数控车床电器控制系统设计

针对数控车床电器控制系统中主轴变频调速、进给系统中数字分频器的电路设计、步进电机的控制与驱动及上位机接口的方案等问题,运用数字电路技术,设计结构简单,运行可靠的数控车床电器控制系统.     

一种模拟信号的远距离隔离传输方法

工业现场中,有时需要将传感器转换后的模拟信号传到控制中心进行AD转换后再送到控制器进行处理.提出了一种适用于高压环境下远距离传输模拟信号的方法：利用AD650构成压频和频压转换电路,先将模拟信号经压频电路线性变成一定频率的方波脉冲列,并经光纤传输到远处的控制中心.在控制中心再将脉冲列送入频压转换电路还原成电压信号,最终送入AD芯片转换成数字信号送入控制器进行处理.详细设计了电路结构和参数,并进行了实验.实验结果表明,设计方案可以有效地远距离传输模拟信号,既无衰减,又有良好的抗干扰能力.传输过程中的延时可控制在20us以下.     

Feedback control of one-link flexible manipulator with gear train

This article reports experimental results in control of a one-link flexible manipulator. A d.c. drive with gear train rotates the link with a tip-mass in the horizontal plane. A “stiff” hardware servo-system tracks the commanded drive velocity. We describe the experimental setup and develop a dynamic model for the one-mode flexible vibration control. We design and experimentally test controllers for active damping of the vibrations and stabilization of the link-tip position. Results for continuous control implemented with an analog computer and a sampled-data, digital-computer control are reported. A high control performance is achieved despite the gear-train friction influence. In addition, sampled-data digital controllers for tracking control of the link reference motion are designed and tested.     

Advanced control of a continuous oscillatory flow crystalliser

This paper presents the application and challenges of achieving Model Predictive Control (MPC) on two continuous oscillatory baffled crystallisation reactors, delivering precise product quality control in the face of raw material fluctuations. A key advantage of MPC is that it effectively deals with multivariable interactions and constraints that appear within the continuous crystallisation process. Using a flexible real-time software package, a control scheme is proposed that incorporates three MPC blocks for controlling reactor cooling profile, API (Active Pharmaceutical Ingredient) concentration and crystal size distribution, respectively. Furthermore, the solution is customisable and transferable to different crystallisation reactors as well as various APIs.     

Optimal design of dispersive tubular reactors at steady-state using optimal control theory

This paper studies the design of optimal temperature profiles for a class of exothermic, jacketed dispersive tubular reactors under steady-state conditions and subject to maximum temperature constraints. The studied class ranges from perfectly mixed continuous stirred tank reactors to plug flow reactors. The aim is to derive the Pareto optimal set of temperature profiles for conflicting conversion and energy costs, while extracting generic features from the obtained solutions. Hereto, a four step procedure which is based on a weighted sum of both costs and which combines indirect, analytical and direct, numerical optimal control techniques, is employed. The generic features are studied (i) along the Pareto set by varying the weights and (ii) along the reactor class by adapting the dispersion level.     

Fuzzy adaptive control of delayed high order nonlinear systems

This paper deals with the problem of tracking control for a class of high order nonlinear systems with input delay. The unknown continuous functions of the system are estimated by fuzzy logic systems (FLS). A state conversion method is introduced to eliminate the delayed input item. By means of the backstepping algorithm, the property of semi-globally uniformly ultimately bounded (SGUUB) of the closed-loop system is achieved. The stability of the closed-loop system is proved according to Lyapunov second theorem on stability. The tracking error is proved to be bounded which ultimately converges to an adequately small compact set. Finally, a computer simulation example of high order nonlinear systems is presented, which illustrates the effectiveness of the control scheme.     

数控伺服电脑绗缝系统设计

论述了基于Windows下开发的数控伺服电脑绗缝机的系统设计.该设计使用ISA接口的数字IO卡进行伺服电机控制,采用了主轴变频器计算机串口控制的先进技术.本文还对数控伺服电脑绗缝机的硬件和软件上的关键技术进行了详细的阐述.     

Suboptimal controls that maximize the probability of entering a target manifold

A suboptimal control scheme is developed for a linear time-dependent process subject to additive random disiturbances. An open-loop control law is chosen from a one-parameter class to optimize the tradeoff between control energy expenditure and the probability of entering a given target set. The computation is done by means of a digital computer simulation.     

Optimal reactor size distribution with fixed terminal constraints

The method of Lagrange multipliers is applied to find the optimal size distributions of isothermal continuous stirred tank reactors (CSTR) with fixed terminal constraints, to carry out a simple reaction. The control variables minimizing the Lagrangian of the problem can be found by the well known first and second order gradient techniques, or simply by using a non-linear root finder computer program. The technique is also applicable to non- isothermal CSTR optimization.     

Stabilization of Arbitrary Switched Linear Systems With Unknown Time-Varying Delays

We consider continuous time switched systems that are stabilized via a computer. Several factors (sampling, computer computation, communications through a network, etc.) introduce model uncertainties produced by unknown varying feedback delays. These uncertainties can lead to instability when they are not taken into account. Our goal is to construct a switched digital control for continuous time switched systems that is robust to the varying feedback delay problem. The main contribution of this note is to show that the control synthesis problem in the context of unknown time varying delays can be expressed as a problem of stabilizability for uncertain systems with polytopic uncertainties.     

