An Experimental Investigation on the Micro Air Vehicle

An experimental investigation was conducted to study the flow characteristics of the flow around the flapping wings of a four-wing flapper as well as the lift and thrust coefficient of a four-wing flapper. In the present study, a clap-and-fling type of four-wing flapper was designed and manufactured by using several flexible materials, such as PET film, latex, and aluminized Mylar. Different cross-strut patterns and dimensions of wings were manufactured and tested to optimize the wing designs. In addition to taking the lift and thrust measurements using a highly sensitive force moment sensor unit, a high-resolution Particle Image Velocimetry (PIV) system was employed to achieve detailed flow field measurements to quantify the evolution of the unsteady vortex flow structure around the wings and in the downstream of the flapper. The force measurements were analyzed in correlation with the detailed flow measurements to elucidate the underlying physics to improve our understanding for an optimized flexible wing design and to achieve better performance for flapping wing micro air vehicles. A woofer loudspeaker was employed at the test section where the four-wing flapper was placed to generate sound distances. The effect of different frequencies and amplitudes of sound waves on the aerodynamic performance was investigated. A sensitive force moment sensor unit and PIV system were utilized to measure the lift and thrust and to take detailed flow field measurements to quantify the effect of sound waves on the flow and wing deformation. The force measurements were analyzed in correlation with the detailed flow measurements and qualitative wing deformation data to elucidate underlying the physics in to improve our understanding of the effect of acoustic disturbances on flexible wings and the overall aerodynamic performance of MAVs

Check-valve design in enhancing aerodynamic performance of flapping wings

[[abstract]]A flapping wing micro air vehicle (FWMAV) demands high lift and thrust generation for a desired payload. In view of this, the present work focuses on a novel way of enhancing the lift characteristics through integrating check-valves in the flapping wing membrane. Modal analysis and static analysis are performed to determine the natural frequency and deformation of the check-valve. Based on the inference, the check-valve opens and closes during the upstroke flapping and downstroke flapping, respectively. Wind tunnel experiments were conducted by considering the two cases of wing design, i.e., with and without a check-valve for various driving voltages, wind speeds and different inclined angles. A 20 cm-wingspan polyethylene terephthalate (PET) membrane wing with two check-valves, composed of central disc-cap with radius of 7.43 mm, supported by three S-beams, actuated by Evans mechanism to have 90° stroke angle, is considered for the 10 gf (gram force) FWMAV study. The aerodynamic performances, such as lift and net thrust for these two cases, are evaluated. The experimental result demonstrates that an average lift of 17 gf is generated for the case where check-valves are attached on the wing membrane to operate at 3.7 V input voltage, 30° inclined angle and 1.5 m/s wind speed. It is inferred that sufficient aerodynamic benefit with 68% of higher lift is attained for the wing membrane incorporated with check-valve.[[sponsorship]]MOST[[notice]]補正完

Reports to the President

A compilation of annual reports for the 1999-2000 academic year, including a report from the President of the Massachusetts Institute of Technology, as well as reports from the academic and administrative units of the Institute. The reports outline the year's goals, accomplishments, honors and awards, and future plans

College of Engineering

Cornell University Courses of Study Vol. 102 2010/201