Morphing nose cone with integrated deformation-locking design for aerospace vehicle inspired by honeybee abdomen

Active adjustment of aerodynamic shape by morphing mechanisms is an effective means to improve the environmental adaptability and maneuverability of aerospace vehicles. In this paper, inspired by the deformation mechanism of honeybee abdomen, a series-parallel morphing nose cone (MNC) mechanism that can realize deformation motions in four levels (2 levels of stretching and 2 levels of bending) and two directions (z-direction and x-direction) is designed. A deformation-locking integrated design method is innovatively proposed to achieve the locking of MNC at any position. Based on the screw theory, the branch-chain synthesis and degree of freedom (DOF) analysis of the mechanism are completed. The kinematics and dynamics models of the proposed mechanism are constructed, and its motion characteristics and working space are analyzed. Aiming at the problem with the heavier driving burden in the starting stage, the driving torque in the initial stage was designed to be compensated. Compensated start-up torque is significantly reduced, and the torque curve is smoother. Finite element analysis confirmed that the design of the locking chains and the force self-locking mechanism greatly enhances the axial stiffness of the MNC. A functional prototype of MNC is manufactured and the deformation experiments are conducted. The prototype can achieve eight independent morphing configuration processes and stable locking at any position, with a maximum bending angle of 19.65°, a maximum stretching of 79.55 mm, a maximum stretching rate of 14.75 %, and a motion deviation of <3 %.