Research And Design Of AUV Electromagnetic Guidance Docking System

The autonomous underwater vehicle(AUV)is an autonomous,highly mobile underwater unmanned vehicle.As a marine space probe,AUV is an important part of the establishment of an underwater network system such as an autonomous marine sampling system,a coastal monitoring system,and a military combat system.By docking with the underwater docking station,energy supply and data transmission can be provided for the AUV,and the backyard guiding technology is a prerequisite for ensuring the smooth connection between the AUV and the underwater docking station.For the near-end docking,the optical guidance is susceptible to the influence of seawater clarity and the low-accuracy acoustic guidance and guidance accuracy.An AUV electromagnetic guided dockimg system is designed.The system is mainly composed of magnetic beacon,three-axis search coil sensor,electromagnetic guidance analysis system and AUV main control system.By establishing the relationship between the parameters of the transmitting coil and the effective magnetic moment of the magnetic beacon,the optimized parameters of the number of turns and the diameter of the coil are analyzed to improve the performance of the magnetic label.In order to adapt to the limited space inside the AUV,the magnetic core structure and variable parameters of the three-axis search coil sensor are optimized to increase the sensitivity of the sensor and increase the guiding distance while reducing the volume.According to the propagation characteristics of low-frequency electromagnetic signals,an automatic variable gain electromagnetic guidance analysis system based on digital quadrature lock-in amplifier is designed to obtain the guiding deflection angle.This design simplifies the overall hardware complexity of the system.The AUV master control system provides the power and heading control required during the docking process.According to the guiding deflection,the PID control servo is combined with the motion control strategy of the auxiliary steering gear to guide the AUV to follow the magnetic field to enter the docking port and complete the docking.After several underwater back-dock tests,the results show that the system realizes the docking guidance within 20 meters,and at the same time,in the case of close-range extreme angle,relying on the auxiliary steering device,the docking process is successfully completed.As a result,the system already has the capability of near-end docking guidance.