的转变,调整对应的步态模式,得到步态规划的输出动作。结果与结论:实验结果表明,智能下肢假肢能够进行步速识别和步态识别,控制器输出不同的控制策略,控制步进电机调整膝关节阻尼的大小,假肢侧能够对健肢侧进行实时跟踪和步速跟随。     

步态模式对人体髋膝踝关节运动协调关系的影响

摘要 目的：分析不同步态模式下髋膝踝关节的运动协调关系,为下肢智能假肢和助行外骨骼控制系统的运动规划提供依据。 方法：利用红外光点运动捕捉系统,采集10名20—35岁健康青年志愿者进行平地行走、上楼梯和下楼梯三种步态的运动轨迹,采用运动循环图对髋膝踝关节运动角度参数进行统计分析。 结果：不同步态模式的髋膝踝关节运动循环图存在显著的差异。 结论：步态模式对髋膝踝关节的运动协调关系有显著影响,下肢假肢和外骨骼可以借鉴相应的运动协调模式降低机械结构和控制系统的复杂性。     

Movement characteristics of upper extremity prostheses during basic goal-directed tasks

Background

After an upper limb amputation a prosthesis is often used to restore the functionality. However, the frequency of prostheses use is generally low. Movement kinematics of prostheses use might suggest origins of this low use. The aim of this study was to reveal movement patterns of prostheses during basic goal-directed actions in upper limb prosthetic users and to compare this with existing knowledge of able-bodied performance during these actions.

Methods

Movements from six users of upper extremity prostheses were analyzed, three participants with a hybrid upper arm prosthesis, and three participants with a myoelectric forearm prosthesis. Two grasping tasks and a reciprocal pointing task were investigated during a single lab session. Analyses were carried out on the kinematics of the tasks.

Findings

When grasping, movements with both prostheses showed asymmetric velocity profiles of the reach and had a plateau in the aperture profiles. Reach and grasp were decoupled. Kinematics with the prostheses differed in that the use of upper arm prostheses required more time to execute the movements, while the movements were less smooth, more asymmetric, and showed more decoupling between reach and grasp. The pointing task showed for both prostheses less harmonic movements with higher task difficulty.

Interpretation

Characterizing prosthetic movement patterns revealed specific features of prosthetic performance. Developments in technology and rehabilitation should focus on these issues to improve prosthetic use, in particular on improving motor characteristics and the control of the elbow, and learning to coordinate the reach and the grasp component in prehension.     

单侧小腿截肢患者穿假肢后的步态运动学参数研究

目的 采用计算机辅助康复环境(CAREN)步态评估系统分析单侧小腿截肢患者穿假肢后的步态运动学参数,并分析其产生差异的原因。 方法 选取单侧小腿中段截肢但均装配假肢的受试者9例设为假肢组,同期选择健全受试者11例设为标准组,通过CAREN步态评估系统对2组受试者的步态运动学参数进行收集、处理、分析,并根据分析报告阐明产生差异原因。 结果 假肢组步态时相性指数为(0.88±0.04),其假肢侧的步长、支撑期百分比、髋关节支撑期最大伸展角度、膝关节支撑期最大屈曲角度、踝关节足跟着地背屈角度、踝关节支撑期最大背屈角度、踝关节支撑期最大跖屈角度与健侧比较,差异均有统计学意义(P<0.05）。假肢组假肢侧的步行速度、步态周期、跨步长、支撑期百分比、髋关节足跟落地屈髋角度、髋关节支撑期最大伸展角度、髋关节支撑期最大屈曲角度、膝关节足跟着地屈膝角度、踝关节足跟着地背屈角度、踝关节支撑期最大跖屈角度、踝关节支撑期最大背屈角度与标准组双侧均值比较,差异均有统计学意义(P<0.05）。 结论 单侧小腿截肢者穿戴假肢后步态时相对称性为（0.88±0.04）,假肢侧踝关节运动学参数显著弱于自身健侧,其时空与运动学参数也显著弱于健全人。     

Sprint kinematics of athletes with lower-limb amputations.

