SINS减振系统参数与耦合角运动的关系

Relationship between parameters of vibration damping system and coupling angular motion of SINS

剧烈的随机振动是捷联惯导系统在飞行器上面临的主要力学环境。如何减小振动耦合给系统引入的伪角运动信号,历来是捷联惯导系统减振设计的重点和难点。为了在减振系统设计参数与耦合角运动之间建立起定量联系,以满足产品精确设计、一次成功的需要,建立了捷联惯导整体减振系统耦合角运动数学计算模型,推导出了耦合角速度与减振系统的偏心距、减振器的跨距、减振系统的谐振频率(与减振器的刚度相关)、减振系统的振动模态阻尼(与减振器的阻尼相关)之间的解析关系,给出了随机振动条件下耦合角速度的理论计算公式,阐释了捷联惯导系统减振器布置及力学参数对耦合角运动的影响规律;在此基础上,以通常采用的平面四点隔振模式和空间八点隔振模式为例,分析比较了减振器布置形式对耦合角运动的影响。经仿真验证,所提出的耦合角速度解析计算公式与有限元模型计算结果相差在5%左右。所提出的数学计算模型和计算公式填补了捷联惯导减振系统耦合角运动理论计算方面的不足,可为捷联惯导减振系统的设计、分析与评估提供直接的理论支撑和具体计算方法。

The violent random vibration is the main mechanical environment that strapdown inertial navigation system(SINS)faces on the rocket.How to reduce the pseudo-angular motion signal induced by vibration coupling has always been the key and difficult point in the vibration reduction design of SINS.In order to establish a quantitative connection between the design parameters of the vibration damping system and the coupling angular motion,so as to meet the needs of accurate product design and one-time success,the mathematical model of coupled angular motion of the integral vibration reduction system of SINS is established,the analytical relationship between coupling angular velocity and eccentricity,and resonance frequency,and modal damping of vibration damping system is derived,the theoretical calculation formula of coupling angular velocity under random vibration is given,the effect laws of vibration absorber arrangement and mechanical parameters on coupling angular motion of SINS are explained.On this basis,taking the commonly used plane four-point vibration isolation mode and space eight-point vibration isolation mode as examples,the effect of vibration absorber arrangement form on coupling angular motion is analyzed and compared.The simulation results show that the difference between the proposed analytical formula and the finite element model is about 5%.The proposed mathematical model and formula fill the gap in the theoretical calculation of coupling angular motion of strapdown inertial navigation damping system,and can provide direct theoretical support and concrete calculation methods for the design,analysis and evaluation of strapdown inertial navigation damping system.