面向单臂弯举的气动肌肉上肢外骨骼系统设计与实验

Design and Experiment of Upper-limb Exoskeleton Robot System Driven by Pneumatic Artificial Muscle in Lifting Task by Single Arm

针对人体手臂负载弯举过程中易产生肩袖损伤的问题,设计了一种气动肌肉上肢外骨骼机器人。其本体结构由一个肘关节外骨骼机器人和气动式外展肩枕构成,并通过双层护肩结构固定于穿戴者上肢。该设计结合了刚性外骨骼机器人结构的力传递优势和柔性仿生式织物结构的柔顺性优势,在负载弯举过程中对穿戴者的肘关节和肩关节提供必要的助力,同时提高了肩关节处的人机相容性。对比实验结果表明,实验者手持负载并穿戴气动式上肢外骨骼机器人后可以在心率无显著性增加的状态下完成弯举动作,并且在气动式外展肩枕的作用下肩部外展轨迹更近似于自然弯举状态下的轨迹。与无穿戴状态下对比,肱二头肌肌电信号的平均绝对值和均方根分别降为69.92%~70.97%和66.46%~78.85%,冈上肌肌电信号的平均绝对值和均方根分别降为80.67%~81.51%和78.02%~89.22%。

Lifting with a single arm is a common upper-limb action but it is easy to cause the rotator cuff injury.An upper-limb exoskeleton was designed to provide assistant force/torque to the human for accomplishing the lifting task on the premise of safety.The proposed prototype was comprised of two parts:1-DOF elbow exoskeleton and a pneumatic shoulder pillow.The proposed structure was combined with the benefit of power transmission in the rigid exoskeleton and flexible double weave shoulder movement in the bionic exosuit.Such devices can provide necessary force assistance for the elbow flexion/extension and shoulder abduction of the wearer and improve the kinematic compatibility between the human arm and the exoskeleton.Further on,to verify the performance of the exoskeleton,a subject was asked to lifting 1 kg and 5 kg weight of loads with and without the robot-assisted,respectively.From the results,the mean absolute values of electromyography on biceps and supraspinatus were reduced to 70.97%and 80.67%of the non-wearable state during the 1kg weight lifting task,and 69.92%and 81.51%in the 5 kg weight lifting task.The root mean squares of the relative muscle electromyography were reduced to 78.85%and 78.02%in 1 kg,and 66.46%and 89.22%in 5 kg.By using the pneumatic abduction shoulder pillow,the abduction trajectory of the shoulder was similar to the natural state during the lifting tasks.The heart rate of the subject was also recorded in the experiment.From the statistical analysis,the heart rate was not obviously changed(p>0.01).These results illustrated the potential risk of rotator cuff injury can be reduced in the robot-assisted lifting task.