Impedance control of a cable-driven series elastic actuator with the 2-DOF control structure
For researchers in physical human-robot interaction, this work provides a practical control method for cable-driven SEAs, though it is an incremental improvement over existing SEA control approaches.
The paper addresses impedance control challenges for cable-driven series elastic actuators (SEAs), such as reduced bandwidth and trade-off between tracking and robustness. A 2-DOF control structure with a torque compensator is proposed and validated through simulations and experiments.
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.