Study Of Bearing-based Formation Control Method For Unmanned Surface Vehicles

With the rapid development of the marine unmanned technologies,unmanned surface vehicles(USVs)have become an important platform of implementing various tasks,such as marine environmental monitoring,marine resource exploration,search and rescue on water,etc.,because of its advantages of low cost,good maneuverability,strong survivability,and etc.In order to extend its operating coverage,make full use of the advantages of USVs and improve the working efficiency and fault tolerance of the USVs,the cooperation of USVs has received widely increasing attentions.The formation control of USVs is one of the foundations and key points of cooperation of USVs,which relies not only on the task scenarios,but also on the hydrodynamic characteristics of USVs and the formation constrains.This article investigates formation control problem,including shape keeping,formation translation and formation scaling maneuver,for unnamed surface vehicles cluster under model uncertainties and external disturbances,according to graph theory,bearing rigidity theory,backstepping method,neural network,adaptive control method,and etc.Main contents of this article are as follows.1)For a formation system of unmanned surface vehicles based on the leader-following dual-agent cooperative model,a distributed bearing-based formation control method is proposed to solve the problem of USV formation control,including formation shape keeping control,formation translation control and formation maneuver control,relied only on the relatives bearing measurement among USVs by onboard sensors and local relative distance information.2)On the basis of the distributed bearing-based formation control method,taking denied environments of GNSS into consideration,a novel distributed adaptive bearing-only formation control scheme is proposed,which can be applied to solve the formation control problem under uncertainties and external disturbance with no state information interacted but only using the relative neighboring bearing measured by onboard sensors.Finally,through the simulation verifications of these two formation control methods proposed in this paper,one can conclude that,if the formation topology meets the infinitesimal bearing rigidity,the formation control tasks of USVs can be completed by utilizing these two formation controllers,while the formation scaling control problem of the cluster can be realized merely by planning the leader trajectory,without designing a new formation maneuver controller for the followers.