Feedforward output-feedback control for continuous exothermic reactors with isotonic kinetics

The robust feedforward (FF) output-feedback (OF) control problem of (possibly open-loop unstable) continuous exothermic jacketed reactors with isotonic kinetics with respect to reactant concentration is considered. The volume, temperature, and concentration must be regulated by manipulating the feed, exit and coolant flowrates on the basis of volume and temperature measurements. The problem is addressed as an interlaced controller-observer design within a constructive control framework. The result is a quasi linear-decentralized (qLD) FF-OF dynamic controller which: (i) recovers (up to observer convergence) the behavior of a robust nonlinear FF-SF controller, (ii) has closed-loop stability conditions coupled with conventional-like tuning guidelines, and (iii) constitutes an add-on to the PI control scheme commonly employed in industrial reactors. The approach is tested with an open-loop unstable reactor example through simulations.     

基于SOPC的嵌入式WTB网络控制节点机的研制

探讨一种基于可编程片上系统的嵌入式绞线式列车总线(WTB)网络控制节点机的研制方案。该方案采用FPGA作为核心器件，将Altera 的NisoII软核处理器与WTB控制逻辑集成在单片FPGA 内，取代了原来的工控节点机和控制部件相组成的方案。减小了产品的体积和重量，降低了硬件开发成本。该文给出了系统的总体设计方案，并分析了测试结果。     

Experimental implementation and validation of a novel minimal control synthesis adaptive controller for continuous bimodal piecewise affine systems

This paper presents the first digital implementation of a novel model reference adaptive scheme for the control of continuous bimodal piecewise affine systems. The algorithm is based on the minimal control synthesis algorithm, originally developed as a MRAC for smooth systems. The resulting adaptive algorithm is a switched feedback controller able to cope with uncertain continuous PWA systems. The analogue continuous-time control law is implemented by using a digital low-cost commercial microcontroller. The aim is to control a piecewise-linear electrical circuit. The experimental validation process is made challenging by the presence of measure uncertainties, noise, quantization errors, unmodeled nonlinear dynamics and computational delays. Experiments confirm the effectiveness of the controller to cope with switching in the circuit dynamics, establishing the strategy as a viable control tool. Nevertheless, the experimental analysis provides a first insight into the robustness of the algorithm.     

CBTC仿真系统中的列车控制系统的研制

本文给出了CBTC仿真系统中的列车控制系统的设计方案。此系统是由PC机通过无线路由跟列车上的无线通信模块连接通信,接收列车运行及列车位置的数据信息。文章主要介绍列车速度调节及列车位置定位的实现方法,本文还给出了VOBC和其它车载设备之间的关系图。     

基于数字PID算法的台达运动控制器在音叉多线切割机上的应用

在连续一时间控制系统中,PID控制器在各类自动化系统中应用得非常广泛。其设计技术成熟,长期以来形成了典型的结构,参数整定方便,结构变化灵活,能满足一般的控制要求。数字PID控制比连续PID控制更为优越,因为计算机程序的灵活性,很容易克服连续PID控制中存在的问题,经修正可得到更为完善的数字PID算法。     

基于EPP工作方式下的CCD图像数据快速采集

为了加快科学级CCD相机图像数据的计算机采集速度，设计了CCD信号读出、A／D转换、数据传输流水线工作方式采集系统，不提高电荷转移速度的情况下快速采集图像。 充分利用计算机资源，采用计算机并行口的EPP工作方式的地址读和数据字读的选通信号，通过硬件电路产生CCD驱动、A／D转换、数据传输等所需控制信号的方法，并用电平标准转换方法，实现了射线数字成像检测中的较远距离图像数据快速采集。     

一种对象具有未建模动态时的间接式混合自适应极点配置方案

In this paper, we propose an indirect hybrid adaptive pole placement scheme for plant with numodeled dynamics. Normalization technique and covariance reset least square method with forgetting factor are used for parameter estimation. We design the discrete adaptive control law directly from continuous plant, which guarantees the robust stability of the closed-loop system. Theoretical analysis and digital simulation results show that this scheme is superior to similar continuous scheme and discrete scheme.     

一种对象具有未建模动态时的间接式混合自适应极点配置方案

本文提出了一种对象具有未建模动态时的间接式混合自适应极点配置方案。在此方案中利用规范化技术和带遗忘因子的协方差重置递推最小二乘法估计对象参数,并直接根据连续对象设计离散自适应控制律,保证了闭环系统的鲁棒稳定性。理论分析和数字仿真均表明此方案优于相类似的全连续和全离散方案。     

基于回归型支持向量机的数字图像水印新算法

以回归型支持向量机（Support Vector Regression,SVR）理论为基础,提出一种数字图像水印新算法.该算法能够结合图像局部相关性,选取稳定的特征向量并获得SVR训练模型,进而利用SVR训练模型嵌入和提取数字水印信息.该算法以保证不可感知性和鲁棒性的良好平衡为前提,实现了数字水印的盲检测.仿真实验表明,本文算法不仅具有较好的不可感知性,而且对叠加噪声、JPEG压缩、锐化、平滑滤波、对比度增强等常规处理及扭曲、剪切等几何攻击均具有较好的鲁棒性,其整体性能明显优于现有SVM图像水印方案.     

双相位编码在数据通信中的应用

双相位码是数据串行通信和记录中使用的一种编码方法。在集散控制系统中使用的磁带机和飞行数据记录器中得到广泛应用。本文主要介绍双相位码的编码、译码原理及双相位码的特点;重点论述双相位码的编码和译码过程在微机上的实现。工程实践和实验表明,用微机实现双相位码的编码和译码过程是切实可行的。试用在TDC-2000集散控制系统中获得了圆满成功。