Accessible Torque Bandwidth of a Series Elastic Actuator Considering the Thermodynamic Limitations
This work addresses performance limitations in robotic actuators for engineers, but it is incremental as it builds on existing thermodynamic and control models.
The paper tackled the problem of inaccessible closed-loop torque bandwidth in series elastic actuators due to thermodynamic limitations, and improved accessibility by implementing a stator winding temperature estimation-based adaptive controller, achieving a 30% increase in accessible bandwidth.
Within the scope of the paper, electromechanical and thermodynamic models are derived for a series elastic actuator and open loop and closed loop torque bandwidth parameters are analysed considering the thermodynamic behaviour of the actuator. It was observed that the closed loop torque bandwidth of the electromechanical subsystem of the actuator was not accessible in the entire torque reference amplitude range due to thermodynamic limitations. Therefore, a stator winding temperature estimation based adaptive controller is utilised and analysed to improve the accessibility of the controller based torque bandwidth. This paper implements the methodology on a HEBI Robotics X5-9 actuator as a case study.