穿戴式下肢外骨骼助行机器人系统研究

目的提出一种新型轻量化穿戴式下肢外骨骼助行机器人系统,探究其辅助步态紊乱者和T4脊髓节段以下损伤的截瘫患者(排除双下肢肌痉挛和明显疼痛者)实现行走及姿态变换康复训练的可行性。方法设计髋关节双电机主动驱动,膝关节被动四连杆模拟人体运动瞬心变化的主被动混合式可穿戴下肢外骨骼助行机器人结构,基于模块化设计思想,提出以STM32F767IGT6及外围电路为主控制器,包含姿态采集、电源和拐杖模块的控制系统。以正常人穿戴该外骨骼机器人进行平地、斜坡及姿态变换实验,分析运动过程中髋、膝、踝关节角度,并对比正常人穿戴和未穿戴该机器人股外侧肌和股内侧肌的肌电信号。结果穿戴者可实现仅基于该外骨骼机器人系统辅助的坐下-站立姿态变换以及平地/斜坡行走,且髋、膝、踝关节角度与正常人行走变化趋势基本一致,穿戴该机器人相比未穿戴行走时,股外侧肌和股内侧肌肌电信号均降低。结论该主被动混合式可穿戴下肢外骨骼助行机器人在仅髋关节两个电机驱动下,依然可实现行走及姿态变换的康复训练,验证了髋关节双电机主动驱动、膝关节被动四连杆结构的下肢外骨骼助行机器人系统帮助截瘫患者和步态紊乱者行走康复的可行性。     

主动型仿生踝关节假肢的设计

背景：与髋、膝关节假肢设计相对比较成熟的技术相比,踝关节作为人体下肢关节的重要组成部分,也是最为灵活的部分,一直以来研究都比较滞后,相关的假肢踝关节产品未能很好的满足假肢患者的需求。目的：从生物力学、解剖学和生理学角度出发,设计和研制出能在矢状面内做屈伸运动的主动型仿生踝关节假肢装置。方法：根据仿生学原理和人体踝关节在步态行走时的受力特点和生理功能,建立二自由度的主动型仿生踝关节的力学模型,设计假肢踝关节的机械结构与控制系统,其主要部件包括仿生踝关节系统、辅助装置、数据控制系统和数据采集系统。结果与结论：利用研制出的踝关节装置进行系统测试,使用正常人行走时的踝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踝关节的运动,通过数据采集系统获得输出的角度数据。测试结果表明仿生踝关节能够跟随输入角度数据运动,实现了仿生踝关节跟随运动的预期目标。     

基于有限状态机控制的智能假肢踝关节

背景：目前智能假肢只是考虑了膝关节的作用,假肢踝关节只是作为假肢膝关节的辅助工具,无法根据外部环境和步态的变化实现假肢自然的行走。目的：研制出可靠的智能假肢踝关节,有效改善截肢者的步态。方法：在阻尼可变式踝足假肢的基础上,提出了有限状态机的控制方法,对踝足步态进行了详细的划分,在每个步态内制定了相关的控制策略。结果与结论：实验结果表明,基于有限状态机控制的智能假肢踝关节能够有效的跟随健肢侧运动,能够适应不同的步速,为以后膝踝协调运动奠定了一定的实验基础。     

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。     

主动型仿生踝关节假肢的设计

背景:与髋、膝关节假肢设计相对比较成熟的技术相比,踝关节作为人体下肢关节的重要组成部分,也是最为灵活的部分,一直以来研究都比较滞后,相关的假肢踝关节产品未能很好的满足假肢患者的需求.目的:从生物力学、解剖学和生理学角度出发,设计和研制出能在矢状面内做屈伸运动的主动型仿生踝关节假肢装置.方法:根据仿生学原理和人体踝关节在步态行走时的受力特点和生理功能,建立二自由度的主动型仿生踝关节的力学模型,设计假肢踝关节的机械结构与控制系统,其主要部件包括仿生踝关节系统、辅助装置、数据控制系统和数据采集系统.结果与结论:利用研制出的踝关节装置进行系统测试,使用正常人行走时的踝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踝关节的运动,通过数据采集系统获得输出的角度数据.测试结果表明仿生踝关节能够跟随输入角度数据运动,实现了仿生踝关节跟随运动的预期目标.     