OBJECTIVE: To determine and compare the kinematics of the sound and prosthetic limb in five of the world's best unilateral amputee sprinters. SUBJECTS: Five men, all unilateral lower-limb amputee (one transfemoral, four transtibial) athletes. The individual with transfemoral amputation used a Endolite Hi-activity prosthesis incorporating a CaTech hydraulic swing and stance control unit, a Flex-Foot Modular III, and an ischial containment total contact socket. Those with transtibial amputations used prostheses incorporating a Flex-Foot Modular III and patellar tendon-bearing socket, with silicone sheath liner (Iceross) and lanyard suspension. DESIGN: Case series. Subjects were videotaped sprinting through a performance area. Sagittal plane lower-limb kinematics derived from manual digitization (at 50 Hz) of the video were determined for three sprint trials of the prosthetic and sound limb. Hip, knee, and ankle kinematics of each subject's sound and prosthetic limb were compared to highlight kinematic alterations resulting from the use of individual prostheses. Comparisons were also made with mean data from five able-bodied men who had similar sprinting ability. RESULTS: Sound limb hip and knee kinematics in all subjects with amputation were comparable to those in able-bodied subjects. The prosthetic knee of the transfemoral amputee athlete fully extended early in swing and remained so through stance. In the transtibial amputee athletes, as in able-bodied subjects, a pattern of stance flexion-extension was evident for both limbs. During stance, prosthetic ankle angles of the transtibial amputee subjects were similar to those of the sound side and those of able-bodied subjects. CONCLUSION: Prosthetic limb kinematics in transtibial amputee subjects were similar to those for the sound limb, and individuals achieved an "up-on-the-toes" gait typical of able-bodied sprinting. Kinematics for the prosthetic limb of the transfemoral amputee subject were more typical of those seen for walking. This resulted in a sprinting gait with large kinematic asymmetries between contralateral limbs.     

Novel passive ankle-foot prosthesis mimics able-bodied ankle angles and ground reaction forces

Background: During gait, the human ankle both bends with ease and provides push-off forces that facilitate forward motion. The ankle is crucial for support, stabilization, and adapting to different slopes and terrains. Individuals with lower limb amputation require an ankle-foot prosthesis for basic mobility.Methods: Inspired by the role of the ankle-foot in an able-bodied gait, the 3D printed Compliant and Articulating Prosthetic Ankle (CAPA) foot was designed. It consists of four articulating components connected by torsion springs and produces forces that are dependent on the ankle angle. Using the Computer Assisted Rehabilitation Environment, able-bodied individuals walked wearing a prosthetic simulator with the Solid Ankle Cushioned Heel foot, Renegade® AT, and multiple versions of the CAPA. These versions test compliant vs. stiff, small vs. large rocker radius, and pretension vs. none. We hypothesized that the CAPA would have larger ankle range of motion, push-off forces, and braking forces.Findings: Compared to existing prostheses, the novel prosthesis exhibits greater and significantly different ankle range of motion and sagittal plane ground reaction forces than existing prostheses during gait. Nine out of ten individuals prefer the novel prosthesis to the existing prostheses, and there is a statistically significant difference in difficulty level ratings.Interpretation: By providing a personalizable and passive alternative to existing designs, the CAPA could improve the quality of life for the growing number of individuals living with limb loss in the United States and around the world.     

