Fault Diagnosis Method Based On Test Set Combined With Structural Features

Fault diagnosis is a main research direction in the field of circuits.As the circuit scale becomes larger,the circuit structure becomes more complicated.When a circuit fails,the cost of diagnosis and repair becomes higher.In order to solve this problem,many scholars and research institutes started research on circuit fault diagnosis.Because of the type of circuit the different circuit fault diagnosis methods can be divided into:digital circuit fault diagnosis,analog circuit fault diagnosis and hybrid circuit fault diagnosis.For digital circuit fault diagnosis,it is an effective diagnosis method that solves candidate fault diagnosis based on test sets currently.In this paper,after studying fault output characteristics in circuits and the solution of ADD test candidate diagnosis,we propose a candidate diagnosis solution method based on test set under the guidance of fault response,ALFDD,namely,proposing the concept of candidate single fault set according to the principle that a single fault with the difference between actual output response and expected output response under current test excitations is more likely to be a fault diagnosis solution.Faced with issues that ADD method to obtain F_same by comparing all single fault of circuit,we give the method which only considers the faults of the candidate single fault set to obtain F_same.This method has three merits.Firstly,it does not need to compare all single faults and improves the efficiency of solving problems.Secondly,it eliminates the reluctant candidate solutions concluded in F_same effectively,so it improves the resolution of candidate diagnostic solutions.In addition,this method improves the accuracy of candidate diagnostic solutions,namely,increasing the number of real diagnostic solutions in the candidate fault sets.As the test result shows,compared with ADD,ALFDD increases resolution,accuracy and solution efficiency for selecting candidate diagnoses a lot.Then in this paper,based on the structural characteristics between the test excitation and the candidate fault diagnosis solution,and by analyzing the circuit fault output response,we proposed a candidate diagnosis solution method based on test set reordering,RTDD,namely,according to the different influence degrees of test on the generation of candidate fault diagnosis solution set,we put forward the concept of test score.By comparing the actual fault output response,non-fault output response and model fault output response of the circuit,we get the test score of the test.The test set is reordered according to the test score,and the reordered test is applied to the fault diagnosis.Compared with the GTreord method,the experiment shows that RTDD method can improve the efficiency of test set reordering,and the solution time is improved by 1-4 orders of magnitude.On the other hand,RTDD method effectively reduces the number of tests required under the same diagnostic accuracy.