Intention Aware Autonomous Driving Decision Making in an Uncontrolled Intersection
Autonomous vehicles need to perform social accepted behaviors in complex urban scenarios including human driven vehicles with uncertain intentions. This leads to many difficult decision making problems, such as deciding a lane change maneuver and generating policies to pass through intersections. In this paper, we propose an intention aware decision making algorithm to solve this challenging problem in an uncontrolled intersection scenario. In order to consider uncertain intentions, we first develop a continuous hidden Markov model to predict both the high level motion intention (e.g. turn right, turn left, and go straight) and the low level interaction intentions (e.g. yield status for related vehicles) Then a partially observable Markov decision process (POMDP) is built to model the general decision making framework. Due to the difficulty in solving POMDP, we use proper assumptions and approximations to simplify this problem. A human like policy generation mechanism is used to generate the possible candidates. Human driven vehicles' future motion model is proposed to be applied in state transition process and the intention is updated during each prediction time step. The reward function, which considers the driving safety, traffic laws, time efficiency, and so forth, is designed to calculate the optimal policy. Finally, our method is evaluated in simulation with PreScan software and a driving simulator. The experiments show that our method could lead autonomous vehicle to pass through uncontrolled intersections safely and efficiently.