QuadGlider: Towards the Design and Control of a Bio-Inspired Multi-Modal UAV with Compliant Wings

Abstract

Multirotors have become the most popular UAV or aerial robot category due to their structural simplicity and ability to take off and land vertically. However, most multirotors suffer from short airborne time and range due to limited battery capacity. Thus we propose a novel hybrid multirotor design, QuadGlider, to increase its capability of traveling long distances with minimal battery consumption. QuadGlider is inspired by the body structure and gliding mechanism of gliding animals. The airframe design of QuadGlider imitates flying squirrels' skeletal and muscular structure with implementation of servo motor to actuate its compliant membrane wings. Therefore, it can transition from quadrotor flight mode to forward gliding mode via morphing and lowering motor speeds to save power. In this work, we first present the conceptual design of QuadGlider. Next, we model its flight dynamics in different gliding scenarios. Then, the design is verified in computational fluid dynamics simulations of gliding scenarios with angles of attack of <tex>$0^{\mathrm{o}}-30^{\mathrm{o}}$</tex>. At last, preliminary gliding experiments are conducted at low Reynolds numbers of around <tex>$Re=4_{*}7_{*}\times 10^{5}$</tex> The equilibrium glide simulation gives a maximum glloe rauo of 4.27: 1 at a takeoff velocity of 14.0 m/s, while the experimental result indicates a glide ratio of 2.97: 1 at a takeoff velocity of 4.17 m/s.