Showing papers on "PID controller published in 1980"

Design and Application of a Microprocessor PID Predictor Controller

Abstract: A digital PID predictor controller is designed and implemented in a microprocessor. The general purpose system controller described permits the use of integer arithmetic for efficient operation with minimum throughput delay time. The stability of the system is investigated and a normalized chart for the selection of the control coefficients for a class of applications is developed. The controller has been applied to the control of a manipulator as a design example.

A Performance Study of Control Systems with Dead Time

Abstract: This paper discusses the performance of the Smith Dead Time (SDT) controller for systems with appreciable dead time. Tuning, modeling accuracy, and the effects of parameter variations and measurement noise are all studied using a simulated second-order process with dead time. The corresponding performance of the conventional proportional plus integral (PI) controller is used as a reference for comparison. It is shown that the SDT controller yields improved results over the PI controller if the plant is fairly stationary and the noise level is moderate. Otherwise adaptive filtering and control will be needed to maintain the superiority of the SDT controller over the PI controller.

MOVE Architecture in Digital Controllers

Abstract: The conditional MOVE processor (CMOVE) has been proposed for replacement of logic table driven sequencers like traffic light controllers and microcomputer I/O processors, in order to take better advantage of hardware-software tradeoffs. Herein the architecture of the CMOVE processor is sketched, and its application to traditional numerical control problems is studied. Two basis types of controllers, of potential use in industrial process control, are taken into account: the digital filter type, expressed as a ratio of two 2-transform polynomials (the proportional-integral-differential (PID) controllers is a particular case of the above), and the matrix multiplication type, which produces a control vector in response to a state vector input. A detailed program for a CMOVE realizatiorn of the digital filter is presented. A number of alternative realizations of the matrix controller are discussed in detail and evatuated.

On the Design of PID Output Feedback Controllers for Linear Multivariable Systems

Abstract: A time-domain technique is proposed for the design of proportional-plus-integral-plus-derivative (PID) output feedback controllers resulting in a closed-loop system having prespecified static accuracy, disturbance rejection, and transient response performance.

Computer control algorithms for a tubular ammonia reactor

Abstract: The specific objective of this paper is to develop direct digital control strategies for an ammonia reactor using the 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. The liner state-space model is simulated on the analog processor of the AD511 hybrid computer and the control algorithms are implemented on the digital computer.

Robust multivariable PI-controller for distributed parameter systems

Abstract: A Robust multivariable PI-controller for distributed parameter systems is introduced The presented theory generalizes Davisons finite-dimensional robust control theory to infinite-dimensional systems

Design of multivariable PID controllers for pole placement

Abstract: The paper puts forward a simple method for the design of PID controllers for pole placement in linear multivariable systems, where the controllers act directly on the available system outputs. For an m-input loutput system of order n, the controller can place 3m + l− 1 poles of the (n + l)th order closed-loop system arbitrarily. The PID controller ensures that in the steady-state the outputs track step commands and reject unmeasurable arbitrary disturbances with constant final values. The design method is illustrated by a numerical example.

Water wheel speed governor

Abstract: PURPOSE:To improve a responding property to the cutting-off of a load, by providing a first order lag element in a power feedback circuit. CONSTITUTION:The output of a power converter 8 is processed through a primary first order lag circuit 9 and then compared with the output of an output setting unit 7. The difference between both the outputs is processed through a speed dropping rate setting unit 6 and then compared with a speed deviation DELTAN. The difference between the former difference and the speed deviation is applied to an auxiliary servomotor 5 through a PID controller. Even if the output of the output setting unit 7 remains at the time of the cutting-off of the load, a power feedback signal is temporarily held by the first order lag element 9. Therefore, a proper output instruction is applied depending on the speed deviation DELTAN due to the rise in the rotational frequency of a water wheel. The responding property of a power-feedback speed governor to the cutting-off of the load is thus improved.

Tuning of a multivariable PID-controller for unknown systems

Abstract: Tuning of a multivariable PID-controller is treated, when the system is assumed to be unknown but linear time-invariant and stable. Discussion is limited to the case, when both the class of reference signals and disturbances consists of step signals.

Parameter identification and the self-tuning adaptive control by a sensitivity approach

Abstract: Parameter deviation identification and optimal controller tuning are derived by the sensitivities of the parameters. There are non-iterative and iterative algorithms which can be used for parameter identification, no matter the data come from an open-loop test or from a closed-loop operation. The controller tuning is based on the parameter sensitivities of an optimal regulator. The same tuning algorithm has been proved satisfactory for the PID control of the first order process with delay. By sequential implementations of both the identification and tuning, a self-tuning adaptive control system can be obtained. Numerical examples show the feasibility of such algorithms.

