IEEE Trans Neural Syst Rehabil Eng. 2021;29:320-329. doi: 10.1109/TNSRE.2021.3049194. Epub 2021 Mar 2.
This paper describes a semi-powered ankle prosthesis and corresponding unified controller that provides biomimetic behavior for level and sloped walking without requiring identification of ground slope or modulation of control parameters. The controller is based on the observation that healthy individuals maintain an invariant external quasi-stiffness (spring like behavior between the shank and ground) when walking on level and sloped terrain. Emulating an invariant external quasi-stiffness requires an ankle that can vary the set-point (i.e., equilibrium angle) of the ankle stiffness. A semi-powered ankle prosthesis that incorporates a novel constant-volume power-asymmetric actuator was developed to provide this behavior, and the unified controller was implemented on it. The device and unified controller were assessed on three subjects with transtibial amputations while walking on inclines, level ground, and declines. Experimental results suggest that the prosthesis and accompanying controller can provide a consistent external quasi-stiffness similar to healthy subjects across all tested ground slopes.
本文介绍了一种半主动式踝关节假肢和相应的统一控制器，该控制器在不识别地面坡度或调整控制参数的情况下，为水平和倾斜行走提供仿生行为。该控制器基于这样的观察：健康人在水平和倾斜地形上行走时，保持外部准静态不变（小腿和地面之间的弹簧行为）。模拟不变的外部准静态需要一个能够改变踝关节刚度设定点（即平衡角度）的踝关节。一种半主动式踝关节假肢，结合了新型的定容功率非对称执行器，以提供这种行为，并且在其上实现了统一的控制器。该设备和统一的控制器在三个小腿截肢者身上进行了评估，他们在倾斜、水平和下降的地面上行走。实验结果表明，该假肢和配套的控制器可以在所有测试的地面坡度下提供类似于健康受试者的一致的外部准静态。
