An Experimental Study of Wind Resistance and Power Consumption in MAVs with a Low-Speed Multi-Fan Wind System

Abstract

This paper discusses a low-cost, open-source and open-hardware design and performance evaluation of a lowspeed, multi-fan wind system dedicated to micro air vehicle (MAV) testing. In addition, a set of experiments with a flapping wing MAV and rotorcraft is presented, demonstrating the capabilities of the system and the properties of these different types of drones in response to various types of wind. We performed two sets of experiments where a MAV is flying into the wake of the fan system, gathering data about states, battery voltage and current. Firstly, we focus on steady wind conditions with wind speeds ranging from 0.5 m s −1 to 3.4 m s −1 . During the second set of experiments, we introduce wind gusts, by periodically modulating the wind speed from 1.3 m s −1 to 3.4 m s −1 with wind gust oscillations of 0.5 Hz, 0.25 Hz and 0.125 Hz. The "Flapper" flapping wing MAV requires much larger pitch angles to counter wind than the "CrazyFlie" quadrotor. This is due to the Flapper's larger wing surface. In forward flight, its wings do provide extra lift, considerably reducing the power consumption. In contrast, the CrazyFlie's power consumption stays more constant for different wind speeds. The experiments with the varying wind show a quicker gust response by the CrazyFlie compared with the Flapper drone, but both their responses could be further improved. We expect that the proposed wind gust system will provide a useful tool to the community to achieve such improvements.

Battle the Wind: Improving Flight Stability of a Flapping Wing Micro Air Vehicle Under Wind Disturbance With Onboard Thermistor-Based Airflow Sensing

“…The time-averaged airspeed measurement at each stage of wind intensity from the three groups of tests are shown in Fig. 14, along with the freestream speed at 1 m downstream from the fan arrays as reference [21]. It can be seen that the redesigned airflow sensor is capable of providing repeatable airspeed measurement under various wind intensities overall.…”

“…Delfly Nimble hovers at a set waypoint (1 m downstream from the fan system, with the roll axis x b pointing towards the center of the fan system as illustrated in Fig. 12) in front of a custom-made fan system [21] that is capable of generating wind disturbances at various speeds and time duration.…”

Embodied airflow sensing for improved in-gust flight of flapping wing MAVs

“…The platform uses the Crazyflie Bolt flight control suite with an STM32F405 processor. Compared to the DelFly Nimble, the Flapper Drone has a higher mass and wingspan, resulting in a more generous payload and wing loading capacity, as seen in Table 1 .To generate the desired dynamic wind conditions in flight experiments, an open-source fan system consisting of an array of 135 axial fans ( Olejnik et al, 2022 ) is employed. With pulse width modulation (PWM) based control of the fans, the fan system can render various types of continuous winds and gusts with an effective wind surface area of approximately 1 m 2 , at flow speeds of different intensities and frequencies.…”