转炉汽包液位测量分析

汽包在转炉冶炼生产过程中扮演着比较重要的角色,汽包液位测量直接影响到氧枪冶炼是否能顺利进行。本文介绍了几种汽包液位测量方式,总结了各种测量方法的优缺点。     

Tracking the best level set in a level-crossing analog-to-digital converter

In this paper, we investigate level-crossing (LC) analog-to-digital converters (ADC)s in a competitive algorithm framework. In particular, we study how the level sets of an LC ADC should be selected in order to track the dynamical changes in the analog signal for effective sampling. We introduce a sequential LC sampling algorithm asymptotically achieving the performance of the best LC sampling method which can choose both its LC sampling levels (from a large class of possible level sets) and the intervals (from the continuum of all possible intervals) that these levels are used based on observing the whole analog signal in hindsight. The results we introduce are guaranteed to hold in an individual signal manner without any stochastic assumptions on the underlying signal.     

Optimizing fuel consumption and pollutant emissions of gasoline-HEV with catalytic converter

Because of more and more stringent vehicle emission standards, Hybrid Electric Vehicles (HEV) are developed. Gasoline-HEV are equipped with 3-Way Catalytic Converter (3WCC). So the energy management systems of such vehicles, which must reduce not only fuel consumption, but also vehicle pollutant emissions, have to consider the 3WCC heating. A pollutant constrained energy management strategy is presented. A 3WCC multi-0D model is built from physical equations, with a good complexity-performances compromise. An off-line optimal strategy allows the joint minimization of pollution and fuel consumption with only one parameter to tune, while considering all the standardized pollutant emissions. This strategy reduces significantly the vehicle emissions for a minor fuel consumption increase and leads to define 3WCC smart heating. Thus an on-line smart heating strategy is implemented in a HyHIL (Hybrid Hardware In the Loop) test bench, reducing the pollutant emissions of the classical charge sustaining strategy by 30% for CO and 10% for NO_X.     

Foam level control in a water model of the LD converter process

This paper deals with estimation and control of foam level in dynamic foaming. An improved foam level estimation methodology from a microphone signal and its automatic calibration is presented. The dynamical reaction of the foam level on air lance movements is modelled using system identification. Based on the resulting mathematical model, a controller for foam level stabilisation is designed and applied to a water model, representing the LD converter process. It is shown that the foam level can be controlled using a microphone as the measurement device and air lance movement as the actuator.     

Shape modeling with front propagation: a level set approach

Shape modeling is an important constituent of computer vision as well as computer graphics research. Shape models aid the tasks of object representation and recognition. This paper presents a new approach to shape modeling which retains some of the attractive features of existing methods and overcomes some of their limitations. The authors' techniques can be applied to model arbitrarily complex shapes, which include shapes with significant protrusions, and to situations where no a priori assumption about the object's topology is made. A single instance of the authors' model, when presented with an image having more than one object of interest, has the ability to split freely to represent each object. This method is based on the ideas developed by Osher and Sethian (1988) to model propagating solid/liquid interfaces with curvature-dependent speeds. The interface (front) is a closed, nonintersecting, hypersurface flowing along its gradient field with constant speed or a speed that depends on the curvature. It is moved by solving a “Hamilton-Jacobi” type equation written for a function in which the interface is a particular level set. A speed term synthesized from the image is used to stop the interface in the vicinity of object boundaries. The resulting equation of motion is solved by employing entropy-satisfying upwind finite difference schemes. The authors present a variety of ways of computing the evolving front, including narrow bands, reinitializations, and different stopping criteria. The efficacy of the scheme is demonstrated with numerical experiments on some synthesized images and some low contrast medical images     

Numerical study of an optimal control problem for a catalytic converter function

We introduce a model of a catalytic converter, and we study mathematical properties of a control function and a cost function as an optimal control problem. We give a finite-difference scheme for solving various cost functions and discuss the results.     

Nonlinear control of a coupled PDE/ODE system modeling a switched power converter with a transmission line

We consider an infinite dimensional system modeling a boost converter connected to a load via a transmission line. The governing equations form a system coupling the telegraph partial differential equation with the ordinary differential equations modeling the converter. The coupling is given by the boundary conditions and the nonlinear controller we introduce. We design a nonlinear saturating control law using a Lyapunov function for the averaged model of the system. The main results give the well-posedness and stability properties of the obtained closed loop system.     

