Manual lifting tasks involve repetitive raising, holding and stacking movements with heavy objects. These arm movements are notable risk factors for muscle pain, fatigue, and musculoskeletal disorders in workers. An upper-limb wearable robot, as a 6-DOF dual-arm exoskeleton, which was designed to augment workers’ strength and minimize muscular activation in the arm during repetitive lifting tasks. To adjust the robot joint trajectory, the user needs to apply an interactive torque to operate the robot during lifting tasks when a standard virtual mechanical impedance control structure is used. To reduce overshooting of the interactive torque on the user’s joint, a three-tier hierarchical control structure was developed for the robot in this study. At the highest level, a human arm movement detection module is used to detect the user’s arm motion according to the surface electromyography signals. Then, a Hammerstein adaptive virtual mechanical impedance controller is used at the middle level to reduce overshooting and yield an acceptable value of torque for the user’s elbow joint in actual lifting tasks. At the lowest level, the actuator controller on each joint of the robot controls the robot to complete lifting tasks. Several experiments were conducted, and the results showed that the interactive torque on the user’s elbow was limited and the muscular activations of erector spinae and biceps brachii muscles were effectively decreased. The proposed scheme prevents potential harm to the user due to excessive interactive torque on the human elbow joint, such as related muscle fatigue and joint injuries.

中文翻译：

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一种具有人体手臂运动检测功能的安全人机交互控制结构，用于上肢可穿戴机器人在起重任务中使用

手动提升任务涉及重复提升、保持和堆叠重物的动作。这些手臂运动是工人肌肉疼痛、疲劳和肌肉骨骼疾病的显着危险因素。上肢可穿戴机器人，作为 6 自由度双臂外骨骼，旨在增强工人的力量，并在重复性举重任务期间最大限度地减少手臂肌肉活动。为了调整机器人关节轨迹，当使用标准的虚拟机械阻抗控制结构时，用户需要在提升任务期间施加交互扭矩来操作机器人。为了减少用户关节上交互扭矩的过冲，在本研究中为机器人开发了三层分层控制结构。在最高级别，人体手臂运动检测模块用于根据表面肌电信号检测用户的手臂运动。然后，在中间层使用 Hammerstein 自适应虚拟机械阻抗控制器来减少超调，并在实际提升任务中为用户的肘关节产生可接受的扭矩值。在最底层，机器人每个关节上的执行器控制器控制机器人完成举升任务。进行了多次实验，结果表明，用户肘部的交互扭矩有限，竖脊肌和肱二头肌的肌肉激活有效降低。所提出的方案可防止由于人体肘关节上的过度交互扭矩而对用户造成潜在伤害，例如相关的肌肉疲劳和关节损伤。