Three-dimensional formation control based on nonlinear small gain method for multiple underactuated underwater vehicles

This paper proposes a distributed formation tracking controller for multiple underactuated underwater vehicles (UUVs) which move in three dimensional space. The formation controller designing process is divided into two parts. In the first part, the condition which the formation controller must be satisfied is given. And the controllers are designed to ensure the condition mentioned before. In the second part, decentralized formation controller are proposed, and the stability analysis based on small gain theorem is introduced. Simulation results illustrate that the designed controller can track three-dimensional formation trajectory accurately.