Design of a non-inverting synchronous buck-boost DC/DC power converter with moderate power level

This paper presents the design of a non-inverting synchronous buck-boost DC/DC power converter with moderate power level for a solar power management system. The buck-boost requirement arises from the rapid changes in the atmospheric condition or the sunlight incident angle. The system mainly consists of the non-inverting synchronous buck-boost DC/DC power converter, MOSFET drivers, anti-cross conduction logic circuitry, feedback compensator, and PWM regulator. The system is capable of converting the supply voltage source to higher and lower voltages to the load terminal with voltage polarity unchanged. The voltage at the load terminal is controlled by continuously adjusting the duty cycle of the PWM regulator. Application of the buck-boost converter in battery management system design is also addressed.     

浅析锅炉水包数学模型及控制方法

锅炉汽包水位是现代电厂锅炉安全运行的重要监控参数。本文在综合分析了以往汽包蒸发区数学模型的基础上,针对锅炉蒸发区的特点,依据质量和能量平衡,建立了汽包水位非稳态数学模型,并提出了水位控制的方法,对汽包锅炉的安全运行和控制具有参考意义。     

Thermodynamic modeling of the yttrium–oxygen system

The updated thermodynamic evaluation of the yttrium–oxygen (Y–O) system is presented. Thermodynamic model parameters of all phases, i.e., liquid, α$\alpha$-Y, β$\beta$-Y, α$\alpha$- Y ₂O₃ and β$\beta$- Y ₂O₃, have been derived by the least-squares minimization procedure using Thermo-Calc^®software. The backward compatibility of the refined parameters with experimental data has been demonstrated by calculation of phase and property diagrams.     

Stability of the solutions of the observation error equations at control of the steel converter process

Consideration was given to the nonlinear observer with the feedback sensitivity function which showed itself well in estimating the carbon and silicon content in the converter melt on the basis of the nonlinear model with time-constant parameters. In the case of controlling the melt temperature by the cooling additives, the plant parameters vary in time, which requires additional studies. For the estimation error under permanent perturbations where the matrix of the linear part is time-dependent, the zero solution of the equation system was proved to be stable.     

Analytical subthreshold current modeling of nanoscale ultra-thin body ultra-thin box SOI MOSFETs with a vertical gaussian doping profile

Microsystem Technologies - Based on the evanescent-mode analysis, an insightful study of the channel potential is performed for the nanoscale ultra-thin body ultra-thin box SOI MOSFETs with a...     

Extended Kalman filter and adaptive backstepping for mean temperature control of a three‐way catalytic converter

This contribution is concerned with an adaptive control strategy for the mean temperature of an automotive three‐way catalytic converter. Tailored finite‐dimensional approximations of the complex infinite‐dimensional mathematical model of the catalytic converter serve as a basis for the design of an extended Kalman filter for state profile estimation and of an adaptive backstepping controller for the mean temperature. Although the model used for observer design relies on (semi‐)discretising the infinite‐dimensional model, a simple model for the mean temperature employing a phenomenological approach to describe the reaction heat is used for control design. The observer/controller is tested in simulation scenarios using a validated model of the three‐way catalytic converter. Copyright © 2013 John Wiley & Sons, Ltd.     

CLB总线事务级建模及其仿真平台的设计

提出了采用事务级建模的方法对国内具有自主知识产权的国芯CLB总线进行建模的方案,并利用多时钟技术来保证模型的周期精确.同时对所建模型进行了VCI接口协议的封装,便于其在不同平台上的移植.为了验证本设计的正确性,在电子系统级平台上实现了基于CLB的SoC.实验结果表明,本模型可以大大提高软、硬件协同开发验证的效率,增强I...     

Modeling task completion time of in-vehicle information systems while driving with keystroke level modeling

The use of touchscreen-based in-vehicle information systems (IVIS) is increasing. To ensure safe driving, it is important to evaluate IVIS task performance during driving situations. Therefore, we proposed a model to assess the task completion time (TCT) of IVIS tasks while driving using a keystroke-level modeling (KLM) technique. The basic assumptions and heuristic rules of driver behaviors were considered. In addition, based on the characteristics of visual and manual IVIS interactions, we determined the basic unit operators (i.e., visual, manual, and mental operators). User experiments were conducted to determine the individual execution times of unit tasks and to measure the TCT of IVIS tasks while driving. Based on the heuristic rules for model development and individual task execution times, we derive a predictive model for the TCT of IVIS tasks. We used a regression analysis to validate the modeling procedure, showing that the observed TCT was found to have a strong positive correlation with the predicted time from the modeling process. The findings showed that the task completion time needed to perform a secondary task in a driving context can be predicted by KLM. This study provides meaningful insights into the design of touchscreen-based IVIS to enhance driving safety.