安装于慢走丝电火花机床上嵌入式可视检测系统的验证和改进
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摘要
嵌入式可视检测系统(英文名称：Integrated Vision Unit,以下简称：IVU)是一种新型光电检测系统,可被安装在电火花加工机床上,并嵌入阿奇夏米尔公司的数控系统以用来实时观测放大后工件形貌以及进行精密测量。整个系统从初步的设计构思到后来成形为实体己经由瑞士阿奇夏米尔公司研发部在前期工作中完成,本文的主要工作就是提出改进和提升该系统检测精准度的方案,并对其结果进行验证。
IVU系统的硬件部分由电荷耦合阵列探测器(英文名称：Charge Couple Device,简称：CCD)成像器件和发光二极管组成。CCD探头可在数控系统的控制下快速,精准的完成各种制定任务。发光二极管提供正面和背面两个方向的光,辅助测量。检测时CCD探头通过摄像的方式将工件表面情况传送到显示屏上,因此可以实时观测该检测系统的工作情况。
本文通过对IVU系统精准度提高方法的研究,提出四步校准方法。校准后又从两方面来验证校准效果：一方面,我们设计了一组同样条件下的重复测量实验,实验结果主要对测量系统的稳定性做了验证；另一方面,又组织了一系列与不同类型检测仪器的对比实验,从而验证了校准后IVU的精准度。
形貌扫描功能是研发后期为客户特别设计的一项功能,能够在不预先设定工件形貌的情况下对任意形状的部件进行扫描,并且能够在扫描完成后显示出与标准形貌对比分析的结果。这项功能提高了检测系统的灵活性,在实际使用过程中对客户会有很大帮助。为了验证这项功能的精确度和稳定性,本文设计了两部分实验：首先,将该功能与系统中其他功能相对比,从内部检验该功能与其他功能精准度一致性；其次,再将该功能与其他仪器中的相似功能相对比,从而确定该功能的精准度在实际使用中能否满足客户的需求。为了补充说明该功能在实际运用中的效果,本文还设计了形貌扫描功能在实际工件上作用的实验。
本文在最后还提到了下一步研究的方向,即利用这项功能使得IVU不仅能观察和测量工件,还能计算出修正电火花加工机床电极丝加工路径的方案,进一步提高电火花加工机床加工精度。
IVU is an optical measurement system, integrated by the company AgieCharmilles to visualize and measure work pieces directly on the machine tool, particularly in Electric Discharge Machining (EDM). The entire system from initial design concept to later become the entity has been done by the R&D department of AgieCharmilles in the previous work. The main work of this paper is to verify the accuracy and stability of the system in practical work, and give the advices to promote and enhance the monitoring capacity of the system.
CCD sensor and LED light are the main hardware parts of IVU. CCD sensor can move to the top of eroded piece and do the measurements in a short time. According to the video detected by the CCD sensor, the surface condition of work piece can be showed on the screen in order to check the measuring directly from it. Get edge is one of the basic functionalities on IVU.
There are four methods to calibrate the IVU system. After the calibration, two experiments were designed to verify it:on one hand, after calibrating, several experiments were organized to test the precision condition and dependency of IVU; on the other hand, In order to make sure the measuring ability of IVU, some alternative measuring systems are used to compare with IVU.
Contour scanning is a special functionality designed for customers, which can scan and measure the profile of work piece without knowing before the shape of it. Especially, at the end the results can be seen directly in image and statistic way. This functionality will be very useful in the real manufacturing process. We tested this functionality in two ways:firstly, it was internal check; then, contour scanning was compared with another popular used optical-based instrument. At the end, there was an example of the application experiment.
At the end of this paper, we also talked about the next step of this project. In the future, more functions on IVU will be developed, like correcting. With this function, we hope the system can not only visual and measure the work piece, but also help EDM machines to correct the erosion errors.
