Abstract: In the special case, the sub-mini underwater vehicle (SMUV) is only asked to perform transverse movement. But because of the limited size, the requirement is difficultly realized or the cost is dear. This paper expounds upon the design scheme of a kind of dish-shaped SMUV. It enables the vehicle to fulfill many degrees of freedom of movement in many directions. The mechanical structure designs fulfill the SMUV movements. Compared with those common SMUVs, the characteristics of this vehicle are that it adopts revocable properller with two rotated axises to accomplish synchronously the robot ascending and descending and direction changing. And the relationship between movements and conditions of control forces is derived. An expression for ensuring the normal function of the dish-shaped SMUV is obtained.

Key words: sub-mini, underwater vechicles, horizontal propeller, synchronous movement, ascend and descend the device