Adaptive Learning: A New Decentralized Reinforcement Learning Approach for Cooperative Multiagent Systems

Multiagent systems (MASs) have received extensive attention in a variety of domains, such as robotics and distributed control. This paper focuses on how independent learners (ILs, structures used in decentralized reinforcement learning) decide on their individual behaviors to achieve coherent joint behavior. To date, Reinforcement learning(RL) approaches for ILs have not guaranteed convergence to the optimal joint policy in scenarios in which communication is difficult. Especially in a decentralized algorithm, the proportion of credit for a single agent's action in a multiagent system is not distinguished, which can lead to miscoordination of joint actions. Therefore, it is highly significant to study the mechanisms of coordination between agents in MASs. Most previous coordination mechanisms have been carried out by modeling the communication mechanism and other agent policies. These methods are applicable only to a particular system, so such algorithms do not offer generalizability, especially when there are dozens or more agents. Therefore, this paper mainly focuses on the MAS contains more than a dozen agents. By combining the method of parallel computation, the experimental environment is closer to the application scene. By studying the paradigm of centralized training and decentralized execution(CTDE), a multi-agent reinforcement learning algorithm for implicit coordination based on TD error is proposed. The new algorithm can dynamically adjust the learning rate by deeply analyzing the dissonance problem in the matrix game and combining it with a multiagent environment. By adjusting the dynamic learning rate between agents, coordination of the agents' strategies can be achieved. Experimental results show that the proposed algorithm can effectively improve the coordination ability of a MAS. Moreover, the variance of the training results is more stable than that of the hysteretic Q learning(HQL) algorithm. Hence, the problem of miscoordination in a MAS can be avoided to some extent without additional communication. Our work provides a new way to solve the miscoordination problem for reinforcement learning algorithms in the scale of dozens or more number of agents. As a new IL structure algorithm, our results should be extended and further studied.