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, enabling 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 deformation, 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.