Showing papers on "Proportional control published in 1978"
01 Feb 1978
TL;DR: Some recent research results on algorithms designed for use in stand-alone, single-loop calculator or microprocessor-based controllers are presented, specifically tailored for simple implementation in a relatively low computing power, discrete-time environment.
Abstract: Process control applications and control algorithms suited for microprocessors are surveyed. Applications are noted both in large, general purpose process control systems and in specialized applications that have been made possible by the availability of computing power in small packages. Distributed control and use of extended data buses (data highways), both made possible by extensive use of microprocessors, are becoming standard in general purpose systems. General purpose process control systems still utilize proportional-integral-derivative (PID) algorithms and variants of them for the most part. Some recent research results on algorithms designed for use in stand-alone, single-loop calculator or microprocessor-based controllers are presented. These algorithms, which could also be used in direct digital control (DDC) systems, are specifically tailored for simple implementation in a relatively low computing power, discrete-time environment.
66 citations
Patent•
02 Feb 1978
TL;DR: In this article, a feedback servo is used to provide a control signal to the liquid crystal devices (LCDs) for precisely controlling illumination with the LCD, thereby providing a form of proportional control with signals that provide on-off type characteristics.
Abstract: Illumination amplifier devices such as liquid crystal devices (LCDs) are controlled with feedback servo arrangements using pulse modulated signals such as pulse width modulated signals or using proportional analog signals. In a preferred embodiment, illumination is controlled with an LCD, where the controlled illumination is monitored with a electro-optical sensor to generate a feedback signal related to a characteristic of the controlled illumination. The feedback signal is processed with an illumination servo to provide a control signal to the LCD for precisely controlling illumination with the LCD. A pulse modulation circuit provides pulse modulation signals to control the LCD, thereby providing a form of proportional control with signals that provide on-off type characteristics. This arrangement provides more precise control for illumination amplifiers and provides proportional control with the illumination amplifier operating in an on-off manner.
36 citations
TL;DR: In this article, the authors present a systematic development of the analysis, design, and testing of a SCR controlled separately excited dc motor drive system, where the motor armature voltage is supplied from a three-phase fully controlled six-pulse thyristor bridge.
Abstract: This paper presents a systematic development of the analysis, design, and testing of a thyristor (SCR) controlled separately excited dc motor drive system. The motor armature voltage is supplied from a three-phase fully controlled six-pulse thyristor bridge. Closed loop control is analyzed using transfer function techniques and the necessity of an inner current control loop is demonstrated. Armature reconnection is used to enable regenerative braking and speed reversal. Design of both a proportional and proportional integral controller is outlined and experimental results are given.
31 citations
Patent•
25 Oct 1978
TL;DR: In this paper, an overshoot judging circuit is added to a proportional control system to restrict the overshoot caused by a rapid decrease of water supply. But this circuit is not suitable for the case of a small amount of water.
Abstract: PURPOSE: To restrict an overshoot to be caused at a rapid decrease of water supply amount by the additional provision of an overshoot judging circuit in a proportional control system included in the combustion control device of the proportional control system which carries out the control based on the temperature of water. CONSTITUTION: In the combustion control device of the proportional control system including a water temperature detector which provide a signal representing the detected value, a PID control circuit which includes a common integrating circuit comprising an OA amplifier 41 and the like and receives the signal from the detector, and a fuel supply means which determines the amount of fuel supply based on the output from the PID control circuit and supplies the fuel accordingly, a circuit for detecting an overshoot occurrence of the water temperature is provided which fanctions in accordance with the water temperature detection signal. In such a construction, if the water supply rate W o rapidly decreases to W 2 , a thermister 6 detects this decrease after a short period, And when the detected value exceeds an overshoot judging temperature, the overshoot judging circuit reverses to compulsively make an unreversible input of the OA amplifier 41 to be of a low level. Accordingly, the current flowing through a proportional valve 3 is decreased to such a value as to allow the amount of gas at the necessary minimum. COPYRIGHT: (C)1982,JPO&Japio
13 citations
Patent•
19 Jan 1978
TL;DR: In this article, a processing machine is driven by an electric motor, its load varies, and the circuit consists of a speed control circuit and a current control circuit, and a variable proportional to the load torque is applied to the current controllers as an additional nominal value.
