Realization of Efficient Rotational Springs and Series Elastic Actuators Using DC Motors

In this paper, a review of adjustable rotational springs is presented along with their application in robotic systems. To this end, the process of implementing an adjustable rotational spring using DC motors and their limitations is presented. Additionally, Series Elastic Actuators (SEAs) as one of the important applications of an adjustable spring are investigated. A review of motor parameters and their effect on achievable stiffness values is presented using available DC motors in the market. Finally, Simulations and comparative studies are presented using MATLAB/Simulink to show that correct selection of the series spring plays a significant role in achieving an efficient SEA with a relatively good stiffness tunability. To this end, a comprehensive parametric sweep study is conducted over different parameters such as amplitude of the rotational deflection, angular velocity, inertia of the rotor, and gearbox ratio of the motor. The findings of this study, facilitates the road for a systematical development of SEAs for various robotic applications.