本文提出了一种新的基于非线性状态观测器的鲁棒故障诊断策略 .该方法在传统故障检测滤波器 (FDF)的基础上 ,针对一类满足 L ipshitz条件的仿射非线性系统 ,构造了非线性故障检测滤波器 ,给出了故障检测增益阵的设计算法及其闭环观测误差系统稳定性的证明 ,解决了非线性系统的故障可检测性问题 .在残差决策阶段 ,采用模糊自适应门限的判决方法 ,提高了故障检测的鲁棒性 .最后 ,针对歼击机结构故障的仿真 ,验证了本文方法的有效性 In this paper, a new robust fault diagnosis method based on nonlinear state observer is proposed. On the basis of traditional fault detection filter (FDF), aiming at a class of affine nonlinear systems satisfying L ipshitz condition, The nonlinear fault detection filter is given, and the design algorithm of the fault detection gain matrix and the stability of the closed-loop observation error system are given, and the fault detectability problem of the nonlinear system is solved. In the residual decision-making phase, Adapt to the threshold decision method, improve the robustness of fault detection.Finally, the simulation of the fighter structural failure, verify the effectiveness of the proposed method