Multi-loop networked process control: A synchronized approach

Modern day process control uses digital controllers which are based on the principle of distributed rather than centralized control. Distributing controllers, sensors and actuators across a plant entails considerable wiring which can be reduced substantially by integrating the components of a control loop over a network. The other advantages include greater flexibility and higher reliability with lower hardware redundancy. The controllers and sensors are on a network and can take over the function of a failed component automatically, without the need of manual reconfiguration, thus eliminating the need of having a redundant component for each and every component. Though elaborate techniques have been developed for Single Input Single Output (SISO) systems, the major challenge lies in extending these ideas to control a practical process plant where de-centralized control is actually achieved through control of individual SISO control loops derived through de-coupling of the original system. Multiple loops increase network load and hence the sampling times associated with the control loops and makes synchronization difficult. This paper presents a methodology by which network based process control can be applied to practical process plants, with a simple direct synchronization mechanism.     

一种新型单电源IGBT驱动电路

通过分析几种常用IGBT驱动模块电路的优缺点,结合IGBT对可靠性驱动的要求,提出了一种新型的IGBT驱动方案.它采用单电源供电,能够产生负栅压,使用脉冲变压器隔离,无需提供单独的浮地电源便可产生两路脉宽可调的驱动脉冲.最后通过实验给出了实验波形.根据实验波形,证明了此方案具有实用性强、简单可靠等优点.     

基于MAX Ⅱ的多通道同步数据采集系统

介绍了以CPLD为核心的GPS同步,大容量数据采集系统。该系统完全使用硬件来完成数据采集的时序控制,使用一片AD7663可以实现以每通道10K/S的采样速率完成16通道模拟信号采集,32路开关量的采集,并且可以根据需要,灵活扩展采集通道数。另外采集的数据被打上时间标签,所有的数据和时间标签组成数据帧.,直接写入双口RAM。文章最后给出了主蔓控制信号的QuartusⅡ的时序仿真。     

A four-channel 24-bit analog-to-digital converter synchronized with the universal-time clock

A four-channel 24-bit analog-to-digital converter with a sampling frequency of up to 32 kHz, which is capable of synchronizing data to the universal-time clock (UTC) with a root-mean-square error of no more than 1 μs is described. The data exchange with a recorder is carried out via the Ethernet interface.     

A switched supply tunable red-green-blue light emitting diode driver

This paper presents a new switched supply tunable red-green-blue (RGB) light emitting diode (LED) driver. The RGB LEDs act not only as light emitting devices but also as rectifying diodes in the presented driver circuit. The RGB LED color control is realized by controlling the switched supply voltage amplitude, frequency, and duty cycle. The driver efficiency is high since the only loss in the driver circuit is the switch and can be further reduced by direct alternate current supply.     

基于COM技术的测试仪器驱动研究

在分析COM技术和测试仪器驱动原理的基础上,论述了运用COM技术开发测试仪器驱动的可行方案,以开发Agilent公司生产数字万用表34401的COM驱动为例,运用VC语言开发仪器驱动,并在VC和CVI两种语言环境下成功调用测试仪器驱动,证明了所开发驱动的可用性和跨语言环境的能力。     

A synchronized emissive probe for time-resolved plasma potential measurements of pulsed discharges

A pulsed emissive probe technique is presented for measuring the plasma potential of pulsed plasma discharges. The technique provides time-resolved data and features minimal disturbance of the plasma achieved by alternating probe heating with the generation of plasma. Time resolution of about 20 ns is demonstrated for high power impulse magnetron sputtering (HIPIMS) plasma of niobium in argon. Spatial resolution of about 1 mm is achieved by using a miniature tungsten filament mounted on a precision translational stage. Repeated measurements for the same discharge conditions show that the standard deviation of the measurements is about 1-2 V, corresponding to 4%-8% of the maximum plasma potential relative to ground. The principle is demonstrated for measurements at a distance of 30 mm from the target, for different radial positions, at an argon pressure of 0.3 Pa, a cathode voltage of -420 V, and a discharge current of about 60 A in the steady-state phase of the HIPIMS pulse.     

同步自动焊接单元的设计

工程机械配件产品形状比较复杂且需要多部位焊接,在焊接过程中采用手工焊接或者自动焊接装置效率比较低而且质量不能保证。本设计根据工程机械配件工厂焊接生产情况,设计一种同步自动焊接单元,介绍其工作原理及结构,实现批量零件的、复杂形状的自动焊接,焊接零件自动转移和交换,焊接区域与上下料区域隔离,并实现焊接工序和上下料工序的同步进行。     

A new switched-capacitor frequency modulated driver for light emitting diodes

A new type of drivers for light emitting diodes (LEDs) is introduced based on the switched-capacitor frequency modulation. In contrast to conventional constant dc current drivers, the current pulse is provided by this new switched-capacitor LED driver. In the present driver, the charging capacitor is charged and discharged through a LED and the current flow direction is controlled by a metal oxide semiconductor switch. The input current (and thus the LED brightness) is proportional to the switch clock frequency at relatively low frequencies and becomes saturated at relatively high frequencies. This new driver circuit is simple and robust and maintains high efficiency for a wide range of input powers. In addition, the dimming control is easily realized by modulating clock frequency. Finally, this LED driver consumes no dc current and thus provides inherent protection to LED in standby mode.     

