Research On Formation Control Method Of Double-USVs For Oil Spill Containment

In the process of offshore oil exploitation and transportation,oil leakage accidents often occur,resulting in serious environmental damage and resource waste.After an oil spill accident occurs,it is necessary to clean up the oil spill as soon as possible to reduce the diffusion and volatilization,so as to avoid a disastrous impact on the environment.In addition,during cleaning the spilled oil,it causes harm to the health of the personnel involved in cleaning up the spilled oil.Towing boom by two ships catching an oil spill is an effective means to deal with spilled oil.Using USVs instead of manned vessels for oil spill containment can reduce manpower and material consumption and protect workers.In this thesis,double USVs towing oil containment booms are taken as research objects,and a formation control method of double USVs for oil spill containment is proposed.In the first part,the mathematical model of the horizontal movement of USV is established.Considering the hydrodynamic effect of oil containment boom,which is equivalent to the drag force suffered by USV.Combined with the mathematical model of the horizontal movement of USV,the mathematical model of the horizontal movement of USV considering the dynamic influence of the boom is established.Simulation experiments are carried out and the results are analyzed to verify the effectiveness of the improved trajectory tracking obstacle avoidance method.In the second part,assuming that the formation center of double USVs as virtual navigator,considering the local minimum and large turning point of artificial potential field method,considering the virtual pilot tracking the direction of oil spill,combined with the requirements of double USVs formation mission,the improved artificial potential field method was used to make the virtual pilot perform trajectory tracking and obstacle avoidance tasks,and the expected heading of the virtual pilot was obtained.Then,the formation control method of double USVs is studied.According to the demand of oil spill containing,four formation behaviors,including target tracking,cooperative formation,oil spill containing and distance keeping,were designed for double USVs by combining the expected course and obstacle avoidance,and considering the limitations of motion control.The null-space-based behavior fusion method was adopted to design the behavior priority and behavior fusion.Three sub-tasks of oil spill containment,including formation,oil spill containment and pursuit of oil spill,were designed.Sub-tasks were carried out in turn according to the oil spill containment process,and the expected heading and speed of the double USVs are obtained.Combined with the motion control of USV,the oil spill containment task of double USVs is completed.Finally,considering the influence of the hydrodynamic force of the oil containment boom on the movement of double USVs,the compensation method of the expected movement of the USV is proposed.In this way,the expected course and speed are compensated,and the compensation expected course and expected speed considering the influence of the oil containment boom are obtained.The motion control of USV can compensate the dynamic influence of the boom as much as possible,so as to reduce the damage of the double USVs formation.Considering the above problems,the effectiveness of the formation control method of double USVs for oil spill containment is verified by simulation and result analysis.