Development Of Measurement And Control Software For Measurement Instrument Of Global Sizes

Cylindrical holes and shafts are widely used basic parts.With the rapid development of manufacturing industry,the requirements for their size,geometric accuracy and standardized indication are getting higher and higher.For cylindrical holes and shafts,in addition to the dimensional tolerances and form tolerances specified by the Product Geometric Specification(GPS),the global sizes(including least squares diameter,minimum circumscribed diameter,maximum inscribed diameter and minimax diameter)and calculated sizes(including circumference diameter,area diameter and volume diameter)are also specified.Based on the functional requirements of the measuring instrument for cylinder’s global sizes(hereinafter referred to as the measuring instrument)designed by the research group,this thesis adopts the MFC software interface development tool of C + + language and the data processing technology of Matlab and C + + mixed programming.The related problems in the development of measurement and control software for the measuring instrument were studied.According to the structural characteristics of the measuring instrument,the hardware composition and functional requirements of the measurement and control system,the measurement and control software of the measuring instrument designed.The probe measurement paths of the cylinder extraction strategy based on roundness of profiles,generatrix profiles,bird’s cage profiles,the single spiral profile,and double roundness profiles and single spiral profile were proposed,and the corresponding measurement and control program was developed.According to the automatic centering and leveling worktable developed by the research group,the centering and leveling model was established by using double circular sampling and three-point theory,and the automatic centering and leveling program was compiled.After centering and leveling,the probe contacts the surface of the cylindrical part by controlling the stepper motor of the horizontal arm.Through the C + +timer function,the Z-axis position feedback and angle position feedback of the linear grating ruler and the circular grating are used to accurately judge the position information of the workpiece and realize the precise control of the above measurement path.The data preprocessing of the cylinder’s profiles extracted by the measuring instrument was studied.The system error correction model,singular point removal and digital filtering model of the radial size of the measuring instrument were established,and the corresponding program was compiled with Matlab language.According to the evaluation model of global sizes,cylindricity error and roundness error of cylinder based on the roundness profiles method,the preprocessed profile data was used to evaluate the global sizes,cylindricity errors and roundness errors.Combined with the method of Matlab dynamic link library,the data preprocessing program and the evaluation program of global sizes,cylindricity error,roundness error evaluation program were transplanted into the MFC control evaluation program of system software,and the input of the compiled Matlab data processing function is converted to facilitate the input variables in different programming environments.Based on MFC software,a set of measurement and control software for the measuring instrument was developed,which is composed of motion control,centering,sampling and leveling,data processing and evaluation,and visualization of the evaluation results.The integrated debugging,positioning accuracy and centering and leveling function test of the measurement and control software and the measuring instrument were carried out.The debugging and testing results showed that the measurement and control software can meet the needs of multi-path profiles extraction of cylinder features and automatic centering and leveling.The centering range is < 3 mm,the minimum step distance is 7.8 nm,and the leveling range is < 1°.The positioning accuracy of X-axis linear displacement is 1μm,and the positioning accuracy of Z-axis linear displacement is 0.5μm.