膝-踝动力型假肢解耦控制研究

摘要 目的：膝-踝假肢的动力学模型是一个高阶、非线性、强耦合的系统。假肢膝踝关节运动之间存在耦合性,这种耦合性会导致系统控制效果不理想,甚至不可控。需设计解耦器简化膝-踝假肢系统动力学模型,降低假肢关节间的耦合度,提高系统的控制效果。 方法：首先根据拉格朗日方程分别建立下肢假肢支撑步态阶段与摆动步态阶段的动力学模型;然后设计积分型解耦器,在假肢动力学模型之前串联积分型解耦器,将假肢模型简化成多个单输入、单输出的系统;最后利用自适应迭代学习控制算法对解耦前后的膝-踝假肢的各关节运动轨迹进行跟踪。 结果：解耦后的膝-踝假肢系统收敛速度加快且收敛误差降低。 结论：积分型解耦器可以简化假肢系统动力学模型,降低假肢关节间的耦合度,提高系统的控制效果。     

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。     

弹力绷带膝踝联合捆扎改善脑卒中患者步态及日常生活活动能力的疗效观察

目的:观察应用弹力绷带进行膝踝关节联合捆扎治疗对改善脑卒中患者步态及日常生活活动能力的临床疗效。方法:40例脑卒中患者随机分为试验组和对照组,两组患者均接受脑卒中后常规康复治疗,试验组患者在常规康复治疗中的站立、迈步、行走等训练时应用弹力绷带对患侧膝、踝关节进行同步捆扎,保持膝关节微屈、踝关节背屈。在治疗前及治疗8周后进行三维步态分析、患侧下肢Fugl-Meyer运动功能评定(FMA-L)及改良Barthel指数(MBI)评分,试验组患者在首次应用弹力绷带捆扎前后各做1次三维步态分析。结果:试验组患者在首次应用弹力绷带捆扎后三维步态分析显示其患侧步长、步速及支撑相髋、膝、踝各关节力矩峰值各项分值较捆扎前有显著改善(P0.05);治疗8周后试验组患者下肢FMA-L、MBI评分及三维步态数据较对照组有显著改善(P0.05)。结论:应用弹力绷带进行膝踝关节联合捆扎可显著提高卒中后偏瘫患者的异常步态及日常生活活动能力。     

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...     

六连杆假肢膝关节优化设计

目的：假肢膝关节的设计对于膝上截肢者的安全与步态关系重大。为了改善膝上假肢穿戴者的步态,设计了六连杆假肢膝关节。方法：采用最优化设计使摆动相步态尽可能逼近正常步态;在结构设计上利用瞬停节特性使膝关节在支撑期有自锁功能并具有很强的抗干扰能力。结果：计算机仿真为踝关节运动轨迹均方误差不超过１．９６％。结论：该膝关节假肢在支撑期保持稳定性的同时,在摆动期内膝、踝关节运动轨迹,以及大小腿的角度变化关系相对于正常人具有很好的逼近效果,能够有效改善患者步态。     

Dynamic analysis of above-knee amputee gait

BACKGROUND: It is important to understand the characteristics of amputee gait to develop more functional prostheses. The aim of this study is to quantitatively evaluate amputee gait by dynamic analysis of the musculoskeletal system during level walking and stair climbing. METHODS: Dynamic analysis using gait analysis, electromyography and musculoskeletal modeling for above-knee amputees (n=8) and healthy adults (n=10) was performed to evaluate the muscle balance, muscle force, and moment of each major muscle in each ambulatory task. Time-distance parameters and the kinematic parameter of gait analysis were calculated, and a root mean square electromyogram of major muscles and hamstring and tibialis anterior coactivity was measured using electromyography. Lastly, dynamic analyses of above-knee amputee gaits were performed using musculoskeletal models with scaled bones and redefined muscles for each subject. FINDINGS: Most kinematic parameters showed statistically no difference among the tasks, excluding pelvic tilt, pelvic obliquity, and hip abduction. Major muscle activities and coactivities of the hamstring and tibialis anterior showed that the stair ascent task needed more muscle activity than the stair descent task and level walking. The muscle activity and coactivity of amputees were greater than those of healthy subjects, excluding the hamstring coactivity during stair ascent (P<0.05). Lastly, dynamic analysis showed that weakened abductor and excessive adductor and then inadequate torque during all tasks were quantitatively observed. INTERPRETATION: Dynamic analysis of amputee gait enabled us to quantify the contribution of major muscles at the hip and knee joint mainly in daily ambulatory tasks of above-knee amputees and may be helpful in designing functional prostheses.     

