Department of Mechanical Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA.
Department of Movement and Sports Sciences, Ghent University, Ghent, Belgium.
Sci Robot. 2020 Mar 25;5(40). doi: 10.1126/scirobotics.aay9108.
Exoskeletons that reduce energetic cost could make recreational running more enjoyable and improve running performance. Although there are many ways to assist runners, the best approaches remain unclear. In our study, we used a tethered ankle exoskeleton emulator to optimize both powered and spring-like exoskeleton characteristics while participants ran on a treadmill. We expected powered conditions to provide large improvements in energy economy and for spring-like patterns to provide smaller benefits achievable with simpler devices. We used human-in-the-loop optimization to attempt to identify the best exoskeleton characteristics for each device type and individual user, allowing for a well-controlled comparison. We found that optimized powered assistance improved energy economy by 24.7 ± 6.9% compared with zero torque and 14.6 ± 7.7% compared with running in normal shoes. Optimized powered torque patterns for individuals varied substantially, but all resulted in relatively high mechanical work input (0.36 ± 0.09 joule kilogram per step) and late timing of peak torque (75.7 ± 5.0% stance). Unexpectedly, spring-like assistance was ineffective, improving energy economy by only 2.1 ± 2.4% compared with zero torque and increasing metabolic rate by 11.1 ± 2.8% compared with control shoes. The energy savings we observed imply that running velocity could be increased by as much as 10% with no added effort for the user and could influence the design of future products.
可降低能量消耗的外骨骼可使休闲跑步更愉快并提高跑步表现。虽然有很多方法可以帮助跑步者，但最佳方法仍不清楚。在我们的研究中，我们使用了一种系绳式踝部外骨骼模拟器，在跑步机上跑步时优化了动力和弹簧式外骨骼的特性。我们预计动力条件会提供较大的节能效果，而弹簧式模式则可以提供更简单的设备所能实现的较小益处。我们使用人机交互优化来尝试为每种设备类型和个人用户确定最佳外骨骼特性，从而可以进行良好的对照比较。我们发现，与零扭矩相比，优化后的动力辅助可将能量经济性提高 24.7 ± 6.9％，与正常穿鞋相比则提高 14.6 ± 7.7％。个人优化后的动力扭矩模式差异很大，但都导致相对较高的机械功输入（0.36 ± 0.09 焦耳/千克/步）和峰值扭矩的延迟（75.7 ± 5.0％的支撑阶段）。出乎意料的是，弹簧式辅助效果不佳，与零扭矩相比仅提高了 2.1 ± 2.4％的能量经济性，与对照鞋相比，代谢率提高了 11.1 ± 2.8％。我们观察到的节能效果意味着，用户无需额外努力，跑步速度可以提高 10％，这可能会影响未来产品的设计。