IVU系统的硬件部分由电荷耦合阵列探测器(英文名称：Charge Couple Device,简称：CCD)成像器件和发光二极管组成。CCD探头可在数控系统的控制下快速,精准的完成各种制定任务。发光二极管提供正面和背面两个方向的光,辅助测量。检测时CCD探头通过摄像的方式将工件表面情况传送到显示屏上,因此可以实时观测该检测系统的工作情况。
本文通过对IVU系统精准度提高方法的研究,提出四步校准方法。校准后又从两方面来验证校准效果：一方面,我们设计了一组同样条件下的重复测量实验,实验结果主要对测量系统的稳定性做了验证；另一方面,又组织了一系列与不同类型检测仪器的对比实验,从而验证了校准后IVU的精准度。
形貌扫描功能是研发后期为客户特别设计的一项功能,能够在不预先设定工件形貌的情况下对任意形状的部件进行扫描,并且能够在扫描完成后显示出与标准形貌对比分析的结果。这项功能提高了检测系统的灵活性,在实际使用过程中对客户会有很大帮助。为了验证这项功能的精确度和稳定性,本文设计了两部分实验：首先,将该功能与系统中其他功能相对比,从内部检验该功能与其他功能精准度一致性；其次,再将该功能与其他仪器中的相似功能相对比,从而确定该功能的精准度在实际使用中能否满足客户的需求。为了补充说明该功能在实际运用中的效果,本文还设计了形貌扫描功能在实际工件上作用的实验。
本文在最后还提到了下一步研究的方向,即利用这项功能使得IVU不仅能观察和测量工件,还能计算出修正电火花加工机床电极丝加工路径的方案,进一步提高电火花加工机床加工精度。
IVU is an optical measurement system, integrated by the company AgieCharmilles to visualize and measure work pieces directly on the machine tool, particularly in Electric Discharge Machining (EDM). The entire system from initial design concept to later become the entity has been done by the R&D department of AgieCharmilles in the previous work. The main work of this paper is to verify the accuracy and stability of the system in practical work, and give the advices to promote and enhance the monitoring capacity of the system.
CCD sensor and LED light are the main hardware parts of IVU. CCD sensor can move to the top of eroded piece and do the measurements in a short time. According to the video detected by the CCD sensor, the surface condition of work piece can be showed on the screen in order to check the measuring directly from it. Get edge is one of the basic functionalities on IVU.
There are four methods to calibrate the IVU system. After the calibration, two experiments were designed to verify it:on one hand, after calibrating, several experiments were organized to test the precision condition and dependency of IVU; on the other hand, In order to make sure the measuring ability of IVU, some alternative measuring systems are used to compare with IVU.
Contour scanning is a special functionality designed for customers, which can scan and measure the profile of work piece without knowing before the shape of it. Especially, at the end the results can be seen directly in image and statistic way. This functionality will be very useful in the real manufacturing process. We tested this functionality in two ways:firstly, it was internal check; then, contour scanning was compared with another popular used optical-based instrument. At the end, there was an example of the application experiment.
At the end of this paper, we also talked about the next step of this project. In the future, more functions on IVU will be developed, like correcting. With this function, we hope the system can not only visual and measure the work piece, but also help EDM machines to correct the erosion errors.
引文
[1]余晓琴.浅析微细电火花加工机床加工误差及提高精度的措施[J].科技创新导报,2011,80(7)：40.
[2]陈德忠.模具电火花加工技术的新发展[C].第十一届中国国际模具展先进模具制造技术研讨会论文集,2011,80(7)：40.
[3]Norliana M A, Darius G S, Md. Fuad B. A review on current research trends in electrical discharge machining (电火花加工) [J].International Journal of Machine Tool & Manufacture,2007,47:1214-1228.
[4]Dominiek R, Wim M, Hendrik V B. Machining of three-dimensional microstructures in silicon by electro discharge machining [J]. Sensor and Actuators,1998,67(1-3): 159-165.
[5]李克君.电火花线切割技术的发展与中国文化的冲突[C].2008年数控电火花线切割加工发展研讨会交流文集,2008：24-26.
[6]朱宁.微细丝数控电火花线切割技术及直线电机驱动技术研究简介[C].2008年数控电火花线切割加工发展研讨会交流文集,2008：14-17.
[7]朱耆祥.CCD成像器件[J].现代物理知识,2009,21(6)：8-11.
[8]Shaklan S, Sharman M C, Pravdo S H. High-precision measurement of pixel positions in a charge-coupled device [J]. Applied Optics,1995,34(29):6672-6681.
[9]Li Mei-song, Ming Ping-wang, Lu Lu, et al. High precision camera calibration in vision measurement [J]. Optics and Laser Technology,2007,7(39):1413-1420.
[10]Wilkinson J A, Meaden G, Dingley J D. High-resolution elastic strain measurement from electron backscatter diffraction patterns:new levels of sensitivity [J]. Ultramicroscopy,2006,4(106):307-313.
[11]Everett E M, Howell B S. A Technique for Ultrahigh-Precision CCD Photometry [J]. The astronomical Society of the Pacific,2001,789(113):1428-1435.
[12]Meinhart D C, Wereley T S, Santlago G J. Particle image velocimetry measurements of a microchannel flow[J]. Experiments in Fluids.1999,5(27):414-419.
