Design of an Elastic Component for a Dual-stage Reaction Force Series Elastic Actuator

Abstract

Series Elastic Actuator(SEAs) are widely used for a precise torque control. The importance of the precision in torque control is underscored in wearable robots; especially in cable-driven soft robots. Depending on the phase of the human motion, both large assistive torques and the precision in controlling the torque are required for a better performance. In the case of soft wearable robots utilizing single spring SEAs, the trade-off between the precision of torque control and the stiffness of the spring puts a limit on the choice of the springs with larger stiffness for applying a larger assistive torque. To resolve this issue, we designed a Dual-stage Series Reaction Force Elastic Actuator (DRFSEA) that acts as a SEA with a better precision and with a larger appliable torque by dividing the working range of the springs into two segments.