容差条件下的模拟电路多故障诊断

针对容差模拟电路多故障诊断问题,提出了包括故障状态检测、故障粗糙集生成和故障元件定位的分步诊断方法。将有限测点的故障状态检测转化为容差约束下的线性规划问题;推导得到故障特征等式并生成故障粗糙集,证明了在容差条件下的故障特征等式中可选用标称参数电路的节点电压;对故障粗糙集中元件参数的偏差限值进行修正,对修正后的电路进行状态检测,实现故障元件定位,并估算故障参数偏差。仿真实例表明,该方法具有较高的诊断准确度和参数辨识精度。

Multiple fault diagnosis of analog circuit under tolerance

A novel method consisting of fault detection,rough set generation,element isolation and parameter estimation is presented for multiple-fault diagnosis on analog circuit under tolerance.Firstly,a linear-programming concept is developed to transform the fault detection of circuit with limited accessible terminals for measurement to check existence of a feasible solution under tolerance constraints.Secondly,the fault characteristic equation is deduced to generate a fault rough set.It is proved that the node voltage of nominal circuit can be used in fault characteristic equation under tolerance.Finally,fault detection of circuit with revised deviation restriction for suspected fault components is proceeded to locate faulty elements and estimate their parameters.The diagnosis accuracy and parameter identification precision of the method are verified by simulation results.