Application Of Modern Control Theory Research Articles

The Vector Control System of Induction Motor Based on Fuzzy Control

Classical control theory method often cannot obtain good static and dynamic performance in speed control system of asynchronous motor that is multivariable, nonlinear and strong coupling. However, with the application of modern control theory, it can effectively improve the operating performance of system in a complicated environment. This paper introduces the basic principle of vector control system and establishes the simulation model of vector control system of asynchronous motor. Meanwhile, according to fuzzy control theory, this paper shows a design of fuzzy controller and it is applied to the vector control system of speed adjusting module. Finally, it uses Matlab/Simulink to simulate and it verifies that Fuzzy vector control system response faster has better stability and stronger robust performance compared to the traditional vector control. Key words: induction motor; vector control; fuzzy control

Next Generation Mold Level Control: Development of LevCon 2.0

Siemens VAI develops the next generation of the successful mold level controller LevCon. The new controller uses the most modern control principles from optimal control theory while being robust enough to operate in the difficult conditions of a steel work. One prerequisite for the application of modern control theory is a good mathematical model of the process. In the past, the models used for mold level control design were quite simple, neglecting some of the important limiting factors such as surface resonance waves of the mold level. For the derivation of a resonance surface wave model, extensive water model trials have been carried out. With the help of the plant model, modern control theory is applied and a mathematically optimal controller feedback is designed. It offers an increased disturbance rejection compared to earlier algorithms, which is significantly reducing the mold level deviation due to disturbances as, e.g., unclogging events. However, there are still disturbances that cannot be eliminated completely, like mold level hunting caused by instationary bulging. In the past, mold level hunting was reported to be a very slow disturbance with a wavelength of approximately one roller pitch and a frequency below 0.1 Hz. During the development work, it turned out that also higher harmonics of this base frequency exist with wavelengths of 1/2, 1/3, up to 1/7 of the roller pitch. These high frequency fluctuations cannot be eliminated by feedback control only. However, an additional feed-forward loop which utilizes the withdrawal drives power for direct compensation of the mold level hunting steel flow is developed. With this approach, it is possible to reduce even fast mold level hunting.

M-3 S-II 型ロケットの制御理論の応用

M-3 S-II 型ロケットの制御理論の応用

WAM(s)! global views from its pioneers [From the Editor

H 4 ieee power & energy magazine september/october 2008 How prophetic it was! In 1977, Prof. Fred C. Schweppe of MIT was elected an IEEE Fellow ?for contributions to the application of state estimation, load forecasting and system dynamics to the control electric power systems.? His initial interest in power systems was motivated by what was, at that time, the biggest power failure in history, the Great Northeast Blackout of 9?10 November 1965. To learn about the industry, Fred spent a year in residence at American Electric Power Service Corp. (AEP ). His initial work involved the application of modern control theory to power system control and stability. Eventually his interests expanded into a broad array of power systems issues, including the development of analytical methods for optimizing power system operations and planning with emphasis on environmental constraints, and short- and long-term load demand modeling. Having had the privilege of working with Fred during the year he spent at AEP and subsequent contacts, I can readily understand him being regarded as an individualist, almost a renegade, with new and highly creative ideas, and someone who was determined to bring these ideas to fruition.

An H∞ approach to congestion control design for AQM routers supporting TCP flows in wireless access networks

In this paper, we aim at developing an H∞ approach, from control-theoretic viewpoint, to the design of an active queue management (AQM) based congestion control algorithm for wireless networks supporting the Internet Protocol. We study networks in which the backbone is a traditional wired network supporting Internet TCP, while end user access is via wireless. First, a dynamic model for the congestion control problem of wireless networks is built up, which enables the application of modern control theory on time-delay systems to this problem. Second, an H∞ design approach for general time-delay systems is presented. Finally, the proposed approach is applied to the congestion control algorithm design of wireless networks, yielding an effective and systematic way for the design problem. Simulation results are provided to illustrate the design procedure and the effectiveness of the proposed method. Our design method is described by linear matrix inequalities (LMI), which can be solved very efficiently by LMI toolbox in Matlab.

