In Social Robot Navigation, autonomous agents need to resolve many sequential interactions with other agents. State-of-the art planners can efficiently resolve the next, imminent interaction cooperatively and do not focus on longer planning horizons. This makes it hard to maneuver scenarios where the agent needs to select a good strategy to find gaps or channels in the crowd. We propose to decompose trajectory planning into two separate steps: Conflict avoidance for finding good, macroscopic trajectories, and cooperative collision avoidance (CCA) for resolving the next interaction optimally. We propose the Probabilistic Gap Planner (PGP) as a conflict avoidance planner. PGP modifies an established probabilistic collision risk model to include a general assumption of cooperativity. PGP biases the short-term CCA planner to head towards gaps in the crowd. In extensive simulations with crowds of varying density, we show that using PGP in addition to state-of-the-art CCA planners improves the agents’ performance: On average, agents keep more space to others, create less tension, and cause fewer collisions. This typically comes at the expense of slightly longer paths. PGP runs in real-time on WaPOCHI mobile robot by Honda R&D.

This paper presents a deep reinforcement learning (DRL) sframework for safe and efficient navigation in crowded environments. Here, the robot learns cooperative behavior using a new reward function that penalizes robot actions interfering with the pedestrian's movement. Also, we propose a simulated pedestrian policy reflecting data from actual pedestrian movements. Furthermore, we introduce a collision detection that considers the pedestrian's personal space to generate affinity robot behavior. To efficiently explore this simulation environment, we propose distributed learning using Ape-X [1]. We deployed the robot in a real environment and verified its crowd-aware navigation performance compared with an actual human in terms of path length, travel time, and the number of abrupt avoidances.

The autonomous navigation in the crowded environment is a challenging task due to the sensor occlusion and the complex nature of the abstract social interactions. And yet, humans are capable of navigating in such complex environment. In this paper, we propose an effective navigation method that combines the learning-based and model-based methods in a way that a cost function that includes human imitation factor learned via deep learning is integrated into the dynamic window approach (DWA) [1]. The experiments conducted on simulations show that by training the robot to imitate the human trajectory, our navigation method is safer and more efficient than the state-of-the-art methods. Additionally, we successfully deployed a physical robot in an actual environment, and we validate that our navigation quality shares similar tendency with human in the path length, travel time, and the collision avoidance.