High-performance actuators are crucial to enable mechanical versatility of wearable robots, which are required to be lightweight, highly backdrivable, and with high bandwidth. State-of-the-art actuators, e.g., series elastic actuators, have to compromise bandwidth to improve compliance (i.e., backdrivability). In this article, we describe the design and human–robot interaction modeling of a portable hip exoskeleton based on our custom quasi-direct drive actuation (i.e., a high torque density motor with low ratio gear). We also present a model-based performance benchmark comparison of representative actuators in terms of torque capability, control bandwidth, backdrivability, and force tracking accuracy. This article aims to corroborate the underlying philosophy of “design for control,” namely meticulous robot design can simplify control algorithms while ensuring high performance. Following this idea, we create a lightweight bilateral hip exoskeleton to reduce joint loadings during normal activities, including walking and squatting. Experiments indicate that the exoskeleton is able to produce high nominal torque (17.5 Nm), high backdrivability (0.4 Nm backdrive torque), high bandwidth (62.4 Hz), and high control accuracy (1.09 Nm root mean square tracking error, 5.4% of the desired peak torque). Its controller is versatile to assist walking at different speeds and squatting. This article demonstrates performance improvement compared with state-of-the-art exoskeletons.

中文翻译：

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具有高反向驱动能力和高带宽的轻质髋部外骨骼的准直接驱动驱动


高性能执行器对于实现可穿戴机器人的机械多功能性至关重要，这些机器人需要重量轻、高度可反向驱动且具有高带宽。最先进的致动器，例如串联弹性致动器，必须牺牲带宽以提高顺应性（即反向驱动能力）。在本文中，我们描述了基于我们定制的准直接驱动驱动（即具有低速比齿轮的高扭矩密度电机）的便携式髋部外骨骼的设计和人机交互建模。我们还对代表性执行器在扭矩能力、控制带宽、反向驱动能力和力跟踪精度方面进行了基于模型的性能基准比较。本文旨在证实“为控制而设计”的基本理念，即细致的机器人设计可以简化控制算法，同时确保高性能。遵循这个想法，我们创造了一种轻型双侧髋部外骨骼，以减少正常活动（包括行走和蹲下）期间的关节负荷。实验表明，该外骨骼能够产生高标称扭矩（17.5 Nm）、高反向驱动能力（0.4 Nm反向驱动扭矩）、高带宽（62.4 Hz）和高控制精度（1.09 Nm均方根跟踪误差，5.4％的所需的峰值扭矩）。它的控制器用途广泛，可以帮助以不同的速度行走和蹲下。本文展示了与最先进的外骨骼相比的性能改进。