Design of an angular radial robotic stingray

Abstract

The propeller is the primary propulsion method for underwater vehicles. It is relatively simple to implement and generally uses rotational motion from the drive through to the propeller. However, it is difficult to seal a high speed propeller shaft from water ingress. As an alternative we can look at nature's own underwater inhabitants and study their locomotive methods. The fish species provides us with a wide variation of fin and body locomotive methods. The fin motion in all species is predominately undulating with varying wavelengths and is particularly defined in the stingray species. The purpose of this project was to undertake the various stages that involved producing a biomimetic robotic platform that mimics the two undulating horizontal fins of a stingray. The robot possesses the necessary flexibility to enable complex motions but through the use of simple servos, linkages and a microcontroller is itself not a complex design. The range of motion available for the robot in this paper is similarly limited to those of solidly linked fins. However, the opportunity to develop more complex motion is now available. Control strategies and modified radial displacements can be easily implemented in this design.