Effects of prosthetic mass and mass distribution on kinematics and energetics of prosthetic gait: a systematic review

OBJECTIVE: To introduce the theoretical models used in literature that describe the relation between prosthetic inertial loading and amputee gait and to derive specific predictions from these models: to systematically review experimental studies on the relation between prosthetic inertial loading and energetics and kinematics of lower-limb prosthetic gait; and to compare the review outcomes with predictions derived from theoretical models. DATA SOURCES: Studies selected from Medline and from examining references in the selected Medline publications. STUDY SELECTION: Theoretical models were selected that are used in the present literature to predict the effects of prosthetic mass and mass distribution on kinematics and energetics of prosthetic gait. Experimental studies were selected that investigated the effects of prosthetic mass or center of mass location on the economy, self-selected walking speed, stride length, or stride frequency of lower limb amputee patients. DATA EXTRACTION: The design and methodologic quality was assessed using a checklist of nine criteria. Data on economy, self-selected walking speed, stride frequency, and stride length were extracted from the studies selected. DATA SYNTHESIS: The predictions of the theoretical models suggest that inertial loading of the present lightweight prostheses need not be decreased and sometimes may need to be increased to improve the gait of amputee patients. The methodologic quality of most of the experimental studies was limited. Review of the experimental studies suggests that the inertial loading of the present lightweight prostheses need not be further reduced. The discrepancy between theoretical models and experimental findings may be related to both the poor methodologic quality of the experiments as well as to the limited predictive value of the existing models.     

Human-prosthesis coordination: A preliminary study exploring coordination with a powered ankle-foot prosthesis

BackgroundPowered ankle-foot prostheses were developed to replicate the mechanics of the biological ankle by providing positive work during the push-off phase of gait. However, the benefits of powered prostheses on improving overall human gait efficiency (usually quantified by metabolic cost) have not been consistently shown. Here, we have focused on the mechanical work produced at the prosthetic ankle and its interaction with the amputee's movement.MethodsFive unilateral transtibial amputees walked on a treadmill using 1) a powered ankle-foot prosthesis and 2) their daily passive device. We determined the net ankle work and ankle work loops on the prosthesis-side to quantify the efficiency of the human-prosthesis physical interaction. We further studied peak propulsion timing and the posture of the amputee's lower limb and prosthesis as indicators of the human-prosthesis coordination. Comparisons were made between the passive and powered prosthesis conditions for each participant.FindingsThe powered prosthesis did not consistently increase net ankle work compared to each participant's passive device. For participants that lacked efficiency in interacting with the powered prosthesis, we observed 1) early prosthesis-side peak propulsion timing (≥ 4% earlier) and 2) a more vertical residual shank at the time of peak propulsion (> 2° more vertical) indicating that the human's limb movement and the prosthesis control during push-off were not well coordinated.InterpretationResults from this preliminary study highlight the need for future work to systematically quantify the coordination between the human and powered prosthesis and understand how such coordination at the joint level influences overall gait efficiency.     

Inertial sensor-based measures of gait symmetry and repeatability in people with unilateral lower limb amputation

BackgroundPeople with lower limb amputation often walk with asymmetrical gait patterns potentially leading to long-term health problems, ultimately affecting their quality of life. The ability to discreetly detect and quantify the movement of bilateral thighs and shanks using wearable sensor technology can provide additional insight into how a person walks with a lower limb prosthesis. This study investigated segmental symmetry and segmental repeatability of people with unilateral lower limb amputation, examining performance of the prosthetic and intact limbs.MethodsGyroscope signals were recorded from four inertial measurement units worn on bilateral lower limb segments of subjects with unilateral lower limb amputation during the 10-m walk test. Raw angular velocity signals were processed using dynamic time warping and application of algorithms resulting in symmetry measures comparing similarity of prosthetic to intact limb strides, and repeatability measures comparing movement of one limb to its consecutive strides.FindingsBiomechanical differences in performance of the prosthetic and intact limb segments were detected with the segmental symmetry and segmental repeatability measures in 128 subjects. More asymmetries and less consistent movements of the lower limbs were exhibited by subjects with transfemoral amputation versus transtibial amputation (p < .004, Cohen's d = 0.65–1.1).InterpretationSensor-based measures of segmental symmetry and segmental repeatability were found to be reliable in detecting discreet differences in movement of the prosthetic versus intact lower limbs in amputee subjects. These measures provide a convenient tool for enhanced prosthetic gait analysis with the potential to focus rehabilitative and prosthetic interventions.