High lift force with 275 Hz wing beat in MFI

Abstract

Abstract-The Micromechanical Flying Insect (MFI) project aims to create a 25 mm (wingtip to wingtip) flapping wing micro air vehicle inspired by the aerodynamics of insect flight. A key challenge is generating appropriate wing trajectories. Previous work [1] showed a lift of 506 µN at 160 Hz using feedforward control. In this paper, refinements to the MFI design including those in [2] increased wing beat frequency to 275 Hz and lift to 1400 µN using pure sinusoidal drive for a fixed benchtop experiment. We show through simplified aerodynamic models that not only do sinusoidal actuator drives produce close to maximal lift, but significantly improved wing trajectories due to non-sinusoidal actuator drives are practically unobtainable due to actuator limitations.

Challenges for 100 Milligram Flapping Flight

“…Each wing is driven by two piezoelectric bimorph bending actuators [22], which provide an unloaded displacement of ±250µm, and blocked force of ±60 mN [22]. The transmission is designed [14,15,20,3] to convert this high-force small-displacement to an ideal wing stroke of ±60 • , with an equivalent transmission ratio of approximately 3000 rad m −1 .…”

“…Case 2 is a pure sinusoid trajectory and Case 3 is a sinusoidal drive voltage. Slow rotations could be achieved by passive aerodynamic and compliant mechanisms [14].…”

“…9(a) shows several candidate wing rotation profiles, including a simple sinusoidal profile and higher harmonics in rotation, to generate a faster wing rotation at the end of each halfstroke. Using a dynamic model of the thorax and wing [14], the required actuator forces can be predicted, as shown in Fig. 9(b).…”

“…A benchtop, one-wing version of the MFI was tested using over-sized actuators [14]. Through careful tuning of the amplitude, phase, and frequency of the two actuators (4 parameters), an operating point with decent wing rotation was found as shown in Fig.…”

The design and micromachining of an electromagnetic MEMS flapping-wing micro air vehicle

“…In MEMS area, the researchers from Europe and America do much more about FMAV, Fearing et al from University of California made attempts to create a micromechanical flying insect with a 2.5 cm wingspan (Avadhanula and Fearing 2005;Steltz et al 2007); Wood from Harvard proposed an insect-scale flapping-wing micro air vehicle with a 3 cm wingspan based on piezoelectric actuator (Wood 2007a(Wood , b, 2008. While, piezoelectric driving needs very high driving voltage (about 200 V) but the output displacement is small.…”