基于WinCE流接口模型的设备驱动设计

为提高嵌入式系统的适应性,根据WinCE．NET下流接口驱动模型结构、流接口驱动加载机制特点,借助WinCE．NET下USB设备驱动框架,设计出USB软驱驱动程序,并给出USB软驱的格式化实现方法和完整步骤。此驱动程序已成功应用在基于ARM9的嵌入式区域水质监测站系统,从而扩展了系统的功能,并为其他外设驱动设计与实现提供参考。     

Pulsed acousto-optical modulator driver

A gated rf driver for an acousto-optic modulator used to actively mode-lock a laser is described. The modulator is driven in a pulsed mode, so that much higher rf power can be applied to obtain high modulation indices.     

A new robotic assembly modeling and trajectory planning method using synchronized Petri nets

In this paper, a new approach to trajectory planning, performance Evaluation, and control for robotic assembly is presented. The assembly process is modeled as a discrete event system using synchronized Petri nets (SynPN). In a SynPN model, transitions are associated with firing conditions depending on external events. Due to this characteristic, SynPN is commonly used to model the connection between system states and external signals. The most important force/moment and position/orientation information in the assembly process serve as external events. Using the external events, the assembly states can be recognized and the system will be directed to the desired end state. Furthermore, trajectory planning algorithms and performance evaluation criteria of a discrete event system are also studied based on SynPN model. Finally, simulation and simple experiments are discussed in which a successful peg-in-hole assembly is fulfilled.     

一种新型的伺服驱动系统开发平台IRMCS201

本文介绍了一种新型的伺服驱动控制系统开发平台IRMCS201。它是一个基于IRMCk201电机控制专用芯片，采用电压矢量控制方法完整的伺服驱动系统设计平台，系统允许用户根据不同的应用要求来配置，简单价廉且结构灵活，支持永磁马达和感应马达。     

SubLVDS驱动电路的设计

SubLVDS是一种超低压摆幅的差分信号技术,与传统的低摆幅差与信号技术相比,它具有更高的比特率、更低的功耗、更好的噪声性能和更稳定的可靠性.分析了SubLVDS的技术原理和优势,并给出了SubLVDS高速驱动电路的设计,其中采用MOS电容组成的高速降幅电路,利用负反馈和米勒补偿稳定共模点,采用SMIC 0.18 μm工艺,1.8 V的供电,最后实现摆幅为150 mV的、速度为1 Gbps、PSRR大于60 db的驱动电路.     

筒式柴油打桩机的优化设计

介绍了用一台老式履带起重机改装成打桩机的优化设计过程     

论变频器与交流主轴驱动器

分析了变频器与交流主轴驱动器的特点,指出了它们的性能区别.     

机车司机疲劳驾驶监测

本文针对机车驾驶员疲劳驾驶的监测问题,对采集的图象进行预处理之后,首先利用最大类间方差法,将人脸区域分割出来;然后采用灰度积分投影技术对人眼区域准确定位;再利用小波分析对人眼区域进行两层分解,提取各层的近似分量和细节分量的能量,构造为特征向量,并输入到SVM分类器,实现对机车驾驶员眼睛睁开、闭合状态的判断,最后运用PERCLOS原理对驾驶员驾驶状态作出判断。实验数据表明:本文提出的方法能够准确地对机车驾驶员的驾驶状态作出监测。     

翻车机隔栅自动同步清料、报警装置

翻车机是铁路运输业对装有散料的车皮进行快速倾卸的大型机械 ,它直接将整车皮的散状物料一次性地倾卸到漏斗仓中。为了缓解翻车机倾卸时对下层设备的冲击 ,隔阻车皮内散料中夹杂的异物“大块”被倾卸到漏斗仓内 ,从而引发输送料线的后序事故 ,一般都在漏斗仓上部设置有隔栅层。隔栅层通常由条形铁板焊接而成 ,其竖立面间隔一般为 30 0mm× 30 0mm的“井”字空间 ,它安装在整个漏斗仓的顶部。隔栅层在发挥功能的同时 ,客观上也把车皮倾卸的部分物料截留在“井”字形竖立面的交叉点上形成了积料。如果把“井”字空间扩大来减少隔栅的交叉点 ,…     

一种低电压高速激光二极管驱动器

介绍了一种低电压高速激光二极管驱动器 ,可以 +3.3V单电源供电 ,其特殊的高速电流源结构使其满足激光二极管阈值电流的温度特性 ,并可以 62 2 Mbps驱动激光二极管。