Using parallel elasticity in back-support exoskeletons: a study on energy consumption during industrial lifting tasks

The potential areas of application for exoskeletons are expanding as technological advances are made in their realization. Among the technological challenges still unsolved, actuator design affects many important properties of the resulting device, such as weight and user comfort. We consider here the case of an active exoskeleton designed to assist the lower back during lifting tasks. In previous studies, a parallel-elastic actuator was shown to improve torque control bandwidth over a “traditional” stiff actuator in generating the required torque profiles, by enabling lower-inertia designs. This paper reports our results on energy consumption showing that an appropriately designed parallel spring also substantially reduces the electrical energy consumption (by well over 50% in the proposed case), enabling exoskeleton designs with reduced weight and improved power autonomy.