Showing papers on "Open-loop controller published in 1976"

Numerical control system for machines utilizing a programmable sequence controller

Abstract: A numerical control system utilizes a programmable sequence controller as a data transmitter for transmitting numerical control data from a digital computer to machine controllers associated with numerically controlled machine tools. The digital computer converts each of the least units of the numerical control data to a predetermined number of output commands and, upon request, transfers the output commands along with address codes to the sequence controller which has an input-output circuit connected at its output terminals with data input terminals of the machine controllers, so that by selectively setting and resetting the output terminals designated by the address codes, the sequency controller can supply the numerical control data to any one of the machine controllers.

Machine control system employing a programmable machine function controller

Abstract: A machine control system including a programmable machine function controller comprised of a logic processor and a data processor. The logic processor is responsive to first devices on a machine, e.g. limit switches and push buttons, for controlling second devices on the machine, e.g. motor starters and solenoids, in accordance with a program representing a desired machine operation. The data processor operates asynchronously with the logic processor but responds thereto for selecting programs of arithmetic instructions relating to the machine operation. The system includes a panel of push buttons, lights and read-outs located remotely from the controller. Signals are transmitted between the controller and the panel using asynchronously operating receiver/transmitters which multiplex and transfer the signals on a serial basis. The machine includes at least one movable member in mechanical communication with a driving mechanism. The controller employs circuits which are responsive to the data processor and logic processor for producing signals to the driving mechanism to control the motion of the movable element.

Vehicle turbine manual control

Abstract: A vehicular gas turbine engine includes a first electronic controller responsive to a plurality of engine operating parameters and associated with a power relay box to control operation of engine functions and further includes a manual controller that allows open loop operation of the engine to start and run it at a speed and power level independent of the electronic controller and associated signals of engine parameters. The manual controller includes a timer set to shut the engine down after a preselected time period of manual operation to prevent excessive use of the open loop control thereby to minimize possibility of engine damage.

Controller for environmental conditioning apparatus

Abstract: A controller is disclosed for use in controlling environmental conditioning apparatus such as heating and air conditioning equipment in a building or the like. The controller is flexible in that it can control most types of such control devices and apparatus and it eliminates the necessity of a conventional local controller while permitting the use of a centrally controlled automated system if such is desired. The controller is self-contained in that it preferably has a display and keyboard for establishing and changing the operational limits of the apparatus that is to be controlled. Only one sensing device is needed for each apparatus that is controlled, since the signals that are generated by the sensing devices are compatible with the controller as well as with a central automated system if such is used. The controller eliminates the need for a conventional local controller for each apparatus and permits one controller to be used in conjunction with a plurality or a group of control devices.

Control system for time sharing multiple stepper motors with a single controller

Abstract: A plurality of stepper motors are energized one at a time in any order by repeating sets of drive pulses generated by a single motor controller. The actual winding state of each motor is stored in a memory unit. Upon selecting the next motor the controller is cycled until the actual motor winding state and controller winding state compare. The selected motor is then switched and moved by steps to a commanded position while entering new motor winding state data into the memory unit.

An adaptive flight controller for the F-8 without explicit parameter identification

Abstract: In view of the computational restrictions imposed upon any implementable flight control algorithm, a linear model reference adaptive controller which does not require the explicit online identification of aircraft parameters has been developed. Related analysis shows this algorithm to be at least stable in the sense of bounded plant-model errors provided that certain constraints can be satisfied. If in addition the open loop system satisfies the conditions of perfect model following the closed loop system will be asymptotically stable. Procedures were developed for satisfying the constraints and for adjusting the transient and steady state behavior. Results using the linearized lateral F-8 equations show the algorithm to be capable of adjusting to sudden flight condition changes within 1-2 seconds.

Eigenvalue control in distributed-parameter systems with parameter variations

Abstract: The state-feedback eigenvalue control problem is studied for a class of distributed-parameter systems subject to parameter variations about given nominal values. The feedback controller derived contains two parts, namely, the nominal controller which is based upon the nominal open-loop system parameter values, and the correcting controller which is designed such as to compensate for the parameter variations. Actually, the resulting eigenvalue controller may be regarded as a controller which reduces the sensitivity of the closed-loop eigenvalues to variations of the open-loop parameters. Two examples are worked out to support the theoretical results.

Design of multivariable digital control systems using the sequential return difference method

Abstract: The sequential return difference method is applied to the design of a digital controller for a multivariable digital system Although the open loop system is unstable, it is shown that a controller which provides good transient behaviour and low interaction may be designed by the appropriate sequence of single-loop, digital, root-locus designs

Use of Fast-Time Process Analogs in Two-Position Control

Abstract: It has been shown [1] that use of a ``fast feedback'' loop incorporating a plant model and a two-position controller results in better control of first-order thermal plants with inherent time delay In this paper such a control scheme is analyzed with a view of adapting it for process control Both steady-and unsteady-state analyses are carried out for the case where disturbance variations occur during regulatory control Based on the results obtained, criteria are evolved for the selection of suitable model parameters which result in zero offset in plant output, minimum period of steady-state cycling, and acceptable transient behavior

Design of a disturbance accommodating controller an airbrone pointing device

Abstract: This paper describes the practical application of "Disturbance Accommodating Control Theory" to a high-performance laser pointing (sighting) device mounted in a helicopter. The disturbances considered include the fundamental and first harmonic rotor-induced vibrations, weapon recoils, and a general class of uncertain pitching motions. It is shown that the disturbance accommodating controller can be designed by systemmatic linear algebraic techniques using state variables. The final controller is completely linear and yields a controller "transfer function" having rather unique properties in terms of controller poles and zeroes. The comparative pointing accuracy of the laser device using both a commercially designed classical controller and our "disturbance accommodating" controller is studied via analog simulation. By this means, it is shown that the proposed disturbance accommodating controller can (ideally) improve laser pointing accuracy by 2500%, compared to the classical controller.

Feedback control of discrete linear systems with random state and input dependent noise

Abstract: A generalization of the O.L.F.O. technique is proposed for the design of feedback controls of discrete linear systems with random input and state dependent noise. The control strategy is optimized at any time by assuming for the future, instead of an open loop, a feedback structure with given state estimator. The choice of the optimum estimator and of the control strategy for the future is approached with an original recursive algorithm which generates a monotonic convergent sequence of upper bounds of the cost-to- -go (CUB).

Suboptimal closed-loop control from open-loop algorithms

Abstract: An algorithm, based on numerical techniques, for calculating the open-loop optimal control for time-varying linear multivariable systems is considered. An approximation to the open-loop control is developed to provide a suboptimal closed-loop controller which is shown to be close to controllers computed using the maximum principle or dynamic programming procedures. Application to a nonlinear level control system shows that the measured response is close to the predicted optimal response for disturbances of up to 25% from the operating point.