M.M.F. Sakr

On the discrete time-optimal regular control problem

This paper considers the time-optimal regulator control of linear discrete multiple-input systems. A new algorithm for realizing the optimal control law is proposed. The feedback gain matrix is expressed in compact closed-form which does not require a recursive solution as in earlier approaches. Numerical examples are worked out to illustrate the procedure.

ROBUST SLIDING MODE CONTROL FOR SERVO SYSTEMS

Abstract Variable structure controllers (VSS) with sliding mode has proved to exhibit satisfactory performance for servo systems concerning disturbance rejection and time response. In the presence of disturbance reachability of the system can not be guaranteed and the sliding curve may not be reached. In this paper a new method is proposed based on maintaining the sliding mode all-over the trajectory. New sliding lines are proposed to ensure robustness all-over the trajectory. Straightforward equations for the gain variations are derived.

Process Control Using Programmable Logic Controllers: Application Considerations

Abstract The use of programmable logic controllers (PLCs) in food industries provides various benfits concern-ing the improvement of quality and productivity. In this paper, special considerations in the application of PLCs in industrial processes are discussed. PLC-based distributed control system for a food packing plant is introduced as case study. The experience gained during different stages of the development cycle of this automation system is also presented

Knowledge Base Controller for Cold Forming Mills in Iron and Steel Production Process

Abstract Cold forming mills in the steel production process comprises of two cascaded DC motor stands and a flying shear to cut steel coils in accurate lengths. The main objective of the control scheme is to maintain the speed difference between the two stands within a specified limit in order to prevent producing inaccurate lengths. In this paper a new knowledge based controller is proposed to ensure that the speed difference is within permissible range under different operating conditions. Testing the proposed expert controller showed efficient performance under a wide range of operating conditions

A Knowledge-Base Power System Stabilizer

Abstract Power system stabilizers have been used successfully to improve power system stability. The major problem facing the design of a suitable controller for power systems is that they are nonlinear in nature and can operate over a wide range of parameter variations. Adaptive controllers were used to solve such a problem but they are usually computationally intensive and may not compensate large variations in system parameters. Motivated by the substantial growth of Artificial Intelligence (AI) techniques and their application in control systems, knowledge based controllers began to take place as a wide range stabilizers. This paper introduces a newly developed power system stabilizer using a knowledge base controller. The proposed knowledge base controller is acting on the system while keeping the conventional stabilizer. Rules and facts that represent the core of the controller are deduced using fuzzy logic. A single synchronous machine with its speed governor and voltage regulator connected to an infinite bus is used as an example to illustrate the features of the proposed expert controller. Simulation results showed great improvement in system performance when the auxiliary knowledge base controller is used together with the speed governor and the voltage regulator.

Database-Aided Tuning for the BOF Static Model

Abstract This paper presents a case study for the development of a static model to apply the computer, in a supervisery mode, to control the steel converter shop at the EIS Co. . The experience gained to check the static model validity has revealed its sensetivity to variations in both the input conditions as well as the adopted blowing regime. In an attempt to tune the model to reduce its sensitivity to variations in specific parameters the need for storing the data using a structured model has become necessary. This data model has been structured to reflect the experience gained from both the static model mechanism requirements as well as the operating conditions at the steel converter shop. A database, therefore, has been developed making use of the IDMS-1900 package. The schema pertinent to this database comprises 99 record types. This database would: 1. Furnish the sorted data necessary for botter tuning the static model by following better statistical analysis for the different parameters affecting the efficiency of the model. 2. Improve the sorting of the historical data pertine t to the operating conditions at the steelmaking department to enhance its productivity. 3. Assist the management to coordinate between the continuous casting department and the steel converter shop for better productivity. The paper presents the developed schema as well as samples of the potential reports that can be generated from this database together with the corresponding navigation routes.

Optimal Reduced Order Model for Two Generating Stations

Abstract The study of the dynamic behavior of large scale power systems involves the solution of large number of coupled differential and algebraic equations, whose solution requires enormous computation efforts. This paper presents the application of a new method for model reduction on a two closely tied generating stations which are connected to a large network. An effecient algorithm is presented to obtain, with a greatly reduced computation time, the alpha-beta coefficients of the reduced model which minimizes an objective function representing the difference between the impulse response of the system and the model respectively. Results illustrate the effectivness of the method when applied on the two closely tied generating stations. Improvements achieved using the optimal reduced order model are discussed at the end of the paper.

MULTI-STAGE STATIC MODEL OF LD-STEEL CONVERTER FOR HIGH P-CONTENT

Abstract The nature of the operation in the LD-Convorters in the Egyptian Iron & Steel Co. (EIS Co) is characterized by severe operating conditions surrounding the operator. The adopted technology in the EIS Co. converter shop is based on a deslagging operation after a first fixed time blow then followed by a second blow to compensate for high irregularity in the input materials. In the absence of dynamic control facilities, a static model is developed to handle the operation difficulties. This static model is of multi stage nature that operates in real-time fashion making use of a Newly installed supervisory computer in the converter shop. At the first stage, the model will output, first, the required quantity of scrap and lime for the first blow interval, second, the incremental adaptively adjusted time interval for the assumed fixed time of the first blow. The quantity of lime required for the second interval as well as its duration are to be obtained when applying the model during its second stage. This model can be operated on past data to statistically estimate certain unknown coefficients in the structure such as the heat loss coefficients.

Development of The Egyptian Iron and Steel Industry Using Process Computer Control

Abstract This paper addresses the problem of modernizing the Egyptian Iron and Steel factory at Helwan, using process computer Control. The problem of priorities within different sections of the factory to first apply the process computer control is encountered. It is shown that, for the Helwan factory, computerization procedure should commence first in the Oxygen Steel Converter Shop, then followed by the Hot Rolling Mill process. For the steel converter shop, statistical data analysis are carried out as a pre-requisite for developing the necessary mathematical model for the on-line computer control application. It is demonstrated that, with the random trend appearing in the steel making data, statistical components in modeling are mandatory. Finally, the future steps to be followed for model building, economical justification of computerization and real life model implementation are elucidated.

Techno-Economic Consideration Concerning Appropriate Technologies

Publisher Summary This chapter discusses techno-economic consideration concerning appropriate technologies. Simply appropriate technologies could be defined as those keeping economic, social, and environmental objectives of development. The concept of appropriate technology has to be accepted from the developing countries as an instrument of economic development with social justice. Mainly three elements are relevant and leading to the choice of appropriate technologies: goals, resources, and economic and social constraints. The goals of development are easy to describe. In case of developing countries, they may be summarized in raising the national income and self sufficiency. Mostly in developing countries, natural resources are not fully scanned and programmed for utmost utilization. Economic and social constraints include the environment, social structure, inherent culture, traditions, market size, financing educational state, and infrastructure.