Analysis And Research Of Influencing Factors On Autonomous Underwater Vehicle Maneuverability In Vertical Plane

As an effective platform for measuring sensors, autonomous underwater vehicle(AUV) has become a hot research of ocean exploration and investigation. Forfulfilling the task precisely, a good maneuverability particularly in vertical plane isindispensable. The effect of dynamic stability of the pitch, submergence-emergencevelocity by steering, the Venturi Effect, wave disturbances and balance weight of theAUV on the maneuverability in vertical plane are investigated in this paper. Whensailing near the surface, due to the free surface restrict the divergence of the flow fieldaround the AUV there will be an extra attraction and torque caused by the Venturieffect, coupled with the influence of the waves and other environmental factors, thevehicle may have difficulties in diving and depth-keeping. When carrying out aseafloor surveying task, the vehicle should submerge or emerge to consistent its depthwith the terrain. An irrational configuration of the balance weight could result inoscillations or overshoot of the AUV after steering, and these may impact on theaccuracy of the data directly.Focused on the AUV developed by Tianjin University, a volume of fluid (VOF)model is used to investigate the influence of the Venturi Effect on the maneuverabilitywhen voyaging near the surface. The decoupled linear maneuvering model and thesteering response equation of the trim angle in vertical plane are analyzed to discussthe effect of the distance between the barycenter and the buoyant centre and thepositive buoyancy. Achievements of this paper are summarized as follow:(1) Voyaging near the surface at different depths and Froude number of thevehicle is simulated and the result shows that because of the wave-making resistance,the resistance of the near surface navigation is greater than the one unbounded. Whenthe submergence depth is less than three times diameter of the hull, the vehicle will bemore obvious to subject to the suction and torque. Oppositely, when the submergencedepth is greater than three times diameter, the suction and the torque is a small valuethat can be neglected. The suction and the torque decrease exponentially with respectto the depth. (2) Based on the steering response equation of the trim angle, the impact on theresponse characteristics by the distance between the barycenter and the buoyant centreis investigated, and a formula is proposed for calculating the distance. Besides that theeffect on the diving speed and depth-keeping ability in turning is discuss.(3) The positive buoyancy and the distance between the barycenter and thebuoyant centre in longitudinal effect on balance quality is discuss and the proper valuefor this vehicle is presented, which provides a reference for the practical experiments.