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A DATA-BASED MEASURE FOR INTERACTIONS IN MULTIVARIATE SYSTEMS

IFAC Proceedings Volumes 2006年第2期39卷 681-686页

作者： M. Rossi A.K. Tangirala S.L. Shah C. Scali Computer Process Control Lab Dept. of Chemical Engineering University of Pisa Pisa Italy Dept. of Chemical Engineering IIT Madras Chennai India Department of Chemical & Materials Engineering - University of Alberta Edmonton Canada

This article focusses on the control loop performance diagnosis of a multivariate system with emphasis on the presence of interactions and poor performance of control loops. The paper provides a data-driven technique to determine if a decentralized PI(D) + controller will suffice or if an advanced controller ( e.g. , MPC) is necessary to handle the control interactions and improve the loop performance. Two different techniques are proposed: the first one, based on the Power Spectrum of the error, analyzes interactions in the frequency domain, while the second one, based on the evaluation of a modified IAE (Integral of Absolute Error), analyzes interactions in the time domain. A performance index for the controller is also proposed for the case of set-point tracking. Simulation and experimental case studies are presented to highlight the applicability of the proposed techniques.

关键词： Interactions MIMO systems frequency domain time domain

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Closed-Loop Identification of State Space Models using Subspace Techniques

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IFAC Proceedings Volumes 1997年第9期30卷 37-42页

作者： Hemant Jha Christos Georgakis Chemical Process Modeling and Control Research Center and Department of Chemical Engineering Lehigh University Bethlehem Pennsylvania 18015 Phone: (610)-758-5432 Fax:(610)-758-5297

The paper presents a subspace algorithm which identifies the process model from closed-loop data. The algorithm is based on the use of a closed-loop oblique projection for the direct identification of the plant dynamics. This closed-loop oblique projection is particularly useful because it eliminates the use of a minimal realization step after the identification has been performed. Similar to the open-loop algorithm, the proposed closed-loop algorithm is ideally suited for MIMO problems.

关键词： Closed-loop Identification Subspace Methods State Space Models Multivariable Systems Matrix Projection

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A Method for Assessing the Effects of Design Parameters on controllability

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IFAC Proceedings Volumes 1994年第7期27卷 85-91页

作者： P.R. Lyman W.L. Luyben Chemical Process Modeling and Control Research Center Department of Chemical Engineering Lehigh University Bethlehem Pennsylvania USA 18015 Phone:(610)758-4256 Fax:(610)758-5297

A method is presented for identifying process design modifications that improve process controllability. The methodology includes the use of designed experimentation to examine multiple design and control factors simultaneously. Each trial within the designed experiment includes estimation of the capital and operating costs and quantification of the controllability. A recycle process is used in an example of the method. The method reveals that the size of the reactor has a large influence on the controllability and the control structures in combination with the other factori show potential for dynamic response improvement. Physical arguments are used to explain these observations.

关键词： Computer simulation control system analysis control system design dynamic response simulation sensitivity analysis

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Multivariable Anti-Windup controller Synthesis incorporating Multiple Convex Constraints

Multivariable Anti-Windup Controller Synthesis incorporating...

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American control Conference (ACC)

作者： Pradeep Y. Tiwari Eric F. Mulder Mayuresh V. Kothare Chemical Process Modeling and Control Center Department of Chemical Engineering Lehigh University Bethlehem PA USA Exxon-Mobil Chemical Baytown TX USA

We study the problem of multivariable anti-windup controller synthesis that incorporates trade-offs between unconstrained linear performance and constrained anti- windup performance. In our previous work [13], we presented a framework for simultaneous design of a linear output feedback controller and a static anti-windup compensator using Linear Matrix Inequalities (LMIs). This framework deviated from the conventional two step paradigm of anti-windup by proposing a one-step synthesis while still maintaining the anti-windup structure. However, the work in [13] did not provide conclusive demonstration of the efficacy of this formulation through realistic practical examples. In this paper, we further study the framework in [13] and explicitly demonstrate its capability in providing effective constrained anti-windup controller performance for two benchmark problems, viz. a vibration isolation table and a multivariable model for the longitudinal dynamics of an F8 aircraft.

