高精度惯性测量系统热应力分析与优化设计

Thermal stress analysis and optimum design of inertial measurement system

针对高精度惯性测量系统内仪表结构正交性误差在使用过程中的不稳定性问题,重点开展了结构热应力分析与优化设计。通过构建系统结构热应力模型,并对关键性参数进行系统实测,得到更为精确的优化模型。用有限元分析软件ANSYS对其进行的仿真表明,计算出的结构变化特性与实测正交性误差变化量一致。对仿真结果的进一步分析表明,结构部件的材料线膨胀系数的差异导致仪表安装基面的热应力变形是影响惯性仪表正交性误差稳定性的主要原因。采用上述方法对某高精度惯性测量系统开展热应力分析与优化设计后,同等环境条件变化情况下,惯性仪表正交性误差变化量减少了一半(由10″减少至4.1″),有效减小了惯性仪表正交性误差受长期使用及环境变化的影响,提高了高精度惯性测量系统的综合性能。

Aiming at the orthogonality error instability of the instrument structure in high precision inertial measurement system,the structural thermal stress analysis and optimization are mainly carried out.By constructing the thermal stress model of the system structure and measuring the key parameters systematically,a more accurate optimization model is obtained.Simulations are made by using the finite element analysis software ANSYS,which shows that the calculated structural variation characteristics are consistent with the measured orthogonality error.Further analysis of the simulation results shows that the thermal stress and deformation of the instrument installation base caused by the material linear expansion coefficient difference of the structural components are the main factor affecting the stability of the orthogonality error of the inertial instrument.After carrying out the thermal stress analysis and optimization design on a high-precision inertial measurement system by the proposed method,the variation of orthogonal error of inertial instruments is reduced by half(reduced from 10″to 4.1″)under the same environmental conditions,which shows that the influences of long-term use and environmental changes on the orthogonal errors of inertial instruments are reduced effectively,and the comprehensive performance of high-precision inertial measurement system is improved.