On the Role of the Action Space in Robot Manipulation Learning and Sim-to-Real Transfer

Elie Aljalbout, Felix Frank, Maximilian Karl, Patrick van der Smagt

Keywords: Reinforcement Learning, Sim-to-real transfer, Manipulation, Action Spaces

TL;DR: We study the role of the action space in robot manipulation learning and sim-to-real transfer and provide guides for this choice and metrics to evaluate and predict transfer performance.

Abstract:

We study the choice of action abstractions in robot manipulation learning and sim-to-real transfer.
We define metrics that assess the performance, and examine the emerging properties in the different action spaces.
We train over 250 reinforcement learning~(RL) agents in simulated reaching and pushing tasks, using 13 different control spaces.
The choice of spaces spans combinations of common action space design characteristics.
We evaluate the training performance in simulation and the transfer to a real-world environment.
We identify good and bad characteristics of robotic action spaces and make recommendations for future designs.
Our findings have important implications for the design of RL algorithms for robot manipulation tasks, and highlight the need for careful consideration of action spaces when training and transferring RL agents for real-world robotics.

Submission Number: 27