Adversarial Motion Priors Make Good Substitutes for Complex Reward Functions

IEEE International Conference on Intelligent Robots and Systems (IROS 2022)

Alejandro Escontrela (1,2)    Xue Bin Peng (1)    Wenhao Yu (2)    Tingnan Zhang (2)    Atil Iscen (2)    Ken Goldberg (1)    Pieter Abbeel (1)

(1) University of California, Berkeley    (2) Google Brain


Training a high-dimensional simulated agent withan under-specified reward function often leads the agent to learn physically infeasible strategies that are ineffective when deployed in the real world. To mitigate these unnatural behaviors, reinforcement learning practitioners often utilize complex reward functions that encourage physically plausible behaviors. However, a tedious labor-intensive tuning process is often required to create hand-designed rewards which might not easily generalize across platforms and tasks. We propose substituting complex reward functions with “style rewards” learned from a dataset of motion capture demonstrations. A learned style reward can be combined with an arbitrary task reward to train policies that perform tasks using naturalistic strategies. These natural strategies can also facilitate transfer to the real world. We build upon Adversarial Motion Priors – an approach from the computer graphics domain that encodes a style reward from a dataset of reference motions – to demonstrate that an adversarial approach to training policies can produce behaviors that transfer to a real quadrupedal robot without requiring complex reward functions. We also demonstrate that an effective style reward can be learned from a few seconds of motion capture data gathered from a German Shepherd and leads to energy-efficient locomotion strategies with natural gait transitions.

Paper: [PDF]       Webpage: [Link]       Code: [GitHub]       Preprint: [arXiv]



	title={Adversarial motion priors make good substitutes for complex reward functions. 2022 IEEE},
	author={Escontrela, Alejandro and Peng, Xue Bin and Yu, Wenhao and Zhang, Tingnan and Iscen, Atil and Goldberg, Ken and Abbeel, Pieter},
	booktitle={International Conference on Intelligent Robots and Systems (IROS)},