Development of propulsion mechanism for Robot Manta Ray

Manta rays are very efficient swimmers which are able to travel at high speed over large distances despite their large sizes. This paper covers the design, experiment and prototype testing of a propulsive mechanism for Robot Manta Ray. The propulsive mechanism and the pectoral fins of the Robot Manta Ray were designed based on some of the hydrodynamic concepts of manta ray locomotion. The designs focus on simplicity and utilize passive flexibility to generate high forward thrust while achieving high energy efficiency. In order to find out the effects of flexibility on the fins, experimental tests were conducted with fin materials of various thicknesses. Also, experimental tests were performed to find out the effects of changing amplitude and frequency of flapping. A prototype of the Robot Manta Ray was designed and fabricated in order to test the swimming capability of the propulsion mechanism. The prototype was tested in a swimming pool to obtain its swimming speed.