球墨铸铁汽车转向节球化质量在线检测技术

发布时间：2019-05-17 03:36

【摘要】：球墨铸铁汽车转向节的球化质量决定了其机械性能,传统的金相法、拉伸法等方法需要制作试样,然后对试样进行检测,无法满足对产品在线检测的需求。由于材料的球化质量决定了其初始磁导率,本文提出一种基于初始磁导率的汽车转向节球化质量在线检测方法,搭建了在线检测系统并设计评价模型对其可靠性进行评价。基于初始磁导率的汽车转向节球化质量在线检测系统由传感器探头、运动推进机构和电路部分组成。传感器探头是整个检测系统的核心部分,实现了初始磁导率向电信号的转换。现在常用的初始磁导率传感器多为内穿过式线圈,只能测量试棒的初始磁导率。本文设计了含有U型磁芯的传感器探头,该传感器只需要一小块检测面,对试样形状、尺寸要求低,增加了初始磁导率法的应用范围。运动推进机构包括推进器、导轨和姿态调整机构三部分,实现了传感器自动推进和姿态调整。其中推进器可以实现当试样到达工位后自动推进;导轨保证了传感器运动过程中姿态不会发生变化;当U型传感器与被测试样接触不好时,通过姿态调整机构来纠正传感器姿态。电路部分主要包括激励信号发生、检测信号采集和控制部分,实现了整个系统工作流程控制和信号的调理。激励信号发生部分使用DDS芯片产生正弦激励信号并且转换成交流恒流源;检测信号采集部分对检测信号进行放大、滤波,然后使用高速AD进行采样;控制部分作用包括整个系统工作流程控制和特征信号提取。为了评价该在线检测系统的可靠性,本文使用混合建模方法建立了评价模型,通过对探头与试样之间的接触状况、试样材料、电路噪声等因素的研究,在此基础上,建立检测模型,通过统计模拟方法得到系统的误检概率和漏检概率均小于0.5%,验证了系统的可靠性。
[Abstract]:The nodular quality of nodular cast iron steering knuckle determines its mechanical properties. The traditional metallographic method, drawing method and other methods need to make samples, and then test the samples, which can not meet the needs of on-line inspection of products. Because the spheroidizing quality of the material determines its initial permeability, this paper proposes an on-line detection method of automobile steering pitch quality based on initial permeability, builds an on-line detection system and designs an evaluation model to evaluate its reliability. The on-line detection system of automobile steering spherical quality based on initial permeability is composed of sensor probe, motion propulsion mechanism and circuit. The sensor probe is the core part of the whole detection system, which realizes the conversion from the initial permeability to the electrical signal. At present, most of the commonly used initial permeability sensors are inner-pierced coils, which can only measure the initial permeability of the test rod. In this paper, a sensor probe containing U-shaped magnetic core is designed. The sensor only needs a small detection surface, and the requirements for the shape and size of the sample are low, which increases the application range of the initial magnetic conductivity method. The motion propulsion mechanism includes three parts: thruster, guideway and attitude adjustment mechanism, which realizes the automatic propulsion and attitude adjustment of the sensor. The thruster can automatically push when the sample reaches the station, and the guideway ensures that the attitude of the sensor will not change during the movement of the sensor. When the U-shaped sensor is not in good contact with the measured sample, the attitude of the sensor is corrected by the attitude adjustment mechanism. The circuit mainly includes excitation signal generation, detection signal acquisition and control, and realizes the workflow control and signal conditioning of the whole system. The excitation signal generation part uses DDS chip to generate sinusoidal excitation signal and converts it into AC constant current source. The detection signal acquisition part amplifies and filters the detection signal, and then uses high-speed AD to sample. The control part includes workflow control and feature signal extraction. In order to evaluate the reliability of the on-line detection system, the evaluation model is established by using the hybrid modeling method. Through the study of the contact condition between the probe and the sample, the sample material, the circuit noise and so on, on this basis, The detection model is established, and the false detection probability and missed detection probability of the system are less than 0.5% by statistical simulation method, which verifies the reliability of the system.
【学位授予单位】：中国计量学院
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：U463.46

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