Bioengineering Department, Stanford University, 318 Campus Drive, Stanford, CA 94305; George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30309.
Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, 313 Ferst Dr NW, Atlanta, GA 30332.
J Biomech Eng. 2024 Dec 1;146(12). doi: 10.1115/1.4066370.
Crouch gait is one of the most common compensatory walking patterns found in individuals with neurological disorders, often accompanied by their limited physical capacity. Notable kinematic characteristics of crouch gait are excessive knee flexion during stance and reduced range of motion during swing. Knee exoskeletons have the potential to improve crouch gait by providing precisely controlled torque assistance directly to the knee joint. In this study, we implemented a finite-state machine-based impedance controller for a powered knee exoskeleton to provide assistance during both stance and swing phases for five children and young adults who exhibit chronic crouch gait. The assistance provided a strong orthotic effect, increasing stance phase knee extension by an average of 12 deg. Additionally, the knee range of motion during swing was increased by an average of 15 deg. Changes to spatiotemporal outcomes, such as preferred walking speed and percent stance phase, were inconsistent across subjects and indicative of the underlying intricacies of user response to assistance. This study demonstrates the potential of knee exoskeletons operating in impedance control to mitigate the negative kinematic characteristics of crouch gait during both stance and swing phases of gait.
蹲行步态是一种在神经障碍患者中常见的代偿性行走模式，通常伴随着他们身体能力的受限。蹲行步态的显著运动学特征是在站立时过度的膝关节屈曲和摆动时运动范围减小。膝关节外骨骼有可能通过直接向膝关节提供精确控制的扭矩辅助来改善蹲行步态。在这项研究中，我们为一个动力膝关节外骨骼实现了基于有限状态机的阻抗控制器，以便在五个患有慢性蹲行步态的儿童和年轻人的站立和摆动阶段提供辅助。辅助提供了很强的矫形效果，使站立阶段的膝关节伸展平均增加了 12 度。此外，摆动阶段的膝关节运动范围平均增加了 15 度。诸如最佳行走速度和站立阶段百分比等时空结果的变化在受试者之间不一致，表明了用户对辅助的反应的潜在复杂性。这项研究表明，在行走的站立和摆动阶段，以阻抗控制方式运行的膝关节外骨骼具有减轻蹲行步态负面运动学特征的潜力。
