A novel modular deployable mechanism for the truss antenna: Assembly principle and performance analysis

The truss antenna based on the tetrahedral deployable mechanism has the advantages of good deployment stability, high stiffness, large folding rate and high profile accuracy. A new modular deployable antenna mechanism based on the 3RR-3URU tetrahedral symmetrical combination unit is proposed in the present study. It should be indicated that the construction method of the modular mechanism is proposed initially based on the 3RR-3URU tetrahedral symmetrical combination unit as a basic module. The assembly method of modular mechanism and the arrangement of the joints connecting different modules are introduced in detail. Moreover, the large aperture antenna mechanism composed of more modules is described. The basic module and the modular mechanism composed of multiple modules belong to the spatial multi-closed-loop mechanism, so the degree of freedom (DOF) of the one-circle modular mechanism is analyzed by using the idea of ‘equivalent mechanism’ and screw theory. Moreover, the law of DOF of the multi-circle modular mechanism is further explored. The screw topological graph and screw coefficient matrix are applied for this kind of multi-closed-loop mechanism to obtain the results of the reasonable choice of actuation. Then, kinematics analysis of the modular mechanism is completed by the coordinate transformation and vector method. The folding rate is discussed and compared with other mechanisms for the truss antenna based on the kinematics. Finally, the simulation analysis model is established by using Solidworks and Adams modeling and simulation software. The correctness of the DOF and kinematics theory analysis is verified by the simulation analysis. Furthermore, the proposed mechanism is compared with the existing mechanisms. The proposed modular deployable antenna mechanism has the advantages of large folding rate and high reconfigurability. Therefore, it obtains great application prospects in the fields of the aerospace deployable antennas.