Nguyen Vinh Q, Umberger Brian R, Sup Frank C
IEEE Int Conf Rehabil Robot. 2019 Jun;2019:53-58. doi: 10.1109/ICORR.2019.8779368.
The human ankle provides significant positive power during the stance phase of walking, which has resulted in studies focusing on methods to reduce the energetic walking cost by augmenting the ankle with exoskeletons. Recently, a few devices have successfully reduced the metabolic cost of walking by replacing part of the biological ankle plantar flexor torque. Despite these achievements, development of assistive ankle devices remains challenging, partly because the current practice of design and control of powered exoskeletons is highly time and effort consuming, which prevents quickly exploring different design and control parameters. Predictive simulations using musculoskeletal models coupled with robotic devices may facilitate the process of design and control of assistive devices. In this study, we simulate human walking augmented by a powered ankle exoskeleton. The walking problem was formulated as a predictive dynamic optimization in which both the optimal assistive device torque and the gait were solved simultaneously. Cases with exoskeletons assisting one ankle and both ankles were considered. The results showed that the energetic cost of walking could be reduced by 45% with one ankle augmented, and by 52% with both ankles augmented. This study contributes towards the goal of providing optimal assistive torque through external devices and theoretical peak reductions that could be expected from such devices.
人类脚踝在步行支撑期提供显著的正功率，这导致了一些研究聚焦于通过外骨骼增强脚踝来降低步行能量消耗的方法。最近，一些装置通过替代部分生物脚踝跖屈扭矩，成功降低了步行的代谢成本。尽管取得了这些成果，但辅助脚踝装置的开发仍然具有挑战性，部分原因是当前动力外骨骼的设计和控制实践非常耗时费力，这阻碍了快速探索不同的设计和控制参数。使用肌肉骨骼模型与机器人装置相结合的预测性模拟可能有助于辅助装置的设计和控制过程。在本研究中，我们模拟了由动力脚踝外骨骼增强的人类行走。将行走问题表述为一个预测性动态优化问题，并同时求解最佳辅助装置扭矩和步态。考虑了外骨骼辅助单脚踝和双脚踝的情况。结果表明，单脚踝增强时步行的能量消耗可降低45%，双脚踝增强时可降低52%。本研究有助于实现通过外部装置提供最佳辅助扭矩以及此类装置预期的理论峰值降低这一目标。