Knee joint moments during stair climbing of patients with anterior cruciate ligament deficiency

OBJECTIVE: To establish the gait adaptations of patients with anterior cruciate ligament deficiency during stair ascent. DESIGN: Joint kinematics and kinetics during stair climbing were measured in both knees of normal subjects and unilateral anterior cruciate ligament deficient patients. BACKGROUND: As there is limited research pertaining to activities other than level walking, the purpose of the current study was to elucidate the gait of patients with anterior cruciate ligament deficiency during stair climbing to determine the effects of the deficiency on knee joint motion and moments as compared with normal knee function. METHODS: A motion analysis system was used to measure and calculate kinematic and kinetic data for six normal subjects and nine patients with unilateral anterior cruciate ligament deficiency during stair ascent on a specially constructed staircase. Left and right leg data were analysed to reveal between-limb differences for each subject. RESULTS: Patients with anterior cruciate ligament deficiency displayed a significant (P < 0.05) reduction of up to 50% in peak knee flexion moments in their involved knee. In the present study where a step height of 15.5 cm was used, peak flexion moments in all subjects' limbs occurred at knee flexion angles of about 40 degrees during single limb support. CONCLUSION: The current study showed that most patients with an anterior cruciate deficient knee adapted their gait during stair ascent. RELEVANCE: As stair climbing is a common activity, its effect on gait is relevant to better understand appropriate treatment and management strategies of patients with anterior cruciate ligament deficient knees.     

Changes of kinematic parameters of lower extremities with gait speed: a 3D motion analysis study

[Purpose] The purpose of this study was to investigate the changes in hip, knee and ankle kinematic variables of the lower extremities at different gait speeds. [Subjects and Methods] Forty healthy subjects who had no previous history of neurological, musculo-skeletal or other medical conditions that could affect gait were recruited. The subjects were asked to walk 10 m down a walkway at three different gait speeds: normal gait speed, and self-selected fast, and slow speeds. The experimental order was randomly chosen across these gaits. The hip, knee and ankle kinematic data were evaluated using a VICON 3D motion analysis system and force plates. [Results] The flexion peak and external rotation peak of the knee joint significantly increased with the increase of gait speed. The plantarflexion peaks of the ankle joint significantly increased with increase of gait speed. However, none of the kinematic data of the hip joint were significantly dependent on increase of gait speed. [Conclusion] The relationship of the knee and ankle joint can be described as coupling motion which is dependent on gait speed. Our present findings suggest that coupling motion of the knee joint and plantarflexion of the ankle joint significantly increase with increase of gait speed. These results will provide important insight into gait mechanisms for the evaluation of pathological populations.Key words: Gait speed, 3D motion analysis, Lower extremity     

Review of hybrid exoskeletons to restore gait following spinal cord injury

Different approaches are available to compensate gait in persons with spinal cord injury, including passive orthoses, functional electrical stimulation (FES), and robotic exoskeletons. However, several drawbacks arise from each specific approach. Orthotic gait is energy-demanding for the user and functionally ineffective. FES uses the muscles as natural actuators to generate gait, providing not only functional but also psychological benefits to the users. However, disadvantages are also related to the early appearance of muscle fatigue and the control of joint trajectories. Robotic exoskeletons that provide joint moment compensation or substitution to the body during walking have been developed in recent years. Significant advances have been achieved, but the technology itself is not mature yet because of many limitations related to both physical and cognitive interaction as well as portability and energy-management issues. Meanwhile, the combination of FES technology and exoskeletons has emerged as a promising approach to both gait compensation and rehabilitation, bringing together technologies, methods, and rehabilitation principles that can overcome the drawbacks of each individual approach. This article presents an overview of hybrid lower-limb exoskeletons, related technologies, and advances in actuation and control systems. Also, we highlight the functional assessment of individuals with spinal cord injury.     

