Modeling and Application of Series Elastic Actuators for Force Control Multi Legged Robots

TL;DR

This paper discusses the design, benefits, and applications of Series Elastic Actuators, highlighting their low impedance, high force fidelity, and shock tolerance for use in various robotic systems.

Contribution

It introduces a novel mechanical design for Series Elastic Actuators that enhances force control capabilities in robots and other devices.

Findings

High force fidelity demonstrated in experiments

Low impedance and shock tolerance achieved

Effective in legged robots and exoskeletons

Abstract

Series Elastic Actuators provide many benefits in force control of robots in unconstrained environments. These benefits include high force fidelity, extremely low impedance, low friction, and good force control bandwidth. Series Elastic Actuators employ a novel mechanical design architecture which goes against the common machine design principal of "stiffer is better". A compliant element is placed between the gear train and driven load to intentionally reduce the stiffness of the actuator. A position sensor measures the deflection, and the force output is accurately calculated using Hooke's Law (F=Kx). A control loop then servos the actuator to the desired output force. The resulting actuator has inherent shock tolerance, high force fidelity and extremely low impedance. These characteristics are desirable in many applications including legged robots, exoskeletons for human performance amplification, robotic arms, haptic interfaces, and adaptive suspensions. We describe several variations of Series Elastic Actuators that have been developed using both electric and hydraulic components.