A Study On Connectivity Fault Localization Method With The Aircraft Cable Auto-test System

Aircraft cable auto-test technology is one of the key technologies for aircraft ground test.The quick fault localization has great impact on efficiency of the test.In this dissertation,an aircraft cable auto-test system with distributed structure is built for the mission of cable testing on large aircraft.To solve the connectivity fault localization problem upon the intricate cable net on airplane,the dissertation build up a model of cable connection and fault with the state matrix and Boolean algebra,and propose a solution for inter-plug misconnection faults based on states exchanging method,and another solution for outer-plug misconnection faults based on Huffman tree searching.The dissertation consists of the following six chapters:Chapter 1 details the research background of the dissertation.The researches and applications status of aircraft cable auto-test technology are reviewed.The last part of this chapter raises a brief summary of the main contents of the dissertation.Chapter 2 introduces the principles and the methods of cable testing.And to meet the demands of aircraft cable auto-test,an aircraft cable auto-test system is designed,which is consisted of control bays,distributed test cabinets,active LRUs(Line Replace Unit),loopbacks,adapter cables,control bus.Chapter 3 divides the connectivity fault localization problem into two parts,one for inter-plug misconnection fault localization,and the other for outer-plug misconnection fault.Based on the connectivity table of cables and the connectivity testing results,the model of cable connectivity is built,and the solution of inter-plug misconnection fault localization is provided based on states exchanging method.The last part of this chapter lists the advantages of the states exchanging method.Chapter 4 provides the solution of outer-plug misconnection fault localization problem.By building up the suspicion distribution model of cables,Huffman tree searching method(HTS)is used to achieve efficient searching.Considering that the model might not fit the fact,the solution with dynamic suspicion distribution model of cables(DSHTS)is provided.Chapter 5 gives the simulations and experiments of the solutions of inter-plug misconnection fault localization and outer-plug misconnection fault.Simulations on two cases prove the effectiveness of states exchanging method.Experiments on HTS method and DSHTS method prove that the two methods,comparing to binary search,can reduce the average searching length by 28%to 68%with different conditions.Chapter 6 summarizes the dissertation and draws conclusions.And some of the possible further research directions are listed.