Online Synchronous Approximate Optimal Learning Algorithm for Multiplayer Nonzero-Sum Games With Unknown Dynamics

In this paper, we develop an online synchronous approximate optimal learning algorithm based on policy iteration to solve a multiplayer nonzero-sum game without the requirement of exact knowledge of dynamical systems. First, we prove that the online policy iteration algorithm for the nonzero-sum game is mathematically equivalent to the quasi-Newton's iteration in a Banach space. Then, a model neural network is established to identify the unknown continuous-time nonlinear system using input-output data. For each player, a critic neural network and an action neural network are used to approximate its value function and control policy, respectively. Our algorithm only needs to tune the weights of critic neural networks, so there will be less computational complexity during the learning process. All the neural network weights are updated online in real-time, continuously and synchronously. Furthermore, the uniform ultimate bounded stability of the closed-loop system is proved based on Lyapunov approach. Finally, two simulation examples are given to demonstrate the effectiveness of the developed scheme.