Research On Multi-AUSs Formation Control Based On Graph Theory

With the development of the science of multi-robots systems and the technique of underwater robots, multi under water robots cooperating system is regard as an important application of underwater robots in future. Travelling in formation is the most basic and representative cooperation task, usually referred to as a process that several robots travel together in certain geometry. Compared with multi-UGV system and multi-UAV system, the fundamental problem the formation control of multi under water robot system lies in the constraints of communication and inter-sense between robots. These constraints make it impossible for robots to deliver real-time position information between robots; neither can they get that information with sensors. So it is a problem to accomplish formation control task in this condition with uncertainty and incomplete information.When the communication net cannot be built, a way to solve the problem of multi-AUVs formation control is to find out the basic units of the formation, then divide the desired formation into basic formations so that the desired formation can be realized. Based on this idea, this paper introduces graph theory into formation control problems. A research is made on the perspective of modeling, analyzing and controlling of formation control problems.1) Analysis is made on the relationship between graph and the control graph of multi-AUVs formation. The definition of rigidity and persistency of control graph is given, and the control graph model of multi-AUVs formation and basic formations are built.2) An analysis is made on the control graph of formation consists of several basic formations, working out the features of the control graph of the formation of this kind, and the methods of generating the adjacent matrix of the control graph.3) Aiming at realizing the basic formations with different communication constraints, three kinds of formation control methods for basic formations are proposed, with constraints of each method analyzed.4) The proposed formation control methods for basic formations and methods for generating the control graph for multi-AUVs formations are testified with simulations and experiments.It is shown that it is an efficient way to realize multi-AUVs formations under uncertain communication conditions by dividing the formations using graph theory. Multi-AUVs formations can be divided into basic formations, and choose proper formation control methods according to communication conditions to achieve steady voyage keeping certain formation...