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Deep Q-learning (DQL) method has been proven a great success in autonomous mobile robots. However, the routine of DQL can often yield improper agent behavior (multiple circling-in-place actions) that comes with long training episodes until convergence. To address such problem, this project develops novel techniques that improve DQL training in both simulations and physical experiments. Specifically, the Dynamic Epsilon Adjustment method is integrated to reduce the frequency of non-ideal agent behaviors and therefore improve the control performance (i.e., goal rate). A Dynamic Window Approach (DWA) global path planner is designed in the physical training process so that the agent can reach more goals with less collision within a fixed amount of episodes. The GMapping Simultaneous Localization and Mapping (SLAM) method is also applied to provide a SLAM map to the path planner. The experiment results demonstrate that our developed approach can significantly improve the training performance in both simulation and physical training environment. 

Economic dispatch in a multi-microgrid (MMG) system involves an increasing number of states from distributed energy resources (DERs) compared to a single microgrid. In these cases, traditional reinforcement learning (RL) approaches may become computationally expensive or less effective in finding the least-cost solution. This paper presents a novel RL approach that employs local learning agents to interact with individual microgrid environments in a distributed manner and a global agent to search for actions to minimize system cost at the MMG system level. The proposed distributed RL framework is more efficient in learning the dispatch policy compared to conventional approaches. Case studies are performed on a 3-microgrid system with different types of DERs. Results substantiate the effectiveness of the proposed approach in comparison with conventional methods in terms of operation costs, computation time, and peak-to-average ratio. 

Generalization problem of reinforcement learning is crucial especially for dynamic environments. Conventional reinforcement learning methods solve the problems with some ideal assumptions and are difficult to be applied in dynamic environments directly. In this paper, we propose a new multi-virtual- agent reinforcement learning (MVARL) approach for a predator-prey grid game. The designed method can find the optimal solution even when the predator moves. Specifically, we design virtual agents to interact with simulated changing environments in parallel instead of using actual agents. Moreover, a global agent learns information from these virtual agents and interacts with the actual environment at the same time. This method can not only effectively improve the generalization performance of reinforcement learning in dynamic environments, but also reduce the overall computational cost. Two simulation studies are considered in this paper to validate the effectiveness of the designed method. We also compare the results with the conventional reinforcement learning methods. The results indicate that our proposed method can improve the robustness of reinforcement learning method and contribute to the generalization to certain extent.