Abstract: The processing machine is driven by an electric motor, its load varies, and the circuit consists of a speed control circuit and a current control circuit. A variable proportional to the load torque is applied to the current controllers as an additional nominal value. The speed controller (10) is a pure proportional controller, and the additional nominal value (mL) is generated by an automatic controller (12) controlled by the driving motor (1) current (iM). The speed (nM) of the motor is controlled. A differential rotary speed is developed between the driving motor (1) and the working machine (3) which is proportional to the current in the circuit.
12 citations
Patent•
27 Jan 1978TL;DR: In this article, a condition responsive time proportional control means which has a relatively fast time constant when operating in its proportional band has the time constant expanded by means of a digital counter, which is repetitively switched by the condition responsive means and counts the switched operation.
Abstract: A condition responsive time proportional control means which has a relatively fast time constant when operating in its proportional band has the time constant expanded by means of a digital counter. The counter is repetitively switched by the condition responsive means and counts the switched operation. During the period that the switched operation is occurring, the time constant is expanded by simultaneously counting pulses from a pulse generating means.
12 citations
Patent•
06 Apr 1978TL;DR: In this article, a condition responsive time proportional control means which has a relatively fast time constant when operating in its proportional band has the time constant expanded by means of a digital counter.
Abstract: A condition responsive time proportional control means which has a relatively fast time constant when operating in its proportional band has the time constant expanded by means of a digital counter. The counter is a resettable unidirectional type counter. The output of the counter drives a switch means and a load along with a means for altering the time constant of the condition responsive time proportional control means. The time constant is altered by a switching means that changes the charge and discharge path of a capacitor used in creating the time constant.
9 citations
01 Jan 1978
TL;DR: A simple method for the design of proportional-plus-integral controllers for multivariable systems where the controllers act directly on the available system outputs and the transient responses of the closed-loop system may be improved by tuning the controller.
Abstract: The paper presents a simple method for the design of proportional-plus-integral controllers for multivariable systems where the controllers act directly on the available system outputs. For an m-input l-output system of order n, the PI controller can place 2m+l-1 poles of the (n+l)th order closed-loop system at any desired locations. In the closed-loop system, the outputs follow step commands in the steady-state and reject unmeasurable arbitrary disturbances with constant final values. The steady-state properties are preserved for variations or uncertainities in the system parameters provided the closed-loop stability is maintained. The transient responses of the closed-loop system may be improved by tuning the controller as described in the paper. The controller design method is illustrated by a numerical example.
9 citations
Patent•
21 Dec 1978
TL;DR: An electromagnetic proportional control valve capable of operating with ease and certainly is described in this paper, where it is shown to operate in the electromagnetic field. But it is not available in practice.
Abstract: PURPOSE:An electromagnetic proportional control valve capable of operating with ease and certainly.
2 citations
TL;DR: Sampled-data proportional control of an exothermic CSTR has been studied in this article using the classical linear analysis and by the application of the averaging technique in the context of CSTRs.
1 citations
Patent•
09 Mar 1978
TL;DR: In this paper, the proportional regulator has a small gain and advances correction circuit for the remaining standard deviation o +/- the speed with an additive switch for a thrust or braking force proportional to the speed.
Abstract: The remote control for the train has a low gain proportional control circuit and provides correction from the prescribed speed by addition of torque proportional signals to the reference speed signal. The torque signals are either positive or negative depending on the train operating mode. The proportion regulator has a small gain and advances correction circuit for the remaining standard deviation o +/- the speed with an additive switch for a thrust or braking force proportional to the speed.
01 Jan 1978
TL;DR: In this article, the steady state performance of a series motor for electric traction is analyzed for the following cases: a) open loop b) closed loop and proportional controller c) closed-loop and proportional plus integral controller through a double point of a recurrence, on a Lamerey diagram, the periodic steady state is characterized; some variables are calculated with the objective of evaluation and comparison of the steady-state performances.
Abstract: In this work, the steady state performance of pulsewidth torque control system of a series motor for electric traction is analysed for the following cases: a) open loop b) closed loop and proportional controller c) closed loop and proportional plus integral controller Through a double point of a recurrence, on a Lamerey diagram, the periodic steady state is characterized; some variables are calculated with the objective of evaluation and comparison of the steady state performances.