An Ankle-Foot Prosthesis Emulator With Control of Plantarflexion and Inversion-Eversion Torque
An Ankle-Foot Prosthesis Emulator With Control of Plantarflexion and Inversion-Eversion Torque
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DOI：
10.1109/tro.2018.2830372
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发表时间：
2018-10-01
影响因子：
7.8
通讯作者：
Collins, Steven H.
中科院分区：
文献类型：
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作者：
Kim, Myunghee;Chen, Tianjian;Collins, Steven H.
踝关节内翻-外翻顺应性是传统假足的一个重要特征，在主动假肢中控制内翻或滚动可以改善截肢者的平衡。我们设计了一个拴系踝足假体，两个独立驱动的脚趾协调提供跖屈和内翻外翻扭矩。一个鲍登电缆系绳提供了一系列的弹性。该假肢结构简单，重量轻，质量为0.72 kg。脚趾上的应变片测量扭矩的均方根（RMS）误差小于1%。台架测试表明，阶跃响应上升时间小于33 ms，跖屈时的峰值扭矩为250 N.m，内翻-外翻时的峰值扭矩为+/- 30 N.m，峰值功率大于3 kW。相位限制闭环扭矩带宽为20 Hz，跖屈时的线性调频范围为10至90 N.m，倒置时的线性调频范围为24 Hz，-20至20 N.m。该系统在高达18 Hz的频率下对脚趾位置干扰的灵敏度较低。截肢受试者的行走试验表明，跖屈时RMS扭矩跟踪误差小于5.1 N·m，内翻-外翻时RMS扭矩跟踪误差小于1.5 N·m。这些特性使该平台适合在人类实验中测试与反转相关的假体功能和控制器。
Ankle inversion-eversion compliance is an important feature of conventional prosthetic feet, and control of inversion, or roll, in active prostheses could improve balance for people with amputation. We designed a tethered ankle-foot prosthesis with two independently actuated toes that are coordinated to provide plantarflexion and inversion-eversion torques. A Bowden cable tether provides series elasticity. The prosthesis is simple and lightweight, with a mass of 0.72 kg. Strain gauges on the toes measure torque with less than 1% root mean squared (RMS) error. Benchtop tests demonstrated a step response rise time of less than 33 ms, peak torques of 250 N.m in plantarflexion and +/- 30 N.m in inversion-eversion, and peak power above 3 kW. The phase-limited closed-loop torque bandwidth is 20 Hz with a chirp from 10 to 90 N.m in plantarflexion, and 24 Hz with a chirp from -20 to 20 N.m in inversion. The system has low sensitivity to toe position disturbances at frequencies of up to 18 Hz. Walking trials with an amputee subject demonstrated RMS torque tracking errors of less than 5.1 N.m in plantarflexion and less than 1.5 N-m in inversion-eversion. These properties make the platform suitable for testing inversion-related prosthesis features and controllers in experiments with humans.