Optimization Design Of Space Multi-dimensional Micro-vibration Simulator Based On Six Dimensional Parallel Mechanism

The variety of devices which are equipped on spacecraft, such as solar refrigeration compressor, rotating mechanism, adjusting gyroscope etc., will produce micro vibrations. The micro vibration has the characteristics of wide bandwidth,small amplitude and complex form, which seriously affect the image quality of optical remote sensor in space vehicle. The common solution is to install the vibration isolation device for optical remote sensor. In order to evaluate the effectiveness of the vibration isolation device, a large number of ground tests are needed. The premise of the work is to reproduce the micro vibration spectrum characteristics. Therefore, it is a subject with great significance to design a micro vibration simulator which can reproduce with different spectrum characteristics of micro vibration.Firstly, the dynamic characteristics of the space micro vibration simulator based on Gough-Stewart platform are studied. The dynamic model of the micro-vibration simulator is derived by Newton-Euler’s method, in which the quality of the legs and the hinge and the eccentricity of the load center are included.The mathematical analytic formula which can calculate the natural frequency and the main vibration mode of the micro vibration simulator is derived. Through the finite element simulation and the experimental test, the axial rigidity of a single driving leg is studied. At the same time, the dynamic characteristics of the first generation prototype are analyzed with theoretical method and finite element method. The natural frequency of the micro vibration simulator is tested. The simulation and test results show that the three methods are consistent with the natural frequency and the main vibration mode, and the error value of the natural frequency is not more than 5%. The accuracy of the theoretical model is verified.Combined with the performance index and the research results of the natural frequency of the first generation micro vibration simulator, the optimization method of the system structure is obtained. The driving leg is optimized, and the radial anti overturning ability of the spring in the driving leg is improved. The structural rigidity of the hinge is improved, and eliminate the nonlinear problem caused by the upper and lower hinge in the platform control. The problem that mutual conduction between the drive legs of the first generation prototype is solved. The finite element modeling and simulation analysis are carried out for the second generation model,and the experimental test of the prototype is carried out. It is shown that the structure design of the second generation prototype achieves the expected goal.