Combining Performance and Passivity in Linear Control of Series Elastic Actuators

Fuente: arXiv
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Main Authors: Mehta, Shaunak A., Losey, Dylan P.
Format: Preprint
Published: 2025
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author Mehta, Shaunak A.
Losey, Dylan P.
author_facet Mehta, Shaunak A.
Losey, Dylan P.
contents When humans physically interact with robots, we need the robots to be both safe and performant. Series elastic actuators (SEAs) fundamentally advance safety by introducing compliant actuation. On the one hand, adding a spring mitigates the impact of accidental collisions between human and robot; but on the other hand, this spring introduces oscillations and fundamentally decreases the robot's ability to perform precise, accurate motions. So how should we trade off between physical safety and performance? In this paper, we enumerate the different linear control and mechanical configurations for series elastic actuators, and explore how each choice affects the rendered compliance, passivity, and tracking performance. While prior works focus on load side control, we find that actuator side control has significant benefits. Indeed, simple PD controllers on the actuator side allow for a much wider range of control gains that maintain safety, and combining these with a damper in the elastic transmission yields high performance. Our simulations and real world experiments suggest that, by designing a system with low physical stiffness and high controller gains, this solution enables accurate performance while also ensuring user safety during collisions.
format Preprint
id arxiv_https___arxiv_org_abs_2509_17210
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Combining Performance and Passivity in Linear Control of Series Elastic Actuators
Mehta, Shaunak A.
Losey, Dylan P.
Robotics
When humans physically interact with robots, we need the robots to be both safe and performant. Series elastic actuators (SEAs) fundamentally advance safety by introducing compliant actuation. On the one hand, adding a spring mitigates the impact of accidental collisions between human and robot; but on the other hand, this spring introduces oscillations and fundamentally decreases the robot's ability to perform precise, accurate motions. So how should we trade off between physical safety and performance? In this paper, we enumerate the different linear control and mechanical configurations for series elastic actuators, and explore how each choice affects the rendered compliance, passivity, and tracking performance. While prior works focus on load side control, we find that actuator side control has significant benefits. Indeed, simple PD controllers on the actuator side allow for a much wider range of control gains that maintain safety, and combining these with a damper in the elastic transmission yields high performance. Our simulations and real world experiments suggest that, by designing a system with low physical stiffness and high controller gains, this solution enables accurate performance while also ensuring user safety during collisions.
title Combining Performance and Passivity in Linear Control of Series Elastic Actuators
topic Robotics
url https://arxiv.org/abs/2509.17210