Research On The Design And Test Of HIL Simulation System For On-Orbit Docking Dynamics

It is of great significant to launch the research on HIL (Hardware-In-the-Loop) simulation technique for on-orbit docking, because that spacecraft docking technique play very important role in human space program. In the past and present, the spacecraft rendezvous and docking technique played important role in human space program, and it will undertake even more important jobs in future. Nevertheless, on-orbit docking process is a complex dynamics process; the docking mechanism is complex automatic assembly. So the developing process of a docking mechanism and the research on spacecraft on-orbit docking process dependent on HIL simulation system to test or simulate docking process. The validation or accreditation of the spacecraft docking system or its subsystem is also relay on HIL simulation. The on-orbit docking technique can be transformed into a skilled technique through the HIL simulation.The HIL simulation system for on-orbit docking is not only a complex Multiple Input and Multiple Output (MIMO) system, but also a hybrid system. The strong coupling and strong non-linearity make the system analysis or synthesis difficult. Based on the reachable literature, the fundamental system design procedure of the HIL simulation for on-orbit docking has not been fully established. So it is with great value in theory or engineering to do research work on itAfter synthesizing numerous related literatures at home and abroad, the outline of the HIL simulation for on-orbit docking was summarized and the design problems it facing were point out. The current trends of the HIL simulation system for on-orbit docking were summarized in this dissertation. The summarization of its supporting technique laid a foundation for breakthrough.This thesis discussed the overall design ideas of the HIL simulation system design. The necessity of HIL simulation was point out basing on analysis of the research task of the HIL simulation for on-orbit docking. After analyzing the simulated object system, the complexity, which bring about difficult to design HIL simulation system, was point out and the frequency limitation of its dynamic process is also point out, which is the key condition for the establishing of HIL simulation system. Mathematical model of the docking dynamics of spacecraft bodies was derived, which would be used in HIL simulation system. System design problems were presented by comparing the simulated object system and the HIL simulation system. Its essence is to artificially build a dynamic system and made its dynamic characteristics similar with the characteristics of the simulated object.The ideas of building HIL simulation system for on-orbit docking were presented; the settling methods were discussed. The HIL simulation design problems were transformed into the design problems of a simulation/hardware interface. The HIL simulation problems should be settled by the system design process were generalized into three fundamental problems.A single-DOF (Degree-Of-Freedom) HIL simulation system for on-orbit docking was presented and its simulation/hardware interface was analyzed. Three system design methods were presented on single-DOF situation. The verification to the system design idea and method was made with simulation. The settling situation of the fundamental problems of HIL system design was summarized.The simulation/hardware interface of the practical HIL simulation for on-orbit docking which is a MIMO system was established. The design problems and design method were discussed. Based on natural frequency analysis of parallel robot, the dynamic characteristics don't change greatly while the parallel robot moving in docking working space, which is the condition to use the system design method of the single-DOF situation in the multiple-DOF situation. The verification problems of the dynamic characteristics of the loop of the HIL simulation system were discussed. The settling situation of the fundamental problems of HIL system design was summarized on practical HIL simulation condition.The modeling process of the virtual prototype of the HIL simulation system for on-orbit docking dynamics was presented. The primary verifications on the system design ideas and realization methods were made on the virtual prototype. Simulation process and its results demonstrated that the system design methods are practical and can be easy to use. The research work on the prototype can increase system-tuning experience for the experimental research.The experimental research system of the HIL simulation system for on-orbit docking dynamics was introduced. It is the important part of the verification work of the HIL simulation for on-orbit docking in this thesis. Sine signal tracing test was done on the parallel robot of the HIL simulation system. And Bode plots of the two degrees of the freedom of the parallel robot were presented based on the sine signal tracing test result. The motion-coupling situation between degrees of freedom of the parallel robot was examined. The phase delay from the parallel robot to the force signal channel was tested. All above testing results provided fundamental support to the experimental research work on the building theory of the HIL simulation system. A serial of experimental research work, which would demonstrate the feasibility and validity of the system building ideas and its realizing methods of the HIL simulation system for on-orbit docking dynamics, was done on the experimental system of the HIL simulation.