Abstract：This paper presents for underwater robot a theoretical hydrodynamic model, and some basic definitions of dynamic positioning, coordinate transformation and system structure for positionings with and without orientation.
[1] Daniel J J S. Dynamic positioning system
[2] Harold Drager, Det Norske Verilas. Classification of dynamic positioning systems, OTC, 1977
[3] LIU Chenhui. General decoupling theory of multivariable process control systems, Berlin, Spring-Verlag, 1983
[4] 李俊鹏,关于海洋机器人去藕.海洋技术二989;(3)
[5] 李俊鹏,海洋机器人的闭环控制与流体动力学模型·机器人·1987;(1)50-56
