Impedance control of a cable-driven series elastic actuator with the 2-DOF control structure

TL;DR

This paper presents a 2-DOF control approach for a cable-driven series elastic actuator, improving impedance control performance in human-robot interaction by balancing robustness and torque tracking through simulation and experiments.

Contribution

It introduces a novel 2-DOF control method tailored for cable-driven SEAs, enhancing impedance control effectiveness in HRI applications.

Findings

Validated the 2-DOF control approach through simulations.

Demonstrated improved impedance control in practical experiments.

Abstract

Series elastic actuators (SEAs) are growingly important in physical human-robot interaction (HRI) due to their inherent safety and compliance. Cable-driven SEAs also allow flexible installation and remote torque transmission, etc. However, there are still challenges for the impedance control of cable-driven SEAs, such as the reduced bandwidth caused by the elastic component, and the performance balance between reference tracking and robustness. In this paper, a velocity sourced cable-driven SEA has been set up. Then, a stabilizing 2 degrees of freedom (2-DOF) control approach was designed to separately pursue the goals of robustness and torque tracking. Further, the impedance control structure for human-robot interaction was designed and implemented with a torque compensator. Both simulation and practical experiments have validated the efficacy of the 2-DOF method for the control of cable-driven SEAs.