Hip, knee, ankle kinematics and kinetics during stair ascent and descent in healthy young individuals

BACKGROUND: Few studies have reported the biomechanical aspects of stair climbing for this ergonomically demanding task. The purpose of this ethically approved study was to identify normal functional parameters of the lower limb during stair climbing and to compare the actions of stair ascent and descent in young healthy individuals. METHODS: Thirty-three young healthy subjects, (16 M, 17 F, range 18-39 years) participated in the study. The laboratory staircase consisted of four steps (rise height 18 cm, tread length 28.5 cm). Kinematic data were recorded using 3D motion analysis system. Temporal gait cycle data and ground reaction forces were recorded using a force platform. Kinetic data were standardized to body mass and height. FINDINGS: Paired-samples t tests showed significantly greater hip and knee angles (mean difference standard deviation (SD): hip 28.10 degrees (SD 4.08), knee 3.39 degrees (SD 7.20)) and hip and knee moments (hip 0.25 Nm/kg (SD 0.18), knee 0.17 Nm/kg (SD 0.15)) during stair ascent compared to descent. Significantly greater ankle dorsiflexion angles (9.90 degrees (SD 3.80)) and plantarflexion angles (8.78 degrees (SD 4.80)) were found during stair descent compared to ascent. Coefficient of variation (mean (SD)) in percentage between repeated tests varied for joint angles and moments, respectively (2.35% (SD 1.83)-17.53% (SD 13.62)) and (4.65% (SD 2.99)-40.73% (SD 24.77)). INTERPRETATION: Stair ascent was shown to be the more demanding biomechanical task when compared to stair descent for healthy young subjects. The findings from the current study provide baseline measures for pathological studies, theoretical joint modelling, and for mechanical joint simulators.     

Quality of life and gait after unicondylar knee prosthesis are inferior to age-matched control subjects

OBJECTIVE: Evaluation of quality of life, gait pattern, and muscle activity after implantation of unicondylar sledge prostheses in comparison with control group. DESIGN: A total of 17 patients were examined at an average follow-up of 21.5 mo after implantation of unicondylar sledge prostheses. In addition to clinical evaluation with different scores, our patients underwent three-dimensional gait analysis and surface electromyographic investigation of the lower limb and quality-of-life assessment using the Short Form-36 health questionnaire. The control group consisted of 11 healthy subjects. RESULTS: Statistical analysis showed significantly lower results for the patient group in the Hospital for Special Surgery score, the Knee Society score, the patella score, and the Visual Analog Scale for pain. In quality of life, significant differences could be found for the following items: physical functioning, role limitation because of physical problems, and bodily pain. Electromyographic activities during gait were significantly lower in the patient group, except for the rectus femoris and the tibialis anterior. Regarding gait analysis, the variables for ground reaction forces and stride length differed significantly, whereas maximum knee extension and flexion did not. CONCLUSIONS: Unicondylar knee replacement has failed to restore functional capabilities, quality of life, gait pattern, and muscle activity compared with healthy subjects of the same age. The assumption that unicondylar sledge prostheses preserve normal joint function must be questioned.     

Trunk kinematics during locomotor activities.

We investigated upper-body (ie, trunk) angular kinematics (motions) during gait, stair climbing and descending, and rising from a chair in two reference frames--relative to the pelvis and to room coordinates. Bilateral kinematic data were collected from 11 healthy subjects (6 female, 5 male), who were 27 to 88 years of age (mean = 58.9, SD = 17.9). During stair climbing, maximum trunk flexion relative to the room was at least double that during stair descending and gait. Arising from a chair required the most trunk flexion/extension range of motion (ROM) but the least abduction/adduction and medial/lateral (internal/external) rotation. Trunk ROM during gait was small (mean less than or equal to 12 degrees) and consistent with previous literature. Trunk range of motion relative to the room during stair climbing and descending was greater than trunk ROM during gait in all planes. The pelvis and trunk rotate in the transverse plane in greater synchrony during stair descending (mean = 8.1 degrees, SD = 5.6 degrees) than during gait (mean = 12.0 degrees, SD = 4.2 degrees). For all activities, trunk frontal and sagittal ROM relative to the pelvis was greater than that relative to the room coordinates. This finding suggests that trunk/pelvis coordination may be used to reduce potentially destabilizing anti-gravity trunk motions during daily activities. We conclude that upper-body kinematics relative to both pelvis and gravity during daily activities are important to locomotor control and should be considered in future studies of patients with locomotor disabilities.     

