Structural Designs of Gear-Based Flapping Actuation and Parallel-Coupled Flight Control Mechanisms for a Compact Twin-Winged, Tailless Flapping Robot
摘要
In this paper, we proposed a compact, lightweight flapping actuation mechanism and a flight control mechanism for a twin-winged, tailless, hover-capable flapping robot named HiFly-Hummingbird, which has a total mass of 14.4 g and a wingspan of 18.8 cm. A four-bar linkage and gears set were adopted to convert the rotation motion of DC motor into flapping oscillation and amplify the flapping amplitude. As well as, a parallel coupled flight control mechanism was designed to implement the aerodynamic moments generation strategies. The proposed flapping actuation mechanism, with a mass of 2.95 g, has been validated to achieve a 168° amplitude at a frequency of 26 Hz with an asymmetrical stroke deviation of 3.5%, operating at a power consumption of 4.05 W. The parallel coupled control mechanism weights 2.14 g (including three servos). Benefit from the nonlinen inverse kinematics model of the parallel coupled control mechanism, the proposed control mechanism exhibits a roll motion range of ± 10° with an accuracy error of 0.8° and a pitch motion range of ± 12° with an accuracy error of 0.6°. The proposed mechanical systems are beneficial to lightweight design, manufacture and assemble under stringent size, weight and power (SWaP) constraints of flapping wing micro air vehicles (FW-MAVs), and possess favorable efficiency and accuracy. Relying on the hardware control circuit and feed-back attitude control algorithm, the robot hummingbird successfully achieved untethered lifting off and reached a maximum flight altitude of 4 m in several flight tests, demonstrating that the proposed mechanical designs of the flapping robot platform effectively enhances the miniaturization and light-weighting of the hummingbird-like FW-MAVs under the conditions of meeting the propulsion and control requirements for lifting off.