ADS7869:完整的模拟马达控制前端

1993年,德州仪器（T）旗下的Burr—Brown公司宣布针对三相AC马达控制系统推出一款名为“VECANA01”的模拟前端。该产品具有多种功能独特的模数转换器（ADC）、采样／保持（S＆H）、模拟输入通道、比较器和其它特有功能,因此它非常适用于高端马达控制系统。ADS7869是这系列的最新产品。除了能以更低的价格提供VECANA01具有的各种功能以外,它还提供了几种新的功能,像对于整个马达控制系统的增益与失调的校准、数字上／下计数器、高度灵活的数字接口,并且ADS7869的运行速度比以前的产品提高了10倍。     

基于CAN控制器SJA1000的智能高速控制系统设计

本文介绍了一种新型的现场总线控制器SJA1000的基本原理结构及功能的特点，重点叙述了基于CAN控制器SJA1000的智能控制系统硬件电路及软件设计，给出了初始化程序。     

改进Smith预估时延补偿的模糊网络控制系统研究

在网络控制系统中,针对通过网络进行数据传输时产生网络诱导时延使得系统性能恶化的问题,提出一种改进Smith预估器的模糊控制方法。在控制器端引入改进的Smith预估控制器,解决被控对象模型不匹配的问题,同时,增大系统的截止频率,得到较快的系统响应。在控制器设计中采用模糊控制算法将控制器设计为模糊控制器,模糊控制器是一种无需被控对象精确数学模型且采用模糊集合论的语言控制器,能够取得较好的控制效果,具有较强的鲁棒性。最后通过仿真,验证了该方法的有效性。     

用于控制变速电动机的功率模块

改善洗衣机、电冰箱以及空调等家用电器能源使用效率的需求正在增加。从传统的固定转速马达转换到变速马达可以节省能耗30％之多。但这种设计的难度较大，虽已经出现了几种方案来降低此类项目的数字设计工作难度，但是设计人员仍需要集成模块和相关的设计工具来促进功率级的设计。为了使低成本变速马达控制器成为可能，元器件供应商设法通过简化设计和降低结构复杂度来减少变速控制器的成本。例如，已经出现了几种数字信号控制平台，它们结合了DSP和集成PWM和马达控制外围设备的RISC处理器。这些平台可运行第三方或者自行开发的马达控制算法。     

基于TMS320LF2407的步进电机控制系统

步进电机适用于在数控开环系统中做执行元件,具有十分广泛的用途.本文从工程应用的角度出发,以TMS320LF2407 DSP芯片作为控制核心,结合专用步进电机驱动器,设计了一套可同时控制8个电机,且具有位移控制和多级调速功能的步进电机控制系统.文中对控制系统中有关以TMS320LF2407 DSP芯片为核心的步进电机控制器的软、硬件设计与开发进行了重点介绍.该控制系统目前已在多个工程项目中得到应用.     

基于NIOSⅡ处理器的智能家居控制系统设计

根据目前智能家居系统的需求发展,完成一种基于NIOSⅡ处理器的智能家居控制系统的设计.系统在FPGA上搭建硬件平台,利用以太网实现对家居系统的远程智能控制,给出软件设计的主要流程以及部分设计要点,并编写了客户端的桌面控制软件,最后,对实验系统进行了测试和验证.结果表明,以N10SⅡ处理器搭建的智能家居控制系统可以很方便地远程控制模拟的家居环境,结构简单,并且设计灵活,扩展性强.     

基于AT89S51的PCB制版喷雾腐蚀控制系统设计

提出了喷雾腐蚀制版新方法和基本原理,介绍了PCB制版喷雾腐蚀机的主要组成部分及技术要求,并且使用单片机(AT89S51)完成了喷雾蚀刻控制系统的硬件设计,具体包括整机原理框图、单元电路分析、软件设计,解决了职业院校和小型电子企业的腐蚀工艺问题,具有一定的商业开发价值.     

Quantization Noise and Limit Cycling in Digital Closed-Loop Systems

The practical and reliable application of direct digital control in industrial systems is a long way from the study of sampling control in modern control literature. Numerous mechanical failures of hydraulic tubes, seals, and mechanical connections have demonstrated that these systems are easily fatigued by ``jitter' or the type of noise that can arise in digital systems due to quantization of signals. Yet the transition from analog to microprocessor-based control implies a sampled control with inherent noise due to finite word length and finite sampling period. Even if the sampling frequency does not cause instability, it can fatigue the system with limit cycles. This paper investigates the effects of quantization and establishes bounds on limit cycles in digital closed-loop systems by examining a typical proportional plus integral type of controller found in process control. The work is based on the technique used by Long and Trick [1] to establish bounds on limit cycles in digital filters.     

