Design And Performance Analysis Of Series Elastic Actuators.pdf

- Topic: Impedance Control and Performance Measure of Series Elastic Actuators (SEAs)
- Authors: Ye Zhao, Nicholas Paine, Steven Jens Jorgensen, Luis Sentis
- Publication: IEEE Transactions on Industrial Electronics, Vol. 65, No. 3, March 2018
- Key Points:
- SEAs are prevalent in torque-controlled robots for compliant interactions with environments and humans.
- The article addresses the design of optimal impedance controllers and characterization of impedance performance for SEAs with time delays and filtering.
- A critically damped gain design method is proposed for a class of SEA cascaded control architectures, composed of outer impedance and inner torque feedback loops.
- The proposed gain design criterion solves optimal controller gains by maximizing phase-margin-based stability.
- A tradeoff between impedance and torque controller gains is analyzed in terms of closed-loop stability and overall impedance performance.
- Frequency-domain methods are used to analyze the effects of time delays, filtering, and load inertia on SEA impedance performance.
- A novel impedance performance metric, "Z-region," is proposed to quantify achievable impedance magnitude range (Z-width) and frequency range (Z-depth).
- Simulations and experimental implementations validate the proposed method and performance metric.
- Funding: National Aeronautics and Space Administration (NASA) Johnson Space Center, National Science Foundation (NSF), NASA/NSF NRI Grant, Office of Naval Research Grant, NASA Space Technology Research Fellowship Grant.