基于LSTAR的机载燃油泵多阶段退化建模

机载燃油泵的性能退化呈现出平稳—加速—平稳的非线性、多阶段模式,针对现有退化模型难以准确描述其全寿命周期性能退化的问题,以逻辑平滑转换自回归(LSTAR)模型为工具,对机载燃油泵出口压力传感器信号进行建模。首先,对转换后的压力传感器信号建立自回归(AR)模型,通过非线性检验说明建立LSTAR模型的必要性;然后,应用非线性最小二乘法完成参数估计;最后,在AIC准则最小及拟合优度最大的原则下,选择转换变量,通过残差进行模型的适应性检验与正态性检验。结果表明:基于LSTAR模型的拟合精度明显优于线性自回归模型。本文提出的方法成功解决了机载燃油泵性能退化的多阶段准确建模问题,为机载燃油泵的预测与健康管理(PHM)奠定了坚实的基础。

Multi-stage degradation modeling for airborne fuel pump based on LSTAR

The performance degradation of airborne fuel pump is nonlinear and multi-stage with stationary-accelerated-stationary degradation pattern.The existing degradation models are unsuitable for the modeling of this degradation problem in life cycle,so the signal output from the pressure sensor attached to the fuel pump is modeled based on the logistic smooth transition auto-regression (LSTAR) model.First,auto-regressive (AR) model was established for the converted pressure signal,the necessity of the LSTAR model was examined by nonlinear test,and parameters of the model was estimated by nonlinear least square method.The transfer variable was chosen by minimizing the AIC value and maximizing the goodness of fit.Adaptive test and normality test of the model have been done based on residual analysis.The results show that the LSTAR based method is superior to the AR model.The dividing of the degradation stage and the modeling problem are solved by the presented method,which lays better foundation for the prognostics and health management (PHM) of airborne fuel pump.