Contents I. Introduction
With limited land resources, human beings gradually put their eyes on the oceans, which account for about 71% of the total area of the earth. The exploration of oceans and the development and utilization of marine resources have become a new strategic area for every country. The acquisition of deepsea resources has been risen to the national strategy[1]. At present, AUVs have been widely used in ocean resource detection, hydrological environment monitoring, underwater search, and other fields [2]. In the civil field, AUVs can be used for diagnosis of underwater pipelines, such as submarine natural gas pipeline monitoring. However, large-scale AUVs are extremely inconvenient when operating on the seafloor, bringing many difficulties to deployment. The diameters of the AUVs are mostly from 200 millimeters to several meters, and the weight of the AUVs is usually from several hundred kilograms to tons. What is more, the control system is the core part of the autonomous underwater vehicle[3] and it is also the key to determining whether the AUV can work steadily and reliably. Therefore, considering the limited space inside an AUV, it is especially important to design a complete set of underwater vehicle control systems.
