Research On Robotic Fish Model And Coordinated Strategy Of Multi-robotic Fish

70% of the earth's surface is made up of water.The abundant water resources can not only be used for daily drinking,but also contain rich mineral and biological treasures.The research and exploration of the oceans,lakes and rivers have never stopped.As a new type of autonomous underwater vehicle,bionic robotic fish has a series of advantages such as small size,high propulsion efficiency,flexibility and high concealment,which arouse the enthusiasm of many researchers.In this paper,the bionic robotic fish will be studied from two aspects: model building and multiple robotic fish coordination control.(1)Aiming at the problem that it is difficult to establish the accurate model of the bionic robotic fish,this dissertation studies the dynamic model of the bionic robotic fish,and establishes the dynamic model of the bionic robotic fish under the straight and steering conditions respectively.Secondly,the head-yawing of the robotic fish is analyzed,and the dynamics model of the robotic fish is improved by combining the model of the head-yawing.Finally,a comparative experiment was designed to analyze the tracking performance of the improved model and the improved model for the same reference signal under the same conditions,and the validity of the improved model with consideration of rolling was verified.(2)Then,based on sliding mode control,two coordination strategies of straight and steering of robotic fish were designed respectively: 1)straight coordination.Through the two steps of pose adjustment and linear tracking successively,the vertical coordination goal of keeping a constant distance between the follower robot fish and the vertical leader robot fish for stable swimming is achieved.A discrete sliding mode controller is designed to enhance the robustness of linear tracking.2)Steering coordination.Based on the sliding mode control algorithm,the follower robot fish can make the angle deviation and position deviation converge to zero successively within a limited time,so as to achieve the steering coordination goal of completely tracking the movement trajectory of the leader robot fish in the turning process.In this dissertation,the above straight line and steering coordination strategies are verified by MATLAB simulation experiments,and the simulation results show that the designed coordination scheme is effective and robust.(3)Finally,the multi-joint biomimetic robotic fish platform is designed from the aspects of mechanical structure,shape,hardware and software,etc.,and based on this platform,an improved dynamic model verification experiment is designed.The experimental results show that,under the same control condition,the robotic fish mechanical model with head-yawing considered in this dissertation has better performance in tracking velocity and angular velocity than the dynamic model without head-yawing,which verifies the effectiveness and rationality of the improved dynamic model designed in this dissertation.