Various active back-support exoskeletons have been developed to assist manual materials handling work for low back injury prevention. Existing back-support exoskeleton actuation either suffers from rigid transmission structure, or fails to efficiently generate assistance via portable actuation system with flexible transmissions. In this article, a novel cable-driven series elastic actuation (CSEA) system is proposed to realize a flexible and portable back-support exoskeleton design with safe, efficient, and sufficient assistive torque output capability. The CSEA system realizes a flexible actuation based on cable transmission for an ergonomic human–exoskeleton interaction. Based on a torsion spring–support beam mechanism, it achieves an efficient assistance output capability to prevent high cable force demand and resultant lumbar compression, assuring a safe and synergistic operation for flexible exoskeleton actuation. Meanwhile, this mechanism enables the CSEA system to integrate series elastic actuator (SEA) with cable transmission and operates with multiple statuses to leverage SEA advantages and to overcome its torque output limitation. Dynamic model is established for the CSEA system, and a unified torque controller is designed for stable, continuous, and accurate torque control of the CSEA system despite its discontinuous dynamics during operation status transition. The efficacy of the closed-loop CSEA system to enable an ergonomic and efficient back-support exoskeleton actuation with the capability of accurately delivering desired level of assistance is verified via bench tests and human tests. Results verified that the CSEA system actuated exoskeleton can effectively reduce activity of relevant muscles during trunk flexion and extension motions compared to no exoskeleton case, validating successful application of the CSEA system on the exoskeleton for an effective back support effect.

中文翻译：

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用于灵活便携式背部支撑外骨骼的新型电缆驱动串联弹性驱动系统的设计、控制和验证

各种主动背部支撑外骨骼已被开发出来，以辅助手动材料搬运工作，以预防腰部受伤。现有的背部支撑外骨骼驱动要么受到刚性传动结构的影响，要么无法通过具有柔性传动装置的便携式驱动系统有效地产生帮助。在本文中，提出了一种新型缆索驱动串联弹性致动（CSEA）系统，以实现一种灵活、便携式的背部支撑外骨骼设计，具有安全、高效、足够的辅助扭矩输出能力。 CSEA系统实现了基于电缆传输的灵活驱动，实现符合人体工程学的人外骨骼交互。基于扭簧支撑梁机构，它实现了高效的辅助输出能力，以防止高索力需求和由此产生的腰椎压缩，确保灵活的外骨骼驱动的安全和协同操作。同时，该机构使CSEA系统能够将串联弹性执行器（SEA）与电缆传输相结合，并以多种状态运行，以发挥SEA的优势并克服其扭矩输出限制。建立了CSEA系统的动态模型，设计了统一的扭矩控制器，以实现CSEA系统在运行状态转换过程中动态不连续的情况下稳定、连续、精确的扭矩控制。闭环 CSEA 系统能够实现符合人体工程学且高效的背部支撑外骨骼驱动，并能够准确提供所需水平的辅助，其功效已通过台架测试和人体测试得到验证。结果验证，与无外骨骼情况相比，CSEA系统驱动的外骨骼能够有效减少躯干屈伸运动时相关肌肉的活动，验证了CSEA系统在外骨骼上的成功应用，达到了有效的背部支撑效果。