Research On The Optimal Selection And Correction Algorithms Of Displacement Measuring System In Caliper Detector

With the increasing of service time,the aging of oil-gas pipeline may results in the corrosion,deformation and leakage,which may cause the increasing of accidents,huge loss of economy and leads to the environment pollution.Thus,it makes sense to detect the faults in long-distance pipelines.How to detect the pipeline deformation and defects timely is an important task of caliper detector.Meanwhile,the precise location is an important guarantee for the timely repair of pipeline defects.By now,the existence displacement record wheel positioning technology still lacks the efficient optimization methods.Thus,develop a high precision optimization and correction algorithm makes a lot of senses to the location of pipeline.In this thesis,it proposed a new method to achieve the algorithm in optimal choose and correction of the displacement measuring system.This thesis mainly reflects the following aspects:(1)For the low accuracy and completeness in the old system,the thesis presented a complete hardware design of the displacement measuring device.The design includes the design of hardware structure,the selection of pulse generator,the design of displacement pulse acquisition circuit.A new type of rotary encoder as pulse generator and a high efficiency FPGA are used as the central processing unit to collect the pulse signal from displacement record wheels.(2)For the original systems's simplicity,the thesis proposed a new optimal selection algorithm of the displacement pulse signals,designed the optimal algorithm includes abnormality determination algorithm,the curve judgment algorithm based on the cross-validation of Lasso-Ridge linear regression method,multiple straight line optimization algorithm and multiple curve optimization algorithm.These algorithm aim to get the pulse optimal selection and improve the accuracy of displacement measurements.(3)Considering the offline displacement data correction method in the displacement measurement technology is incomplete,this paper proposed a new kind of displacement correction algorithm.By studying the influence of pipeline internal defects of displacement measurement data and the acceleration or deceleration in the caliper detector,the thesis studied and designed different correction algorithm to correct the displacement data.Based on the theoretical research and simulation of the displacement signal optimization and correction algorithm,it has been proved that multichannel displacement signal pulse optimization algorithm can measure the displacement efficiently and accurately,which guarantees the reasonability of the measurement.Meanwhile,the displacement signal correction algorithm can correct the data properly,which ensures the usefulness of the data.With the development of theoretical research and operational capacity,the proposed method can play a significant role in the displacement measuring system.