Deep Compliant Control for Legged Robots

Supplementary video for the ICRA 2024 paper
"Deep Compliant Control for Legged Robots" by Adrian Hartmann, Dongho Kang, Fatemeh Zargarbashi, Miguel Zamora, and Stelian Coros.
2024 IEEE International Conference on Robotics and Automation (ICRA 2024)

Abstract:
Control policies trained using deep reinforcement learning often generate stiff, high-frequency motions in response to unexpected disturbances. To promote more natural and compliant balance recovery strategies, we propose a simple modification to the typical reinforcement learning training process. Our key insight is that stiff responses to perturbations are due to an agent’s incentive to maximize task rewards at all times, even as perturbations are being applied. As an alternative, we introduce an explicit recovery stage where tracking rewards are given irrespective of the motions generated by the control policy. This allows agents a chance to gradually recover from disturbances before attempting to carry out their main tasks. Through an in-depth analysis, we highlight both the compliant nature of the resulting control policies, as well as the benefits that compliance brings to legged locomotion. In our simulation and hardware experiments, the compliant policy achieves more robust, energy-efficient, and safe interactions with the environment.

Acknowledgment:
This work has received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme.

Preprint version:
https://crl.ethz.ch/papers/hartmann20...

Computational Robotics Lab:
- https://crl.ethz.ch/

Dongho Kang:
- https://donghok.me/
-   / eastskykang  

Stelian Coros:
- http://crl.ethz.ch/coros.html