The Study On Autonomous Formation Control Of Multi-robotic Fish Based On Electric Field Communication

Bionic underwater robots has attracted increasingly attention in the field of underwater robots,as the result of the potential advantages in flexibility,propulsion efficiency and invisibility.Compared with the individual robots,multiple-robot system can adapt to complex environment more easily.So,the research of the multiple-robot formation has important scientific value and application prospects.Due to the limitations of the underwater communication technology,the research of the multiple-robot formation seems to have a bottleneck,and the related production is seldom.In this paper,to ensure the stability of communication in the underwater multiple-robot,a new technology,electric field communication,is evaluated comprehensively by experiment at first.Then,using the electric field communication,we complete the information interaction between the bionic robotic fishes,developed by Peking University.Lastly,we achieve the underwater autonomous circle formation control in the multiple-robot fish by the distributed control protocol.Specific researches are as follows:Firstly,this paper tests the applied environment and the quality of underwater electric field communication,and explores the influence of different water environment on electric field communication to ensure the stability of communication in multiple-robotic fish formation.The test is mainly carried out in four kinds of water environments,such as water resting,water flow,obstacle in water and large water area.The experimental data indicates that the flow of water and the small obstacle have little effect on the communication performance.These experimental conclusions laid the foundation for the experimental design of the subsequent formation.Secondly,in order to solve the problem that communication distance is short in multiple-robotic fish formation experiment,this paper studies the the influence of the physical conditions on the communication,such as the distance between electrode plates and communication power,and carries out the theoretical analysis and experimental verification.Then,according to the conclusion of the study,we optimizes and improves the distance between electrode plates and the communication power of the robotic fish.Finally,the yaw angle in the experimental environment of the robotic fish is corrected to ensure that the robotic fish has a more accurate position and velocity state.Thirdly,based on the distributed control protocol,the numerical simulation of multiple-robot formation is realized.Then,the relationship between the angular velocity of the fish and the swing frequency of the caudal fin is established.The control law is properly improved according to the experimental requirements,and the control experiment of the multiple-robotic fish underwater control is finally designed and realized.And,the experimental results of the robotic fish formation coincide with the simulation curves.