Soft Action Particle Deep Reinforcement Learning for a Continuous Action Space

Recent advances of actor-critic methods in deep reinforcement learning have enabled performing several continuous control problems. However, existing actor-critic algorithms require a large number of parameters to model policy and value functions where it can lead to overfitting issue and is difficult to tune hyperparameter. In this paper, we introduce a new off-policy actor-critic algorithm, which can reduce a significant number of parameters compared to existing actorcritic algorithms without any performance loss. The proposed method replaces the actor network with a set of action particles that employ few parameters. Then, the policy distribution is represented using state action value network with action particles. During the learning phase, to improve the performance of policy distribution, the location of action particles is updated to maximize state action values. To enhance the exploration and stable convergence, we add perturbation to action particles during training. In the experiment, we validate the proposed method in MuJoCo environments and empirically show that our method shows similar or better performance than the state-of-the-art actor-critic method with a smaller number of parameters.N