Omni-Egg: A smooth, spheroidal, appendage free underwater robot capable of 5 DOF motions

This paper describes the performance of a new type of highly maneuverable underwater robot developed at MIT. The robot, titled “Omni-Egg,” is smooth, spheroidal, and completely appendage free. Propulsion is provided using a novel pump-jet system that can be completely built into the streamlined shell. No fins or stabilizers are used on the vehicle, and directional stability is instead achieved using feedback control. Experimental results show how the turning performance of this smooth design is superior to a similar one that uses fins to achieve stability. Due to this unique design the robot is capable of unique motions such as forward and reverse motions, high speed turning, and sideways translations. This type of robot is designed for tasks requiring a large degree of maneuverability within tight spaces. Some examples of such tasks include the inspection of water-filled infrastructure and the exploration of cluttered environments. Such applications have a high risk of collisions or snagging on obstacles, so a smooth outer shape is desirable. The vehicle is designed to be capable of 5 DOF, and surge, sway, heave, and yaw are all demonstrated in this paper. Pitch, the 5th DOF, remains under development.