Research On Space Docking Mechanism And Six Degrees Of Freedom Simulation Test Platform

Space docking mechanism is one of core equipment in the spacecraft rendezvous and docking process. The design rationality of the docking mechanism is the main part of rendezvous docking, ensuring the smooth completion of space docking mission. In order to improve the reliability and design rationality of space docking mechanism, simulated space environment and analysis of prototype testing were carried out with simulation test platform of ground six degrees of freedom(DOF). The significant performance of docking mechanism was ensured. Aiming at the actual demand of spacecraft rendezvous and docking mission, the mechanisms were designed with the docking mechanism of three claws model and simulation test platform of six DOF on the basis of characteristics of rendezvous and docking. The rationality of the design and safety of application were studied with numerical simulation and experimental research. The main contents are as follows:According to the analysis of the kinematics characteristics of space docking mechanism pose, the pose mathematical model was established by using the active and passive docking mechanism, which includes the corresponding coordinates of each part, attitude parameter and the mutual transformation relationship for parameters. According to the analysis of the kinetic characteristic of spacecraft rendezvous and docking, the kinetic model was established for docking mechanism.The kinematics analysis of the active and passive falcula was made,falcula impact and buffering dynamics were researched by using mathematical model. These are theoretical basis to the three claw space docking mechanism and the simulation test platform of ground six DOF in the aspect of configuration design.The space docking mechanism of three claws model was designed to meet the project requirements of the docking. Among the advantages of three claws model are larger range of capture, lightweight, high reliability of docking, convenient detection,and easy control. The kinetic model of the docking mechanism was established in the process of the docking, and the kinetic characteristics of the falcula collision was analyzed in the process of the buffer docking. The falcula are analyzed with static finite element simulation and mode of vibration. The parameters of the three claws structure are optimized to solve the problem of the structural mechanical strength and the excitation-resonance in the docking process.The kinetic model of three DOF motion simulator was established in the docking process. The friction torque of globe joint, contact torque of docking mechanism, and kinetic characteristic of active and passive platform were analyzed in the docking process. Based on analysis of docking pose error, the control strategy was studied to improve the precision of motion. The vertical docking test platform and composite docking test platform were designed for global configuration. The docking test platform is composed of four DOF motion simulator with lifting type and the movable sliding table with two DOF. The functions of yaw, roll, pitch,horizontal, and vertical movements were provided with six DOF simulation platform.Experimental simulation of spacecraft space docking was realized throughout the entire process. Based on the static and dynamic stability criterion of the test platform,the combined determination method was proposed by using the Sm stability margin and the Sne energy margin method. The steady state determination of the compound docking test platform was realized to meet stability requirements in two forms of static and dynamic.Based on theoretical research and optimization results, the physical prototype were developed respectively for docking mechanism of three claws model and vertical six DOF simulation test platform. The motion performance, functional parameter and mechanical property were measured in overall unit way to the characteristic test. The combined experiment between docking mechanism and simulation test platform was carried out. The results given by the experiments indicate that they are consistent with the theory analysis, verifying the design rationality of two physical prototypes.