DOF and kinematic analysis of a deployable truss antenna assembled by tetrahedral elements

Abstract

Deployable structure has played a more and more important role in the large-caliber antennas. This paper deals with the degree of freedom (DOF) and kinematics of a kind of deployable truss antenna composed of tetrahedral elements. Firstly, based on the reciprocal screw theory the DOF of one tetrahedral element is analyzed. Then, the equivalent mechanism of the minimum composite unit of the deployable truss antenna is obtained according to the characteristic of the DOF of the tetrahedral element. Sequentially, the DOF of the deployable truss antenna is derived. Further, the analytical expressions of the positions and velocities of the connection nodes of the antenna during its deploying/folding process are formulated by resorting to the coordinate transformation matrices. Finally, the correctness of the kinematic analysis of the deployable truss antenna is verified by simulation based on the Adams software.