The quadriceps are particularly susceptible to fatigue during repetitive lifting, lowering, and carrying (LLC), affecting worker performance, posture, and ultimately lower-back injury risk. Although robotic exoskeletons have been developed and optimized for specific use cases like lifting-lowering, their controllers lack the versatility or customizability to target critical muscles across many fatiguing tasks. Here, we present a task-adaptive knee exoskeleton controller that automatically modulates virtual springs, dampers, and gravity and inertia compensation to assist squatting, level walking, and ramp and stairs ascent/descent. Unlike end-to-end neural networks, the controller is composed of predictable, bounded components with interpretable parameters that are amenable to data-driven optimization for biomimetic assistance and subsequent application-specific tuning, for example, maximizing quadriceps assistance over multiterrain LLC. When deployed on a backdrivable knee exoskeleton, the assistance torques holistically reduced quadriceps effort across multiterrain LLC tasks (significantly except for level walking) in 10 human users without user-specific calibration. The exoskeleton also significantly improved fatigue-induced deficits in time-based performance and posture during repetitive lifting-lowering. Last, the system facilitated seamless task transitions and garnered a high effectiveness rating postfatigue over a multiterrain circuit. These findings indicate that this versatile control framework can target critical muscles across multiple tasks, specifically mitigating quadriceps fatigue and its deleterious effects.

中文翻译：

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多功能膝关节外骨骼可减轻举重、降低和搬运任务中的股四头肌疲劳


股四头肌在重复举重、降低和搬运 （LLC） 时特别容易受到疲劳，影响工人的表现、姿势，并最终导致下背部受伤的风险。尽管机器人外骨骼已经针对升降等特定用例进行了开发和优化，但它们的控制器缺乏多功能性或可定制性，无法在许多疲劳任务中针对关键肌肉。在这里，我们展示了一个任务自适应膝关节外骨骼控制器，它可以自动调节虚拟弹簧、阻尼器以及重力和惯性补偿，以辅助深蹲、水平行走以及坡道和楼梯上升/下降。与端到端神经网络不同，控制器由可预测的有界组件组成，这些组件具有可解释的参数，这些参数适用于数据驱动的优化，以实现仿生辅助和后续的特定应用调整，例如，在多地形 LLC 上最大化股四头肌辅助。当部署在可反向驱动的膝关节外骨骼上时，辅助扭矩全面减少了 10 个人类用户在多地形 LLC 任务中的股四头肌努力（显着减少水平行走除外），而无需进行用户特定的校准。外骨骼还显着改善了重复升降过程中基于时间的表现和姿势的疲劳诱导缺陷。最后，该系统促进了无缝任务转换，并在多地形回路上获得了疲劳后的有效性评级。这些发现表明，这种多功能控制框架可以针对多项任务中的关键肌肉，特别是减轻股四头肌疲劳及其有害影响。