Study On Degradation Law Of Motion Function Reliability For A Three-Claw Cone-Like Space Docking Mechanism

Space rendezvous and docking is an indispensable operation of spacecraft during long-term orbit operation,it is a basic technology that must be mastered by manned space activities.Space docking mechanism is a system to realize the on-orbit mechanical connection of space vehicles,establish the connection between space vehicles and ensure the safe separation of space vehicles,it is very important to study and improve the motion function reliability of space docking mechanism for the successful completion of space docking mission.The degradation law of motion function reliability of space docking mechanism is studied deeply and systematically in this thesis.Based on the improvement of the existing docking mechanism,a three-claw conelike space docking mechanism was proposed,taking the three-claw cone-like space docking mechanism(hereinafter referred to as "docking mechanism")as the research object,modal analysis was carried out on its core components(gripper and active docking joint),which provided a basis for avoiding resonance failure of space docking mechanism.The fuzzy optimization design of the spring base of the space docking mechanism is carried out to obtain the best comprehensive performance of the spring.The constitutive equation of spring creep was established,the creep and stress relaxation of helical spring were simulated,the process curve of spring base gradually failing under constant load for a long time was obtained.A two dimensional gap hinge model is established by vector method,based on this,the minimum distance method is introduced to establish the hinge model with threedimensional clearance,the analytical expressions of the four minimum distances in the hinge and the trajectory equation of the grasping point are obtained by solving the hidden contact points between the shaft sleeve and the pin shaft in the hinge,the dynamic simulation of the trajectory of the grasping point is carried out by ADAMS,the influence of different coaxial clearance on the motion trajectory of the claw was investigated.Based on D ’Alembert’s principle,the dynamic equation of the hinge with three dimensional clearance is established,considering the influence of friction coefficient,clearance size and ambient temperature,the dynamic response of the hinge with three dimensional clearance is analyzed by ABAQUS.First order second moment method was used to analyze the motion function reliability of the butt mechanism,based on the stress intensity interference model,the motion function reliability of the butt mechanism was obtained.The degradation law of motion function reliability of space docking mechanism studied in this thesis has certain theoretical significance and practical value for improving the design rationality,service safety and operational reliability of space docking mechanism.