Showing papers on "Control theory published in 1971"

Learning control systems and intelligent control systems: An intersection of artifical intelligence and automatic control

Abstract: A supplement to Fu [1] is presented. Three areas are briefly reviewed: 1) control systems with human controller, 2) control systems with man-machine controller, and 3) autonomous robot systems. Problems for further research are discussed.

The control of a synchronous machine using optimal control theory

Abstract: The selection of stabilizing signals to improve power system dynamic behavior is presented. Some results from modern control theory are used to show how such stabilizing signals may be derived systematically for a turboalternator model connected through a double circuit line to an infinite bus. The closed-loop performance of this nonlinear system model with the derived linear optimal controller is then evaluated for a wide range of input disturbances and operating conditions which include three-phase fault studies with autoreclosure.

Controller design for time lag systems via a quadratic criterion

Abstract: Theoretical results on the optimal control of linear time lag systems with respect to a quadratic criterion are shown to provide a practical feedback controller design procedure. A computational procedure is given for obtaining a stable linear feedback controller. A comprehensive illustration is given of the application of the quadratic criterion results to the design of a feedback controller for a chemical process having transport lag.

On the stochastic control of linear systems with different information sets

Abstract: This paper deals with the stochastic control of linear systems in which the information available to distinct controllers is different. Constraints on the control structure are imposed. Necessary conditions for optimality of the controller structure parameters are obtained. The results show that the separation theorem does not hold in this case.

Adaptive controller having optimal filtering

Abstract: A self-adaptive controller for use in a control process for providing ordered changes in a manipulated process variable in response to measured changes in a controlled process variable having means for using measured and predicted values of the controlled variable to obtain an estimated value of the controlled variable which estimated value is used via a self-adaptive controller to determine the change in manipulated variable. The controller is described with reference to a paper manufacturing process for controlling the basis weight and moisture content of a continuous web of paper.

Control system for an engine system

Abstract: A control system for an engine system which has means for optimizing the performance of the converter in the engine system by regulating a set point of a controller. In one embodiment, secondary air flow to the converter is the variable utilized to control the performance of the converter and is regulated in response to the ratio of gas flow in respect to the engine of the system to secondary gas flow to the converter. In another embodiment the air to fuel ratio to the engine is utilized as a variable to control the performance of the converter.

Manned Vehicle Systems Analysis by Means of Modern Control Theory

Abstract: Optimal control theory and systems analysis of man machine systems and operator performance prediction model for compensatory tracking tasks are discussed.

Human factors applications in teleoperator design and operation

Abstract: Book on human factors application in teleoperator design and operation covering aerospace environments, transportation, remote control, sensors and actuator subsystems

A Computer-Based Learning System for Remote Manipulator Control

Abstract: A concept of adaptive aiding for performance improvement in remote handling is described. The concept incorporates an autonomous control subsystem (ACS) that is able to supplement the operator's control function. The behavior of the ACS is established through a process of learning by observing the operator's control function in relation to the environment and manipulator output. The computer-based system establishes a decision-making policy which is based on conditional probability. Initially, the output device is totally controlled by the operator, while the computer system acts as a passive observer. As the operation continues, the computer system gradually assumes the role of active controller, reducing the operator's function to that of an action initiator and inhibitor. A pilot experiment indicates the feasibility of the concept; with a relatively short training period, the ACS was able to assume the bulk of the decision-making load and guide a three-dimensional manipulator satisfactorily through a series of manipulative tasks.

Reachable Sets for Linear Dynamical Systems

Abstract: The properties of reachable sets for linear dynamical systems for specified control sets are discussed. Iterative procedures for determining numerical approximations of the reachable set are suggested and methods of obtaining an admissible control function which transfers an initial state to as near a prescribed target as possible is described. The problem of reachability with multiple control constraints is discussed and certain aspects of reachability for time-invariant systems with adjustable parameters is considered.

