基于旋转水槽试验的水下与陆上泥石流对比研究

使用最近研发的旋转水槽制作稳定循环流动的水下泥石流和陆上泥石流,通过实测泥石流的流动形态、阻力坡降和流动速度,对比研究水下泥石流与陆上泥石流的运动特性。本研究表明,在陆上泥石流的基础上直接通过增加水量的方法,在特定条件下可以得到水下泥石流。在旋转水槽试验中,水下泥石流与陆上泥石流具有某些相似的运动特性,例如在水下泥石流中同样可以观测到粗颗粒聚集现象。同时证实了水下泥石流与陆上泥石流两者都具有速率效应。

水下机器人最优刹车轨迹规划设计

为使得以较高速进行运动的水下机器人能最终悬停于指定深度,需使该水下机器人在垂向上减速直至停止。针对水下机器人刹车上浮过程的特性,结合最优控制理论与数值积分方法,完成了水下机器人的最优刹车轨迹规划设计。研究结果表明,通过规划算法所得的刹车轨迹能保证水下机器人刹车距离最短且恰好悬停在指定悬停位置,提出的规划算法求解时间消耗较短,有较强实时性。

Two-Stage Scheme for Disturbance Rejection Hovering Control of Underwater Vehicles

A two-stage model-independent hovering control scheme for underwater vehicles,which are subject to unknown yet constant external disturbance,to eliminate steady-state depth error is proposed.Proportionalderivative(PD)state feedback control law is adopted as the ballast mass planner at the first stage for the vehicle to reach both hydrostatic balance and a steady depth.The residual depth error is then removed by an additional disturbance rejection control at the second stage.Global asymptotic stability of the whole system is guaranteed via Lyapunov approach.The effectiveness of the proposed scheme is illustrated by the simulation of diving control of an underwater vehicle with hydraulic variable ballast system.