人間の下肢機構をモデルとした拮抗駆動関節を有する2足歩行型ヒューマノイドの開発

Many groups are researching a biped walking robot, although they have different objectives in mind such as applications of modern control theory, the study of mechanisms, or practical use to medical fields. The authors and others are engaged in studies of biped walking robots, with "human form" as a key word, from two points of view: one is human engineering, and the other is toward the development of anthropomorphic robots. The authors and others have obtained the following results to date. In 1984, the authors and others succeeded in achieving a dynamic biped walking of 1.3 [s/step] by the use of a hydraulic biped walking robot, WL-10 RD (Waseda Leg-No.10 Refined Dynamic). From 1986 to 1994, the authors developed hydraulic biped walking robots of the WL-12 series that compensated for lower limbs moment using an upper body and realized not only fast dynamic biped walking (0.54 [s/step] with a step length 0.3 [m]) but also walking on an unknown surface. In 1995, the authors developed an electrical powered biped walking robot WL-13, in which each leg joint is driven antagonistically via a rotary-type, nonlinear spring mechanism, and realized quasi-dynamic walking (7.68 [s/step] with a 0.1 [m] step length). In the current research concerning a biped walking robot, however, there is no developed example of a life-size biped walking robot which can perform manipulation and locomotion by dynamically coordinating arms and legs. Therefore, the authors proposed the construction of a biped humanoid robot that has a hand-arm system, a head system with visual sensors, and antagonistic driven joints using a rotary-type non-linear spring mechanism, on the basis of WL-13. We designed and built it. In addition, as the first step to realize the dynamically coordinated motion of limbs and trunk, the authors developed a control algorithm and a simulation program that generates the trunk trajectory for a stable biped walking pattern even if the trajectories of upper and lower limbs are arbitrarily set for locomotion and manipulation respectively. Using this preset walking pattern with variable muscle tension references corresponding to swing phase and stance phase, the authors performed walking experiments of dynamic walking forward and backward, dynamic dance and carrying, on a flat level surface (1.28 [s/step] with a 0.15 [m] step length). As a result, the efficiency of our walking control algorithm and robot system was proven. In this paper, the mechanism of WABIAN and its control method are introduced.

The control of tension in textile filament winding

The application of modern control theory to a textile winder for acetate and other fine filaments in which the tension variations must be kept to a minimum is described. It has proved possible to extend the operational speed from 800 to 2000 m min −1 with substantially reduced tension variations. Previous attempts to operate at higher speeds caused increased tension variations. A new drive system with fuzzy control and a synchronised compensator has been incorporated in the system to achieve these results. A low-displacement, high-bandwidth filament tension sensor has been developed as an integral part of the system.

Application of advanced control theory to enhance molding machine performance

The computing power and system design of recent custom designed control systems makes possible the application of modern control theory in injection molding machines to achieve new standards of performance without expensive, special purpose equipment. The new line of controls from the Van Dorn Demag Corporation uses digital filters, state transition logic, and high order temperature state control to control more accurately the molding machine process. The use of digital filters together with state transition logic reduces the controller response time latency, improves cycle-to-cycle repeatability, and predicts future positions of the molding machine clamp for use in clamp braking. The temperature state control system uses real-time mathematical modeling of the barrel and tracking of estimated thermal disturbances to better control the barrel temperature, These techniques are applied to a wide variety of injection molding machine types and sizes and can be done in a way which makes the programming and operation of the machines less difficult than with traditional methods.

Optimal, sub-optimal and adaptive control methods for the design of temperature controllers for intelligent buildings

The application of modern control theory to design control systems for buildings are explored. Example problems dealing with HVAC systems and indoor environment control are considered. Linear models of the systems are used to design controllers based on (i) pole-placement technique, (ii) optimal regulator theory and (iii) adaptive control. The responses of the systems subject to disturbances are investigated. The results illustrate the advantage of one method over the other and emphasize the importance of the use of improved methods to design control systems for intelligent buildings.

