Research On Fault Monitoring Technology For Photoelectric Precision Target Of Linear Array Camera

Aiming at the problems of time-consuming,labor-intensive,low work efficiency,false test and missed detection in the series of faults that occurred in the actual engineering of the photoelectric precision target of the line array camera by manual investigation,this thesis deeply analyzes the working principle of the precision target,combined with the fault diagnosis technology,and establishes the precision target.Fault tree,qualitatively and quantitatively analyzed the background light source and the fault tree of the trigger light curtain target,established the fault diagnosis process of the line array camera,and designed the fault monitoring circuit of the related fault monitoring objects.The main work and innovations of the thesis are as follows:1)Combining the theory of the fault tree analysis method,according to the structure composition and working principle of the precision target,the total fault tree of the precision target and the fault tree of the three key components of the background light source,the trigger light curtain target and the line array camera are established.Analyze the fault tree from two perspectives quantitatively,and find the minimum cut set of the fault tree of the background light source and the triggering light curtain target;According to the product failure rate calculation model,combined with the actual application of the product,the probability of the occurrence of each bottom event of the fault and the importance of the bottom event are solved.The most important bottom event in the fault tree of the background light source and the trigger light curtain target is found,and the fault monitoring object is determined;2)Designed a precision target background light source current parameter fault monitoring circuit,real-time monitoring of the background light source operating current,data transmission by CAN bus,mainly including test node circuits(Signal Acquisition Circuit,Signal Processing Circuit,CAN Transceiver Circuit)and main Control circuit(Optocoupler Isolation Circuit,Signal Processing Circuit,CAN Transceiver Circuit,Power Supply Isolation Circuit,Fault Prompt Circuit);3)The delay monitoring circuit of the trigger light curtain target is designed to monitor the delay function of the original control circuit of the trigger light curtain target.The signal generating circuit outputs an analog pulse signal as the input signal,and the original control circuit is triggered to output the camera trigger signal.The time interval of the channel signal to obtain the delay time;4)Analyze the failure mode of the line scan camera,establish the camera status query table according to the camera register;establish the camera failure diagnosis process for the camera LED lamp failure,image failure(No Image,Poor Image Quality),interface failure,serial port failure,etc.;5)The function of the designed fault monitoring circuit is verified.The results show that the background light source node current monitoring circuit can obtain the working current of the lamp group in real time,reflect the actual working status of the circuit,and can effectively determine the cause and location of the fault after a fault occurs;Trigger the light curtain The target delay monitoring circuit can effectively judge the accuracy of the delay function of the original control circuit,which provides a guarantee for obtaining the camera trigger signal.