Rendezvous And Docking Simulation System

Rendezvous and docking technology is essential in space-assembly, space-succor, outer space-exploration and so on, and is also a key technology of the second step of Chinese manned spaceflight. Building rendezvous and docking simulation system is the important way for studying rendezvous and docking technology. Rendezvous means that two or more spacecrafts meet in space on preconcerted site and time. Docking indicates that two spacecrafts are connected each other in the mechanical structure after meeting in the space orbit.The dynamics model of rendezvous and docking, optimal rendezvous problem and the framework of the rendezvous and docking simulation system are studied in this thesis. The main achievements are summarized as following:1. The dynamics model of rendezvous and docking is generalized. According to the process of and characteristic of rendezvous and docking, the dynamics model comprises the three following parts: two-body dynamics model, relative dynamics model and docking dynamics model. The Hill equation of relative dynamics model is simulation, and some conclusions are derived. The influence of ellipticity on relative dynamics characteristic is analyzed.2. The two impulses optimal rendezvous between coplanar neighboring circular orbits is studied using genetic algorithms. For considering the influence of the first impulse's position and not doing, optimal rendezvous index considering of fuel and time is respectively constructed, and genetic algorithms is respectively designed. Simulation results show that the value of performance index, considering the influence of the first impulse's position, is better than that if not considering, and prove that the design of GA is successful.3. Spacecraft optimal finite-thrust rendezvous is studied using nonlinear programming method. The method employs a recently developed direct optimization technique that uses a piecewise polynomial representation for the state and controls, thus converting the optimal control problem into a nonlinear programming problem. The method is remarkably robust to initial guesses, which is better than traditional method. When using the method, state transfer matrix is applied to produce the constraints, which can reduce the error from numerical method. At last, the simulation of two dimension rendezvous verified the effectiveness of the method.4. Guided by object-oriented methodology, the framework of rendezvous and dockingsimulation system is analyzed and designed by use of Unified Modeling Language (UML).UML is a standard approach to object-oriented modeling, and building the framework by it can improve the flexibleness of system. The framework can guarantee stability, reusability and better maintainability, and is a well choice of Chinese rendezvous and docking simulation system.5. The prototype of rendezvous and docking simulation system, implementing the technology of object-oriented simulation and the concept of prototype, is built up. The prototype system is mainly used to study the key technology of dynamics and control. The development of the prototype makes the requirement of simulation system definite, and leads to the accumulation of experience. The prototype system is expansible, and can be upgraded conveniently. The simulation results verify the effectiveness and tightness of the prototype.The conclusions of this thesis are a well reference of Chinese manned spaceflight, and will be beneficial for flight to moon, the outer space-exploration, space warfare, and so on.