Variable slope pulse pump controller for stepping position servocontrol system using frequency-locked technique

A stepping position servomotor system based on frequency-locked technique is proposed for high-performance incremental position control. A novel microcomputer-based variable slope pulse pump controller (VSPPC) using multi-rate sampling technique is exploited. The proposed VSPPC can adaptively generate motor motion profile, and it can replace the traditional PID controller for applications in stepping motor position control. System models are constructed for stability study and computer simulation. A prototype is designed and implemented to verify the theoretical studies and examine the performance of the proposed system. Position and speed responses of a realized system for 0-50 cm movement with 10 mm resolution is investigated. With the variable slope technique employed in VSPPC, the acquisition time for long-distance movement is reduced significantly and is close to that of short-range movement. In particular, the position acquisition time has improved about 67-79% compared to the conventional position control system     

LQG/LTR control of an AC induction servo drive

A new design method based on the linear-quadratic-Gaussian with loop-transfer-recovery (LQG/LTR) theory has been developed for the design of high performance AC induction servomotor drives using microcomputer-based digital control. The principle of field orientation is employed to achieve the current decoupling control of an induction motor. An equivalent model representing the dynamics of the decoupled induction motor has been developed. Based on the developed model with specified parameter uncertainties and given performance specifications, a frequency domain loop-gain-shaping method based on the LQG/LTR theory is proposed for the design of the servo loop controller. A microcomputer-based induction servomotor drive has been constructed to verify the proposed control scheme. Simulation and experimental results are given to illustrate the effectiveness of the proposed design method     

Microcomputer-Based Synchronous Multichannel Data Acquisition System

Most of the multichannel data acquisition systems invariably use a sequential data conversion method. Thus, the sampling instants of the analog signals are dispersed in time. However, synchronous sampling is desirable when the data are required for system indentification studies, or when fast data conversion of a large number of analog channels is involved. A cost-effective technique is proposed here for a microcomputer-based 8-channel synchronous data acquisition system. The software routine for complete data conversion and storing the values in RAM takes only 93 /s=u/s of CPU time, when used with a single-board microcomputer SDK-85. As the A/D converters (ADC's) are operated in a memory mapped mode, the system can be expanded almost indefinitely. The circuit can handle ADC's of 12-bit resolution as well.     

基于模糊控制的定子电阻辨识研究

定子电阻的变化对异步电机矢量控制系统的性能具有重要的影响,准确获取定子电阻值在高性能电机控制系统中具有十分重要的意义。本文基于模糊控制理论,设计了一种结构简单的模糊定子电阻辨识器。在此基础上,根据矢量控制理论,采用Matlab/Simulink软件设计了异步电机矢量控制系统。仿真结果表明,辨识的定子电阻误差较小,系统响...     

A Microcomputer-Based Fluid Infusion System for the Resuscitation of Burn Patients

Fluid replacement therapy, essential in the treatment of burn patients, continues to be a difficult clinical responsibility. Inherent variability of individual patient response to conventional burn fluid formulas and the practical limitations involved in manually adjusting fluid infusion rates on a continuous basis combine to hamper proper fluid administration. A microcomputer-based fluid infusion, data acquisition, and control (FIDAC) system has been developed to optimize fluid volume restoration and maintenance in the clinical treatment of burn and trauma patients. The FIDAC system provides real-time measurement of infused fluid and urine output, the display and routine recording of fluid balance parameters, and closed-loop control of fluid resuscitation. The system has been evaluated through a series of animal tests and is currently in clinical use at the University of Utah Medical Center Intermountain Burn Unit.     

WK系列挖掘机电机辨识研究

从理论分析出发,重点阐述了WK系列电铲调试过程中电机辨识的意义及过程。首先,从异步交流电机的数学模型分析,对变频调速系统的电机辨识进行了理论分析。然后,分别对矢量控制系统和直接转矩系统进行阐述,论述了电机辨识的意义,作用。最后,通过分析现场实验结果,数据表明辨识后的变频传动系统实现了高性能速度控制。     

基于LabVIEW的电机转速监测系统的设计

在电机控制系统中,转速测量的精确度、实时性和稳定性直接影响电机调速系统的性能。文中设计了一种基于LabVIEW软件平台的电机转速监测系统,选择绝对式光电编码器和单片机作为前端转速信号的采集系统,通过RS-232串口通信将数据传送至上位机;利用LabVIEW的数据处理和显示功能,对转速信号进行实时地处理、显示和保存。该设计在开关磁阻电机调速系统中进行了实验测试,结果证明,该方法人机界面良好、测速范围宽、精度高、响应速度快、抗干扰能力强。     

