Discrete Deep Reinforcement Learning for Mapless Navigation

Our goal is to investigate whether discrete state space algorithms are a viable solution to continuous alternatives for mapless navigation. To this end we present an approach based on Double Deep Q-Network and employ parallel asynchronous training and a multi-batch Priority Experience Replay to reduce the training time. Experiments show that our method trains faster and outperforms both the continuous Deep Deterministic Policy Gradient and Proximal Policy Optimization algorithms. Moreover, we train the models in a custom environment built on the recent Unity learning toolkit and show that they can be exported on the TurtleBot3 simulator and to the real robot without further training. Overall our optimized method is 40% faster compared to the original discrete algorithm. This setting significantly reduces the training times with respect to the continuous algorithms, maintaining a similar level of success rate hence being a viable alternative for mapless navigation.