Research on Unpowered Trim Ascent Motion Characteristics of Deep-sea Vehicles

Abstract

To improve the ascent response speed of unpowered deep-sea vehicles, and meet the requirements of mission loads for its water-exit attitude, considering the effect of ocean currents and buoyancy changes, a space motion simulation model of the vehicle was established. The quaternion method and the space motion equation of autonomous undersea vehicles were used to solve the singular problem of a large trim angle and vertical ascent motion. The effects of net buoyancy, distance between the center of gravity and buoyancy, rudder angle, initial launch conditions, and marine environmental disturbances on the trim ascent motion of the vehicle were explored and investigated. The results show that the space motion equation of a deep-sea vehicle based on the quaternion method can effectively avoid solving the singular problem of the attitude when the vehicle is ascending at a large trim angle or vertical attitude. Unpowered deep-sea vehicles can achieve a large vertical ascent speed and reduce the horizontal drift distance with a large trim angle or a vertical attitude. The disturbance of buoyancy changes and initial launch conditions have a great influence on the ascent state of the vehicle. The research provides references for the overall layout and the prediction of large trim angles and vertical ascents of deep-sea vehicles.

Keywords

• deep-sea vehicle
• unpowered ascent
• autonomous undersea vehicle
• large trim angle
• quaternion method
• buoyancy