Prescribed-Performance-based Trajectory Tracking Control for 6-DOF Underactuated Unmanned Surface Vehicles with Event-based Mechanism

Objectives This paper addresses the trajectory tracking problem for 6 degree-of-freedom (DoF) underactuated unmanned surface vehicles (USVs) subject to output state constraints and limited communication resources. A prescribed performance control (PPC) strategy integrating the transverse function and event-triggered mechanism is proposed to enhance control performance while avoiding redundant communication. Methods Firstly, considering the non-holonomic motion constraints for the underactuated system, a transverse function is constructed where the prescribed performance function is employed to transform the tracking errors. Such method can enable quantitative constraints ton transient overshoot and steady-state accuracy. Additionally, the radial basis function neural network (RBFNN) is utilized for online approximation and dynamic compensation to estimate the nonlinear hydrodynamic coefficients and disturbances. Furthermore, an event-triggered mechanism is designed to optimize the communication resources in the limited bandwidth which can achieve the trade-off between the transmission frequency and tracking accuracy. Results The simulation results show that the 6-DoF underactuated USV can track the desired position and attitude under the proposed PPC-based event-triggered control scheme. Furthermore, the data transmission can be reduced by 77.55% between the controller and actuator. Conclusions The proposed adaptive constrained control algorithm can tackle the underactuated problem with non-diagonal configurations. Moreover, such method can guarantee the prescribed performance while balancing the computational and communication efficiency. This provides a technical way for the reliable control for 6-DoF underactuated USV in complex marine environments.