Research On Control Method Of Bionic Fish Autonomous Swimming Based On CPG

After hundreds of millions of years of natural selection,the fishes of the biological world have evolved their excellent motor abilities,enabling them to adapt to the unpredictable underwater environment.By imitating the movement patterns of fish,scholars have developed bionic fish,which have played a huge role in biological research,water quality monitoring and engineering applications.As an emerging underwater mobile platform,bionic fish has many advantages such as high speed,high maneuverability and low noise compared with traditional underwater vehicles,so it is gradually becoming a research hotspot.This paper has carried out research on the mechanical and electrical design of bionic fish,dynamic modeling,CPG modeling,autonomous swimming control,etc.The main research contents are as follows:Firstly,according to the swimming modes and functional requirements of the bionic fish,a multi-joint bionic fish with chest and tail cooperative propulsion is designed,and the body and control system of the bionic fish are designed with the idea of modularization.In addition,the force of the swimming process of the bionic fish was analyzed,and the swimming dynamics model of the bionic fish in the horizontal plane was established by Lagrange equation and D-H(Denauit-Hertenbery)coordinate transformation.Secondly,the biological motion control mechanism of animal CPG is studied theoretically,and different kinds of CPG oscillators are compared and analyzed.Chose a kind of parameters can be adjusted independently Hopf oscillator,in-depth study the Hopf convergence speed,amplitude and frequency of oscillator and the relationship between the parameters,which applies to bionic fish CPG model is established,and by using the CPG model simulation and experimental verification,successfully realized the bionic fish forward,acceleration,steering mode of winding control.In addition,the conversion relationship between state variables of the bionic fish system and CPG model parameters is quantitatively analyzed through experiments.Then,in order to improve the autonomous swimming ability and environmental adaptive ability of bionic fish,a cpG-sliding mode based bionic fish posture tracking controller is proposed.According to bionic fish kinematics model is established,we design a conversion function based on the experimental data,converts the output velocity and angular velocity of the sliding mode controller CPG parameters,then change the bionic fish swimming mode,realized the position tracking control of biomimetic fish,based on CPG-sliding mode is verified by simulation the feasibility of the bionic fish position tracking controller.Finally,the introduction of environmental feedback can adapt the bionic fish to the complicated water environment,in the form will appear all sorts of obstacles in the process of tracking,in order to effectively avoid these obstacles to achieve autonomy of biomimetic swimming fish,analyzed the CPG output signal and the signal feedback mechanism between the environment,according to the infrared distance sensor signals and senior central control instruction,Cpg-fuzzy controller was designed to realize the autonomous obstacle avoidance of bionic fish,and the rationality of the control strategy was verified by simulation.