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Showing papers on "Control theory published in 1984"


Book
01 Jan 1984
TL;DR: This unified survey focuses on linear discrete-time systems and explores the natural extensions to nonlinear systems and summarizes the theoretical and practical aspects of a large class of adaptive algorithms.
Abstract: This unified survey focuses on linear discrete-time systems and explores the natural extensions to nonlinear systems. In keeping with the importance of computers to practical applications, the authors emphasize discrete-time systems. Their approach summarizes the theoretical and practical aspects of a large class of adaptive algorithms.1984 edition.

4,293 citations


Journal ArticleDOI
TL;DR: In this article, a typical control actuator system consisting of a brushless synchronous motor and a transistor chopper inverter is described, and several types of construction are described.
Abstract: High-quality electrical servo drives can only be designed and manufactured by using especially compatible and sophisticated components. A typical control actuator system is described consisting of a brushless synchronous motor and a transistor chopper inverter. Important aspects of the design and rating of a three-phase motor with rare-earth permanent magnets are pointed out. Several types of construction are described. The machine control system used is the familiar method of cascade control. By application of "space vectors" two special methods for fast response current control are developed. In the first case, inverter control signals are derived only from measured quantities. In the second case, the optimum controller output can be calculated if additional information about the controlled system exists. Finally, experimental results prove the excellent performance of this drive system.

229 citations


Journal ArticleDOI
TL;DR: A new time-domain method of quadratic-optimum control synthesis for systems described by finite-memory output predictors is presented, which leads to algorithms which are numerically robust and therefore suitable for real-time computation using microprocessors with reduced wordlength.

225 citations


Journal ArticleDOI
TL;DR: In this article, the authors present an apparatus in which each basic sensor/actuator non-colocation configuration is available, and inertias can be abruptly halved or doubled during control maneuvers.
Abstract: While the stable control of such flexible structures as limber spacecraft is easily achieved through the colocation of control actuators with sensors, noncolocation renders this extremely difficult. The most difficult case in point is that in which structural damping is low and spacecraft stiffness and inertia values are uncertain and changing. Attention is presently given to an apparatus in which each basic sensor/actuator noncolocation configuration is available, and inertias can be abruptly halved or doubled during control maneuvers. This feature can impose a sudden reversal in the plant's pole-zero sequence, which is a very difficult condition for the controller. Test results obtained to date demonstrate the inherent difficulty of achieving robustness in the case of noncolocation. It is noted that there may be very simple configurations in which there is no alternative to adaptive control.

203 citations


Journal ArticleDOI
TL;DR: A continuous-time version of the Extended Horizon Adaptive Controller (EHAC) is developed using the Delta Operator formulation and uses the Internal Model Principle to reduce off-set.

195 citations


Book
Dale Enns1
01 Jan 1984
TL;DR: In this article, an approach and a technique for effectively obtaining reduced order mathematical models of a given large order model for the purposes of synthesis, analysis and implementation of control systems is developed.
Abstract: An approach and a technique for effectively obtaining reduced order mathematical models of a given large order model for the purposes of synthesis, analysis and implementation of control systems is developed. This approach involves the use of an error criterion which is the H-infinity norm of a frequency weighted error between the full and reduced order models. The weightings are chosen to take into account the purpose for which the reduced order model is intended. A previously unknown error bound in the H-infinity norm for reduced order models obtained from internally balanced realizations was obtained. This motivated further development of the balancing technique to include the frequency dependent weightings. This resulted in the frequency weighted balanced realization and a new model reduction technique. Two approaches to designing reduced order controllers were developed. The first involves reducing the order of a high order controller with an appropriate weighting. The second involves linear quadratic Gaussian synthesis based on a reduced order model obtained with an appropriate weighting.

195 citations


Journal ArticleDOI
TL;DR: In this paper, a variable-structure load-frequency controller for a single-area power system is proposed to enhance the dynamic performance of the integral controller, which is usually designed with the primary aim of zero steady-state error.
Abstract: This paper presents a new technique for designing the variable structure load-frequency controller for a single-area power system. The variable-structure controller effectively enhances the dynamic performance of the integral controller which ia usually designed with the primary aim of zero steady-state error. Further, when the variable-structure system is operated in the so-called sliding mode, the response of the system becomes insensitive to changes in the plant parameters. The control problem is formulated and the results of a simulation study are presented for illustration.

