Seam Tracking Signal Detection And Processing Based On Capacitive Sensor

Sensor technology has been widely used in all walks of life among machinerymanufacturing.Capacitive sensors have characteristics of high sensitivity,fast dynamicresponse,simple structure,good stability,and so capacitive sensors has been widelyused in the fields of measuring linear displacement,angular displacement vibrationamplitude,particularly suitable for measuring the amount of high frequency vibrationamplitude, precision shafting rotating accuracy,acceleration and other mechanical,andcapacitive sensors can also be used in the fields of measurement ofpressure,differential pressure,level,material surface,the moisture content in thefood,the coating of non-metallic materials,the thickness of film,the humidity, densityand thickness of the dielectric etc.This article studied the physical characteristics ofthe capacitance sensor,put capacitive sensor technology into the seam trackingresearch areas.Combine the problem of seam tracking system and the own merits ofcapacitive sensor,to extract the deviation signal of V-shaped groove weld,achievingtorch automatically tracing.This article conduct a brief introduction to the seam tracking technology andwelding automation trends at home and abroad in the beginning.and elaborate theprinciple, types, development, and application areas of capacitance sensor.throughanalyzed the feasibility study,we found capacitive sensor is not used in the field ofseam tracking technology,and its characteristics applicable to the complex and harshenvironment of the welding process.Put forward the theory of capacitive seamtracking sensor technology.Make a detailed description of the basic theory of the capacitive seam trackingsensor technology, introduced the basic principle of seam tracking system based onthe capacitive sensor,the system has modeling and simulation analyzed,analysis ofexperimental data on the physical characteristics of the capacitive seam trackingsensor in the welding experiments,studied the variation on several major impactparameter of the capacitive seam tracking sensor.Design a capacitive seam tracking sensor which have the structure of complex electrode,and modeling and simulation of the circuit which used for sensor probe,putforward the theory of parasitic capacitance compensation technology through analysisthe parasitic capacitance which produced in the structure of sensor probe interferenceand influence to extract the sensor signal.Designed the signal processing circuitinclude amplifier circuit,rectifier circuit,zero circuit and designed the temperaturecompensation circuit which consider the interference of the intense heat in thewelding process to achieve temperature compensation.Optimized linearity of the capacitive seam tracking sensor,and using the leastsquares method to fitting the output characteristic curve of capacitive seam trackingsensor through analysis of the advantages and disadvantages of the two kinds of curvefitting method.Designed a differential measured manner to improve the sensitivity andlinearity of the capacitive sensor.