The Design of a Novel Tensegrity-Based Synthetic Pectoral Fin for Bio-Inspired Propulsion.

摘要

The three main contributions of this research to the design of a BAUV are: (1) the development of an analytical kinematic model that describes manta ray pectoral fin motion (2) the experimental hydrodynamic study of a pure flapping artificial pectoral fin and (3) the derivation of the mechanics to explore novel active tensegrity structures.;An analytical model to describe the three-dimensional pectoral fin kinematics of the manta ray is developed. It captures the dominant components of ray locomotion: curved spanwise deformation coupled with a chordwise traveling wave. The model is extended to quantify the kinematics of the entire batoid family, Batoidea, with examples presented of two other species, the Atlantic stingray, Dasyatis sabina, and the cownose ray, Rhinoptera bonasus.;To determine the importance of different kinematic features utilized by rays, a pectoral fin that exhibits only flapping has been fabricated and tested. This fin can produce a variety of motions, where the thrust and propulsive efficiency are measured for each prescribed motion. It is found that the undulatory wave exhibited by rays is of prime importance for efficient swimming and high thrust production.;To produce an artificial pectoral fin that incorporates both a chordwise traveling wave and curved spanwise deformation, a tensegrity-based solution is developed. Various actuation strategies are explored involving either embedding the actuators into the tensegrity structure (embedded actuation) or migrating the actuators outside of the structure (remote actuation). Remote actuation overcomes the limitations of embedded actuation by placing the actuators outside of the active region and connecting to the structure via a routed cable. A general numerical model---applicable to any topology and any actuation strategy---has been derived. This is used to identify an optimal remote actuation strategy.;Lastly, analytical solutions for planar tensegrity beam structures are derived. These solutions allow for the direct calculation of optimal parameter values without the need to perform an exhaustive parametric study using the general numerical solution. Moreover, the analytical solutions provide physical insight into the mechanics of tensegrity beams and are used in the design of a tensegrity-based artificial pectoral fin.