Hydrodynamic Analysis And Control Research Of Underwater Cleaning Robot

Due to the harsh underwater environment and the limited diving depth of human beings,the Unmanned Underwater Vehicle(UUV)has become an important tool to complete the given underwater tasks.Vehicle,ROV)and Autonomous Underwater Vehicle(Autonomous Underwater Vehicle,AUV),this paper studies an open-frame operation underwater robot for jacket platform cleaning,and makes the following improvements to the original robot structure:(1)The original large hydraulic manipulator was changed to an electric manipulator driven by a servo motor to reduce the influence of attachment;(2)According to the structural characteristics of the underwater robot,a ducted propeller with a fixed frame was designed,install the motor that drives the propeller in the motor compartment of the fixed frame.The CFD software Star CCM+ is used to model and simulate the working state of ROV before the column is mounted,and the hydrodynamic performance of ROV is obtained.The thrust control distribution is carried out,and the control system design of the underwater robot is completed through MATLAB simulation.First,based on the modular design concept,the composition and distribution of each ROV system are clarified.With the help of the three-dimensional modeling software SOLIDWORKS,the modeling of each module and the overall assembly are completed,and some are made on the basis of the original underwater robot structure.Functional improvements.After the model is built,the software can automatically calculate the initial parameters such as mass,center of gravity,and moment of inertia in all directions,providing a basis for hydrodynamic calculations.In order to improve the calculation efficiency,the ROV structural parts were simplified without affecting the calculation accuracy,and the simplified ROV model was imported into the commercial software STAR-CCM+,and the straight flight and lateral movement were respectively analyzed by the computational fluid dynamics(CFD)method.Numerical simulation calculation is carried out for the motion states such as diving,bow turning,etc.,and the viscous hydrodynamic parameters are obtained through analysis.Then,the acceleration motion under six degrees of freedom is calculated through the numerical simulation of the plane motion mechanism(PMM),and the additional mass coefficient is obtained.A complete maneuverability motion equation of the underwater robot is established to provide a basis for the control system;improve the designed thrust system according to the obtained ROV motion parameters,calculate the open water performance curve and thrust distribution of the designed ducted propeller,and obtain a new thrust matrix,which is based on This design controls the system.Based on the sliding mode control(Sliding Mode Control SMC)method,the ROV is controlled by the underwater maneuvering motion,and the sliding mode surface is designed by the integral sliding mode control.The kinematic controller and dynamics controller are used,and the stability of the system is verified by simulation analysis.The results show that the control method can quickly respond to the target trajectory control and smoothly complete the given navigation trajectory.At the same time,a new six-degree-of-freedom robotic arm driven by servo motors is designed for ROV underwater cleaning operations.In addition to high-pressure water nozzles,it is also equipped with Realsense455 binocular cameras,which can provide forward vision for ROV underwater navigation.In order to avoid obstacles that may be touched in the navigation path,and before the cleaning operation,the surface dirt on the target structure can be identified and processed,so as to complete the cleaning operation more efficiently.Inverse kinematics analysis to obtain the joint limit of the manipulator and the working space.And use the robot operating system ROS(Robot Operating System)to control and analyze the design of the manipulator,complete the simulation configuration of the manipulator through Move It!,and link with the physical model simulation in Gazebo to realize real-time control at the virtual level.