Predefined-Time Cluster Formation Tracking of Networked Unmanned Surface Vehicles With Global Output Constraint

In this paper, the predefined-time cluster formation tracking (PTCFT) of the networked uncrewed surface vehicles (NUSVs) is achieved based on a hierarchical predefined-time output constraint (HPTOC) control algorithm, which is consisted of a predefined-time single-output estimator (PTSOE), a predefined-time disturbance observer (PTDO), and a predefined-time constraint-handling controller (PTCHC) with a predefined-time sliding mode (PTSM). The PTSOE is a single-output estimator, which contains only one output variable such that the estimations of position and velocity are no longer relatively independent. The observation value of the uncertain term in the PTDO is incorporated into the PTCHC to reinforce its anti-disturbance capability. Further, the realization of the global output constraint is by constraining the PTSM directly under the PTCHC, and then deriving the allowable boundary for the state error designed in the PTSM through theoretical analysis. More importantly, the realization of the global output constraint does not require specifying a range for the initial values of both the system states and the PTSM. The theoretical rationality of the HPTOC control algorithm is derived with the help of several sufficiency criteria and constructed Lyapunov functions. And eventually, three examples in numerical simulation are proposed to illustrate the feasibility of the HPTOC control algorithm.