Two-layer distributed cooperative tracking control for leader–follower multi-agent systems with communication delays and velocity constraints

This paper addresses the cooperative tracking problem for leader–follower multi-agent systems subject to fixed communication delays and strict velocity constraints. There are two delay links with different structures: one comes from the state information interaction of adjacent individuals in the first layer, and the other comes from the reference signal transmission between layers. To solve these two problems at the same time, we try to propose a two-layer distributed control architecture. In the first layer, the distributed reference signal generator will use the information of adjacent individuals with delay and Navigator information. We have determined the consistent final boundedness of the estimation error through the functional analysis of Lyapunov–Krasovskii, at the same time ensuring that the generated reference speed strictly conforms to the preset boundary. In the second layer, we use a nonlinear mapping to transform the velocity-constrained tracking error dynamics into an unconstrained equivalent form, so as to promote the systematic design of the backstepping controller; after rigorous analysis, it can be confirmed that the design can strictly meet the speed constraint, and it can also prove that the tracking error will converge to the bounded residual set related to the delay. When the delay approaches zero, the asymptotic convergence feature can be restored. The effectiveness and robustness of this architecture are verified by the simulation of the pilot speed curve being time-varying and constant.