Research On The Stability Of Sea Cucumber Fishing Robot Under The Impact Of Waves

Underwater vehicles are widely used in marine resources exploitation,marine biological exploration and submarine engineering applications.They play an important role in the seabed where human beings cannot be involved or stay for a long time.The underwater vehicles will be disturbed by the wave when it starts to dive from the water surface and works underwater.The wave is a complex random process.The underwater vehicles will inevitably be disturbed by the wave when it is working underwater.The wave is a complex random process.The underwater vehicles will inevitably produce a variety of swings,which will make the overall motion posture of the robot change significantly,and then affect the movement and operation of the underwater vehicles.Therefore,it is necessary to study the stability of underwater vehicles under the influence of waves.The mechanical structure of a self-designed underwater sea cucumber fishing robot is firstly introduced in this article.Based on the mechanical structure,the mathematical model of the random wave is established through the ITTC single parameter spectrum,the wave height is calculated,and then the wave velocity of the long peak wave is calculated.The first-order interference force and moment of the sea cucumber fishing robot under water are calculated using Morison equation,and the interference model of random ocean waves is established and simulated by simulation software.Secondly,the dynamics model of the sea cucumber fishing robot is established,the structure and working principle of the brushless DC motor used in the propeller are analyzed,the mathematical model is deduced,and the transfer function is given;the measuring device is built by using the profile,and the relationship between the thrust and speed of the screw propeller is obtained by measuring and fitting the curve,and then the propeller is obtained It lays a foundation for the later control model.Finally,based on the simulation software,the bow motion and heave motion control models of the sea cucumber fishing robot are established,and the PID controller and fuzzy PID controller for bow motion and heave motion are designed respectively,which are verified by simulation experiments.