[13]Groot D P, Deck L. Three-dimensional imaging by sub-Nyquist sampling of white-light interferograms [J]. Optics letters.1993,17(18):1462-1464.
[14]Viles L C, Sieracki E M. Measurement of Marine Picoplankton Cell Size by Using a Code, Charge-Coupled Device Camera with Image-Analyzed Fluorescence Microscopy [J]. American Society for Microbiology,1992,2(58):584-592.
[15]VALKENBURG J R, MCLVOR M A. Accurate 3D measurement using a structured light system [J]. Image and Vision Computing,1998,2(16):99-110.
[16]Weckenmann A, Nalantic K. Precision Measurement of Cutting Tools with two Matched Optical 3D-Sensors [J]. Annals-Manufacturing Technology,2003,1(52): 443-446.
[17]王婉春,裴仁清.多面阵CCD协同精密检测较大尺寸物体的研究[J]. Optical Instruments,2001,23(4):3-7.
[18]吴上生.机器视觉技术在检测轴类零件弯曲变形中的应用研究[J].机械制造,2005,43(6)：69-71.
[19]薛华,李东涛,熊永超.CCD技术在非接触检测中的应用[J].煤矿机械,2006,27(8)：162-164.
[20]Zhang Hong-tao, Duan Fa-jie, Ding Ke-qi. Study on calibration of linear CCD based on two steps [J]. Acta Metrologica Sinica,2007,28(4):311-313.
[21]刘祚时,倪潇娟.三坐标测量机(CMM)的现状和发展趋势[J].机械制造,2004,27(8)：32-34.
[22]陈宝刚,李光珂,程文涛,赵静.三坐标测量机动态精度影响因素[J].黑龙江科技学院学报,2007,17(1)：62-65.
[23]费业泰,赵静,王宏涛,等.三坐标测量动态误差研究分析[J].仪器仪表学报,2004,25(4)：773-776.
[24]胥杰,赵尚宏,占生宝,等.光电探测器激光损伤因素及其成因分析[J].激光杂志,2006,27(5)：43-44.
[25]蔡德芳,史晓华,文建国,等.CCD探测器的饱和阈值的光谱特性研究[J].激光杂志,2000,21(3)：14-15.
[26]林均仰,舒嵘,黄庚华,等.激光对CCD及CMOS图像传感器的损伤阈值研究[J].红外与毫米波学报,2008,27(6)：475-478.
[27]Nechama L. R, Hiroyoshi M, etc. High time resolution fluorescence imaging with a CCD camera [J]. Journal of Neuroscience Methods,1991,2(36):253-261.
[28]郑颖君,陈吉武,等.CCD测量系统光学设计使用方案[J].激光与红外,2001,27(6)：367-369.
[29]Ming June Tsai, Chuan Cheng Hung. Development of a high-precision surface metrology system using structured light projection [J]. Measurement,2005,3(38): 236-247.
[30]M. Fujigaki, Y. Morimoto. Accuracy of real-time shape measurement by phase-shifting grid method using correlation [J]. JSME International Journal,2000, 43(4):314-320.
[31]Westerweel J. Fundamentals of digital particle image velocimetry [J]. Measurement and science technology,1997,12(8):1379-1392.
[32]叶军.数控低速走丝电火花线切割加工技术及市场发展分析[J].电加工与模具,2005,B04(增刊)：13-16.
[33]朱宁,许庆平,朱伟根,等.低速走丝电火花线切割加工工艺研究[J].电加工与模具,2008(3)：59-63.
[34]狄士春,黄瑞宁,于滨,等.低速走丝电火花线切割加工断丝原因分析及处理[J].电加工与模具,2003(5)：12-15.
[2]陈德忠.模具电火花加工技术的新发展[C].第十一届中国国际模具展先进模具制造技术研讨会论文集,2011,80(7)：40.
[3]Norliana M A, Darius G S, Md. Fuad B. A review on current research trends in electrical discharge machining (电火花加工) [J].International Journal of Machine Tool & Manufacture,2007,47:1214-1228.
[4]Dominiek R, Wim M, Hendrik V B. Machining of three-dimensional microstructures in silicon by electro discharge machining [J]. Sensor and Actuators,1998,67(1-3): 159-165.
[5]李克君.电火花线切割技术的发展与中国文化的冲突[C].2008年数控电火花线切割加工发展研讨会交流文集,2008：24-26.
[6]朱宁.微细丝数控电火花线切割技术及直线电机驱动技术研究简介[C].2008年数控电火花线切割加工发展研讨会交流文集,2008：14-17.
[7]朱耆祥.CCD成像器件[J].现代物理知识,2009,21(6)：8-11.