170 citations


Journal ArticleDOI
TL;DR: In this paper, the authors describe the application of model reference adaptive control (MRAS) to automatic steering of ships, where the main advantages are the simplified controller adjustment which yields safer operation and the decreased fuel cost.

162 citations


Proceedings ArticleDOI
Lawrence Larkin1
01 Dec 1984
TL;DR: This paper describes a model of an autopilot controller based on fuzzy algorithms that maneuvers an aircraft from level flight into a final-approach flight path and maintains the aircraft along the glide path until just before touchdown.
Abstract: This paper describes a model of an autopilot controller based on fuzzy algorithms. The controller maneuvers an aircraft from level flight into a final-approach flight path and maintains the aircraft along the glide path until just before touchdown. To evaluate the performance and effectiveness of the model, the aircraft response to controller actions is simulated using flight simulation techniques. The effect of varying parameters and different defuzzification strategies on controller performance is analyzed.

149 citations


Patent
13 Feb 1984
TL;DR: A video game having a controller for player selection of movement of a plurality of game objects, and for controlling the rate of the selected game objects is defined in this article, where the controller is equipped with a motion sensor.
Abstract: A video game having a controller for player selection of movement of a plurality of game objects, and for controlling the rate of movement of the selected game objects.

128 citations


Patent
26 Dec 1984
TL;DR: In this paper, a distributed environmental/load control system comprising a thermostat operable to supply signals indicative of sensed and desired values of a parameter in an environmentally controlled space is presented.
Abstract: A distributed environmental/load control system comprising a thermostat operable to supply signals indicative of sensed and desired values of a parameter in an environmentally controlled space to a first controller operable to control condition changing equipment for regulating the parameter, the signals being transmitted over a communications link between the thermostat and first controller. A second controller which is operable to control a plurality of loads in accordance with predetermined criteria to limit energy consumed by the loads is connected to the communications link through an interface device operable to process the signals produced by the thermostat in response to instructions furnished by the second controller and to supply the processed signals to the first controller.

Journal ArticleDOI
TL;DR: By increasing the control horizon length, the proposed algorithm, referred to by the acronym MUSMAR, is shown to be a natural generalization of standard self-tuning controllers and closely approximates a steady-state LQG controller inheriting the intrinsic robustness of LQGs design.

Journal ArticleDOI
TL;DR: The design of optimal controllers for use in self-tuning systems is considered and Linear Quadratic Gaussian controllers offer a guarantee of stability (when the plant parameters are known) which is particularly useful for nonminimum phase systems.

Journal ArticleDOI
TL;DR: In this article, a new trajectory-following adaptive control algorithm for linear, time-invariant finite-dimensional systems that possess a stable inverse is presented, and the exponential stability of the control scheme is demonstrated.

Journal ArticleDOI
TL;DR: In this article, a new controlling method of biped locomotion composed of seven links is proposed, which relies mainly on the linear optimal state feedback regulator, which stabilizes the stance supported by both legs as a commanded attitude.
Abstract: The purpose of this paper is to propose a new controlling method of the biped locomotion composed of seven links and to show simulated and experimental data of the locomotive motion of the biped called CW-1 built in our laboratory. The control method depends mainly on the linear optimal state feedback regulator, which stabilizes the stance supported by both legs as a commanded attitude. As a result the biped successfully walks any pre-determined steps such that one step takes only one second.

Journal ArticleDOI
TL;DR: In this article, an application of a finite spectrum assignment method for time-delay systems to a feedback control of the Mach number in a wind tunnel is presented, which is a linear combination of state variables and weighted integrals of some of the state variables over a period equal to time delay.
Abstract: An application of a finite spectrum assignment method for time-delay systems to a feedback control of Mach number in a wind tunnel is presented. The linearized model of Mach number control is a system of three state equations with a delay in one of the state variables. The proposed feedback is a linear combination of state variables and weighted integrals of some of the state variables over a period equal to time delay. The spectrum of the closed-loop system is finite and consists of three eigenvalues that can be placed arbitrarily. Four possible variants of the feedback control law are presented. The calculation of feedback coefficients is very simple, which makes it possible to update the controller's parameters on-line with the changes of the operating point. An extensive numerical simulation of the system dynamics and the feedback controllers was done and led to several conclusions. In particular, a very good settling time under problem constraints has been obtained, and several nice features of the proposed feedback controller have been demonstrated.

