| Pico-satellite is a new concept of micro-satellite based on MEMS technology. Compared with conventional satellite, it owns the advantages of shorter development cycle, lower manufacturing and launching cost, stronger functional targeted and load interface flexibility. As an important part of the Pico-satellite project, the separation mechanism directly determines the success or failure of the pico-satellite mission. Supported by the’Eleventh Five-Year’pre-research project ’pico-satellite technology*****’, a pico-satellite separation mechanism is developed. The research work of this dissertation is carried out through the methods of theoretical analysis, computer simulation and experimental verification. On September22,2010,’ZDPS-1A’ satellite was successfully launched, and download pictures of the earth taken by built-in camera. Downlink data show that the pico-satellite work properly.Paper first discusses the background and significance of the research. The current research situations of the pico-satellite separation mechanism, key technologies of design and analysis theory are expatiated. And then, the research contents of this paper are proposed.According to the technical requirements and functional needs, the proposed separation mechanism is designed and developed. In order to fulfill the task of no-interference separation, key components such as guidance system, power system, and anti-interference system are theoretically calculated and analyzed with simulation softwares.The pico-satellite separation mechanism is mainly composed of thin-walled parts, which are subject to rigid-flexible coupling vibration. Such vibration can cause damages to weak parts. In order to ensure the reliability of the connection between the satellite and the rocket, it is necessary to analyze the vibration characteristics. As the model is too complex to solve as a whole, it is decomposed into four sub-system, namely the pico-satellite, the hatch door, the frame, and the back plate. Each sub-system is theoretically modeled and analyzed respectively. Then coordinates transformation and equations are employed to realize an integrated solution.In addition to complex mechanical environment, thermal vacuum environment is also needed to pay attention to in the process of launch. Temperature difference between sunshine side and shady side will cause thermal deformation, which will affect normal separation of the pico-satellite. Based on the consideration of geometry relations of the satellite, the earth, and the sun in the process of launch, the internal and external heat flow absorbed by the ’ZDPS-1A’ satellite and its separation mechanism is analyzed. Temperature field and thermal deformation are got by finite element analysis. The clearance fit value between the satellite and guide rail is rationally designed based on above analyses.Pico-satellite energy is limited, and pico-satellite attitude control ability is poor, so pico-satellite attitude control system make high claims on orbit injection initial attitude. In order to design the separation mechanism rationally, ensure successful separation between the satellite and the rocket, the pico-satellite separation dynamic model is established based on the analysis of external forces and external moments acting on the pico-satellite. The virtual prototyping model is modified by comparing the results of ground tests and simulation results. After that, the initial attitude was predicted.Finally, experiments are used to verify the correctness of the theoretical analysis and feasibility. The pico-satellite and its separation mechanism is used to carry out mechanical environment tests and separation tests. The dynamic design model of the separation mechanism is verified through comparisons between test results and results of theoretical analysis as well as numerical simulation. |
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