Adaptive Dynamic Programming-Based Optimal Circumnavigation Control of Multi-UAV Systems via Orthogonal Vector...

This article addresses the distributed optimal cooperative circumnavigation problem for multiuncrewed aerial vehicle (UAV) systems operating in 3-D space under composite disturbances. To facilitate controller design, a hierarchical kinematic-dynamic control framework is developed. At the kinematic level, a geometric vector-based kinematic formulation is established by introducing a set of mutually orthogonal spatial vectors in 3-D space, thereby transforming the complex circumnavigation task into a relative velocity tracking problem. At the dynamic level, a hybrid control strategy that integrates feedforward backstepping with feedback adaptive dynamic programming (ADP) is proposed. Specifically, the backstepping component compensates for nonlinear dynamics and composite disturbances, while the critic network approximates the optimal performance index online. Lyapunov stability analysis rigorously proves that all closed-loop signals are ultimately uniformly bounded. In addition, the proposed control strategy guarantees the minimization of the predefined cost function. Comparative simulation results demonstrate the feasibility and superiority of the proposed method over the conventional approach.