Optimal selection of soft sensor inputs for batch distillation columns using principal component analysis

In this paper, a novel methodology based on principal component analysis (PCA) is proposed to select the most suitable secondary process variables to be used as soft sensor inputs. In the proposed approach, a matrix is defined that measures the instantaneous sensitivity of each secondary variable to the primary variables to be estimated. The most sensitive secondary variables are then extracted from this matrix by exploiting the properties of PCA, and they are used as input variables for the development of a regression model suitable for on-line implementation.This method has been evaluated by developing a soft sensor that uses temperature measurements and a process regression model to estimate on-line the product compositions for a simulated batch distillation process. The identification of the optimal soft sensor inputs for this case study has been discussed with respect to the definition of the sensitivity matrix, the data sampling interval, the presence of measurement noise, and the size of the input set. The simulation results demonstrate that the proposed approach can effectively identify the size and configuration of the input set that leads to the optimal estimation performance of the soft sensor.     

基子虚拟仪器技术的直流数字电压表计量系统设计

本文主要介绍了用VB6．0实现的数字电压表检测系统。本系烷由FLUKE公司的5520A的多功能多产品校准器、GPIB板卡以及基于虚拟仪器的用户界面组成。核计量系统使用虚拟仪器技术过GPIB板卡追行信息通信，使系统规模最小化，以提高系统的稳定性。该系统具有友好的操作界面，易于维护和扩展。     

虚拟仪器-测试技术的新领域

虚拟仪器是计算机技术在仪器仪表领域中应用所形成的一种新型的、富有生命力的仪器种类。本文较全面地论述了虚拟仪器的概念、硬／软件基础,着重介绍了以 LabVIEW为例的虚拟仪器软件开发平台及其应用。     

基子视频图像的在线测量技术的研究

在线测量技术在冶金行业中得到了越来越多地应用，本文针对槽钢长度在线测量的主要实现技术进行了研究和模拟仿真，并提出了一种基于视频图像的在线测量运动槽钢长度的方法。该方法利用图像采集卡捕捉两张不同时刻的图像，经过中值滤波预处理后进行图像减法确定槽钢的运动区域，然后根据运动区域得到槽钢的灰度值范围，接着对图像进行阈值分割，最后利用分割的图像计算出槽钢的长度。     

Guaranteed Cost Control for Discrete-time Singular Large-scale Systems with Parameter Uncertainty

The problem of optimal guaranteed cost control for discrete-time singular large-scale systems with a quadratic cost function is considered in this paper.The system under discussion is subject to norm bounded time-invariant parameter uncertainty in all the matrices of model.The problem we address is to design a state feedback controller such that the closed-loop system not only is robustly stable but also guarantees an adequate level of performance for all admissible uncer- tainties.A sufficient condition for the existence of guaranteed cost controllers is presented in terms of linear matrix inequalities(LMIs),and a desired state feedback controller is obtained via con- vex optimization.An illustrative example is given to demonstrate the effectiveness of the proposed approach.     

The Nyquist robust sensitivity margin for uncertain closed‐loop systems

The Nyquist robust sensitivity margin is proposed as a new scalar indicator of robust stability that also provides a meaningful quantitative assessment of the worst sensitivity realized by the uncertain closed loop. After formulating and discussing in detail the underlying optimization problem required for the calculation of the margin, the approach is applied to the characterization of the robust stability of a closed‐loop featuring a linear system with an affine uncertainty structure and a parametric uncertainty set described by a real rectangular polytope. The capabilities of the methodology are illustrated through examples, which include an approach for quantifying alternative robustness margins, such as a parametric stability margin. The computational algorithm is systematic and can be carried out with high numerical precision. Copyright © 2005 John Wiley & Sons, Ltd.     

A robust deconvolution scheme for fault detection and isolation of uncertain linear systems: an LMI approach

Optimal H_∞ deconvolution filter theory is exploited for the design of robust fault detection and isolation (FDI) units for uncertain polytopic linear systems. Such a filter is synthesized under frequency domain conditions which ensure guaranteed levels of disturbance attenuation, residual decoupling and deconvolution performance in prescribed frequency ranges. By means of the Projection Lemma, a quasi-convex formulation of the problem is obtained via LMIs. A FDI logic based on adaptive thresholds is also proposed for reducing the generation of false alarms. The effectiveness of the design technique is illustrated via a numerical example.     

车辆转向系几何参数及测量原理

将主销后倾角和主销内倾角纳入“四轮定位”概念,相对于非转向轮推进线对这些角度进行了定义,推导出转向系统几何参数之间的关系,进而得出后倾角和内倾角的计算公式(测量原理)。由于在不可见的转向轴线平面投影图上无法安装测量装置,因此可以利用推导出的计算公式间接测量后倾角和内倾角,同时阐明了使用这种测量方法必须遵守的限制条件,并以FNCA型非接触式车轮定位仪为例简单介绍了转向轴线几何参数的测量过程。     

基于PSD技术的炮口偏移量测量方法研究

提出了一种基于PSD技术的炮口偏移量测量方法，利用PSD线位移的变化测量角度，从而测量炮口偏移量。介绍了方法的系统组成及测量原理，根据信号传递过程确定了该方法的误差因素，分析了误差产生的原因，估算了该方法的测量精度，结果表明，采用该方法测量炮口偏移量是可行的。     

稳健统计与实验室不确定度和能力验证

介绍稳健统计基础,分析稳健统计性质,并将稳健统计应用于实验室不确定度计算和实验室能力验证.