Design Of Control System For Fishing Remote Operated Vehicle

The greatest feature of a remotely operated vehicle(ROV)is its ability to perform highload,high-intensity,and high-precision operations in dangerous and complex marine environments.It is one of the indispensable major technical equipment for the national implementation of marine resource development.The research in this article is based on the key research and development project in Province,"Key Technology Research of Underwater Robot for Near-Seabed Benthic Organism Fishing".The goal is to design a new type of fishing ROV control system with lightweight,easy carrying and operation,high control precision,high reliability,strong maintainability,and low cost.Key technologies such as the kinematic and dynamic models of the fishing ROV,motion control methods,thrust allocation methods,and the software and hardware design of the control system are studied,the control system framework for the fishing ROV is established.The main research contents are as follows:Firstly,based on the analysis of the development status at home and abroad,the characteristics of the shape and structure,propeller layout,system equipment,and motion control effect of multiple ROVs are analyzed.Regarding the motion control technology of ROVs,the commonly used controller design methods and thrust allocation methods are classified and summarized,and the PID motion controller and direct logic thrust allocation method suitable for this ROV control system are selected.Next,an analysis of the functional requirements for the fishing-type ROV control system was conducted,and the overall framework of the control system was designed.Detailed designs were carried out for the control system’s hardware equipment and control software.The control system was divided into multiple subsystems,and the required hardware equipment for each subsystem was selected and designed.Vertically and longitudinally closed-loop PID controllers suitable for fishing-type ROVs and a thrust allocation method based on direct logic were designed.The program flow for the upper and lower computer control software was separately designed,and the software was written and debugged.The various functional modules in the control software corresponded to the previously designed control system framework and motion control method.Then,a complete six-degree-of-freedom ROV dynamic model and kinematic model were established.During the modeling process,the forces acting on each part of the underwater robot were analyzed and calculated.Ignoring small environmental disturbance forces,the hydrodynamic coefficients calculated from hydrodynamic characteristic experiments were used to establish the ROV dynamic model.The model was simplified and modified according to its motion characteristics.This model was mainly used for ROV motion control simulation verification and guided the construction of the physical control system.Finally,simulation verification and pool experiments were conducted for the fishing-type underwater robot.First,the control function under different ROV control modes was verified in a simulation environment.Then,the hardware and software units of the control system were tested,and the control system platform for water surface and underwater was constructed and debugged.After determining the network connectivity,communication real-time performance,and sealing safety of the control system,remote control tests and pool experiments were conducted to demonstrate the engineering application value of the control system.