Research On Submarine Pipeline Robot Communication And Positioning Based On Permanent Magnet Mechanical Antenna

When the submarine pipeline robot performs in-pipe operations such as cleaning,detection and plugging,etc.It is usually necessary for the outside to determine the specific position of the pipeline robot in the pipe and establish communication with the pipeline robot.At present,the extremely low frequency transmitting system of the pipeline robot mostly adopts solenoid transmitting coil.It has some disadvantages,such as large volume,easy heating,high power and low efficiency.Therefore,this thesis selects mechanical antenna as the extremely low frequency signal transmitter of pipeline robot.Firstly,this thesis studies the mechanical antenna transmitting system.Analyze the working mechanism of mechanical antenna,and the rotating permanent magnet is simulated by finite element method.Secondly,the attenuation effect of metal pipe on magnetic signal is analyzed,and the attenuation coefficient is confirmed by theoretical derivation.And analyze the best frequency of penetrating pipeline.For the external positioning research of pipeline robot based on mechanical antenna,establishing the mathematical model of rotating magnetic dipole.To solve that problem that weak magnetic field signals are easily interfered by noise in the environment,select a signal processing method of dislocation superposition.By finding the peak value of the axial magnetic field signal outside the pipe,the positioning of one-dimensional coordinates of the pipeline robot is realized.Aiming at the three-dimensional positioning technology of pipeline robot,a three-dimensional positioning method based on a single fluxgate sensor to measure the magnetic field of multiple points is proposed.Aiming at the research of internal and external communication of pipeline robot based on mechanical antenna,the common modulation methods of mechanical antenna are analyzed.The feasibility of the frequency modulation scheme is verified by 2FSK modulation simulation.Aiming at the amplitude modulation scheme,an amplitude modulation scheme based on external modulator is proposed,and a mobile cover modulator is designed.The feasibility of this modulation scheme and structure is verified by 2ASK modulation simulation.Comparing the problems existing in the application of different modulation schemes in pipeline robot technology,the 2FSK modulation scheme based on speed control is selected.Based on the structure of rotating permanent magnet mechanical antenna,an experimental prototype of mechanical antenna is developed.Build a pipeline experiment platform,and carry out external positioning and communication experiments of pipeline robot.The experimental results show that mechanical antenna can effectively meet the communication and positioning requirements of pipeline robot.Finally,aiming at the practical application scenario of pipeline robot,an airborne launch prototype is developed based on miniaturization design.The application of mechanical antenna opens up a new idea for the communication and positioning technology of submarine pipeline robot.It is of far-reaching significance to improve the positioning accuracy and internal and external communication efficiency of submarine pipeline robot.