[8]Shaklan S, Sharman M C, Pravdo S H. High-precision measurement of pixel positions in a charge-coupled device [J]. Applied Optics,1995,34(29):6672-6681.
[9]Li Mei-song, Ming Ping-wang, Lu Lu, et al. High precision camera calibration in vision measurement [J]. Optics and Laser Technology,2007,7(39):1413-1420.
[10]Wilkinson J A, Meaden G, Dingley J D. High-resolution elastic strain measurement from electron backscatter diffraction patterns:new levels of sensitivity [J]. Ultramicroscopy,2006,4(106):307-313.
[11]Everett E M, Howell B S. A Technique for Ultrahigh-Precision CCD Photometry [J]. The astronomical Society of the Pacific,2001,789(113):1428-1435.
[12]Meinhart D C, Wereley T S, Santlago G J. Particle image velocimetry measurements of a microchannel flow[J]. Experiments in Fluids.1999,5(27):414-419.
[13]Groot D P, Deck L. Three-dimensional imaging by sub-Nyquist sampling of white-light interferograms [J]. Optics letters.1993,17(18):1462-1464.
[14]Viles L C, Sieracki E M. Measurement of Marine Picoplankton Cell Size by Using a Code, Charge-Coupled Device Camera with Image-Analyzed Fluorescence Microscopy [J]. American Society for Microbiology,1992,2(58):584-592.
[15]VALKENBURG J R, MCLVOR M A. Accurate 3D measurement using a structured light system [J]. Image and Vision Computing,1998,2(16):99-110.
[16]Weckenmann A, Nalantic K. Precision Measurement of Cutting Tools with two Matched Optical 3D-Sensors [J]. Annals-Manufacturing Technology,2003,1(52): 443-446.
[17]王婉春,裴仁清.多面阵CCD协同精密检测较大尺寸物体的研究[J]. Optical Instruments,2001,23(4):3-7.
[18]吴上生.机器视觉技术在检测轴类零件弯曲变形中的应用研究[J].机械制造,2005,43(6)：69-71.
[19]薛华,李东涛,熊永超.CCD技术在非接触检测中的应用[J].煤矿机械,2006,27(8)：162-164.
[20]Zhang Hong-tao, Duan Fa-jie, Ding Ke-qi. Study on calibration of linear CCD based on two steps [J]. Acta Metrologica Sinica,2007,28(4):311-313.
[21]刘祚时,倪潇娟.三坐标测量机(CMM)的现状和发展趋势[J].机械制造,2004,27(8)：32-34.
[22]陈宝刚,李光珂,程文涛,赵静.三坐标测量机动态精度影响因素[J].黑龙江科技学院学报,2007,17(1)：62-65.
[23]费业泰,赵静,王宏涛,等.三坐标测量动态误差研究分析[J].仪器仪表学报,2004,25(4)：773-776.
[24]胥杰,赵尚宏,占生宝,等.光电探测器激光损伤因素及其成因分析[J].激光杂志,2006,27(5)：43-44.
[25]蔡德芳,史晓华,文建国,等.CCD探测器的饱和阈值的光谱特性研究[J].激光杂志,2000,21(3)：14-15.
[26]林均仰,舒嵘,黄庚华,等.激光对CCD及CMOS图像传感器的损伤阈值研究[J].红外与毫米波学报,2008,27(6)：475-478.
[27]Nechama L. R, Hiroyoshi M, etc. High time resolution fluorescence imaging with a CCD camera [J]. Journal of Neuroscience Methods,1991,2(36):253-261.
[28]郑颖君,陈吉武,等.CCD测量系统光学设计使用方案[J].激光与红外,2001,27(6)：367-369.
[29]Ming June Tsai, Chuan Cheng Hung. Development of a high-precision surface metrology system using structured light projection [J]. Measurement,2005,3(38): 236-247.
[30]M. Fujigaki, Y. Morimoto. Accuracy of real-time shape measurement by phase-shifting grid method using correlation [J]. JSME International Journal,2000, 43(4):314-320.
[31]Westerweel J. Fundamentals of digital particle image velocimetry [J]. Measurement and science technology,1997,12(8):1379-1392.
[32]叶军.数控低速走丝电火花线切割加工技术及市场发展分析[J].电加工与模具,2005,B04(增刊)：13-16.
[33]朱宁,许庆平,朱伟根,等.低速走丝电火花线切割加工工艺研究[J].电加工与模具,2008(3)：59-63.
[34]狄士春,黄瑞宁,于滨,等.低速走丝电火花线切割加工断丝原因分析及处理[J].电加工与模具,2003(5)：12-15.