Visual navigation is essential for many applications in robotics, from manipulation, through mobile robotics to automated driving. Deep reinforcement learning (DRL) provides an elegant map-free approach integrating image processing, localization, and planning in one module, which can be trained and therefore optimized for a given environment. However, to date, DRL-based visual navigation was validated exclusively in simulation, where the simulator provides information that is not available in the real world, e.g., the robot's position or segmentation masks. This precludes the use of the learned policy on a real robot. Therefore, we present a novel approach that enables a direct deployment of the trained policy on real robots. We have designed a new powerful simulator capable of domain randomization. To facilitate the training, we propose visual auxiliary tasks and a tailored reward scheme. The policy is fine-tuned on images collected from real-world environments. We have evaluated the method on a mobile robot in a real office environment. The training took approximately 30 hours on a single GPU. In 30 navigation experiments, the robot reached a 0.3-meter neighbourhood of the goal in more than 86.7 % of cases. This result makes the proposed method directly applicable to tasks like mobile manipulation.Index Terms-Vision-based navigation, reinforcement learning, deep learning methods.
I. INTRODUCTIONV ISION-BASED navigation is essential for a broad range of robotic applications, from industrial and service robotics to automated driving. The wide-spread use of this technique will be further stimulated by the availability of lowcost cameras and high-performance computing hardware.Conventional vision-based navigation methods usually build a map of the environment and then use planning to reach