Research On The Application Of Eddy Current Sensor In The Wear Detection Of Shield Hob And The Design Of Installation Hole And Groove

In recent decades,with the rapid development of China’s economy,rail and subway transportation has developed rapidly.Shield tunneling machine has been widely used in related engineering fields by virtue of its advantages.Shield cutter is an important part of the shield machine.However,due to the harsh working environment and complicated working conditions of the shield,the wear and replacement of the shield cutter has become a key factor that seriously affects the progress of the project quality.Eddy current sensor technology has become an important detection technology in shield tool wear detection.In this paper,after consulting the relevant information,a combination of experiment and simulation is used to establish a corresponding detection system to study the online detection method of the hob using the eddy current sensor and the design of the sensor installation slot.The research content of this paper is as follows;the wear state of the hob and the tool change principle are summarized,the existing detection technology of the shield tool is analyzed,and the development and application of eddy current detection technology and its feasibility are analyzed.Establish the model of hob detection,simulate and analyze the effect of excitation frequency on the magnetic field strength,analyze the magnetic field distribution of coils with different radius,and select the appropriate excitation frequency and eddy current sensor during actual detection according to the simulation.The magnetic field distribution of the sensor probe coil in the radial and axial directions is analyzed to determine the range of the installation hole and groove,and the corresponding installation hole and groove is designed.Based on the analysis of the force on the hob,analyze the location and constraints of the hob knife box,establish the corresponding mechanical model,and then analyze the impact of the installation hole on the knife box to ensure the structural strength of the knife box.Establish a hob detection system and analyze the signal transmission method.Collect the actual wear amount of the hob and voltage signal output,and then make a comparative analysis to make the actual wear amount correspond to the signal one by one.The hob detection software is designed through the Stp-isp platform to realize the display and recording of the hob wear amount.And the hob wear user interface is used to track the hob wear curve,which provides a scientific basis for the hob timely tool change.According to the comparative analysis of the actual detection of the hob wear and the software display,the results show that the installation hole groove effectively reduce the impact of metal on the magnetic field of the sensor and the detection result,and expand the linear range of the sensor.The maximum absolute error of the 17-inch hob wear detection is 0.5mm,the relative error is9%,which can basically meet the needs of hob detection and accurately judge its actual wear.