A Robust Impedance Controller Design for Series Elastic Actuators using the Singular Perturbation Theory

Area of Science:

• Robotics
• Control Systems Engineering
• Human-Robot Interaction

Background:

• Series Elastic Actuators (SEAs) offer enhanced safety and compliance compared to rigid robots.
• Existing impedance control methods for SEAs have limitations in flexibility and state measurement requirements.

Purpose of the Study:

• To propose a novel impedance controller for SEA systems.
• To enhance safety and compliance in human-robot interaction.
• To reduce the driving-point impedance of interacting SEAs.

Main Methods:

• Development of an impedance controller based on singular perturbation (SP) theory.
• Integration of the time-delay estimation (TDE) technique for system compensation.
• Validation through simulation and experimental studies.

Main Results:

• The proposed controller effectively adjusts driving-point impedance beyond simple reduction.
• SP theory alleviates the need for extensive state measurement.
• TDE technique efficiently compensates for system dynamics and uncertainties with low computational load.
• Demonstrated efficacy of the combined SP and TDE approach.

Conclusions:

• The proposed impedance controller enhances SEA safety and compliance.
• The combination of SP theory and TDE offers a robust and efficient control solution for SEAs.
• This approach advances human-robot interaction safety and performance.