Design and optimization of repeatable locking/unlocking device for magnetically suspended control moment gyro

Due to the air gap between stator and rotor, magnetically suspended control moment gyro (MSCMG) should be equipped with locking/unlocking device (LUD) to sustain launch vibration and impact. Current LUDs are not repeatable, reliable and compact enough for gyro applications. In this paper, a repeatable locking/unlocking device (RLUD) with several elastic brackets as clamping/releasing mechanism is proposed. Based on the equivalent beam model, static and dynamic analyses of the brackets are carried out, and the maximum stress, the locking/unlocking force and the resonance frequency are obtained. Subsequently, the optimization design using non-linear programming by quadratic Lagrangian (NLPQL) algorithm is implemented, and structural parameters of the optimized brackets are calculated. The maximum stress and first resonance frequency are simulated through finite element method (FEM), and the results are in good agreement with those of the elastic beam analyses. Finally, a MSCMG rotor system with the designed RLUD is fabricated. The environmental mechanics tests including sine sweep and random vibration are performed, which verifies the locking protection effect for MSCMG rotor.