Multi-Task Reinforcement Learning in Continuous Control with Successor Feature-Based Concurrent Composition

Deep reinforcement learning (DRL) frameworks are increasingly used to solve high-dimensional continuouscontrol tasks in robotics. However, due to the lack of sample efficiency, applying DRL for online learning is still practically infeasible in the robotics domain. One reason is that DRL agents do not leverage the solution of previous tasks for new tasks. Recent work on multi-task DRL agents based on successor features (SFs) has proven to be quite promising in increasing sample efficiency. In this work, we present a new approach that unifies two prior multi-task RL frameworks, SF-GPI and value composition, and adapts them to the continuous control domain. We exploit compositional properties of successor features to compose a policy distribution from a set of primitives without training any new policy. Lastly, to demonstrate the multi-tasking mechanism, we present our proof-of-concept benchmark environments, Pointmass and Pointer, based on IsaacGym, which facilitates large-scale parallelization to accelerate the experiments. Our experimental results show that our multi-task agent has single-task performance on par with soft actor-critic (SAC), and the agent can successfully transfer to new unseen tasks. We provide our code as open-source at https://github.com/robot-perception-group/concurrent_composition for the benefit of the community.