Analysis of Digital Errors in Nonlinear PCM Systems

The effect of digital errors in linear pulse code modulation (PCM) systems has been considered by several authors for channels with independent errors. In this paper we present a general approach of analyzing digital errors in linear and nonlinear PCM systems with arbitrary channels. The examples given in this paper cover the different standard nonlinear PCM systems and independent channel errors. The technique used for the analysis leads to the conclusion that there are PCM codes less sensitive to digital errors than the standard binary folded PCM code. An example of such a PCM code is given in this paper.     

工业电机控制系统

本文介绍了直流电机、无刷电机、交流感应电机的差异及其子系统,深入分析了电流监测与测量、温度检测子系统以及电机速度、位置、运动检测系统.     

Vector Quantization Based QoS Classification for Admission Control in CDMA Systems

Optimal power control is of great importance for CDMA systems and it can be controlled to provide the desired quality of service (QoS) to mobile hosts in a cellular radio system. The power levels of all the mobile hosts are determined and constantly tuned in order to achieve the required SINR (signal to interference and noise ratio) which changes dynamically. The SINR of all the K mobiles in a cell can be expressed in the form of a k-dimensional vector. It helps determine the operating point of the system and hence it is constantly monitored and updated due to the variability in the wireless channel conditions and user mobility. We view this continuously changing vector as the motion of a point in a higher dimensional Euclidean space, called the QoS space. We apply vector quantization technique to shrink the infinite-point space to a finite-point space by partitioning the former into N regions such that the points within a region reflect almost similar system performance and are identified by what we call a QoS index. We show how the system operating point can be mapped to one of the QoS indices. The location of the point or the region of operability in the QoS space conveys the system status in terms of the current load and the QoS being delivered. The dynamism in the system's input conditions due to wireless link characteristics and user mobility acts like an opposing force against which the system has to operate. The system reacts to all such changes preventing it from going into a region with an undesirable QoS index. We show how the apriori knowledge of the operating region helps in decision making pertaining to call admission and resource allocation in CDMA systems. Mainak Chatterjee received his Ph.D. from the department of Computer Science and Engineering at the University of Texas at Arlington in 2002. Prior to that, he completed his B.Sc. with Physics (Hons) from the University of Calcutta in 1994 and M.E. in Electrical Communication Engineering from the Indian Institute of Science, Bangalore. He is currently an Assistant Professor in the department of Electrical and Computer Engineering at the University of Central Florida. His research interests include resource management and quality-of-service provisioning in wireless and cellular networks, sensor networks, CDMA data networking, media access control protocols, Internet traffic, and applied game theory. Sajal K. Das is a Professor of Computer Science and Engineering and also the Founding Director of the Center for Research in Wireless Mobility and Networking (CReWMaN) at the University of Texas at Arlington (UTA). His current research interests include resource and mobility management in wireless networks, mobile and pervasive computing, wireless multimedia and QoS provisioning, sensor networks, mobile Internet protocols, distributed processing and grid computing. He has published over 250 research papers, directed numerous funded projects, and holds 5 US patents in wireless mobile networks. He received the Best Paper Awards in ACM MobiCom'99, ICOIN-2001, ACM MSWIM-2000, and ACM/IEEE PADS'97. Dr. Das is also a recipeint of UTA's Outstanding Faculty Research Award in Computer Science in 2001 and 2003, and UTA's College of Engineering Excellence in Research Award in 2003. He serves on the Editorial Boards of IEEE Transactions on Mobile Computing, ACM/Kluwer Wireless Networks, Parallel Processing Letters, Journal of Parallel Algorithms and Applications. He served as General Chair of IEEE PerCom-2004, CIT-2003 and IEEE MASCOTS-2002; General Vice Chair of IEEE PerCom-2003, ACM MobiCom-2000 and HiPC 2000-01; General Chair of ACM WoWMoM 2000-02; Program Chair of IWDC-2002, WoWMoM 1998-99; TPC Vice Chair of ICPADS-2002; and as TPC member of numerous IEEE and ACM conferences. He is the Vice Chair of IEEE TCPP and TCCC. Prior to 1999, Dr. Das was a professor of computer science at Univeristy of North Texas where he twice (1991 and 1997) received the Student Association's Honor Professor Award for best teaching and scholarly research. He received B.Tech. degree in 1983 from Calcutta University, M.S. degree in 1984 from Indian Institute of Science, Bangalore, and PhD degree in 1988 from the University of Central Florida, Orlando, all in Computer Science.     

