Formation Control of Marine Surface Craft using Lagrange Multipliers

We propose a method for constructing control laws for formation control of marine craft using classical tools from analytical mechanics. The control law is based on applying inter-vessel constraint functions which again impose forces on the individual vessels that maintain the given constraints on the total system. In this way, a formation can be assembled and stay together when exposed to external forces. A brief comparison with other control designs for a group of marine craft is done. Further, control laws for formation assembling (with dynamic positioning), and formation keeping during maneuvering is derived and simulated to illustrate the properties of the proposed method.