Control system for automatic transmission

Abstract: A control system for an automatic transmission for an automotive vehicle having at least a torque converter, a planetary gear unit, brake bands and clutches actuated by hydraulic servos, a manual valve, shift valves, line pressure control means, detectors for a plurality of parameters indicative of the operating conditions of the engine, and discriminating circuits for carrying out an automatic shift from one speed ratio to another In the system, an electrically operated shift shock control valve is provided to make an on-off operation in response to a timing control signal applied from a timing controller so as to alleviate the shift shock occurring during a shift from one gear position to another

Bayes and minimax controllers for a linear system with stochastic jump parameters

Abstract: A procedure is given for determining an optimal zero-memory regulator for a linear stochastic plant with an incomplete probabilistic description. For situations in which the initial ambiguity is modeled probabilistically, the equations characterizing the appropriate Bayes control are derived. If no prior distribution is available, a minimax controller is sought and an algorithm for obtaining it is described.

Pattern evaluation method and apparatus for adaptive control

Abstract: A method is provided for automatic adaptation of process controller parameters according to the requirements of a non-linear process in order to achieve optimum control action. This method evaluates the response of a measured process variable to upset in the form of a change in set point or load. The upset initiates the adaptation procedure, which determines evaluation intervals related to process dead time and lag characteristics as evidenced by the response of the measured variable over predetermined portions of said upset; the deviation in the measured variable from set point or related demand reference is examined over the evaluation intervals and preferably integrated, the integrated error result being indicative of a required proportional gain change in the case of one type of evaluation interval and indicative of a required reset gain change in another type of evaluation interval. Proportional and reset gains are altered in accordance with this procedure until the gains are optimized as evidenced by maximum conformity to the demand references of the measured variable response to upsets generally.

Boundary Value Control Theory of the Higher-Dimensional Wave Equation, Part II

Abstract: The present work extends controllability results obtained for the wave equation in two or more space variables in an earlier article [13] In the earlier paper approximate controllability was established for time $T > 2T_0 $, where $T_0 $ is a constant related to the wave propagation speeds in the medium, but only for three or fewer space dimensions In the present article we establish this result for an arbitrary space dimension We also examine the controllability problem for $T = 2T_0 $, the “critical time,” and show that here controllability depends upon certain relationships between the coefficients of the partial differential equation and the shape of the spatial domain under consideration

Two-Level Control of Interconnected Power Plants

Abstract: A two-level controller for interconnected power plants is discussed. Each plant has a first level local optimal or suboptimal controller. The second level of control is an intervention control performed by a central co-ordinator. If a sudden system disturbance causes the system angular acceleration to exceed preset tolerances a priority interrupt to the central co-ordinator initiates intervention control. Angular velocity deviations of all plants are transmitted to the co-ordinator. This data is used to generate coefficient data for each plant. On receiving its coefficient data, each plant generates a local second-level intervention control which augments first level local control.

Pressure regulating controller

Abstract: The invention disclosed is for a pressure monitor and control device having particular utility in medical technology were constant monitor of hydro-static pressure is required. The disclosed device is especially useful in a method for effecting extra-corporeal hemodialysis.

Depth control apparatus for towed underwater cables

Abstract: An apparatus for maintaining at a predetermined depth a tow cable, such as that of a seismic streamer, being towed by a vessel, the apparatus having one or more depth controller devices attached to the cable at spaced intervals therealong and a remote command transmitter on the tow vessel for transmitting commands to the depth controller devices, the depth controller devices having a mechanism responsive to deviations between the commanded depth of the cable and its actual depth for moving diving planes of the controller devices to cause the controller devices to move to the commanded depth as the cable is towed along by the vessel.

Three-phase power controller

Abstract: A three-phase power controller for controlling three-phase power to a non-unity power factor load is disclosed, which employes a separate bidirectional gate in series with each of the lines to the three-phase load for gating the load current to the load. Each bidirectional gate includes a master gate and a slave gate slaved to the master gate. A synchronous control circuit supplies a sequence of gating on signals to the respective gates. The synchronous control circuit includes a zero-crossing sensor for sensing the alternating potential supplied across each set of power supply terminals and a particular half-cycle sensor for sensing the particular half-cycle of each of the alternating potential applied across each respective set of power supply terminals. Light emitting diodes and photo detectors are employed in various ones of the gating control channels to provide high voltage isolation between the gates and the circuits generating the gate control signals.