Development of a Vectored Water-Jet-Based Spherical Underwater Vehicle

The applications of underwater vehicles have shown a dramatic increase in recent years, such as, mines clearing operation, feature tracking, cable or pipeline tracking and deep ocean exploration. According to different applications, the mechanical and electrical configuration and shape of an underwater vehicle are different. For instance, manipulators are necessary when doing mines clearing operation or some other tasks which need to deal with environment. If an underwater vehicle is used for underwater environment detection or observation, it is better to make this vehicle smaller and flexible in motion that it can go to smaller space easily. If the vehicle needs high speed moving in the water then a streamline body is required. Different structures with different size of underwater vehicles are developed. Most of these underwater vehicles are torpedo-like with streamline bodies, like (Sangekar et al., 2009). And there are some small size AUVs like (Allen et al., 2002) and (Madhan et al., 2006). And also there are some other AUVs adopt different body shape, such as (Antonelli & Chiaverini, 2002). Meanwhile, the propulsion system is one of the critical facts for the performance of underwater vehicles, because it is the basis of control layers of the whole system. Propulsion devices have variable forms, for instance, paddle wheel, poles, magneto hydrodynamic drive, sails and oars. Paddle wheel thrusters are the most common and traditional propulsion methods for underwater vehicles. Usually, there are at least two thrusters installed on one underwater vehicle, one for horizontal motion and the other for vertical motion. The disadvantages of paddle wheel thrusters are obvious, for example, it is easy to disturb the water around the underwater vehicles. Meanwhile, the more the paddle wheel thrusters are used, the weight, noise and energy consumption increases. The steering strategies of traditional underwater vehicles are changing the angular of rudders or using differential propulsive forces of two or more than two thrusters. Of course, there are vectored propellers being used on underwater vehicles. Reference (Cavallo et al., 2004) and (Le Page & Holappa, 2002a) present underwater vehicles with vectored thrusters. Reference (Duchemin et al., 2007) proposes multi-channel hall-effect thrusters which involves vector propel and vector composition. Reference (Le Page & Holappa, 2002b) proposes an autonomous underwater vehicle equipped with a vectored thruster. At the same time, the design of vectoring thrusters used on aircrafts is also an example of vectored propulsion system (Kowal, 2002), (Beal, 2004) and (Lazic & Ristanovic, 2007). 1