基于贴片机的伺服辨识系统架构

针对贴片机伺服系统数学模型未知,不能直接测量到频域性能的难题．架构基于贴片机的伺服辨识系统,其中包括激励信号的产生与加载、数据采集、控制对象辨识以及伺服系统控制性能分析等功能。使用伺服辨识系统可以辨识出伺服系统的数学模型,定量分析伺服系统的控制性能。同时,为直观调试伺服系统控制参数,应用先进伺服控制策略提供了条件;为提高贴片机的贴装效率和精度提供了有效研究手段。     

复合材料结构实时撞击监测系统

为实时监测并评估发生在复合材料结构上的外部低速撞击,研制了一套基于压电传感器的被动式传感系统。系统包括分布式压电传感器网络、便携式采集硬件及分析软件。压电传感器网络覆盖结构被监测区域,并实时在线监测由于结构撞击而产生的应力波;多通道采集硬件并行采集各传感器信号,并以直接存储器访问(DMA)形式与分析软件进行数据交换;撞击事件评估采用了系统辨识技术,分析软件利用集成的系统辨识模型及获得的实时传感器数据对撞击位置和撞击载荷进行反问题求解。实验结果表明,研制的被动式传感系统能够准确辨识发生在复合材料结构上的撞击事件,并可有效估计撞击位置及撞击载荷历程。     

LabVIEW与普通数据采集卡连接在伺服电机参数测试方面的应用

随着工业的发展,伺服电机的应用越来越普遍,为了研究伺服电机能否按照相应的要求去工作,研究开发了LabVIEW与普通数据采集卡连接的测试系统,同时本文将该测试系统应用于某旋转台伺服电机速度及电流的测试。实践表明,LabVIEW与普通数据采集卡连接,不仅缩短了软件开发周期,同时由于普通数据采集卡的使用,大大减低了项目的成本。     

基于半实物仿真的异步电机实时运动控制系统实验平台设计

异步电机的控制是本科教学中的重要内容。传统DSP电机控制实验程序复杂,而采用DSPACE的半实物仿真造价昂贵。本文设计了将原有纯软件连续系统仿真改进为DSP控制器所支持的离散化控制算法模型,可以实现从 Simulink 模型到控制器实时硬件代码的自动下载,完成上位机与控制器的数据交互,基于GUI环境可实时对电机运行状态和参数波形在线观测并发送控制指令。本文对异步电机控制的教学有一定的指导作用。     

Modeling and Identification of Elastic Robot Joints With Hysteresis and Backlash

This paper presents a novel approach to the modeling and identification of elastic robot joints with hysteresis and backlash. The model captures the dynamic behavior of a rigid robotic manipulator with elastic joints. The model includes electromechanical submodels of the motor and gear from which the relationship between the applied torque and the joint torsion is identified. The friction behavior in both presliding and sliding regimes is captured by generalized Maxwell-slip model. The hysteresis is described by a Preisach operator. The distributed model parameters are identified from experimental data obtained from internal system signals and external angular encoder mounted to the second joint of a 6-DOF industrial robot. The validity of the identified model is confirmed by the agreement of its prediction with independent experimental data not previously used for model identification. The obtained models open an avenue for future advanced high-precision control of robotic manipulator dynamics.     

嵌入式控制系统的VXI总线数据采集软件设计

嵌入式控制系统需要通过电子测量方式进行数据采集,为控制系统提供输入参量模型,采用VXI总线技术进行嵌入式控制系统的32通道控制数据采集和实时数据记录,方便控制系统和客户端现场分析数据.嵌入式控制系统的VXI总线数据采集软件是建立在对控制信息的特征采样和控制参量的信息输入基础上,进行VXI总线数据采集系统总体设计描述和功能指标分析,数据采集通过发射天线、接收天线、发射机、接收机、控制器等构件实现.数据采集系统的软件模块设计包括了通道设置、触发设置、数据端口设置、数据可视化模块设计和数据读取回放等子模块,通过软件优化设计实现VXI总线数据采集.实验分析结果表明,该系统进行数据采集的输入和输出的波形控制的匹配性能较高,稳定性较好,具有较高的数据采集精度.     

Identification of induction motor parameters from transient statorcurrent measurements

This paper describes three methods for estimating the lumped model parameters of an induction motor using startup transient data. A three-phase balanced induction motor is assumed. Measurements of the stator currents and voltages are required for the identification procedure, but no measurements from the motor shaft are needed. The first method presented applies simple models with limited temporal domains of validity and obtains parameter estimates by extrapolating the model error bias to zero. This method does not minimize any specific error criterion and is presented as a means of finding a good initial guess for a conventional iterative maximum-likelihood or least-squares estimator. The second method presented minimizes equation errors in the induction motor model in the least-square sense using a Levenburg-Marquardt iteration. The third identification method is a continuation of the Levenburg-Marquardt method, motivated by observed properties of some pathological loss functions. The third method minimizes errors in the observations in the least-squared sense and is, therefore, a maximum-likelihood estimator under appropriate conditions of normality. The performance of the identification schemes is demonstrated with both simulated and measured data, and parameters obtained using the methods are compared with parameters obtained from standard tests     

