Fern-inspired design of the spirally foldable antenna mechanism

ObjectiveAiming at the problem of insufficient efficiency and spatial adaptability of flat plate antenna retracting and unfolding, a new type of planar deployable antenna mechanisms was proposed by modeling the unfolding motion of ferns during the growth process.MethodsFirstly, a modular design was adopted to design the shear fork module to realize the spiral-type closing and unfolding in the longitudinal plane. The folding and unfolding motion in the transverse plane was realized by combining a spherical four-bar mechanism, and its degree of freedom was calculated. Secondly, the kinematic analysis of the folding and unfolding mechanism was carried out to investigate the relation among the turning angle of the longitudinal unit, the turning angle of the transverse unit and the dihedral angle during its motion, the angular velocity and angular acceleration of the longitudinal unit's turning angle and each rod were deduced, and the rate of the mechanism's closing was analyzed. Finally, numerical calculations and simulations were carried out.ResultsThe designed bionic deployable mechanism has a simple driving system and high closing efficiency, which provides reference for the design and research of the flat antenna mechanism.