Control system of material flow in hot rolling-mill drive

The problem of forming and wind up loop in a bar, rod and profiles hot rolling mills is considered. A new conception for process forming and wind up loop are presented. Application of modern control theory has led to construction of simple special system (observer) in which of the basis of some state variable mensurations, torque load can be estimated. Also a simplified algorithm of material flow control are presented. The given algorithm structure enables preliminary determined by the range of limited and allowable parameters of rolling-mill line. The describe system are installed in an one rods, profiles and wire rolling-mill in Poland.

Improved speed regulation of an excitation controlled induction motor

Recent trends in variable speed AC motor drives are toward achieving high performance and high efficiency. Speed regulation of a voltage-decoupled induction motor that provides optimal efficiency and quick response is discussed. Although present-day motor drive applications demand robust and faster control techniques, there are only few applications of modern control theory to AC drives. A robust first-order model reference adaptive control (MRAC)-based speed controller whose stability has been proved via Lyapunov's second method is proposed. Computer application to a 100 hp induction motor shows the capability of the proposed controller by investigating the transient response and robustness of the drive system. >

Robust control of accelerators

The problem of controlling the variations in the rf power system can be effectively cast as an application of modern control theory. Two components of this theory are obtaining a model and a feedback structure. The model inaccuracies influence the choice of a particular controller structure. Because of the modelling uncertainty, one has to design either a variable, adaptive controller or a fixed, robust controller to achieve the desired objective. The adaptive control scheme usually results in very complex hardware; and, therefore, shall not be pursued in this research. In contrast, the robust control method leads to simpler hardware. However, robust control requires a more accurate mathematical model of the physical process than is required by adaptive control. Our research at the Los Alamos National Laboratory (LANL) and the University of New Mexico (UNM) has led to the development and implementation of a new robust rf power feedback system. In this article, we report on our research progress. In section 1, the robust control problem for the rf power system and the philosophy adopted for the beginning phase of our research is presented. In section 2, the results of our proof-of-principle experiments are presented. In section 3, we describe the actual controller configuration that is used in LANL FEL physics experiments. The novelty of our approach is that the control hardware is implemented directly in rf. without demodulating, compensating, and then remodulating.

STATE ESTIMATION OF AN INERTIALLY GUIDED AIR VEHICLE

This paper represents an application of modern control theory to the field of aerospace vehicle navigation system. An attention is paid to the reconstruction of the states of aninertially guided aerospace vehicle via a full-order observer. A mathematical model is derived to represent the motion of the vehicle. Linearization by the perturbation method is made, and the state space equations of the perturbed vertical motion are derived. The controllability and observability of the system are tested. A parametric observer is designed that estimates the states of the system. The Eigenvalues of the observer and the free parameters are used as design variables. ResUlts of such parametric observer show the necessity for optimization to achieve acceptable behaviour, of the observer in such application. An optimal observer.is designed by solving the algebraic Riceati equation . The performance of the optimal observer is demonstrated by•reconstructing the perturbed states of motion about a nominal trajectory of a vehicle dynamic light simulation.

The Application of Modern Control Theory to a Turbocharged Diesel Engine Powerplant

A brief review of the intrinsic features of diesel engine performance and control is given. The introduction of electronic control to fuel systems is described. It is shown that engine dynamic performance (in the form of transfer functions) can be both calculated and measured. An example is given of multi-variable control techniques applied to a turbocharged diesel engine with variable geometry turbocharger. It is shown that there are significant benefits in terms of smoke emissions from such a system, and that the synergy of more controllable engine systems together with modern control techniques enable diesel engines to reduce emissions.

