Towards Safe Motion Planning in Human Workspaces: A Robust Multi-agent Approach

It is becoming increasingly feasible for robots to share a workspace with humans. However, for them to do so safely while maintaining agile performance, they need the ability to smoothly handle the dynamics and uncertainty caused by human motions. Markov Decision Processes (MDPs) serve as a common framework to formulate robot planning problems. However, because of its single-agent formulation, such planner cannot account for human reaction when evaluating robot actions. The robot can thus suffer from unsafe motions and move in ways that are hard for nearby humans to understand. To resolve this, we instead model robot planning in human workspaces as a Stochastic Game, and contribute a robust planning algorithm, which enables the robot to account for its prediction errors in human responses to prevent collision, while not losing agility, opposed to traditional maximin optimization techniques, by applying maximin operation only at "critical states". We validate the approach under partial knowledge of pedestrian behaviors, and show that our approach encounters zero collision despite imperfect prediction, while improving path efficiency, compared to baselines.