An Integrated Approach to Digital Control of AC Motor Drives

The paper describes a high-performance microcomputer-based controller for inverter-fed ac motor drives. Both the implementation of high-level drive control policies and on-line computation of three-phase switching patterns for control of the inverter output frequency and voltage, are carried out by a single ?P. The selection of a pulsewidth modulation (PWM) strategy with limited processing requirements, has made the integration of these features possible without devising a multiprocessor architecture, or relying upon dedicated hardware to support specific functions. Peculiar facilities, like on-line reconfigurability of control parameters, real-time tracing of system behavior and diagnostics, have also been implemented to enhance the overall controller performance and flexibility. The validity of the integrated solution has been thoroughly verified by extensive experimental tests carried out with a prototype system composed of an 8085-based microcomputer, a 30-kVA three-phase transistor inverter, and a 20-kW induction motor.     

A design method of the wide-area damping controller of the power system considering the communication time-delay based on an iterative identification

There must be a non-negligible communication time-delay in the transmission process of wide area information through the power system. Communication time-delay will reduce the system stability or even cause system instability, and also there exists an identification error problem in the model identification. Therefore, the identification error will make model parameters not accurate enough, and it cannot ensure the control effect of the power system time-delay damping controller. Aiming at the problem of communication time-delay and identification error in the power system, firstly, a closed-loop time-delay model of the power system is described in this paper. Secondly, a design method of iterative identification damping controller of the power system considering the time-delay (constant delay and time-varying delay) is proposed. In addition, the whole step of the proposed method and a mathematical calculation method of the exact time-delay controller model are given. Finally, the four-machine two-area system model is taken as an example in this paper. Simulation results show that the response of both angle and active power of motor can stabilize within 8 seconds. The designed controller in this paper can effectively suppress low frequency oscillation and ensure the stability of power system.     

光电跟踪转台的控制模型辨识

针对大功率永磁同步电机驱动的光电跟踪转台,提出了一种基于特征系统实现算法的控制模型辨识方法。首先,根据永磁同步电机的矢量控制原理,对白噪声测试系统进行了系统配置;其次,采用功率谱密度函数的分析方法对系统的输入和输出数据序列进行了分析,得到了系统的频率响应函数;最后,通过特征系统实现算法对系统的马尔可夫参数进行了辨识,获得了光电跟踪转台的控制模型。实验结果表明:采用特征系统实现算法可以精确地辨识出光电跟踪转台的控制模型,该控制模型能够较好地反映系统的动态特性,为控制器算法的设计提供了理论依据,具有较好的实用性。     

基于FPGA的图像采集模块的设计

针对传统的PCI图像采集卡的弊端,采用OV7620和Cyclone系列FPGA设计了适用于便携式嵌入式系统的图像采集模块。该模块采用“乒乓模式”设计思想,具有8Mbit的高速缓存空间,并利用嵌入式逻辑分析仪对原始图像数据的采集和缓存。系统实现图像原始数据的采集和缓存,保证图像数据的连续和完整性,该系统外部接口电路简单,便于使用和移植,具有体积小、功耗低、速度快等优点,可应用于便携式设备的图像采集。     

基于云平台的同步电机远程数据采集与监视控制系统设计

数据采集与坚实控制系统在智能制造领域中是一项重要的组成。电动机是一种动力输出设备,并且应用十分广泛,同时还拥有许多的种类。基于工作电源的差异,电动机可以将其分为交流电动机、直流电动机两个大体类型。而同步电机则是一种交流感应电机,与异步电机十分类似。本文将监视控制系统应用于生产中的同步电机,设计数据采集与监视控制系统,该系统可以有效的增强生产的安全性,并获得良好的效果。     

基于加权随机森林算法的空巢电力用户识别方法

针对当前政府和社会对空巢老人的识别缺乏有效技术手段的问题,提出了一种基于加权随机森林算法的空巢电力用户识别方法。首先通过调查问卷获取部分准确空巢用户标签,并从用电水平、用电波动、用电趋势 3 个方面构建用户用电特征库,由于空巢与非空巢存在用户数据不平衡问题,采用加权随机森林算法改善机器学习对数据敏感的现象,将该算法模型在电力公司采集系统部署上线,并对2 000户未知类型用户进行空巢识别,其空巢识别准确率达到 74.2%。结果表明,从用电角度研究对空巢老人的识别,可以帮助电网公司了解空巢老人的个性化、差异化需求,从而为用户提供更精细的服务,也可以协助政府和社会开展帮扶工作。