Overview
Model-free Reinforcement Learning (RL) works well when experience can be collected cheaply and model based RL is effective when system dynamics can be modeled accurately. However, both assumptions can be violated in real world problems such as robotics, where querying the system can be expensive and real world dynamics can be difficult to model. In contrast to RL, Model Predictive Control (MPC) algorithms use a simulator to optimize a simple policy class online, constructing a closed-loop controller that can effectively contend with real-world dynamics. MPC performance is usually limited by factors such as model bias and the limited horizon of optimization. In this work, we present a novel theoretical connection between information theoretic MPC and entropy regularized RL and develop a Q-learning algorithm that can leverage biased models. We validate the proposed algorithm on sim-to-sim continuous control tasks and compare it against information theoretic MPC and soft Q-Learning, where we demonstrate faster learning with much fewer system interactions (a few minutes with real system parameters) and better performance compared to MPC and soft Q-Learning even in the presence of sparse rewards