Design and analysis of ultra-low moment noise flexure pivot in space gravitational wave detectors

Abstract

To control the pointing accuracy of the telescope in the space gravitational wave detector at the nano-radian level, it is essential to design a flexure pivot with extremely low rotational moment nonlinearity during rotation. This study derives the theoretical equation of the nonlinear rotational moment of flexure pivot based on the beam bending strain energy equation and completes the design of ultra-low moment noise flexure pivot by integrating the structural form of conventional cross-spring flexure pivot. The nonlinear moment noise distribution in the frequency domain of three kinds of flexure pivots is then compared regarding TianQin’s circular high orbits. Then the relevant finite element simulation analysis will be performed for the flexure pivot structures, respectively, to ensure the accuracy of its rotational stiffness model and verify the correctness of nonlinear moment theory optimization through physical experiments. The results show that the optimized flexure pivot can effectively reduce the nonlinearity, and basically meet the nonlinear moment requirements in space gravitational wave detection.