Deep Reinforcement Learning for Autonomous Driving Based on Safety Experience Replay

In the field of autonomous driving, safety has always been a top priority, especially in recent years with the development and increasing application of deep reinforcement learning (DRL) in autonomous driving. Ensuring the safety of algorithms has become an indispensable concern. Reinforcement learning (RL), which involves interacting with the environment through trial and error, may result in unsafe behavior in autonomous driving without any safety constraints. Such behavior could result in the drive path deviation and even collision, causing catastrophic accidents. Therefore, this article proposes a reinforcement learning algorithm based on a safety experience replay mechanism, which is primarily to enhance the safety of reinforcement learning in autonomous driving. First, the ego vehicle conducts preliminary exploration of the environment to collect data. Based on the performance of completing tasks observed from each data trajectory, safety labels of different levels are assigned to all state-action pairs, which establishes a safety experience buffer. Further, a safety-critic network is constructed, which is trained by randomly sampling from the safety experience buffer. This enables the network to quantitatively evaluate the safety of driving actions, and the goal of safe driving for ego vehicle is achieved. The experimental results indicate that the proposed method can effectively reduce driving risks and improve task success rates compared with conventional reinforcement learning algorithms.