共查询到18条相似文献,搜索用时 187 毫秒
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研究了电子束钎焊接头温度高精度数字PID控制系统。为了在钎焊过程中使接头温度在所设定的钎焊温度下保持恒定,基于计算机控制及离散控制理论,建立了钎焊温度数字PID控制模型及控制器。通过开环和闭环阶跃响应确定电子束钎焊被控对象类型,在PID模型参数整定过程中比较了扩充临界比例度法及扩充响应曲线法的整定效果。为了得到最优PID参数,采用归一化方法对电子束钎焊数字PID控制器参数进行在线优化。为了进一步提高控制系统的动态性能,采用积分分离PID算法。结果表明,可以达到超调极小、不需调整时间的控制效果,温度控制准确度可达±2.5℃。 相似文献
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研制了一种变规则模糊控制技术,并成功应用于逆变式电阻点焊焊接电流的闭环控制.通过比较常规模糊控制、变规则模糊控制、自适应模糊控制、PID模糊控制、模糊神经网络控制在控制算法复杂性、实现难易程度、运算与响应速度、适应性、控制精度等方面的优势与不足,考虑了电阻点焊焊接电流控制的实际需求.选定变规则模糊控制作为焊接电流调节的控制策略.根据焊接电流误差改变带修正因子模糊控制器中的修正因子,使模糊控制器的控制规则随焊接电流误差变化而变化,结合采取增量A-式输出控制信号,从而使焊接电流控制器的控制性能更符合实际需要. 相似文献
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在通用真空电子束焊机的基础上配置两对电子束偏转线圈、工控机多功能数据采集卡、功率放大器、可编程控制器以及虚拟仪器软件LabVIEW等,构建一个电子束扫描控制系统。利用该系统可对电子束扫描轨迹、扫描频率以及加热区域电子束能量密度的分配进行离线编辑和在线调节。使用该系统进行了不锈钢毛细管板结构的钎焊试验,钎焊接头质量满足结构技术规范。对铌钛异种合金采用不对称热输入的扫描加热方式进行焊接,获得了铌、钛熔化量相当,焊缝形状对称的焊接接头。对于不能直接焊接的异种金属(如Re—Ti),可使用该系统的扫描加热技术,通过粉末冶炼制备中间过渡层。 相似文献
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利用ANSYS软件,建立二维有限元模型,分析了两种不同钎焊工艺对1Cr18Ni9Ti不锈钢散热器电子束钎焊接头残余应力的影响,旨在筛选出一种合适的工艺及参数.结果表明,对于径向残余应力,采用直接加热钎焊工艺,钎焊面上出现明显的应力集中区域;而采用分阶段加热钎焊工艺,钎焊面上没有应力集中区出现,且应力变化曲线比直接加热钎焊工艺平缓得多;对于周向残余应力,分阶段加热与直接加热钎焊工艺相比,拉应力峰值减小了11.2%.两种钎焊工艺的周向残余拉应力峰值均大于径向残余拉应力,钎焊面的危险部位沿圆周方向,即电子束扫描加热的方向. 相似文献
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自适应模糊PID控制器在精密成型系统温度控制中的应用 总被引:4,自引:1,他引:3
温度控制系统具有非线性、大惯性、时变性等特点,常规PID控制和常规模糊控制还不能使精密成型系统温度控制效果理想。笔者设计了一种自适应模糊PID控制器,该控制器在大偏差范围内采用模糊推理控制,根据偏差和偏差变化的需要实时调整PID参数,小偏差范围采用PID精确输出。仿真表明,这种自适应模糊PID控制器既具有模糊控制灵活、响应快、适应性强等优点,又具有PID控制精度高的特点。它改善了精密成型系统温度的控制效果。 相似文献
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为避免在焊接过程中采集焊接正面温度场的缺点,本文使用ICCD工件背面采集焊接温度场图像,通过对焊接温度场图像进行分析,提出了改进的梯度算法获得焊缝偏差信号.利用自调整模糊控制的方式调节纠偏,解决了焊接过程难以控制问题.通过对近L形焊缝跟踪试验表明,该系统能够有效识别焊接偏差,并实现快速纠偏,跟踪精度可控制在0.5mm以内. 相似文献
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Xuedong Wang Qingyu Shi Xin Wang 《Journal of Materials Engineering and Performance》2010,19(2):213-220
Various electron beam (EB) processing methods such as EB brazing, surface modification, heat treatment, etching, evaporation
coating and quick manufacture, etc. require that the energy distribution and processing temperature be controlled. In this
study, the energy distribution control was realized by EB scanning trajectory pattern control, and the temperature control
was realized by the combined use of fuzzy logic and PID control. These were integrated into one system. To obtain large deflection
angle of EB, an external deflection coil was used. The scanning trajectory pattern was the synthesization of deflections of
EB in X and Y directions, and each of the deflections was controlled by an analog. Because of high energy density of the EB, and consequently
high sensitivity of weldment temperature to the beam current, closed-loop control of processing temperature is indispensable,
which was realized in this paper. Satisfactory transient and steady-state specifications were obtained. The brazing of a specially
designed specimen verified the effectiveness of the method. 相似文献
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为满足PDC刀具高频感应钎焊过程中对温度的控制要求,本文设计了一种模糊自适应PID控制系统.用IB51适配AC1226构成K型热电偶温度检测与信号处理电路,给出了模糊自适应PID控制器的工作原理、设计方法及基于DSP的软件流程.实验证明系统具有较好的动态和静态性能,能满足实际需要. 相似文献
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Development of pressure control system in counter gravity casting for large thin-walled A357 aluminum alloy components 总被引:3,自引:0,他引:3
Counter gravity casting equipments(CGCE) were widely used to produce large thin-walled A357 aluminum alloy components. To improve the pressure control precision of CGCE to get high quality castings, a pressure control system based on fuzzy-PID hybrid control technology and the digital assembled valve was developed. The actual pressure tracking experiment results show that the special system by applying PID controller and fuzzy controller to varied phases, is not only able to inherit the small error and good static stability of classical PID control, but also has fuzzy control's advantage of fully adapting itself to the object. The pressure control error is less than 0.3 kPa. By using this pressure control system, large complex thin-walled A357 aluminum alloy castings with high quality was successfully produced. 相似文献
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Some parts with capillary to plate joint have important application in aerocrafi. Vacuum electron beam brazing (VEBB) technology is used to realize this jointing with capillaries. Firstly 3D finite element analysis model is built in this paper according to this special structure. And then ANSYS finite element analysis software is used to analyze brazing temperature field at different brazing parameters. The calculation results show that the temperature field of simulation has good agreement with that measured by experiment, which proves dependence of the model built in this paper. And also reference parameters could be provided for real brazing process through calculation in this model. Brazed joint of capiUary to plate with good performance is achieved using VEBB technology. The achievement of the study will be applied in aerocrafi in the future. 相似文献
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模糊自适应PID控制器在液压AGC系统中的应用 总被引:1,自引:0,他引:1
针对液压AGC(Automatic Gauge Control)系统生产工艺中对厚度控制的要求,设计一种应用于液压AGC系统的模糊自适应PID控制器。该控制器以常规PID控制为基础,根据偏差和偏差的变化率,利用模糊逻辑实现PID参数的在线自调整,进一步完善PID控制器的性能,提高厚度控制系统的控制精度。仿真结果表明:该控制器既具有常规PID控制器高精度的特点,又具有模糊控制器响应速度快的特点,而且具有良好的动态、稳态性能以及较强的鲁棒性,能够使液压AGC系统达到满意的控制效果。 相似文献
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