Drilling torque control using spindle motor current and its effect on tool wear

Drilling torque was estimated using the spindle motor current and controlled through feedrate manipulation for the reduction of drill wear. A PID controller was used to control the cutting torque measured indirectly from the spindle motor current. The effect of cutting torque control on drill flank wear was also investigated. Experimental results showed that the drilling torque was well-regulated at a given reference level and the risk of drill failure and drill flank wear were reduced remarkably through cutting torque control. Moreover, the suggested cutting torque control system does not disturb the cutting process and is practical in an industrial environment.Nomenclature I _rms Root mean square value of spindle motor current (ampere) - I _u,v,w U, V, and W phase current of the spindle motor (ampere) - I _rms,c Spindle motor current due to cutting (ampere) - I _rms,t Tare current of the spindle motor (ampere) - T _c Cutting torque (Nm) - T _s Sampling rate (Hz) - N _r Number of revolution - N _d Number of data per revolution - K _I Spindle motor current gain (ampere N^–1m^–1) - _d Time constant of the spindle system (sec)     

微机控制盒形件超塑胀形控制系统的研究

介绍了微机控制盒形件超塑成形的原理及最佳加压规律数学模型 ,分析了其特点及其计算效果 ,介绍了控制系统软件设计与开发。     

矩形盒体恒压拉深、切边复合模设计

某产品的电源模块外壳是一尺寸精度及外观质量要求均较高的矩形拉深盒体零件,按照常规工艺,需要在专用冲压设备上通过多道工序加工成型。在对工艺参数进行充分计算分析的基础上,根据加工条件设计了一副矩形盒体恒压拉深、切边复合模具。该模具采用特殊机械结构在普通压力机上实现拉深过程的恒力压边,并且在拉深行程终了时对零件进行较高精度的挤切修边,不仅满足了拉深工艺要求,还提高了工效,降低了成本,满足了产品小批量生产需求。     

机床主轴的一种变频调速系统

通过ＺＨ５３４０钻削中心主轴调速系统的设计，介绍一种由变频器和变频电机组成的机床主轴自动无级调速系统。这种调速系统性能稳定可靠，并且价格极其低廉。     

BCD码控制车床主轴分级调速系统

介绍数控车床主轴电机驱动调速系统的控制原理，二位ＢＣＤ码控制调速的软件及变速机构设计方法。     

板材焊接壳体类零件CAD/CAPP集成系统的研究与实践

利用Visual C 和AutoCAD作为开发工具，针对某港口机械厂异型类零件的特征，如焊接箱体类、支座类等各类异型零件作为研究对象，采用特征及特征单元的参数化设计方法，实现了这类零件的特征拼装、二维图形处理、三维特征造型、工艺文件的自动生成等集成系统的基本功能。其集成思想及设计方法对其它类异形零件的CAD／CAPP集成有一定的参考价值。     

机床主轴的机械结构模糊优化设计

采用模糊数学的方法对某机床主轴的截面尺寸进行了优化设计，在满足主轴的静态特性、动态特性和尺寸约束的条件下，使得机床主轴质量最小。在优化设计方案中考虑了影响设计的模糊因素和约束的模糊性，建立了非对称模糊优化模型，采用最优水平截集法求解，得出优化设计结论。结果证明所采用的模糊优化设计方法是比较有效的，具有实际应用价值。     

Communication emitter individual identification based on 3D-Hibert energy spectrum and multi-scale fractal features

For communication emitter identification,a novel method based on Hilbert-Huang transform (HHT) and multi-scale fractal features was proposed.First,the time frequency energy spectrum was derived via HHT,which was called a complicated curved surface in the three-dimension space,namely,3D-Hilbert energy spectrum.Then,the differential box dimension and the multi-fractal dimension was extracted to compose the feature vector under multi-scale segmentation using fractal theory.Finally,communication emitter individual identification was obtained using the two dimensions of features above and the support vector machine (SVM).Moreover,the novel method was compared with two existing methods to identify simulated and actual signals with different and the same modulation modes,respectively.Results show that the identification rate of the novel method is higher than that of the two other methods.The features extracted by the novel method have high stability,sufficiency,and identifiability,also outweigh the negative effects of the change of signal-to-noise ratio and the number of training samples and emitters.     

箱式整流变电站自动化监控系统设计

本文阐述了箱式整流变电站自动化监控系统的电气设计.首先介绍了箱式整流变电站的构成,对箱式整流变电站自动化监控系统的功能进行了说明.另外,对该自动化监控系统的软、硬件设计进行了阐述.集成该自动化监控系统的箱式整流变电站已在青岛公交集团投入使用,运行良好.     

直流变频空调室外机电控箱的设计数值模拟分析研究

以美的某型号直流变频空调室外机电控箱为研究对象,利用Flotherm软件,用热设计和热分析数值计算的方法预测确定模块中温度的最高点,通过对模块布局进行修改或采取必要的散热措施,消除其热问题,防止热失效对于我公司产品可靠运行具有及其重要的意义.