关键词： chemical processes chemical engineering Aircraft Design methodology process control Cities and towns Output feedback Linear feedback control systems Linear matrix inequalities Vibration control

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Effect of steam explosion treatment on biomass size reduction

Effect of steam explosion treatment on biomass size reductio...

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作者： Priyanto, Dedy Eka Ueno, Shunichiro Kasai, Hidekazu Hashida, Koh Dept. of Chemical Engineering Process Development Center IHI Corporation Japan Engineering Centre IHI Corporation Japan The Forestry and Forest Product Research Institute Japan

Size reduction is essential for converting biomass into bio-fuel. It is usually performed using milling machines which consume large amount of energy. Steam explosion treatment which consists of auto-hydrolysis and rapid decompression steps, is a promising pre-treatment process to open up biomass fibers and to recover useful compounds from it. Numerous studies have investigated the effect of steam explosion on biomass composition and on bioethanol production. However, few studies have been conducted to investigate its effect on the reduction of biomass size. In this study, the effects of steam explosion conditions such as temperature and retention time, and type of biomass (hardwood and softwood) on biomass size reduction were investigated in detail using batch-type steam explosion equipment. Sakura (Prunus spp, hardwood) chips and Japanese cedar (Cryptomeria japonica, softwood) chips of 5-10 mm were used in this study. The treatment intensity is determined by a severity factor, which is established as correlation between process temperature and residence time. A rapid increase in the yield of solid biomass of size below 1 mm (fine particles) was observed when the severity factor was above 4. 2. The fraction of fine particles crossed 80%, when the severity factor was 5. 2. We concluded that temperature/pressure significantly influences biomass size reduction and that residence time and biomass type also influence biomass size reduction, particularly at lower severity (5.2). © 2016 ETA-Florence Renewable Energies.

关键词： Biomass

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Independent Single-input-single Output control Schemes for Dual Composition control of Binary Distillation Columns

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IFAC Proceedings Volumes 1986年第15期19卷 249-253页

作者： A.C. Kridiotis Christos Georgakis Department of Chemical Engineering Massachusetts Institute of Technology Cambridge MA 02139 USA Chemical Process Modeling and Control Research Center Lehigh University Bethlehem PA 18106 USA

The steady-state interaction measure of dual composition control schemes for binary distillation columns is examined under the assumptions of constant relative volatility and constant molar overflow. An exhaustive enumeration is made of the control schemes that use column flows or their ratios as manipulated variables and product compositions as the controlled variables. Using a redundancy criterion, it is shown that 34 classes of dual composition control schemes have independent values for the interaction measure. This number reduces to 17 when the feed is a saturated liquid or gas. For high purity columns, the interaction measure of the above 34 control schemes approaches the values for the (L, V), (D, V), and (L3) control schemes. In this case none of the control schemes has a desirable interaction measure.

关键词： Distillation control Interaction Measure Multivarable control process control Decoupling

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Automated micro-ELISA system for allergy checker: A prototype and clinical test

Automated micro-ELISA system for allergy checker: A prototyp...

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10th International Conference on Miniaturized Systems for Chemistry and Life Sciences, MicroTAS 2006

作者： Ohashi, Toshinori Matsuoka, Yoshinori Mawatari, Kazuma Kitaoka, Mitsuo Enomoto, Tadao Kitamori, Takehiko Research Association of Micro Chemical Process Technology Japan Dept. of Otolaryngology Japan Red Cross Society Wakayama Medical Center Japan Graduate School of Engineering University of Tokyo Japan

We report a first prototype machine of an automatic and compact micro-ELISA system for clinical diagnosis of allergy. The excellent performances were verified in three times faster analysis time, one order smaller sample and reagents volume with enough sensitivity compared with conventional systems. The prototype was subjected to a clinical trial authorized by the Ethical Advisory Board and good correlations with conventional method have been verified with 82 allergy patients. We believe our system show most excellent performances as practical systems. © 2006 Society for Chemistry and Micro-Nano Systems.

关键词： chemical analysis

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BURDEN PERMEABILITY STUDIES, FUNDAMENTAL AND APPLIED RESEARCH. 36

BURDEN PERMEABILITY STUDIES, FUNDAMENTAL AND APPLIED RESEARC...

