电阻焊数据采集分析系统研究

【作者】 金丽华；

【导师】 马跃洲；

【作者基本信息】 兰州理工大学 ， 材料加工， 2004， 硕士

【摘要】 传统上，焊接质量是通过稳定焊接工艺参数和焊后检验来保证的。由于焊接过程存在大量随机影响因素，仅通过稳定工艺参数无法完全避免焊接缺陷的产生；焊后检验作为质量保证体系虽必不可少，但其不具实时性，不能及时发现焊接缺陷，有缺陷的接头只能返修或报废。特别对于大量使用电阻焊的场合，亟待解决点焊缺陷在线识别或质量分类，取代或减少目前采用的焊后探伤和破坏性抽检，提高生产率、降低成本。对于电阻焊过程，影响焊接质量的各种随机因素，均直接或间接地蕴涵在焊接电流、电压、电极位移等信号的动态变化之中。因此，本课题以上述信号作为研究对象，进行了电阻焊数据采集分析系统研究，围绕以下三方面展开工作。研制了以AduC812单片机为核心的数据采集分析系统。采用Rogowski大电流传感器解决次级电流信号的传感，利用差动变压器位移传感器对电极位移进行检测：利用USB速度快、安装方便、高带宽、易扩展等特点，进行系统与计算机之间的交互通讯。设计出高速、高精度、大容量的焊接电压、电流、电极位移信号的同步数据采集系统。关于故障预警、质量分类及在线监控功能的实现依赖于进一步探索信号与质量之间的映射关系，因此处于实验阶段，所搭建的硬件平台为寻求信号与质量的映射关系、实现焊接质量的在线监控作准备。为辅助系统的完成，实验初期以AC6115采集板卡进行数据采集。开发支持WINDOWS操作系统下的数据通讯、波形显示、图形编辑、频谱分析等软件。进一步探索电阻点焊信号与焊接质量的映射关系。利用时域、频域、小波等多种方法对电流、电压等信号进行分析，研究信号特征及其与电阻点焊过程的相关性。初步分析认为，电流、电压信号波形以及接头动态电阻、加热功率的变化与熔核形态密切相关，可用于电阻点焊接头质量的在线监控。从信号分析角度丰富对焊接过程的认识，为焊接缺陷在线识别和质量分类奠定基础。更多还原

【Abstract】 In traditional, the quality of welding is guaranted through stabilizing parameter of weld’s arts and crafts and the test after welding. Due to a plenty of random influence factor, can not avoid completely producing welding defect only through stabilizing parameter of arts and crafts; it is necessary that we carry the test after welding, but it hasn’t the character of real time, can not discover welding defect in time, some tie-in of defect can but remedying or rejecting. Especially when we using resistance spot welding, it is desiderate to solving identify on-line or quality classify, replaced or reduced crack detection after welding and devastating spot test, improved productivity and reduced cost.All sorts of random influence factor for welding quality is contained in the change of current, voltage, electrode displacement, etc.signals. Take this signal as researching object, the following works had been done in this thesis.A data collection and analyse system based on AduC812 MCU was developed with the designed current transducer and differential transformer displacement transducer for resistance spot welding, by which the current and displacement signals were acquired. We use great capacitance memory 16M byte data and expert data-base of the relation between signals of resistance spot welding and the quality of welding on NN. Designed the circuit of resistance spot welding on-line control.Developed a data collection system based on AC6115 with designed data communication, waveform showing and frequency spectrum analysis based on WINDOWS operation system by taking current, voltage, electrode pressure, displacement, etc.signals as research objects. It provide for explore the mapped relation of the signals of resistance spot welding and the quality of welding.Time-domain, frequency-domain and wavelet were used to analysis current, voltage, electrode pressure, displacement signals in this thesis, researched the relativity between the character of signals and the process of resistance spot welding. It is conclude that the wave form of current, voltage signals and the transformation of dynamic resistance, power of tie-in and nugget form is correlation osculation, so they can used on on-line control of tie-in quality of resistance spot welding. Enriched the comprehend of the the process of welding by the point of view signal analysis, established the basic for welding defect on-line identify and quality classifying.更多还原