Biomechanical Analysis of Stair Descent in Patients with Knee Osteoarthritis

[Purpose] The purposes of this study were to investigate the lower extremity joint kinematics and kinetics of patients with the knee osteoarthritis (knee OA) during stair descent and clarify the biomechanical factors related to their difficulty in stair descent. [Subjects and Methods] Eight healthy elderly persons and four knee OA patients participated in this study. A 3-D motion analysis system and force plates were employed to measure lower extremity joint angles, ranges of motion, joint moments, joint powers, and ratios of contribution for the joint powers while descending stairs. [Results] Knee joint flexion angle, extension moment, and negative power during the early stance phase in the knee OA group were smaller than those in the healthy subjects group. However, no significant changes in these parameters in the ankle joint were observed between the two subject groups. [Conclusion] Knee OA patients could not use the knee joint to absorb impact during the early stance phase of stair descent. Hence, they might compensate for the roles played by the intact knee joint by mainly using ipsilateral ankle kinematics and kinetics.Key words: Knee osteoarthritis, Stair descent, 3-D motion analysis     

External loading alters lower extremity kinetics,kinematics, and muscle activity in a distribution-specific manner during the transition from stair descent to level walking

BackgroundExcess body mass is thought to be a major cause of altered biomechanics in obesity, but the effects of body mass distribution in biomechanics during daily living tasks are unknown. The purpose of this study was to determine how increasing body mass centrally and peripherally affects lower extremity kinematics, kinetics, and muscle activation when transitioning from stair descent to level gait.MethodsFifteen normal weight volunteers descended a staircase at a self-selected pace under unloaded, centrally loaded, and peripherally loaded conditions. Spatial-temporal gait characteristics and lower extremity joint kinematics, kinetics, and mean electromyography amplitude were calculated using 3D motion analysis.FindingsBoth central and peripheral loading reduced gait velocity. Peripheral loading increased time spent in stance phase, increased step width, and reduced step length. At the hip joint, peripheral loading reduced peak hip extension and adduction angle. Conversely, central loading reduced peak hip flexor moment. Both central and peripheral loading increased peak knee flexion angle, but only peripheral loading increased peak knee extensor moment. Central and peripheral loading increased mean electromyography amplitude of the medial gastrocnemius, but only peripheral loading increased mean electromyography amplitude of the semitendinosus and the vastus medialis.InterpretationIncreasing mass centrally and peripherally differently affects spatial-temporal gait characteristics and lower extremity joint kinematics, kinetics, and electromyography when transitioning from stair descent to level gait. Body mass distribution may be an important factor for obesity-induced biomechanical alterations and should be considered when developing biomechanical models of obesity.     

Changes in foot and lower limb coupling due to systematic variations in step width

BACKGROUND: Motion at the midfoot joints can contribute significantly to overall foot motion during gait. However, there is little information regarding the kinematic coupling relationship at the midfoot. The purpose of the present study was to determine whether the coupling relationship at the midfoot and subtalar joints was affected when step width was manipulated during running. METHODS: Twelve subjects ran over-ground at self-selected speeds using three different step widths (normal, wide, cross-over). Coupling at the midfoot (forefoot relative to rearfoot) and subtalar (rearfoot relative to shank) joints was assessed using cross-correlation techniques. FINDINGS: Rearfoot kinematics were significantly different from normal running in cross-over running (P<0.05) but not in wide running. However, coupling between rearfoot eversion/inversion and shank rotation was consistently high (r>0.917), regardless of step width. This was also the case for coupling between rearfoot frontal plane motion and forefoot sagittal plane (r<-0.852) and forefoot transverse plane (r>0.946) motion. There was little evidence of coupling between rearfoot frontal plane motion and forefoot frontal plane motion in any of the conditions. INTERPRETATION: Forefoot frontal plane motion appeared to have little effect on rearfoot frontal plane motion and thus, had no effect on motion at the subtalar joint. The strong coupling of forefoot sagittal and transverse plane motions with rearfoot frontal plane motion suggests that forefoot motion exerts an important influence on subtalar joint kinematics.