Design optimization and experimental study of a novel mechanism for a hover-able bionic flapping-wing micro air vehicle

Analyzing the kinematics and longitudinal aerodynamics of a four-wing bionic aircraft

This paper designs a bionic aircraft model equipped with multiple degrees of freedom to study the inertial force equation and the aerodynamic interaction between its forewings and hindwings. Each wing's phase difference angle (PDA) and stroke plane angle (SPA) are independently adjustable. Employing the kinematic equation of a single wing, we establish a model for the inertial force of the four-wing aircraft, validating its accuracy through experimental comparisons. Furthermore, we analyze various combinations of PDA and SPA parameters for the fore- and hindwings to ascertain the most efficient aerodynamic motion modes. Our findings reveal that aerodynamic interference between the fore- and hindwings tends to be unfavorable, predominantly due to the hindwings being exposed to the wake generated by the forewings, hindering their lift-capturing ability. Nevertheless, a specific PDA = 270° (forewing ahead of hindwing 270°) helps mitigate this interference across a wider range of SPA. Interestingly, when the stroke plane aligns parallel to the horizontal direction, asynchronous flapping of the fore- and hindwings, forming a lift mechanism akin to clap-and-fling wings, positively impacts lift. Consequently, staggered flapping of the fore- and hindwings reduces fuselage jitter and alleviates aerodynamic interference through specialized PDA, resulting in a temporary lift enhancement. The purpose of this study is to provide theoretical support for the longitudinal attitude control of four-wing aircraft.

A novel bioinspired mechanism to elucidate the movement flexibility of the honeybee abdomen driven by muscles

The abdomen of a honeybee is a blueprint for bioinspired mechanical design because of its movement flexibility and compactness. However, the abdominal muscles closely related to the movement flexibility mechanism have not been fully identified, limiting the potential biological advantage of their use in bionic mechanism design. In this study, we reveal the muscle distribution of the complete muscular driving unit in a honeybee abdomen using stereoscopy and scanning electron microscopy, and the muscle distribution was effectively verified using X-ray tomography. A novel equivalent unit mechanism (EUM) was then proposed and the kinematic analysis indicated that the extension ratio, bending angle, and swing angle of the EUM reached 9.36%, 1.22°, and 4.43°, respectively. The deformation ability of the EUM was consistent with the movement of the abdomen, confirming the movement flexibility. This work may provide a new perspective for distributed bionic mechanism design.