Journal ArticleDOI
TL;DR: In this paper, it was shown that if the controller is error-driven, if perfect tracking is achieved in the limit t \rightarrow \infty, and if a suitable observability condition is present, then the controller necessarily incorporates a copy (internal model) of the exosystem dynamics.
Abstract: Structural aspects are studied of nonlinear control systems in a setting of differentiable manifolds. As a generalization of the setup commonly used in linear multivariable control, the regulator problem is defined as that of controlling a fixed plant to track (or reject) reference (or disturbance) signals generated by a fixed dynamic model called the exosystem. It is shown that, if the controller is error-driven, if perfect tracking is achieved in the limit t \rightarrow \infty , and if a suitable observability condition is present, then the controller necessarily incorporates a copy (internal model) of the exosystem dynamics. This result represents a counterpart in the nonlinear differentiable setting to various results already known for linear systems and for abstract automata.

Journal ArticleDOI
TL;DR: In this article, it was shown that the original balancing method of Moore [1] can be used to generate these reduced order optimal controllers, but the newer balancing methods recently proposed for controller reduction might not generate the reduced-order optimal controllers.
Abstract: The standard linear quadratic Gaussian (LQG) optimal controller is not minimal in general, even if the plant is minimal. Hence, the order of the optimal controller can be less than that of the plant. This note shows that the original balancing method of Moore [1] can be used to generate these reduced order optimal controllers, but the newer balancing methods recently proposed for controller reduction might not generate the reduced order optimal controllers, even when they exist.

Journal ArticleDOI
TL;DR: In this article, the reduction of a controller is based upon the participation of the controller states in the value of a quadratic performance metric, and an error index is defined to evaluate the reduced controller compared to the optimal LQG controller, and bounds on this index are derived.
Abstract: Component cost analysis [1] is used to develop a method for controller reduction. The reduction of the controller is based upon the participation of the controller states in the value of a quadratic performance metric. The controller states which have the smallest contribution to the performance metric are truncated to produce the reduced controllers. An error index is defined to evaluate the reduced controller compared to the optimal LQG controller, and bounds on this index are derived. A numerical example is included to illustrate the procedure.

Journal ArticleDOI
TL;DR: It is shown that this extension of the well-known minimum variance control strategy to the multi-input-multi-output case is straightforward when the system interactor matrix is diagonal but presents some unexpected difficulties in the general case.

Journal ArticleDOI
TL;DR: In this paper, the authors developed a concept of the degree of controllability of a control system, and then developed numerical methods to generate approximate values for any linear time-invariant system.
Abstract: Starting from basic physical considerations, this paper develops a concept of the degree of controllability of a control system, and then develops numerical methods to generate approximate values of the degree of controllability for any linear time-invariant system. In many problems, such as the control of future, very large, flexible spacecraft and certain chemical process control problems, the question of how to choose the number and locations of the control system actuators is an important one. The results obtained here offer the control system designer a tool which allows him to rank the effectiveness of alternative actuator distributions, and hence to choose the actuator locations on a rational basis. The degree of controllability is shown to take a particularly simple form when the dynamic equations of a satellite are in second-order modal form. The degree of controllability concept has still other fundamental uses - it allows one to study the system structural relations between the various inputs and outputs of a linear system, which has applications to decoupling and model reduction.

Patent
Daniel H. Zervos1
07 Jun 1984
TL;DR: In this paper, a system for providing modulated air flow control in response to an on-off thermostat having an onoff heating system is presented. But the system is not suitable for the use of a self-returning, slow moving motor.
Abstract: A system for providing modulated air flow control in response to an on-off thermostat having an on-off thermostat, a self-returning, slow moving motor connected to the thermostat for moving in a first direction when the thermostat is on and moving in a second direction when the thermostat is off, a damper motor adapted to drive a damper, and a controller driven by the self-returning, slow moving motor and connected to the damper motor for modulating air flow in response to the on-off thermostat.

Patent
03 Oct 1984
TL;DR: In this paper, a computer supervising individual controllers has a memory and a programmer, the memory storing a set of operating modules and control information of individual controllers, the programmer making a control program for each controller by providing software wiring of the operating modules based on the control information therefor.
Abstract: A computer supervising individual controllers has a memory and a programmer, the memory storing a set of operating modules and control information of individual controllers, the programmer making a control program for each controller by providing software wiring of the operating modules based on the control information therefor, whereby the individual controllers are started by the control program and control information from the computer, while during operation the controllers transmit the latest control information to the computer for updating the control information in the computer.


