Design and analysis of a scissors double-ring truss deployable mechanism for space antennas

Space deployable mechanism plays an important role in the orbital deployment and stable support of the antenna reflection surface, which is an important component for the spacecraft radar antenna. In order to improve the structural stiffness of the ring truss deployable antenna mechanism when it has a large diameter, a scissors double-ring truss deployable mechanism is proposed in this paper. First, structure analysis of general ring truss deployable antenna and construction of the scissors double-ring truss deployable mechanism are conducted, and the whole mechanism is decomposed to a plurality of mechanism units. Then, degree of freedom (DOF) of the scissors double-ring truss deployable mechanism is analyzed based on screw theory, the result showed that 'it has only one DOF. Furthermore, based on screw theory, kinematic characteristics of the scissors double-ring truss deployable mechanism are examined, velocities and accelerations of the components in the mechanism are obtained, as well as the Jacobian matrixes. Finally, based on Newton-Euler equation and the principle of virtual work, a dynamic model of the whole mechanism is established, numerical calculation and simulation verification are carried out, and the results verified the correctness of the theoretical analysis. The scissors double-ring truss deployable mechanism proposed in this paper can be well applied in the field of space antennas, and the theoretical analysis method based on screw theory used in this paper can provide insights into other spatial deployable mechanisms. (C) 2019 Elsevier Masson SAS. All rights reserved.