Research And Implementation Of AUV Station Keeping Control For Submarine Cable Inspection

Submarine cable is a bridge for power transmission and communication between coastal islands and cities,and plays an important role in people’s life.Since submarine cables are arranged on the seabed,they will inevitably be damaged by natural or human factors,so regular inspection and maintenance of submarine cables are required.The conventional manual or mother ship towing method is expensive,so it will be the trend to use autonomous underwater robots to patrol and repair submarine cables in the future.Aiming at the application of underwater vehicle in submarine cable patrol inspection,this paper focuses on the hover control of autonomous underwater vehicle(AUV)in patrol inspection,designs and implements a set of underwater vehicle control system,and studies the control algorithm.The test platform of this paper is a small AUV with full drive capability.First of all,the software and hardware design of the AUV electronic control system is completed.The hardware includes the design of the main control board and the control system motherboard.The software includes the design of the lower computer and the upper computer.The upper computer,as a human-computer interaction tool,controls the AUV movement through wireless communication and echoes and saves the operation data.Then,the dynamic modeling and hydrodynamic analysis are carried out for the AUV.The hydrodynamic coefficients are obtained by simulation and approximate calculation methods.The basic motion performance of the AUV is tested by simulation.The simulation results show that the AUV has good maneuverability and can meet the motion requirements of hover control.Secondly,the hover control algorithm of AUV is studied.In terms of control strategy,the hover control is decomposed into position control and attitude control.For position control,two control strategies based on Doppler Velocity Log(DVL)and visual servo are proposed.The hover control is decoupled into horizontal plane control and vertical plane control,and the three-dimensional problem is converted into two-dimensional problem;In terms of algorithm,an AUV control algorithm based on Linear Active Disturbance Rejection Control(LADRC)is designed and compared with traditional PID control and sliding mode control.Taking the vertical plane motion of AUV as an example,the effects of different control algorithms on AUV depth control are compared through simulation,and the performance of PID control and LADRC control,especially the anti-interference ability,is tested through the indoor experimental platform.The comprehensive results show that the LADRC control effect is better than PID control and sliding mode control,which can stably track the target signal and effectively deal with the external disturbance kinetic energy,and is suitable for the underwater robot system with more external interference.Finally,the control effect of the control algorithm designed in this paper in the AUV motion is tested through the pool test and the simulation results are verified.The test includes heading control,depth control,joint heading and depth control and fixed-point hover control.The test results show that the comprehensive performance of LADRC is obviously superior to PID control and sliding mode control,and stable control can also be achieved for hover control with strong coupling,which also shows that the control algorithm based on LADRC designed in this paper meets the application requirements of hover control of submarine cable patrol AUV.