Application of Modern Control Theory to Temperature Control of the MBE System

A molecular beam epitaxy control system, whereby one microprocessor manages all the objects, has been constructed. The model-following algorithm, which is one of the applications of modern control theory, has been adopted instead of the conventional PID algorithm in order to improve the dynamic response of the temperature. It has been confirmed by computer simulation and measurement that the model-following algorithm is significantly effective especially when the set temperature is to be changed as a function of time. An application of the model-following algorithm to device fabrication has also been demonstrated.

Observer-based multivariable control of the aluminum cold tandem mill

Innovation in thickness control of the aluminum cold tandem mill has emerged from an application of modern control theory. Any good control system must deal appropriately with two fundamentals of mill operation: (1) the mutual interaction between strip thickness and interstand tension, and (2) disturbances in the mill environment. In this paper, a synthesis of multivariable control systems for aluminum cold tandem mills is presented based on the theory of output regulation established basically by Wonham and his colleagues (Wonham, 1974, Linear Multivariable Control—A Geometric Approach. Springer, New York; Wonham and Pearson, 1974, SIAM J. Control, 12, 5–18; Francis and Wonham, 1976, Automatica, 12, 457–465). The synthesis procedure is composed of the three major steps. The first one is to improve the response characteristics by state feedback. The second one is to compute the feedforward control input to counterbalance the disturbance. The third one is to implement the feedforward control by feedback control based on the estimation of the disturbance by observer. The obtained system was actually implemented and has been in full commercial operation since 1986, making splendid accomplishments.

A Decentralized Load Frequency Control Method by Means of Frequency Measurement of Adjacent Power Systems

The presently used TBC and FFC methods have satisfactorily maintained power system frequency within a prescribed tolerance. With steady increase in power system capacity, however, undue fluctuations in tie-line power flow has become prominent; This fact suggests the sheer necessity of establishing a more sophisticated LFC system. Intensive research efforts have been concentrated on applications of modern control theory, above all the linear optimal control (LOC) using the state regulator theory. This paper presents a decentralized suboptimal LFC method which makes use of the frequencies of adjacent areas in addition to local information to calculate the control variables of each area. This artifice has made it possible to realize a practical yet almost optimal control scheme. Simulation studies on a A area system have demonstrated the effectiveness of the proposed method.

Application of modern control techniques to motor control

An overview is presented of digital control problems arising in the use of microprocessors and the application of modern control theory, from both the theoretical and practical viewpoints. The discussion covers optimal control, robust control, feedback and feed-forward control, and active and passive adaptive control. Various application are described, drawing on the author's own experience. It is concluded that a robust optimal digital controller for motor control can be practically designed and implemented with currently available techniques and hardware.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

STABILIZATION OF ARTICULATED VEHICLES BY SEMI-ACTIVE CONTROL METHOD

SUMMARY This paper describes the stabilization of articulated vehicles at high speeds by a steering system set up on the trailer. First, the equations of motion of the articulated vehicles with a steering system on the trailer were obtained. Furthermore, the steering angle of the trailer in the presence of disturbances was studied by solving these equations through the application of modern control theory. From such analysis, the magnitude of the optimal feedback coefficients of each state variable was obtained. It was found that the stability of articulated vehicles at high speeds was significantly improved by the active control method for the trailer steering system. However, the active control system needs a power supply, and it is difficult to apply it to articulated vehicles at present, especially for passenger car-trailer combinations. Thus, a new trailer steering system with viscous coupling arms to be set between the tractor and trailer was proposed. Furthermore, the semi-active control method whi...

Applications of Modern Control Theory to the MMM Industries

The role of the modern control theory in applications to processes in the mining, mineral and metal (MMM) processing industries is elucidated. The processes are in general multivariable, as the product quality and the actions of control are both multiple quantities. The processes include often time-varying parameters, long transportation delays and severe stochastic disturbances.Examples are given in which ideas and methods of the modern control theory have been utilized in practical applications to realize real time parameter identification, state estimation, prediction, feedback control, decoupling and adaptation.It is concluded that the theory is indispensable to guide and support the development of better process control. The key to success is the right process model, in many cases a relatively simple model combining pre-knowledge and real time model fitting.