Active Precision Adjustment Mechanism for Large Space Reflectors

Abstract The demand for high-precision large-aperture antennas has continued to increase owing to the expanding application of spaceborne deployable active phased array antennas in remote sensing observation, satellite communication, navigation positioning, and deep space exploration. However, deployment errors in deployable mechanisms, particularly hinge-induced deflection errors during array surface deployment, degrade on-orbit surface accuracy. This study proposes an active adjustment strategy that installs compliant parallel mechanisms on the backplane of antenna subarrays to regulate surface splicing precision. For one-dimensional (1D) deployable antennas, a two-translation one-rotation (2T1R) parallel mechanism configuration is employed for precision adjustment, whereas two-dimensional (2D) deployable antennas adopt a one-translation two-rotation (1T2R) configuration. A reconfigurable parallel mechanism architecture satisfying space deployment constraints—the 3 P SS-2RPU-UPR/RPU parallel mechanism—is designed via configuration synthesis. The degrees of freedom (DOF) are verified via the screw theory, with complete inverse kinematics solutions derived. Search algorithms further quantify the adjustment workspace while clarifying the coupling relationships between DOFs. Equivalent compliant parallel mechanism models are obtained using the rigid-body replacement method, followed by a compliance analysis and motion simulation of compliant joints (notched flexure hinges and leaf-spring flexure prismatic joints). A systematic investigation of the deformation characteristics under different actuation modes confirmed the validity of the equivalent models. Ground experiments demonstrated close agreement between the measured and simulated adjustments, with open-loop adjustment errors constituting less than 10% of the adjustment range, thereby validating the feasibility of the method. The precision adjustment mechanism achieved configuration switching (2T1R/1T2R) through an inverted central limb design, integrating dual-mode compensation into a reconfigurable system.