Quantization Noise in ADPCM Systems

The system considered here consists of a differential pulse-code modulator (DPCM) in which the quantizer is replaced by an adaptive quantizer. Adaptation is accomplished by adjusting the stepsize at every sampling instant, depending upon the magnitude of the quantization error. Quantizing noise in adaptive DPCM (ADPCM) systems falls into three categories: granularity, slope overload, and quantizer saturation. Granular noise occurs because only a finite number of levels are available to represent the analog input signal during the encoding process. Slope overload happens when the slope of the input signal increases faster than the adaptive system can follow. Quantizer saturation exists because nonoptimal decisions on step-size adjustments can lead to situations in which quantizer overload occurs without slope overload. The result is an error larger than a purely granular noise analysis would suggest. Equations for the three types of quantizing noise in ADPCM systems are derived, and computer simulations are perforated. For flatand RC-filtered Gaussian input signals, oversampled at various rates, the simulation results agree well with theoretical predictions. Comparisons indicate that the ADPCM can perform better than the best analogous nonadaptive system in terms of signal-to-quantizing-noise ratio. Furthermore, the optimal operating point for the ADPCM is much less sensitive to changes in input signal parameters and system component values than in nonadaptive systems.     

基于音频信号的量化噪声教学实验

量化噪声的产生及其特性，是数字信号处理课程中一个贴近工程实践的重要知识点。有别于传统理论讲授模式，本文设计了一个“量化噪声响起来、看得见”的教学实验，分别通过截尾和舍入两种量化方式对音频信号进行处理，不仅可以让学生直观感受量化噪声的存在与特性，还可以更深刻理解量化方式、量化位数等因素对量化噪声特性的影响。     

SAR实时方位预处理中的量化误差分析

实时方位向预处理是SAR实时成像处理器设计中的关键环节，预处理中运算精度的高低直接影响着SAR图像方位向聚焦的好坏。该文从有限字长角度出发，分析了预处理中滤波器系数量化误差和相乘截取误差对方位向脉冲压缩性能的影响，并提出了降低误差的方法。文中首先针对几种常用的量化字长进行分析，对比了不同的量化字长对滤波器性能的影响最后给出了经过脉冲压缩后的仿真结果。     

Receiver Performances Considering Effects of Gain Control and Quantization in FDM-Based Narrowband Communication Systems

In wireless receivers, in order to prevent the saturation of a received signal in an analog-to-digital converter (ADC), an automatic gain control (AGC), which maintains the amplitude of an analog signal at an appropriate fixed level, is frequently employed. This paper discusses the effects of gain control and quantization in the AGC and ADC on the receiver performance in frequency division multiplexing-based narrowband communication systems. Each communication channel is very narrow in these systems, so the channels are packed without breaks, making it difficult to extract the desired signal using an analog bandpass filter. Therefore, other multiple communication signals are in-band interference signals in these systems. In comparison with a single interference signal, a peak amplitude of multiple interference signals is greater than the that of single interference signal given the same interference power. It is well known that signals having a large peak value cause the degradation of bit resolution due to the AGC and ADC processes. The purpose of this paper is to provide a theoretical and numerical analysis of the effects of gain control and quantization on the receiver performance in such an environment. The analysis results indicated that (i) in-band interference signals decreased the bit resolution of the desired signal amplitude because of these processes and (ii) the effects of these processes depend on the amplitude intensity and the number of in-band interference signals, given the same interference power.     

将RS-485用于数字发动机控制应用

Ⅰ.简介 数字发动机控制采用数字处理器来控制电动机的运转。一般情况下数字处理器可采用一种或多种反馈方式,使其构成一个闭环系统。这可比作模拟控制系统和开环传动系统。 许多应用都采用了数字发动机控制,包括存储设备(如:磁盘驱动器)、工业机器人、高精度半导体制造、打印机以及复印机等。     

Digital Simulation of Field-Oriented Control of Induction Motor

This paper describes the simulation of a control scheme using the principle of field orientation for the control of a voltage source inverter-fed induction motor. The control principle is explained, followed by an algorithm to simulate various components of the system in the digital computer. The dynamic response of the system for the load disturbance and set-point variations have been studied. Also, the results of the simulation showing the behavior of field coordinates for such disturbances are given.