Experimental Investigation on the Aerodynamics of a Bio-Inspired Flexible Flapping Wing Micro Air Vehicle

Abstract

An experimental investigation on a 10 cm bio-inspired flexible Flapping-Wing Micro Air Vehicle (FWMAV) was conducted in both hovering and forward-flight conditions with the objective to characterize its aerodynamic performance. The measurements in hovering conditions were performed with the particular objective to explore the effect of different wing configurations (i.e. different aspect ratios and wing flexibilities), whereas forward flight tests in a wind tunnel were carried out to assess the aerodynamic performance of the FWMAV as a function of flow speed, flapping frequency and body angle. The cyclic variation of forces (lift and thrust) generated as a result of the wing flapping was captured by means of a high-resolution force sensor, in combination with high-speed imaging to track the wing motion. Results of measurements in hover show that the flapping frequency, aspect ratio and wing flexibility have a crucial impact on the efficiency and the force generation during the flapping cycle. An estimated flight envelop for the MAV's operation is defined from the data obtained in the wind tunnel measurements. Furthermore, additional tests on several brushless DC motors provide a feasible option in future engine selection and design.

Unmanned Aerial Systems (UAS) Research Opportunities

“…Most small UAS today have variations of commercial actuators adapted from the commercial hobby world and often electrically compatible with them. The micro UAS discipline moves further away from the hobby industry and towards UAV research programs when flapping wings [44,45] and extreme miniaturization [46] are involved. Autonomy is typically specific to the domain of UAS and mainly in institutions, although developments like the Robot Operating System [47] are causing a convergence of autonomy effort on problems rather than platforms and starting to involve effective hobbyists.…”

Aerodynamic Characterization of ‘DelFly Micro’ in Forward Flight Configuration by Force Measurements and Flow Field Visualization

“…The wind tunnel has an open test section with cross-section of 600 mm × 600 mm, which is large enough to prevent any interaction between the free shear layer from the nozzle exit and the tested model. The free-stream velocity was set at 2 m/s, which is a typical value in the forward flight of DelFly Micro [7]. The DelFly model was mounted on a miniature six-component force sensor (ATI Nano-17 Titanium) to record the instantaneous forces and moments with a date acquisition frequency of 10 kHz.…”

“…The measured forces were filtered using a Chebyshev II type low pass filter to keep the first five harmonics as suggested by previous studies [7]. Fig.…”

“…Previous studies [7,8] have defined the flight envelop of DelFly Micro. The effects of wing flexibility, aspect ratio and flapping frequency on aerodynamic force production have been revealed.…”

Approach to insect wing shape and deformation field measurement

“…Several FWMAVs inspired by insects prove to be promising, including the Micromechanical Flying Insect (Fearing, 2004; Yan et al, 2001), DelFly (de Croon et al, 2009; de Croon et al, 2012; Lentink et al, 2007) and Harvard Microrobotic Fly (Ma et al, 2013). Remarkable progress of the FMAV has been achieved on energetics (Karpelson et al, 2010), actuation (Wood et al, 2005)and aerodynamics (Deng et al, 2014; Nakata et al, 2011; Wilkins and Knowles, 2009). Yet the flight performance of FWMAV can hardly match with that of the insects.…”