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ID:53762801
大小:1.48 MB
页数:5页
时间:2020-04-24
《基于三坐标测量机自适应测量的自由曲面逆向-论文.pdf》由会员上传分享,免费在线阅读,更多相关内容在行业资料-天天文库。
1、第50卷第15期机械工程学报Vl01.5ON0.152014年8月JOURNALOFMECHANICALENGINEERINGAug.2014DoI:10.3901/JME.2014.15.155基于三坐标测量机自适应测量的自由曲面逆向冰何雪明孔丽娟何俊飞武美萍张荣纪小刚f江南大学江苏省食品先进制造装备技术重点实验室无锡214122)摘要:自由曲面的精确测量和重构是决定具有自由曲面特征的零部件复现精度的重要因素,传统逆向中测量与重构是相互独立又不能有效评估的。为提高自由曲面测量速度和重构精度,基于三坐标测量机(Coordinatemeasuringmachine,
2、CMM),提出自适应测量的曲面重构方法。测量过程中,通过不断拟合样件上已测点,预算待测点及其测量矢量,指导CMM自动采集曲面上数据。由点云拟合自由曲面模型后,检验拟合模型上点与样件上相应点的误差;若误差偏大,则在测量点云中加入检测点后重新拟合曲面,进一步检测重拟合实体模型直至满足精度要求,得到精准数据点和精致的自由曲面模型。辅以计算机图形可视化实例验证本法,测量精度及其重构精度可达um级,具有自由曲面特征的零部件整个逆向周期呈数量级下降,算法鲁棒性强。关键词:自由曲面;自适应测量;曲面重构;精度评价中图分类号:TP301Free-formSurfaceRevers
3、eBasedonCMMSelf-adaptingMeasurementHEXuemingKONGLijuanHEJunfeiWUMeipingZHANGRongJIXiaogang(JiangsuProvinceKeyLaboratoryofAdvancedFoodManufacturingEquil;)mentandTechnology,JiangnanUniversity,Wuxi214122)Abstract:Precisemeasurementandreconstructionofafree-formsurfacearetheimportantfactor
4、stoafectthereproductionaccuracyforpartswithfreesurfaces.Inthetraditionalreverse,thetwoprocessesareindependent,andunabletobeevaluatedefectively.Inordertoimprovethespeedandprecisionforsurfacemeasurementandreconstruction,anewmethodisproposedbasedoncoordinatemeasuringmachine(CMM)adaptivem
5、easurementmethodtoreconstructsurfaces.Inthemeasurement,pointsgotfromthesamplearefiredtocalculatethenextpointanditsmeasurementvector,andguidetheCMMmeasuretheautomatically.Afterfiringthefreesurfacemodelofthemeasuredcloud,theerrorbetweenpointsonfiringmodelandsampleisdetectedandcalculated
6、.Iftheerorisbig,theactualdetectedpointsareaddedtoreconstructthemodelagain.Theaccuratedataandtheelaboratesurfacemodelareobtainedbydetectingandupdatingthefiredmodeluntiltheaccuracymeetsrequirement.Furthermore,acomputergraphicsdisplaymethodisusedtomakethecalculationexamplesprocessvisualt
7、overifytheproposedmethod.Theempiricalresultsshowthattheaccuracyofmeasurementandreconstructionreachesthepanlevel,andthereversecycleforfreeformsurfaceismultiplyshorteningdown,andthealgorithmrobustnessishigh.Keywords:free—formsurface;adaptivemeasurement;surfacereconstruction;precisioneva
8、luati
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