DOI
01 Nov 1984
TL;DR: In this article, a new technique based on the theory of variable-structure systems is proposed for the speed control of a separately excited DC motor, which can greatly improve the transient performance of the system, while still keeping the steady state error at zero.
Abstract: A new technique, based on the theory of variable-structure systems, is proposed for the speed control of a separately excited DC motor. A systematic procedure for selection of the switching hyperplane in the design of variable-structure controllers is developed, by minimising a quadratic performance index in the sliding-mode operation. The proposed control scheme is illustrated by digital simulation of a separately excited DC motor. It is shown that use of optimal variable-structure controllers can greatly improve the transient performance of the system, while still keeping the steady-state error at zero.

Journal ArticleDOI
TL;DR: In this paper, a self-tuning regulator is used as a local area controller for interconnected power systems, where the area control error, composed of the area frequency error and the total tie-line power deviation for the area, are used as the regulator input variable.
Abstract: A self-tuning regulator is used as a local area controller for interconnected power systems. The area control error, composed of the area frequency error and the total tie-line power deviation for the area, is used as the regulator input variable. By changing the relative weights on the frequency error and on the tie-line power deviation according to their respective variances, it is possible to approach the minimum variances of the individual variables. The proposed regulator can handle unpredicable load changes of random magnitude and duration. Studies on a two-area power system show that with this regulator the system performance is improved over that with the traditional type of load-frequency controller. Because only locally available measurements are required for each area controller, the proposed regulator can be implemented easily using microprocessors.

Journal ArticleDOI
TL;DR: A linearization analysis of a nonlinear adaptive controller is used to demonstrate analytically some design guidelines which alleviate some of the problems associated with adaptive control in the presence of unmodeled dynamics.

DOI
01 Jul 1984
TL;DR: The application of self-tuning regulators is suggested as a suitable alternative to the integral control, used normally for load-frequency control, and such a regulator, as implemented on a microprocessor is described along with test results on a physical model.
Abstract: An adaptive control strategy for the load-frequency control problem is investigated. The application of self-tuning regulators is suggested as a suitable alternative to the integral control, used normally for load-frequency control. Such a regulator, as implemented on a microprocessor, is described along with test results on a physical model. Adaptive control strategy is found to be very effective in improving the stability and transient response of the system.

Journal ArticleDOI
Yuichiro Anzai1
TL;DR: Using simulators of ship steering, and based on thinking-aloud protocol experiments, it is shown that unskilled persons may devote most of the initial period of learning control skills to understanding the causal behavior of the human-machine interface.

Patent
31 Dec 1984
TL;DR: In this article, a versatile rapid pulsing multiple pulse ignition controller (17) is used in conjunction with an converter power supply (13) with a voltage sensor/controller (16) and with an ignition coil (3) and energy capacitor (4) comprising an ignition system providing rapid firing multiple ignition sparks at high converter powersupp efficiency; which ignition system is suitable for installation on existing automobile engines and other internal combustion engines including diesel engines.
Abstract: A versatile rapid pulsing multiple pulse ignition controller (17) used in conjunction with an converter power supply (13) with a voltage sensor/controller (16) and with an ignition coil (3) and energy capacitor (4) comprising an ignition system providing rapid firing multiple ignition sparks at high converter power supply efficiency; which ignition system is suitable for installation on existing automobile engines and other internal combustion engines including diesel engines. The ignition is powered by an converter (13) working as a gated oscillator driving a power amplifier which is turned off by voltage level sensor/controller (16) when the converter output (14a) reaches a preset value or ground potential, as when an ignition pulse is occurring, giving converter (13) the highest possible efficiency and minimum power dissipation. Controlled ignition firing and multiple pulsing is provided by a multiple pulse controller (17) connected to breaker points or other electronic trigger (18). The ignition controller (17) includes a universal input trigger converter (19) for detecting and shaping the input trigger and providing the initial timing trigger for the spark pulse, a gate pulse width control (20) for providing the pulse train width and varying it with RPM, and a gated clock oscillator (21) for providing the pulse rate. When multiple pulse controller (17) is used in conjunction with power converter (13), voltage sensor (16), and an ignition coil (3) and capacitor (4), a practical, easily installed, low cost, ultra-high efficiency "rapid pulsing" ignition system is provided, capable of producing ignition of lean mixtures for substantially reduced exhaust emissions and increased engine efficiency.