An Experimental Powered Lower Limb Prosthesis Using Proportional Myoelectric Control
An Experimental Powered Lower Limb Prosthesis Using Proportional Myoelectric Control
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DOI：
10.1115/1.4026633
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发表时间：
2014-06-01
影响因子：
0.9
通讯作者：
Ferris, Daniel P.
中科院分区：
文献类型：
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作者：
Huang, Stephanie;Wensman, Jeffrey P.;Ferris, Daniel P.
提供对佩戴者的意图具有更大适应性的动力下肢假肢的一种方式是使用神经信号来提供假肢机械的前馈控制。我们设计并测试了一种实验性动力踝足假肢的可行性，该假肢使用气动人工肌肉和比例肌电控制来改变行走过程中的踝关节力学。人工跖屈肌的力输出与受试者的剩余腓肠肌活动成正比。一对固定在标称长度的人工肌肉产生的最大力为3513 N。行走过程中可能产生的最大种植体屈曲扭矩为176 Nm。气动人工肌肉的力带宽为2 Hz。机电延迟为33毫秒，达到峰值张力的时间为48毫秒，半松弛时间为50毫秒。我们使用两个人工肌肉背屈肌和两个人工肌肉跖屈肌。人工踝关节背屈25 °，跖屈35 °，人工肌肉未充气。该装置的目的不是创造一个商业上可行的假肢，而是有一个实验室原型，以测试运动适应和生物力学的原则。我们招募了一名单侧经胫骨截肢者，在佩戴动力假肢的情况下以1.0 m/s的速度在跑步机上行走。我们使用表面电极记录了受试者规定的假肢接受腔内的肌肉活动。控制器在整个步态周期中是活动的，并且不依赖于步态相位的检测。截肢受试者很快适应了动力假肢，并以功能性步态行走。受试者在蹬离时产生的峰值踝关节力量在截肢侧和假体侧之间相似。我们的研究结果表明，截肢者可以使用他们的剩余肌肉比例肌电控制，以改变假肢力学在步行过程中。
One way to provide powered lower limb prostheses with greater adaptability to a wearer's intent is to use a neural signal to provide feedforward control of prosthesis mechanics. We designed and tested the feasibility of an experimental powered ankle-foot prosthesis that uses pneumatic artificial muscles and proportional myoelectric control to vary ankle mechanics during walking. The force output of the artificial plantar flexor muscles was directly proportional to the subject's residual gastrocnemius muscle activity. The maximum force generated by a pair of artificial muscles fixed at nominal length was 3513 N. The maximum planter flexion torque that could be generated during walking was 176 Nm. The force bandwidth of the pneumatic artificial muscles was 2 Hz. The electromechanical delay was 33 ms, the time to peak tension was 48 ms, and the half relaxation time was 50 ms. We used two artificial muscles as dorsiflexors and two artificial muscles as plantar flexors. The prosthetic ankle had 25 deg of dorsiflexion and 35 deg of plantar flexion with the artificial muscles uninflated. The intent of the device was not to create a commercially viable prosthesis but to have a laboratory prototype to test principles of locomotor adaptation and biomechanics. We recruited one unilateral trans-tibial amputee to walk on a treadmill at 1.0 m/s while wearing the powered prosthesis. We recorded muscle activity within the subject's prescribed prosthetic socket using surface electrodes. The controller was active throughout the entire gait cycle and did not rely on detection of gait phases. The amputee subject quickly adapted to the powered prosthesis and walked with a functional gait. The subject generated peak ankle power at push off that was similar between amputated and prosthetic sides. Our results suggest that amputees can use their residual muscles for proportional myoelectric control to alter prosthetic mechanics during walking.