SUMMARY

Manual labor workers often perform repetitive lifting tasks that have been correlated with increased risk for chronic lower back pain and back injuries. Recently, back exoskeletons have been a popular area of study for potentially mitigating lower back pain from lifting. Most commercially-available back exoskeletons are unpowered, passive devices that can reduce lumbar muscle exertion during lifts but lack an external power source to provide positive net work or an intelligent controller to adjust to different lifting conditions. Powered back exoskeletons can potentially solve these problems at the cost of generally being rigid, heavy, and unaccommodating for different lifting postures, particularly asymmetric lifts. This thesis presents a novel powered exosuit that aims to address these issues with powered exoskeletons.

A cable-driven powered back exosuit is presented to lower the muscular exertion from repetitive lifting motions. The exosuit uses an angle-based impedance controller to provide variable assistance based on user posture. Experimental results using the device across 10 subjects are presented, including electromyography (EMG), metabolic, and user preference data. The results from the powered back exoskeleton are evaluated against the backX, a commercially-available passive back support exoskeleton, and a no-exo control condition.