Showing papers on "PID controller 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
TL;DR: The adaptive control algorithms can be applied for adaptive control of constant and time variant, linear and nonlinear, stable and unstable processes with process computers or micro computers or for self-tuning of control algorithms or tuning of conventional analog PID controllers.
19 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•
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02 Oct 1978
TL;DR: In this paper, the authors propose a mechanism to cope with the frequent change of control objects and the change of the characteristic of the system easily and properly by adding a mechanism which performs automatically the optimum adjustment of parameters on the operation characteristic of PI or PID regulators.
Abstract: PURPOSE: To make it possible to cope with the frequent change of control objects and the change of the characteristic of the system easily and properly by adding a mechanism which performs automatically the optimum adjustment of parameters on the operation characteristic of PI or PID regulators. CONSTITUTION: When a start signal is given, operation control part 3 for optimum adjustment applies prescribed operation quantity yo to control object 4 in steps and leads control quantity C from control object 4 to operation control part 3. Operation control part 3 measures this step response and detects wasteful time L and time constant inclination R and calculates sensitivity K p , integral time T i and differential time T d on a basis of them and gives calculated results to main operation part 2. Control quantity C and objective value r are inputted to main operation part 2, and main operation part 2 obtains deviation e(t) and executes operations of expression (1) or (2) on a basis of deviation e(t) and parameters K p , T i and T d and applies operation result y to control object 4 as an operation quantity. COPYRIGHT: (C)1980,JPO&Japio
11 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
TL;DR: In this paper, the authors present an instrument for the direct measurement of skin friction on cylinders in an external gas flow, using the servo force-balance principle and proportional feedback to increase the natural frequency of the system.
Abstract: Details of the design and construction of an instrument for the direct measurement of skin friction on cylinders in an external gas flow are given. The use of the servo force-balance principle represents a valuable improvement on previous instruments because (i) the sensing element is held in a fixed position by integral (I) control, guaranteeing a constant local flow field, and (ii) the proportional (P) feedback can be used to increase the natural frequency of the system, thus allowing the accurate and sensitive detection of such dynamic features as vortex shedding frequencies. The use of velocity, or derivative (D), feedback instead of oil damping allows operation of the transducer in an arbitrary orientation. It is an important fact that the sensitivity of a force-balance system is independent of the PID settings.
4 citations
Patent•
19 Dec 1978
TL;DR: In this article, the integrating member was added when the measured value entered the prescribed range of the set value, and only when the absolute value was smaller than the prescribed value, the integrating part was added.
Abstract: PURPOSE: To decrease the overshoot and increase the transient response properties by adding the integrating member when the measured value enters the prescribed range of the set value. CONSTITUTION: Control unit 4 obtains the difference, i.e., deviation e between measured value C and set value γ and then decides whether the absolute value is smaller than the prescribed value, for example, 2°C. And only when the absolute value is smaller than the prescribed value, the integrating member is added. Then operation amount m is obtained based on the PID control formula. The signal corresponding to the operation amount is sent to driving circuit 5 to control heater 2. COPYRIGHT: (C)1980,JPO&Japio
4 citations
01 Jan 1978
TL;DR: The specific objective of this paper is to develop direct digital control strategies for an ammonia reactor using quadratic regulator theory and compare the performance of the resultant control system with that under conventional PID regulators.
Abstract: The specific objective of this paper is to develop direct digital control strategies for an ammonia reactor using quadratic regulator theory and compare the performance of the resultant control system with that under conventional PID regulators. The controller design studies are based on a ninth order state-space model obtained from the exact nonlinear distributed model using linearization and lumping approximations. The evaluation of these controllers with reference to their disturbance rejection capabilities and transient response characteristics, is carried out using hybrid computer simulation.
3 citations
01 Jan 1978
TL;DR: In this article, the authors present a design algorithm for pole assignment which gives the designer the freedom to use his expertise within a standardized framework, which is an extension of previous work in which plant and compensator dynamics are described in such a way that the influence of compensation on the poles of the system is directly observed and root locus design techniques can be directly applied.
Abstract: The use of observers, Kalman filters, and PID controllers in design can all be reformulated as a general filter in a feedback loop. Filter design such as PI controllers have been used for many years in industrial processes. However, the methodology in practical applications has been limited somewhat to minimization of a cost functional resulting in large computational burden or to closing one loop after another. This paper presents a design algorithm for pole assignment which gives the designer the freedom to use his expertise within a standardized framework. The algorithm presented is an extension of previous work [9] in which plant and compensator dynamics are described in such a way that the influence of compensation on the poles of the system is directly observed and root locus design techniques can be directly applied.
2 citations
01 Jan 1978
TL;DR: In this article, the current loop for D. C. motor regulation using a PI controller is analyzed and the optimal response is obtained in continuous mode as well as in discontinuous one.
Abstract: The paper deals with the current loop for D. C. motor regulation using a PI controller. Analytic formulas are presented, which give the optimal response as well in continuous mode as in discontinuous one. The gain of the controller must be autoadaptative, because it depends of the operating point (current reference, speed). A realization is presented using a microprocessor.
TL;DR: In this paper, the exact synthesis of transfer function matrices for linear, square, multivariable systems using PID controllers is considered and a numerical test for the admissibility test of a desired transfer function matrix and a method is given for its synthesis.
Abstract: This paper considers the exact synthesis of transfer function matrices for linear, square, multivariable systems using PID controllers. A numerical test is developed for the admissibility test of a desired transfer function matrix and a method is given for its synthesis. The method involves simple real-matrix arithmetic.