Control of the Position of an Underwate Towed Robot

1)开发了海洋复杂水流作用下柔性长缆索三维运动的数值模拟程序，可以较准确地模拟长缆索的非线性行为。2)建立了研究由船舶、柔性长缆和水下拖曳机器人组成的系统的动力稳定性的理论。在拉索横向挠度和张力沿拉索缓慢变化的假设下，用WKB方法求解拉索振动方程，研究了机器人在操纵面作用下的稳定性。3)模拟了海洋中主要由内波引起的统计起伏，开发了拖船操纵水下机器人到指定位置的仿真程序。该模拟程序包含了本项目所获得的所有结果。仿真结果表明，更先进的船舶控制对于机器人更准确的导航是必要的，特别是在海洋流动复杂的情况下。4)为了使被拖曳机器人能够完美地引导到指定位置，研究了一种端点控制理论，该理论可用于改进拖曳船舶的操纵。

1) A simulation program was developed of three-dimensional behavior of a long flexible cable under the influence of complex flow in the ocean, by which nonlinear behaviors can be accurately simulated. We confirmed a good agreement exists between computations and experiments.2) A theory for investigating the dynamic stability of a system composed of ship, long flexible cable, and underwater towed vehicle (robot) was developed. Under the assumption that the transverse deflection and tension are slowly varying along the cable, an equation of the vibration of cable was solved with WKB method, and the stability of a robot to the action of a control surface was investigated.3) We simulated the so-called statistical fluctuation due mainly to the internal waves in the ocean, and developed a simulation program in which an underwater robot is supposed to be guided to a specified position by maneuvering a towing ship. This simulation program involves all the results obtained in this project. Simulation results revealed that more advarfced ship control is necessary for a more accurate guidance of a robot, especially when the ocean flow is complicated.4) A theory of end-point control was investigated for the perfect guidance of a towed robot to a specified position, which can be used for the improvement in how to maneuver a towing ship.