Nonlinear vibration isolation via an innovative active bionic variable stiffness adapter (ABVSA)

During the process of spacecraft launch, the extreme vibration environment is the major influence factor that induces the failure of the mission. Inspired by the smooth motions of ostrich racing, an innovative active bionic variable stiffness device is proposed and installed on the traditional payload adapter fitting (PAF) of the rocket, which constitutes a new type of active bionic variable stiffness adapter (ABVSA). It is used as a novel vibration isolation equipment to improve the extreme vibration environment. Moreover, the bionic part is the main component of the ABVSA, which is controlled using the proportional-integral-derivative (PID) active controller. To explore the benefits of ABVSA, the theoretical model of the spacecraft-ABVSA system has been derived in the frame of the Lagrange principle. Furthermore, the nonlinear output frequency response functions (NOFRFs) approach is imported to solve the periodic problems of the system. Then, the numerical results were obtained to validate the effectiveness of ABVSA. The results indicated that the ABVSA could be recognized as a viable approach for vibration isolation during the spacecraft launching. In addition, the influence of ABVSA parameters was investigated in detail, and several interesting phenomena have been confirmed. Overall, this study can serve as efficient guidance for the optimal design of the PAF in engineering practice.