Modeling of the Test Mass Release Process Based on Improved Genetic Algorithm Identification and Adhesion Analysis

Gravitational waves carry a wealth of cosmic information, offering a new observation perspective for exploring the universe. The grabbing, positioning, and release mechanism is a fundamental element of the gravitational reference sensor used in spaceborne gravitational wave detectors and serves to steadily transition the test mass (TM) from high-load to geodetic conditions. However, implementing comprehensive performance testing on the entire mechanism will inevitably prolong the development period. Conversely, utilizing a dynamic model to predict the behavior of the released TM will facilitate the development and improvement of the mechanism. A dynamic model of the TM release process was established to assess the performance of the release mechanism and analyze the effect of adhesion on TM velocity. Firstly, a dynamic model of the release mechanism was developed, and the unknown parameters were identified using an identification method based on an improved genetic algorithm, which avoids the initial value of the parameters being challenging to guess. Then, considering the roughness of the contact surface between the release tip and the TM, the contact force was analyzed based on the Johnson–Kendall–Roberts theory. The dynamic model of the TM was formulated by incorporating the contact force into the release mechanism dynamic model, and the velocity response of the TM during unilateral release was calculated. Finally, the influence of mechanism parameters on the TM’s velocity was investigated. The TM velocity response indicates that adhesion does not considerably influence the TM velocity. Furthermore, the release mechanism can fulfill the mission requirements under typical release conditions.