Research On Sliding-mode Control Of Underwater Auxiliary Oil Recovery Robot Propulsion System

Facing the problem of less and less resources such as onshore oil and mineral resources,mankind has long turned to the exploration and development of marine resources,and countries around the world have also launched fierce competition for marine resources.Remotely Operated Vehicle(ROV)has become the first choice for underwater operation robots because it has the advantages of strong operation ability,high real-time communication,strong online operation ability,long-term underwater operation,and high safety.In order to overcome the harsh underwater operating environment and complete high-precision and high-intensity underwater operations,the underwater robot must equip with strong maneuverability and good stability,which puts forward higher requirements for its propulsion system.In this paper,a new type of propeller mathematical model based on the load characteristics of the ducted propeller is studied in response to the needs of the underwater auxiliary oil recovery robot independently developed.And a set of integrated,high-power underwater propulsion control system is developed.The main research contents are as follows:First of all,according to the research status of underwater robot propellers at home and abroad,combined with the overall scheme of existing underwater auxiliary oil recovery robots,this paper designs the overall scheme of its propulsion system,expounds the thrust distribution strategy of the propulsion system,introduces the technical requirements,structural composition and main parameters of the propeller,and focuses on the design of the underwater propulsion control scheme.Secondly,the propeller mathematical model based on the duct propeller load characteristics was studied,and the four-quadrant characteristic curve of the duct propeller was fitted using the Chebyshev polynomial.Through simulation,the load characteristics of the ducted propeller under the two conditions of forward acceleration and parking are analyzed.On this basis,the control strategy of the underwater auxiliary oil recovery robot propeller is deeply studied,and a new method of global fast terminal sliding mode speed control combined with the load torque observer is proposed and applied to the underwater propeller Control system.The simulation results show that the new speed control method proposed in this paper enables the propeller control system to better resist external disturbances than PI control and global fast terminal sliding mode control,and improves the chatter suppression and rapid response capabilities of the control system.Then,the control system of underwater auxiliary oil recovery robot propeller was developed.In terms of hardware,the hardware design of the main control board,power board and propeller control board of the propeller control system was completed,and the circuit design schematics of each part were given.The software structure was determined according to the functional requirements,and the software program of the thruster control system was designed.Finally,the experiment and analysis of the underwater auxiliary oil recovery robot propulsion system were carried out.Onshore debugging and experiments were carried out on each part of the propeller control system,and underwater thrust experiments were carried out on the underwater propeller.The experimental data shows that the designed control system can make the underwater propulsion meet the design indexes of speed,thrust and torque,which verifies the effectiveness of the underwater propulsion control system designed in this paper.