Abstract: In this paper, we present the development of our latest flapping-wing micro air vehicle (FW-MAV), named Explobird, which features two wings with a wingspan of 195 mm and weighs a mere 25.2 g, enabling it to accomplish vertical take-off and hover flight. We devised a novel gear-based mechanism for the flapping system to achieve high lift capability and reliability and conducted extensive testing and analysis on the wings to optimise power matching and lift performance. The Explobird can deliver a peak lift-to-weight ratio of 1.472 and an endurance time of 259 s during hover flight powered by a single-cell LiPo battery. Considering the inherent instability of the prototype, we discuss the derivatives of its longitudinal system, underscoring the importance of feedback control, position of the centre of gravity, and increased damping. To demonstrate the effect of damping enhancement on stability, we also designed a passive stable FW-MAV. Currently, the vehicle is actively stabilised in roll by adjusting the wing root bars and in pitch through high-authority tail control, whereas yaw is passively stabilised. Through a series of flight tests, we successfully demonstrate that our prototype can perform vertical take-off and hover flight under wireless conditions. These promising results position the Explobird as a robust vehicle with high lift capability, paving the way towards the use of FW-MAVs for carrying load equipment in multiple tasks.

Key words: Flapping wing , · Biologically inspired robots , · Mechanical design , · Flight dynamics , · Damping enhancement