刹车片背板平面度误差自动检测系统的研制

发布时间：2018-11-06 14:29

【摘要】：刹车片背板的平面度误差是衡量刹车片质量的一项重要指标,然而目前大部分企业仍然采用人工手动方式对出厂背板进行检测,不仅测量效率低,而且测量数据不可靠。本课题通过研发成本适当、数据可靠、测量便捷的平面度误差自动检测系统,为企业提高产品质量,打破国外产品市场垄断提供技术支撑。通过对现有电测方案的分析,提出了高精度、高效率的群测方案对背板待测面进行形貌提取,并通过实验完成对传感器和测量平面的校准。围绕检测方案设计了基于PLC控制的分料机构、检测机构和分选机构,并详细介绍了各机构的工作原理和控制流程。在传统凸包法计算平面度误差的基础上,结合测点空间分布特点,提出了一种新的三维点集的凸包构建方法。对获取的三维数据进行降维分析,以快速获取初始凸包顶点,并借鉴Quickhull算法思想,提高凸包构建速度。结合测点分类法,提高平面度误差计算效率。基于Qt开发框架完成检测系统的上位机程序设计,通过调用QSettings类实现配置文件的读写,调用QSerial Port类实现与PLC、传感器等下位机的通信;利用第三方图形库QWT完成波形和直方图的显示;结合SQLite数据库实现检测数据的存储、查询和导出。分析了系统的单点测量误差,结合平面度误差计算方法,完成对系统测量精度的估算,通过重复实验得到系统相对于三坐标测量机的示值误差以及重复性,从而验证了该系统的可靠性。
[Abstract]:The flatness error of brake plate is an important index to measure the quality of brake pad. However, most enterprises still use manual method to detect the factory backplane, which is not only low efficiency, but also unreliable measurement data. This paper provides technical support for enterprises to improve product quality and break the monopoly of foreign product market through the research and development cost, reliable data, convenient measurement of flatness error automatic detection system. Based on the analysis of the existing electrical measurement schemes, a group measurement scheme with high precision and high efficiency is proposed to extract the surface of the backplane to be tested, and the sensor and the measuring plane are calibrated through experiments. The separation mechanism, detection mechanism and sorting mechanism based on PLC control are designed around the detection scheme, and the working principle and control flow of each mechanism are introduced in detail. On the basis of the traditional convex hull method to calculate the flatness error and combining the spatial distribution characteristics of the measured points, a new method for constructing the convex hull of the three-dimensional point set is proposed. In order to obtain the initial convex hull vertices quickly, the dimensionality reduction analysis of the acquired 3D data is carried out, and the construction speed of convex hull is improved by using the idea of Quickhull algorithm. The calculation efficiency of flatness error is improved by combining the method of measuring point classification. Based on the Qt development framework, the upper computer program of the detection system is designed, the configuration file is read and written by calling the QSettings class, and the communication between the QSerial Port class and the lower computer such as the PLC, sensor is realized by calling the QSerial Port class. The third party graphics library QWT is used to display the waveform and histogram, and the SQLite database is used to store, query and export the detection data. The single point measurement error of the system is analyzed, and the precision of the system is estimated by combining the flatness error calculation method. Through repeated experiments, the indication error and repeatability of the system relative to the CMM are obtained. The reliability of the system is verified.
【学位授予单位】：中国计量大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U463.5;TP274

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