红外探测器保护结构设计与动力学分析

Design and Dynamic Analysis of a Protection Structure of the Infrared Sensor

卫星平台的振动,电磁干扰,温度变化对空间红外探测器的成像质量有很大的影响。为了减小外部干扰对像质的影响,为空间红外探测器设计了一套保护结构。首先应用新型材料—铝基复合材料制作了探测器的屏蔽罩,设计的屏蔽罩不仅质量轻,刚度大,而且电磁屏蔽效果显著。其次在探测器和外部支撑结构的连接中采用了柔性支撑橡胶环。应用变刚度变阻尼方法对柔性支撑结构的迟滞阻尼特性进行了建模和参数识别。应用参数识别的结果建立了整个系统的动力学方程,得到探测器质心位置的最大加速度为21.32m/s2(155Hz)。系统在325Hz后,加速度传递率小于0.5,可以有效的隔离外部振动的干扰。最后把仿真结果与振动试验计算结果进行对比,最大误差为5.25%,进一步证明了计算的正确性。说明了这种保护结构在航天遥感领域具有一定的应用价值。

The vibration, electromagnetic wave and temperature shift of the satellite platform have a great impact on the imaging quality of space infrared sensor. In order to avoid those interruptions from outside, a protection structure of sensor was designed. Firstly, a new type material （ Gr/Al composite） was applied to produce the shield cover of sensor, which not only had lighter weight, higher stiffness, but the function of electromagnetic shielding as well. Secondly, a rubber ring was employed to joint the sensor and its bracket forming a flexible suspension. Then, a novel method called variable coefficients of stiffness and damping was used for modelling the hysteretic damping of the flexible suspension and identifying its characteristic parameter. Establishing the mathematic equation of the system according to the result of parameter identification and acquiring the maximum acceleration of sensor centroid, which can reach 21.32 m/s2 at the frequency of 155Hz. After the frequency of 325Hz, the transmissibility ratio would be less than 0.5 and it was beneficial to isolate the vibration. Finally, compared the simulation result with vibration experiment and calculation, the maximum error was 5.25%. It further proved the validity of identification and simulation. This protection structure has an important application value in the field of remote sensing.