Kelly David J, Wensing Patrick M
IEEE Int Conf Rehabil Robot. 2025 May;2025:456-461. doi: 10.1109/ICORR66766.2025.11062927.
Robust and effective control algorithms are essential for advancing powered lower-limb prostheses from laboratory settings to broader commercial use. Continuous controllers, which estimate an individual's gait progression to determine desired joint actuator outputs, have recently shown great promise. However, their success relies on accurately estimating the individual's progression through the gait cycle to ensure proper actuator behavior. This study investigates and quantifies how two gait estimation methods using only the global sagittal thigh angle for a knee-ankle prosthesis user impact controller performance. Two controllers were tested with each gait cycle estimation algorithm: a joint-level impedance controller and a task-level center of mass controller, extended to the kneeankle configuration herein. Experiments were conducted with an individual without amputation walking on a knee-ankle prosthesis. Higher linearity in gait estimation ($\mathrm{R}^{2}=0.984$ vs. $\mathrm{R}^{2}=0.980$) using the improved method resulted in lower shank velocity ($>25 {%}$), better symmetry of shank velocity ($\sim 75 {%}$), and lower impact into the mechanical hardstop during knee extension in swing for the impedance controller.
强大而有效的控制算法对于将动力下肢假肢从实验室环境推广到更广泛的商业应用至关重要。连续控制器通过估计个体的步态进程来确定所需的关节致动器输出，最近已显示出巨大的潜力。然而，它们的成功依赖于准确估计个体在步态周期中的进程，以确保致动器的正确行为。本研究调查并量化了两种仅使用膝踝假肢使用者的全局矢状面大腿角度的步态估计方法对控制器性能的影响。每种步态周期估计算法都测试了两种控制器：一种关节级阻抗控制器和一种任务级质心控制器，本文将其扩展到膝踝配置。实验是在一名未截肢的个体使用膝踝假肢行走时进行的。使用改进方法的步态估计具有更高的线性度（(R^{2}=0.984) 对 (R^{2}=0.980)），这导致小腿速度降低（(>25%)），小腿速度对称性更好（(\sim 75%)），并且对于阻抗控制器，在摆动期膝关节伸展时对机械硬限位的冲击更小。
