Research On The Mechanical System And Key Technologys Of A Space Infrared Sensor

Space infrared sensor is a kind of precise optical instrument, which is applied in thespace environment, and its main function is to obtain the images of movement objects onthe ground or in the space. Space infrared sensor can acquire large-scale image informa-tion in a short time, which is better than CCD camera, especially reconnaissance in thenight and discerning move objects sending heat. Meanwhile, space infrared sensor alsohas extensive application prospects, for example, in the field of infrared remote sensing,geology investigation, fire early warning and weather forecast and so on. So this researchwill be significant to strengthen capability of infrared remote sensing.Firstly, space infrared sensor must be assembled on a small satellite platform("Experiment III Satellite"), so its whole mass and structure dimensions are strictlyrestricted by the satellite platform. The mechanical structure must be compacted, light,handy and reliable. Task of space infrared sensor structure system is to integrate each partsof system and provide a stable and reliable work platform for the whole body. Concerningthat launch and on-orbit processes, space infrared sensor must experience the harsh me-chanics environment and the part of mechanical structure should attain the high stiffness,high strength and low mass. According to the technique targets of optical system andenvironmental requirements, a set of overall planning of structural system is designed.All detailed design thoughts and implementation kernel about the key divisions are clar-ified. Application of graphite fiber reinforced aluminium matrix composite on bodytubeof space infrared and the technology of magnet locking-electromagnet equipment drivingare highlighted investigated.Secondly, a suit of calibration mechanism with locking system to drive the standardblack body is designed, in order to realize the calibrating function of infrared sensor inspace camera. According to the special mechanics environment in satellite during theprocess of launch and on-orbit, a technology of magnet locking-electromagnet equipmentdriving is proposed and applied into the design of the calibration mechanism in the spaceinfrared camera. During the process of launch, the motion component of the calibra-tion mechanism is attracted by the magnet so as to suppress the rotation degree of free-dom. During the process of calibration, the motion component is droved by electromagnet equipment to lock up and fulfill calibrating function. The magnetic field distribution andmagnetic force of calibration mechanism and performance characteristic of electromag-net equipment are analyzed. The dynamic analysis is conducted, which can verify thevalidity of design and analysis of this mechanism under difference disturbance torques.Finite element modal analysis and reliability analysis at two year end are also proceededto test this design.Thirdly, optimization design of the bodytube isolation system is conducted usingNSGA-â…¡multi-object optimization algorithm and complex stiffness model. This methodcan provide a group of optimal solutions for designer to filter according to reality situa-tion. According to requirements of isolator modeling and dynamics analysis, an approachcalled variable-rate stiffness and damping to describe hysteresis damping characteristicis presented, which consists of a parallel spring and damper. The mathematical mod-els of elasticity coefficient and damping coefficient with variation of vibration amplitudeand frequency would be obtained. Application of this method will make the process ofmodeling and analysis of rubber isolator unification and standardization.Then, the transfer functions of ?exible object and base are analyzed by using me-chanical impedance method and compared with stiffness models. It indicates that spaceinfrared sensor must be considered the ?exible body in?uence for transfer function onsome certain conditions. Using second order Krylov method expresses multi-DOF ?exi-ble substructure, which combines with modal synthesis method to model and analyze twosubstructures connecting with springs and dampers. Compared with traditional modalsynthesis arithmetic is to verify the effectiveness of second order Krylov method.Finally, according to requirements of vibration experiments from satellite, sine, ran-dom and impact vibration experiments are conducted. Acceleration response of crucialpoint is acquired. After vibration experiment checking every parts of space infrared de-tector, there are no bolts loose and parts damage situations. Then imaging experiment ofinfrared detector is carried out and the image is clear and intact.