  Safe autonomous vehicles must be able to predict and react to the drivers
around them. Previous control methods rely heavily on pre-computation and are
unable to react to dynamic events as they unfold in real-time. In this paper,
we extend Model Predictive Path Integral Control (MPPI) using differential game
theory and introduce Best-Response MPPI (BR-MPPI) for real-time multi-vehicle
interactions. Experimental results are presented using two AutoRally platforms
in a racing format with BR-MPPI competing against a skilled human driver at the
Georgia Tech Autonomous Racing Facility.
