Decaying Clipping Range in Proximal Policy Optimization
This is an incremental improvement for reinforcement learning practitioners, offering simple modifications to a widely used algorithm.
The paper tackled improving Proximal Policy Optimization (PPO) by proposing decaying clipping range approaches to enhance exploration early and impose stronger restrictions later, finding them effective alternatives to constant clipping in various reinforcement learning tasks.
Proximal Policy Optimization (PPO) is among the most widely used algorithms in reinforcement learning, which achieves state-of-the-art performance in many challenging problems. The keys to its success are the reliable policy updates through the clipping mechanism and the multiple epochs of minibatch updates. The aim of this research is to give new simple but effective alternatives to the former. For this, we propose linearly and exponentially decaying clipping range approaches throughout the training. With these, we would like to provide higher exploration at the beginning and stronger restrictions at the end of the learning phase. We investigate their performance in several classical control and locomotive robotic environments. During the analysis, we found that they influence the achieved rewards and are effective alternatives to the constant clipping method in many reinforcement learning tasks.