Design and study of a marine vehicle

The ultimate goal of this paper is to achieve the autonomous movement of a robot which is made by two distict units. One of the units floats on the surface of the water and provides power through the propeller and controls the direction. The second unit can sink below the surface of the water and release and retract the net through a rotating hydraulic cylinder. This paper will introduce the robot in two aspects. In the first aspect, the robot size is designed and calculated according to the actual needs of the robot, and the simulation is performed by Inventor software, including robot drawing, material selection, dynamic simulation and finite element analysis. Through the finite element analysis method, we can simulate the underwater force environment of the robot and apply 2 times and 3 times stress to test whether the robot can work normally and damage in case of transient overload. The second aspect is to calculate the power demand of the robot, including calculating the hull draft depth, drainage volume, anterior tilt angle, advection coefficient, square coefficient, friction calculation, residual friction calculation, air resistance, propeller shaft efficiency, propeller open water Efficiency, engine torque, etc. Based on this, the relationship between power, robot speed and water flow speed is established. Through the Matlab software simulation, the relationship between the speed and power of the robot under different water flow velocities is calculated.