Research Of Optimization Design For The Space Vibration Simulator

Motion facilities on space spacecraft will pass vibration to optical remotesensor, which will influence the accuracy greatly. Studying the influence of thevibration isolation is of great significance. To get more effective space microvibration isolation technology, we need to take full test of the space vibration onground, which demands a structure of high reliability and accuracy to simulatespace micro vibration simulation.The space micro vibration simulator is based on parallel Stewart platform.Firstly the basic theory of Stewart platform is introduced and math modeling is done,and then the solution method and the calculation process of the inverse kinematic isshown. Using the related formula on mechanics and multi-body dynamics, detaileddeduction of adjustable speed relations solving process is made for the platform leg,raising the concept of Jacobi matrix. The relationship between exciting force and thegeneralized force is obtained according to the principle of virtual work, as well as thegeneralized stiffness and damping matrix of the system. Then we deduce thecomplete system dynamic formula of the mechanism without considering gravityaccording to the Newton-Euler equation. As for the natural frequency of themechanism, ignoring the coriolis force and centrifugal force and damping, thecomplete system dynamic formula is simplified as the differential equations for theundamped vibration model, which equals the calculation expression of the naturalfrequency.Considering the micro vibration space simulator performance indicators, which mainly means the envelope size and vibration frequency range, the optimizationmethod of the system configuration is obtained. The optimal configuration of thesystem parameters is got based on inherent frequency calculation formula, and wecompare the analyzing result of the natural frequency value of the configuration inoptimal configuration with the simulation result, which is relied on a finite elementmodel through Patran/Nastran. Then the performance requirements of the leg areobtained and so is the design indicator. We selected the universal flexible hinge asthe joints of the mechanism. The stiffness characteristics on structure parameters isstudied for the universal flexure hinge, and taking the mechanism performance andstrength demand into account, the optimal parameter is finally gained.Configuration optimization and optimization design processes of the flexiblehinge are given clearly, and the optimization result shows the natural frequency,stiffness characteristics and strength characteristics are in best situation. We makedetail description of structure design for the leg and take some test to study theperformance of one leg, whose results is of positiveness.