Formation control for multiple unmanned surface vessels with prescribed performance and model uncertainty

This work investigates the formation control of multiple unmanned surface vessels (USVs) in the presence of model uncertainty and input saturation, where the separation requirements must comply with the constraints of prescribed performance. First, a novel fixed-time formation error constraint method is designed. This method strictly constrains the error between the desired and actual distances between the leader and the follower USVs within a prescribed range. Next, a predictor-based fuzzy logic system is proposed to estimate the model uncertainty. The problem of input saturation is addressed using auxiliary systems, which consider more reasonable operational safety constraints and enhance the practical applicability of the formation control. Finally, a fixed-time dynamic surface control approach is employed to design the formation controller. It is proven via the Lyapunov stability theory that all closed-loop signals are ultimately uniformly bounded. Numerical simulation results demonstrate the effectiveness of the proposed control scheme.