A Wearable Flexible Exoskeleton for Upper Limb Assistance

In this paper, a wearable upper limb flexible power assist exoskeleton is proposed, which can be used to assist workers in carrying, provide auxiliary force for upper limbs, and reduce physical damage. The exoskeleton uses flexible ropes to transmit motion power, with the ropes directly connected to the forearm of the person via a shoulder anchor point. The motion power is directly applied to the forearm, thereby reducing the complexity of the system. The system uses a PID control strategy to track the movement posture of the human body, provide torque assistance to the upper limbs during operation. Four healthy men participated in the trial to assess muscle activity in four muscles of the upper limbs: deltoid muscle (DM), biceps femoris (BFM), femoral muscle (FM), and wrist flexor (FWF). Compared with the case without using the designed exoskeleton, the test results showed that the average decrease in muscle activity, during lifting action was 28.4% (DM), 27.85% (BFM), 32.64% (FM), 35.22% (FWF), during keeping action was 24.92% (DM), 29.47% (BFM), 20.89% (FM), 28.24% (FWF). The experiments verify the effectiveness of the newly designed exoskeleton system.