Distributed extended state observer based formation tracking control of under-actuated unmanned surface vehicles with input and state quantization

This paper delves into the distributed formation control of unmanned surface vehicles (USVs) under conditions of simultaneous input and state quantization. The primary objective is to ensure that USVs in the formation can effectively follow the specified trajectory in a bandwidth-limited communication environment. A distributed extended state observer (ESO) is proposed to observe the state information of the virtual leader in the USV formation. Furthermore, another ESO is introduced to address the impact of uncertainty terms in the ship model and quantized state variables during communication on the formation control system. Subsequently, the USVs formation guidance laws are formulated in the kinematics subsystem. In addition, the quantized control laws are described linearly in the kinetics subsystem so that the USVs distributed formation controller does not need to anticipate specific information about the quantization parameters. Meanwhile, the USVs formation tracking underlying control laws are designed in the quantized environment to achieve the tracking of the desired kinematic guidance signal. Then, the stability of the designed distributed formation tracking control system for USVs is proved using Lyapunov stability theory. Finally, the effectiveness of the proposed strategy is validated through two sets of simulation experiments, providing empirical evidence of its practical applicability.