Design and Control of a Lifting Assist Device for Preventing Lower Back Injuries in Industrial Athletes

Although many lifting assist devices (LADs) have already been launched to the commercial market, and diverse types of LADs are under development with the recent advances in robotics technology, such LADs are not yet widely used in industrial fields. One of the main reason is the lack of versatility of fully passive type LADs and relatively high power consumption of fully active type LADs. In this study, our goal was to design a LAD that is not only more versatile than fully passive type LADs but also more energetically efficient than fully active type LADs. We analyzed the biomechanics of the lifting movement and developed a bi-articular elastic tendon mechanism based on our results. This conceptual mechanism was realized via a physical LAD operated by a series elastic actuator with a Bowden cable transmission. In this paper, we introduce our LAD and control strategy for assisting with lifting movements. Our LAD is capable of adjusting the output force behavior and assisting with lifting tasks at a low mechanical power consumption. Our preliminary testing suggests that our LAD reduces the muscle activation levels of the erector spinae and rectus abdominis muscles during a lifting task.