Robust Situational Reinforcement Learning in Face of Context Disturbances

In many real-world tasks, the presence of dynamic and uncontrollable environmental factors, commonly referred to as context, plays a crucial role in the decision-making process. Examples of such factors include customer demand in inventory control and the speed of the lead car in autonomous driving. One of the challenges of reinforcement learning in these applications is that the true context transitions can be easily exposed to some unknown source of contamination, leading to a shift of context transitions between source domains and target domains, which could cause performance degradation for RL algorithms. To tackle this problem, we propose the robust situational Markov decision process (RS-MDP) framework which captures the possible deviations of context transitions explicitly. To scale to large context space, we introduce the softmin smoothed robust Bellman operator to learn the robust Q-value approximately, and extend existing RL algorithm SAC to learn the desired robust policies under our RS-MDP framework. We conduct experiments on several locomotion tasks with dynamic contexts and inventory control tasks to demonstrate that our algorithm can generalize better and be more robust against context disturbances, and outperform existing basic RL algorithms that do not consider robustness and robust RL algorithms that consider robustness over the whole state transitions.