Development of a Compliant Mechanism for Series Elastic Actuators

This paper presents a comprehensive study on the design and performance of a rotational spring mechanism for Series Elastic Actuators (SEAs), fabricated using 3D printing techniques. The spring consists of six symmetrically arranged elastic blades that connect concentric inner and outer rings, en- abling bidirectional compliance and large angular deflection. By systematically varying geometric parameters, particularly blade thickness, we investigate the influence on torque-displacement behavior and overall stiffness. A lumped parameter model is developed to analyze the spring mechanics under rotational de- formation, and closed-form expressions for torque response are derived. An experimental setup is developed using a DC motor to apply torque to the designed springs and assess the torque- displacement relationship. The results provide key insights into how design parameters affect spring performance and offer practical guidelines for the development of lightweight, customizable compliant elements in next-generation robotic actuator systems.