Biorobotics Lab
 
Biorobotics Lab

Active Shoulder-Support Exoskeleton

A novel, lightweight shoulder support exoskeleton with for industrial workers who perform overhead tasks.

an image of a person wearing a back exoskeleton

Shoulder injuries rank as the second most prevalent injuries in the workplace. In sectors such as construction and manufacturing, workers frequently engage in tasks demanding shoulder flexion, such as lifting heavy objects overhead, wielding tools at elevated angles, and installing fixtures or components above head height. Given the recurrent nature of these actions and their associated risks, there's a pressing need for an assistive solution. We have developed a novel shoulder support exoskeleton that assists the shoulder joint in these type of tasks. We have designed both passive and active versions of the exoskeleton design.

Design


Our shoulder exoskeleton supports the weight of the arm when the shoulder joint is flexed / adducted. It uses a single torque generator with a cable driven differential mechanism to deliver equal assistive forces to both shoulder joints. The exoskeleton may also disengage one side if assistance is needed only on one shoulder. At just 3.5 kg, the device is lightweight - improving comfort for the workers and our cable driven design lets the heaviest parts of the device sit close to the core while a lightweight structure delivers assistive forces to the targeted joints. The passive version of the device uses a spring to generate the torque. The active version of the device uses a brushless electric motor to produce the assistive torque.

Actuation and Control


The active version of our device includes an embedded real-time controller that coommands the torque of a brushless electric motor through a Series Elastic Actuator (SEA) to achieve an inherently compliant mechanism and force control. The active device also includes on-board motion sensors that let the controller intelligently determine the assistive torque needed based on the pose and motion of the joint and adjust the assistance in real-time. The active device weights around 3.5kg is capable of delivering up to 30 Nm of assistive torque to the shoulder joint. The use of a real-time controller also allows us to implement a variety of control strategies to improve the performance of the device in different working conditions.

Video

Publications

  1. S. Ding, A. Reyes Francisco, T. Li, and H. Yu, “A novel passive shoulder exoskeleton for assisting overhead work,” Wearable Technologies, vol. 4, p. e7, 2023.