中文摘要：

水下自航行器（AUV）的续航能力主要取决于其所携带能源总量．为了有效地减少能耗，提出了一种具有变浮力系统、能够着陆坐底的小型AUV，它可以利用有限的能源实现长时间的海洋环境监测．首先介绍了该AUV的总体结构，然后对AUV的着陆策略进行了详细研究．在对三种着陆策略进行对比的基础上，选择下潜航行到位控制注水着陆策略作为最佳的水下着陆方案．该策略能够使着陆时的冲击力保持在安全范围内，并且着陆时间最短．最后对着陆轨迹进行规划．仿真和水域实验的结果都证明采用该着陆策略能够安全、平稳地实现水下着陆．

英文摘要：

The cruise range of autonomous underwater vehicles （AUVs） mainly depends on the onboard electric power. In order to reduce the power consumption effectively, a small buoyancy changing AUV with the capacity of soft landing and bottom-sitting is developed, which can carry out long time ocean environment measuring missions with the limited power. The general configuration of the AUV is described first. Then the landing strategies of the AUV are discussed in detail. Based on the comparison of three landing strategies, the strategy of diving to the desired position and then landing with controlled water injection is selected. This strategy can confine the impact force in landing process within a safe range, as well as make the landing time shortest. Finally, the landing trajectory is planned, Results of simulations and sea experiments show that the AUV can land safely and smoothly on the sea bottom with the strategy.