Research On Mechanical Characteristics And Control Of Docking Mechanism Based On High Temperature Superconducting Flux Pinned Effect

The docking mechanism is one of the important ways to set up a space station,which can supply the strong foundation to set up Chinese space station.The traditional docking mechanism has obtained a series of docking mission,but it has the problems of large impact and plume pollution,which has the risk to affect the normal work of spacecraft precision instruments and equipment.In order to assist the drawback of the traditional docking mechanism,the high temperature superconducting magnetic docking mechanism consisting of a high temperature superconductor and an electromagnet is designed based on the flux pinning effect of the high temperature superconductor.Due to the non-contact passive stability of the flux pinning effect,the novel docking mechanism can realize the docking process of two modules of the mechanism with low impact and no plumes.This manuscript considers the diamagnetic properties and trapped magnetic field characteristics of high temperature superconductors,and proposes an equivalent method of processing high temperature superconductors(equivalent processing method).Based on this method,the force between the high temperature superconductor and the permanent magnet is calculated.Moreover,the correctness of the equivalent processing method is verified by the experimental data.Considering the similarity of the magnetic field between an electromagnet and a permanent magnet,the equivalent treatment method is used to calculate the quantitative relationship between the force of the high temperature superconducting magnetic docking mechanism and the current density and gap based on the finite element method.In order to facilitate the dynamic modeling the functional relationship of the force is fitted to be obtained.based on the obtained force relationship and C-W equation,the dynamic equation of the relative motion of the two modules of the high temperature superconducting magnetic docking mechanism in the target spacecraft orbital coordinate system can be obtained.Through the dynamic equation,the dynamic response of the high temperature superconducting magnetic docking mechanism in case of different parameters are studied.Based on the mechanical characteristics of the high temperature superconducting magnetic docking mechanism,the dynamic model of the docking mechanism is established,and the docking simulation analysis platform for the novel docking mechanism is set up.Based on the simulation analysis platform,it can be known that the high temperature superconducting magnetic docking mechanism can also complete the docking without control.In order to improve the docking performance of the mechanism,the influence on the dynamic response of the mechanism with PID control,RBF neural network PID control and BP neural network PID control and PD control based on mathematical model is analyzed.The docking performance of the high temperature superconducting magnetic docking mechanism is evaluated based on the three indicators of maximum overshoot,peak time and adjustment time.The simulation results show that the docking performance of the high temperature superconducting magnetic docking mechanism has been improved to varying degrees of four different control strategies.In particular,the control effect of the PD controller based on the mathematical model is better than other control strategies,which is the active spacecraft docking control provides new ideas.