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36th Ironmaking Conference

作者： Poveromo, Joseph J. Propster, Mark Szekely, Julian Research Department - Bethlehem Steel Corp United States Dept. of Chemical Engineering Center for Process Metallurgy State University of New York Buffalo United States Dept. of Materials Science and Engineering Massachusetts Institute of Technology Cambridge MA United States

The premeability of the blast furnace burden may be defined as the reciprocal value of flow resistance of the burden. The overall burden permeability determines the furnace wind rate and therefore productivity, whereas the radial distribution of the flow resistance affects gas-solid contacting effectivenesand hence the coke rate. Experimental and theoretical work has been carried out aimed at defining the structure of the burden, with emphasis on the mixing of materials dissimilar in size or shape, and relating the burden structure to both overall permeability and the distribution of gas flow in the burden. For these purposes, methods were specifically developed for measuring: the void fraction, or porosity, of the region between layers of dissimilar burden materials, and the increased pressure loss caused by the change infraction in this interfacial region.

关键词： Blast furnace practice

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Simulation environment for an autonomous and decentralized multi-agent robotic system

Simulation environment for an autonomous and decentralized m...

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1992 IEEE/RSJ International Conference on Intelligent Robots and Systems, IROS 1992

作者： Habib, Maki K. Asama, Hajime Ishida, Yoshiki Matsumoto, Akihiro Endo, Isao Control and System Eng. Dept. University of Technology Baghdad Iraq Institute of Physical and Chemical Research Chemical Engineering Lab. Hirosawa 2-1 Wako-shi Saitama351-01 Japan Information Network System Operation Center University of Tokyo Japan Dept. of Mechanical Engineering Faculty of Engineering Toyo University Japan

ISBN: (纸本)0780307372

An autonomous and decentralized system called ACTRESS (ACTor based Robot and Equipment Synthetic System) is being under development as an intelligent robot system which can execute high level tasks. ACTRESS is composed of multiple robotic agents. Each robotic agent is called "robotor". A robotor may be a robot, a computing system and any other equipments. While researching in this field, many research issues need to have solutions, such issues may include, the communication among the agents and protocols, cooperation among a group of' agents, describing the tasks to be executed, multi-agent motion planning, multi-agent task planning, task description, human interface role, solv ing deadlocks ... etc. The aim or this paper Ls to develop a simulation environment for an autonomous and decentralized multi-agent robotic system. For this purpose, it is necessary to simulate and analyze the main functions of each agent, design and analysis of the actions to be carried out by each agent, analyzing their real time behavior with a variety of situations considering their environment and the treatment of unexpected events. Also, it is necessary to find out an efficient strategy to realize effective means for the agents to form a cooperating manner that support task execution and problem solving. In parallel with the mentioned purposes the ACTRESS structure is simulated as functions and behavior using the developed simulation environment. This simulation includes a roup of mobile robots, human interface and global environment manager. Then, software integration that deal with various aspect of the overall problem is developed. Different experiments are performed to analyze the performance or each individual robotor and the overall system. © 1992 IEEE. All rights reserved.

关键词： Intelligent robots

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The Effects of Operational and Design Characteristics of Catalytic Cracking Reactors on the Closed-Loop Performance of Linear Model Predictive controllers

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IFAC Proceedings Volumes 1994年第7期27卷 209-214页

作者： Lokesh Kalra Christos Georgakis Chemical Process Modeling and Control Research Center and Department of Chemical Engineering Lehigh University Bethlehem Pennsylvania 18015 USA Phone:(610)758-543t Fax:(610)758-5t97

In closed-loop simulations of the catalytic cracker, it was observed that the model identified at a low throughput operating point, when used in MPC did a better job on the high throughput operating point than a model identified at the latter operating point. At the same time MPC utilising a model identified at a high throughput operating point did not perform well when used at the low throughput operating points. In this paper we examine this behavior through an analysis of the closed-loop catalytic cracker under unconstrained MPC. The persistent appearance of an upward spike in stack carbon monoxide concentrations immediately following a disturbance, despite extensive tuning efforts suggests that it is due to process rather than control system design characteristics. At high throughput operating points this phenomenon is of concern because it seriously impairs the ability of a control system to keep CO below its upper constraint. In the paper we trace the source of this dynamic behavior to the design of the catalytic cracker and suggest modifications that may favorably affect control performance.

关键词： Catalytic Cracking Model Predictive control Nonlinear control

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