| Popis: |
The main focus of this research was on the aerodynamic characteristics of a Bumblebee Micro Air Vehicle (BMAV) recently developed at ASU. The BMAV prototype has a flexible membrane with an aspect ratio of 4.18 and a chord of 8 cm. The aspect ratio of a typical queen bumblebee is 5.78. One wing area is 90.38 cm measured from the SolidWorks model and an inner area-fuselage of 6.78 cm. The planform area, S was calculated as 187.56 cm. Since MAVs typically fly at low Reynolds number (Re), a Reynolds number of approximately 63,000 (12 m/s) was used for wind tunnel testing. The dynamic wing behavior is able to articulate in two degrees of freedom; i.e. a figure 8 rotational flapping pattern characteristic of many insects. The wing span, b of the prototype is 28 cm. The current BMAV model was designed through SolidWorks and manufactured using 3D printing to build a rapid prototype. The rapid prototype replicates an actual bumblebee, mimicking the insect’s articulation for its aerodynamic attributes. The BMAV prototype has a 12 volt, six winding brushless motor with a maximum speed of 8,750 rpm. The motor provides hovering equilibrium which presented a persistent challenge in previous prototypes. Experimentally, from wind tunnel tests, the lift coefficient was found to be 0.5894. The stall angle was observed at +16 degrees angle of attack, α. The minimum drag coefficient was observed to be -0.2389 at an α of -7 degrees. The collected experimental data permits a computation of aerodynamic derivatives that will be used in the near future to model the micro air vehicle within future nonlinear 3DOF/6DOF MATLAB/Simulink simulators. |
