Novel Series Elastic Actuator Towards High Torque Capacity With High Sensitive Torque Measurement

Series Elastic Actuator (SEA) has widely been used in various robotic applications due to its ability to provide safe and accurate force. However, conventionally, securing the high torque sensitivity of the SEA of the spring is challenging due to the limitation of natural frequency and torque capacity, making it less applicable in certain situations. Therefore, this letter proposes a novel Series Spring-Embraced Elastic Actuator (SSE-EA), which uses a Transmitted Force-Sensing SEA (TFSEA) structure and a vertical torsional spring to high torque sensitivity. The design method of the spring is proposed to maximize the advantages of the structure. In addition, mechanisms and controller designs are presented to achieve sensitive torque control for heavy load tasks. Through several validations, we evaluate the performance and applicability of the SSE-EA.