Jiantao Yao, Wenlan Liu, Yundou Xu, Lijian Li, Jianjun Li, and Yongsheng Zhao
Parallel mechanism, stiffness matrix, screw theory, Rayleigh quotient, minimum singular value
This paper deals with the stiffness modelling of the sub-reflector adjustment mechanism (SAM) of a large antenna. The base of the SAM can be movable due to the structural features of the antenna. First, assuming that the base of the SAM is fixed, the complete stiffness model of the SAM is established based on screw theory and principle of virtual work, in which the stiffness of active and passive joints and the effects of external loads and gravity are considered. Then, the complete stiffness model of the SAM is constructed by introducing a variable parameter, when the base of the SAM moves along with the main-reflector of the antenna. Finally, the comparisons between the theoretical values and simulation values of linear micro-displacements of the moving platform’s centre of the SAM are given to show the correctness of the complete stiffness model. This work lays theoretical foundations for the structural design of the SAM and accuracy compensation of the antenna.
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