IEEE Trans Biomed Eng. 2021 May;68(5):1714-1725. doi: 10.1109/TBME.2020.3046357. Epub 2021 Apr 21.
We aimed to develop a system for people with amputation that non-invasively restores missing control and sensory information for an ankle-foot prosthesis.
In our approach, a wrist exoskeleton allows people with amputation to control and receive feedback from their prosthetic ankle via teleoperation. We implemented two control schemes: position control with haptic feedback of ankle torque at the wrist; and torque control that allows the user to modify a baseline torque profile by moving their wrist against a virtual spring. We measured tracking error and frequency response for the ankle-foot prosthesis and the wrist exoskeleton. To demonstrate feasibility and evaluate system performance, we conducted an experiment in which one participant with a transtibial amputation tracked desired wrist trajectories during walking, while we measured wrist and ankle response.
Benchtop testing demonstrated that for relevant walking frequencies, system error was below human perceptual error. During the walking experiment, the participant was able to voluntarily follow different wrist trajectories with an average RMS error of 1.55 after training. The ankle was also able to track desired trajectories below human perceptual error for both position control (RMSE = 0.8 ) and torque control (RMSE = 8.4%).
We present a system that allows a user with amputation to control an ankle-foot prosthesis and receive feedback about its state using a wrist exoskeleton, with accuracy comparable to biological neuromotor control.
This bilateral teleoperation system enables novel prosthesis control and feedback strategies that could improve prosthesis control and aid motor learning.
我们旨在为截肢者开发一个系统，该系统可以非侵入性地恢复缺失的踝关节 - 足部假肢的控制和感觉信息。
在我们的方法中，腕部外骨骼允许截肢者通过遥操作控制和接收来自假肢踝关节的反馈。我们实现了两种控制方案：在腕部处具有踝力矩触觉反馈的位置控制；以及允许用户通过移动手腕抵抗虚拟弹簧来修改基线力矩曲线的扭矩控制。我们测量了踝关节 - 足部假肢和腕部外骨骼的跟踪误差和频率响应。为了演示可行性并评估系统性能，我们进行了一项实验，其中一名胫骨截肢者在行走时跟踪期望的腕部轨迹，同时我们测量了腕部和踝部的响应。
台式测试表明，对于相关的行走频率，系统误差低于人类感知误差。在行走实验中，参与者在经过训练后能够以平均 RMS 误差为 1.55 的平均值自愿跟随不同的腕部轨迹。对于位置控制（均方根误差 = 0.8）和扭矩控制（均方根误差 = 8.4%），脚踝也能够跟踪期望的轨迹，低于人类感知误差。
我们提出了一种系统，允许截肢者使用腕部外骨骼控制踝关节 - 足部假肢并接收其状态的反馈，其准确性可与生物神经运动控制相媲美。
这种双侧遥操作系统能够实现新型的假肢控制和反馈策略，从而改善假肢控制并帮助运动学习。
