Research And Simulation Of ROV Control System For Shallow Water Application

Underwater robot technology is receiving more and more attention.It is widely used in such fields as underwater pipeline inspection,underwater breeding,ship physical examination and repair,underwater entertainment,underwater archaeology and scientific research and investigation.However,the research of underwater robot at present mainly focuses on the large-scale operation level robot for deep-sea application.With the continuous development of this field,low-cost and high-precision ROV(Remote Operated Vehicle)in shallow water application environment with the increasing demand of vehicle,the research and development of observation level ROV and its supporting simulation system and underwater navigation application has gradually become a hot research direction of underwater robot.Based on this background,aiming at the typical low-cost observation level robot system in shallow water environment,this paper develops and realizes the control system software and hardware system of the observation type underwater robot and the corresponding high-performance underwater robot simulation platform,and then focuses on solving the problem of ROV high reliability underwater terrain modeling based on multibeam sonar in the underwater environment.The specific research work is as follows:At present,the ROV has many shortcomings such as high cost,poor exploitability of control system,unable to be redeveloped which seriously affects the application and promotion of underwater robot in shallow water field.In this paper,the control system of the ROV is studied,and a ROV control system with small volume,light weight,easy to deploy and use in shallow water area is developed.In the hardware part,according to the requirements of the application of the shallow water underwater observation robot,this paper developed the overall ROV scheme,completed the control system architecture design and hardware selection of the upper computer,the middle communication layer and the lower computer.In the software part,this paper realizes the data acquisition function,motion control function,communication function,sonar terrain modeling function,carrier monitoring and operation function,fault alarm and fault tolerance function,underwater ROV simulation function and other functional modules of ROV.Different from the land environment,the status of the robot can not be directly observed.The direct experiment is inefficient and prone to accidents.In order to solve this problem,the simulation system of the underwater robot is built and the virtual real control system of the simulation environment is developed.Firstly,according to the characteristics of underwater environment perception,the virtual sensor models such as camera,depth sensor and sonar are established,noise and interference are added to the original simulation data,and the sensor data obtained can be directly used for image processing,terrain modeling and other algorithm validation after postprocessing;secondly,aiming at the problem that the robot underwater operation can not be directly observed,this paper sets up two control systems of simulation environment are designed.One is the control simulation of ROV motion and operation in pure simulation environment.The other is the information interaction between simulation environment and real underwater robot,which realizes real-time visualization of real operating robot in simulation environment,fast and lifelike online simulation,real-time response to interactive operation.Finally,in order to ensure the real-time performance of underwater simulation system authenticity,this paper systematically studies the parameters of the underwater environment and ROV motion in the real scene,constructs the motion simulation system of the underwater robot,analyzes the force situation of ROV itself,establishes the six degree of freedom space motion equation of ROV,simulates the real motion situation of buoyancy and ROV motion resistance in the water environment,accurately describes the real-time motion state of ROV and carries out simulation experiments.Underwater topographic survey and visualization is the key to the interpretation of terrain data.With the gradual improvement of sonar system technology,underwater terrain modeling with underwater robot provides a new method for underwater geological survey.In this paper,the problems of bottom tracking and terrain post-processing in underwater terrain modeling are studied.Based on the existing multi beam bathymetric bottom tracking technology,this chapter proposes an underwater position detection algorithm based on the echo amplitude energy gradient map,which transforms the signal processing problem of amplitude data into the image processing problem and introduces the mature algorithm in image processing to calculate the underwater depth value from the perspective of spatial correlation.At the same time,the linear state space model of bathymetry is constructed,and Kalman filter is used to smooth the underwater curve.Then,the continuous nonparametric model of underwater terrain is established by Gaussian process regression to fill the void of terrain model.In order to verify the feasibility of the algorithm,this paper takes the underwater robot as the experimental platform,takes the real underwater environment as the experimental environment,and builds a simulation system of underwater terrain measurement.The experimental results show that the underwater terrain modeling algorithm proposed in this paper is effective and feasible.