Coordinated Control Of Multi-module Vessels In Consistent Formations

In this paper,the module vessel object studied a rectangular semi-submersible fully driven moving ship with dynamic positioning capability on the sea surface.The modular vessel has the characteristics of symmetrical shape,so it is usually possible for multiple module vessels to move together to form a mob-mobile offshore base to jointly perform maritime transportation,aircraft take-off and landing,and maritime rescue work needs.Power positioning technology for the control of single ship has been very mature,mainly reflected in the single ship fixed point positioning control,such as offshore drilling ships,cable laying ships,etc.have the application of power positioning technology.The offshore work of module ships often requires multiple ships to cooperate to achieve relative position control,and the formation of a fixed relative position between multiple module ships is also a key step before completing the construction and splicing of mobile offshore bases,so for the formation control of multiple module ships,to achieve a fixed relative position,the formation of a stable formation structure can lay a good foundation for the construction of offshore mobile offshore bases.In this paper,the formation part of multiple module ships before the construction of mobile offshore base splicing is controlled,and the consistency theory is introduced,and the control realizes that multiple module ships can reach the desired position collaboratively and maintain a stable formation structure,the specific work content is as follows:1.When considering the control strategy of multiple modular ship formations,the traditional leader-follow strategy has the advantage of simple implementation,but there is a disadvantage that the follower can only receive the leader’s information,so when the follower cannot receive the leader’s information,it will cause a situation that does not work.In view of the above problems,this paper improves the traditional leadership-follow control strategy,and establishes a communication topology relationship between the module ships,so that when the follower cannot receive the status information sent by the leader,through the communication topology relationship,the state information interaction with its neighboring ships can also achieve the adjustment of the relative position,reach the desired position,and form the desired formation structure.Finally,simulation verification shows the effectiveness of the control strategy and controller design.2.In order to further improve the reliability of the formation and the redundancy of the system,a virtual leadership ship leader-follow control strategy is proposed,because the actual ship leader is not required,it can avoid the problem of leading the ship in the formation and causing the mission to fail,and also has the advantage of being able to adjust the desired position through the switching of the guidance system to solve the problem of sudden change of the desired position.First,by simulating a virtual module ship that is similar to the kinematics and dynamic model of the actual module ship,it is possible to provide state information that is more in line with the performance of the real ship,and secondly,the reverse footwork method is used to design the guidance system and the passive collaborative control algorithm is introduced to design the collaborative formation controller of the module ship.Finally,simulation proves the effectiveness of the control strategy and controller design,which can realize the control of multiple module ships reaching the desired position and maintaining a straight line formation.3.On the basis of the virtual leadership control strategy,the problem of the limited communication perception range of the module ship in the formation process is further considered,by defining the communication perception radius range of each module ship,establishing the communication connection description between the module ships,using the artificial potential function gradient method,by selecting a potential function with attraction function,and combining the speed consistency algorithm,designing a collaborative formation controller that can keep the communication of the module ship to maintain communication,and analyzing and verifying the stability.Finally,through simulation,the effectiveness of the control method and controller design is proved,which can enable multiple module ships that need to communicate with each other to maintain a communication perception distance,and reach the desired position,maintain a straight line formation,and realize the collaborative control of the consistent formation with communication maintenance.