磁悬浮控制力矩陀螺锁紧机构可靠性设计及优化

鉴于传统确定性优化方法没有考虑结构参数的随机性对结构性能的影响,本文提出了一种基于可靠性灵敏度的锁紧弹片结构优化方法。首先,以某磁悬浮控制力矩陀螺锁紧弹片为研究对象,研究了有限元建模和失效模式;然后,考虑弹片结构尺寸和材料参数的随机性,结合响应面法与一次二阶矩法,研究了串联失效模式下弹片的可靠度计算方法,进而推导了可靠性关于设计变量均值和方差的灵敏度计算公式;最后,根据灵敏度分析结果,研究确定了弹片结构优化策略,构建了弹片可靠性优化模型。分析了安全系数法和可靠性法优化结果的差异,结果表明:与安全系数法相比,可靠性法的优化结果更好;在保证弹片可靠度的前提下,采用可靠性优化方法不仅使弹片质量下降了23.71%,使锁紧机构更加优化,而且使陀螺房质量也下降了0.98kg,有利于磁悬浮控制力矩陀螺整机结构的轻量化。

Reliability design and structural optimization of locking device for magnetic suspension control moment gyro

To avoid the negative effects of structural parameters' randomness on its properties, an optimization method of locking elastic sheet based on reliability sensitivity was proposed. Firstly, the finite element model and failure modes of the locking elastic sheet for a magnetic suspension control moment gyro were analyzed. Afterwards, considering the randomness of the structural sizes and material parameters of the elastic sheet, the reliability of the elastic sheet in the series failure mode were studied by using the response surface method and the first order second moment method. Furthermore, the calculating formulas of reliability sensitivity with respect to the mean and variance of random variables were derived. Eventually, the model of elastic sheet reliability optimization was built with the optimization strategy determined by the result of reliability sensitivity analysis. The difference influence of safety factor optimization and reliability optimization was analyzed. Experimental results indicate that the reliability optimization could get better optimization results compared with the safety factor optimization. The reliability sensitivity optimization method not only reduces the weight of the elastic sheet by 23.71% under the premise of ensuring the high reliability of the elastic sheet, but also reduces the weight of gyro room by 0.98 kg, which is beneficial to weight reduction of the magnetic suspension control moment gyro.