Research On The Bottom Support Structure Of The Extra-wide Coverage Remote Senor

Space remote sensing multispectral imaging technology is one of the coretechnologies of space remote sensing satellite. Various countries have invested greatefforts in the researches because of the wide range of its application requirements.Multispectral imaging remote sensing technology in China has entered into thepractical stage. Space remote sensor is the major equipment for aerospace remotesensing satellite. Space remote sensor gets two development directions with theusers’ different requirements of optical remote sensor. One is the ground resolution;another is the coverage width earth imaging. The space remote sensor researched inthe thesis is developed in order to meet the requirement of the wide coverage ofimaging.The coverage width of the space multispectral ultra-wide remote sensors in thisthesis is more than1000km. An optimization design was carried out on the bottomsupport assembly of the remote sensor, in order to meet the requirements of thestructural stability and optical imaging quality, and enable them to meet the dynamicand static stiffness requirements.The characteristics of the extra-wide coverage remote sensor and difficulties inthe structural design have been analyzed. The structure form of the extra-widecoverage space remote sensor is large ratio of width to length, which is close to1.5:1 Therefore, it is difficult to meet the requirements of the optical imaging quality, if wetake the traditional structure and design means. Because of the stringent requirementof the whole weight, the design margin is extremely small. It requires the structuremore compact and higher accuracy in design, then the difficulty of the structuraldesign is increased.The purpose of this thesis is to design the bottom support structure of theremote sensor. It contains: analysis on kinematic bottom support program, influenceon the pointing accuracy of remote sensor by support structure, analysis on theimaging quality of remote sensor ensured by support structure, dynamiccharacteristics analysis on support structure, the statics and dynamics test forextra-wide field space remote sensor.Firstly, the bottom support structure has been designed. The advantages,disadvantages and applications of rigid support, flexible support and kinematicsupport commonly used in space remote sensors at present are compared, and withthe structure characteristics of the extra-wide space remote sensor, the kinematicsupport has been chosen. Different kinematic support schemes are analyzed in detail.Ultimately, the bottom support is determined to choose the2-RRR+2-RRRR parallelmechanism.Secondly, the installation positions of the bottom support structure have beendetermined, and the influence on the remote sensor’s optical pointing accuracy hasbeen analyzed by means of equivalent mechanism, error analysis of the parallelmechanism and so on. The pointing accuracy has been calculated. The max anglesaround the X,Y,Z are2.6s、2.1s and2.3s, which meets the pointing accuracyrequirements.Thirdly, the contact theory is introduced. Platform adaptability of the bottomsupport structure consists of rotational and motion pairs has been analyzed bynonlinear finite element. And the flatness requirements of satellite platform are putforward. At the same time, the thermal adaptation has been analyzed, and the resultsindicate that the bottom support structure has a good thermal adaptation. So that the remote sensor can keep a good optical imaging quality at the20℃difference intemperature between the remote sensor and environment.After that, dynamic characteristics of the bottom support structure have beenanalyzed, by calculating the model of the kinematic support with gaps. The rotatingpair gaps can be neglected in modal analysis because they have little effect on themodal of the structure. Analysis and calculation of the dynamic characteristics of thebottom support structure have been carried on by means of MPC. The results areconsistent with the component-level mechanical test, and the design requirementshave been met.Finally, the statics and dynamics test for extra-wide field space remote sensorhave been carried out. The statics test includes platform flatness adaptability test,temperature bias test. A good optical imaging quality of the remote sensorthroughout the statics and dynamics test illustrates a point that the design of bottomsupport structure is very successful.