The Study Of Contact 3D Scanning Probe Based On PSD

As an important branch of precision measurement,3 D measurement has been widely used in many fields,such as industry,military,scientific research,etc With the rapid development of optoelectronic devices,the 3D treasurerment method based onPSD has been widely studied.At present,most of the research on 3D measurement system based on PSD is non-contact measurement.Compared with the contact probe,it's measuring accuracy is relatively low,easily affiected by external light,and poor stability.According to the characteristics of high precision of contact probe,this thesis presents a contact scanning measurement methodFirstly,this thesis introduces the composition of the 3D scanning probe and measurement primciple.According to the measure principle of 3D scanning probe,when the measuring head changes in different directions,the reflector changes and causes the ciiange of optical system.The mathematical model of the three direction of the measurement system is established on this basis.Secondly,the structure of 3D scanning probe and the data acquisition system is designed,The semiconductor laser is used as the system light,and the high precision t.wo dimensional pillow type PSD sensor is used to realize the position detection The design of PSD signal conditioning circuit is completed,which includes I/V conversion circuit and anplifier circuit The data is collected by PCI6221 data acquisition.The background light and dark current is eliminated with the photoelectric method.The design of system software is conpleted on the LabVIEW platform,which includes data acquisition module,the calculation of PSD sensor light spot data processing,display and preservation etc,Finally,the experiment platform of 3D scanning probe is built.The calibration of PSD sensor is completed.According to the analysis of system parameters calibration algorithm,the parameter calibration of X direction is completed based on the Levenberg-Marquart algorithm,and the parameter calibration of Y and Z direction is completed based on the nonlinear least squares method.The experimental data were analyzed,and the feasibility of the 3D scanning probe structure and mathematical model were verified.According to the measurement results,the system error is analyzed.