Open loop performance of a biomimetic flapping foil autonomous underwater vehicle

Abstract

Flapping foil propulsion is emerging as an alternative to conventional propulsion for underwater vehicles. MIT's Biomimetic Flapping Foil Autonomous Underwater Vehicle is a prototype vehicle that uses four three-dimensional flapping foil actuators as its means of propulsion. The vehicle providing an opportunity for investigating the efficiency and maneuverability capabilities of a flapping foil system. This thesis presents and analyzes open-loop performance test data for the Biomimetic Flapping Foil Autonomous Underwater Vehicle. The vehicle is capable of actuating in four different modes of motion, surge, heave, sway, and yaw. These four modes are explored through a range of flapping parameters. For each mode, the parameters were varied to obtain an approximate maximum velocity for the vehicle. Maximum velocity in surge was measured as 1.3827 mis, in sway as 0.4810 m/s, and in heave as 0.3831 m/s. In yaw, the maximum angular velocity was measured as 80.2 degrees per second.

(cont.) The performance of the vehicle as reported in this thesis compare well to the previously recorded performance measurements and to theoretical estimates based on the capabilities of the actuators. However, measurements of performance would benefit greatly from better control during testing and from a larger testing space. Developing a more effective means of sway actuation would also benefit the vehicle's performance.