An automated high precision calorimeter for the temperature range 200 K–400 K. Part II. Design of temperature controllers

Abstract: The design and construction of precision temperature controllers, capable of tracking the temperature of the samples to within 1 mK for ramp heating rates from 0.05 to 10 K per hour, are discussed. A tutorial section on the evolution of the control loop configuration is first given. This is followed by an outline of the refinements of the basic control loop desirable in the actual implementation of the electronic controller. The novel features of the present system and its performance are then briefly discussed. Finally the inadequacy of the conventional PID controllers for this application, the estimation of the time constants of the physical system needed in the design of the electronic controllers and the pitfalls in using a simple model of the heater plus thermometer assembly with a single pole are also discussed.

A Design Method for PID Type Decoupled Control Systems Based upon Partial Knowledge about Controlled Processes

Abstract: 制御対象の動特性を完全 に正確 に測定す ることは, 特 にプ ロセス制御の分野では きわめて難 しい. したが って, 設計の 目的にとって必要最少限 の知 識で設計で きる設計 法を開発することが望まれ る. この観点か ら 筆者 は先 に一般的な設計原理を明 らか に し, I-PD方 式非干渉 制御系などの設計公式を導いた1)~3). ここで導 くPID方 式非干渉制 御系の設計公式 は, す で に上記I-PD方 式 につ いて展開 した基本 的手法を適 用す るにす ぎないが, 現在PID方 式 のほうが多 く使 われてい るので, その実用に供す るた めに ここに設計 例 と共 に示 す. しなが って, ここでは設計公式 に関連 す ることのみ記述 し, 基本 的な考 え方 はI-PD方 式 に つ いて の所論3)にゆず る. ここで扱 う制御対象はp入 力p出 力で, その伝 達関 数行列 はB(s)/a(s)(注1)と し, 平衡状態 で入 力 の平 衡 値 と出力 の平衡値 との間に1対1の 対応 関係が成 立す るよう, その直流ゲ イン行列. B0/a0が 正則, したが っ て, |B0|≠0, a0≠0と する. 設計すべ き制御系は, つ ぎの要請条件 を満たす非干 渉 制御系であ る. 非干渉化 された各部分制御系 につ いて (C1) 定 常位置偏差 がゼ ロになること, (C2) 適切な減衰特性を もつ こと, (C3) (C1) お よび (C2) の条件を満た した うえで, 立 上 り時 間が最小 であ ること, そ して部分 制御系相互 の間 の干渉 につ いて (C4) 低 周波領域か らで きるだ け高周波領域 まで非 干 渉化 が達成 され ること, で ある.

Electric type speed governor

Abstract: PURPOSE:To realize the best response by preventing excessive integral operation by bringing negative feedback to the integrator of a PID control part to detect that an actuator has reached a saturation range. CONSTITUTION:A speed signal from speed setter 1 and a signal from speed detector 2 are processed by comparing to generate deviation signal DELTAf and a signal obtained by adding this and output deviation signal DELTAp together is supplied to PID control part 3. Then, PID control part 3 performs proportional integral and differential processing of the input deviation signal to output an opening-degree command to actuator 5. Integral limiter 20 is supplied with the output of PID control part 3 and the difference of differential transformer 4 to provide negative feedback. The output of PID control part 3 is therefore controlled so that the deviation of actuator 5 from differential transformer 4 will not exceed the saturation value of actuator 5 much.

Identification and improved control of GTAW voltages utilizing digital series compensation

Abstract: Present methods for automatically controlling the voltage of a Gas-Tungsten-Arc-Welding (GTAW) process utilize an analog servo system to regulate the welding electrode to workpiece distance. The controllers currently being used in this facility are characterized by large over-shoot to a step input, and steady-state error due to deadband. An attempt to use microprocessor technology to improve the performance is underway. Such a method of improving the performance of the voltage controllers has been developed using an on-line identification procedure to determine the mathematical model of the present controller. Once an adequate model has been determined, a digital compensation scheme is designed to acquire the desired performance. The identification procedure used was the Model Reference Adaptive Technique, by which a model is postulated and its performance is compared to the actual plant performance for a set of given inputs. The squared error between the plant performance and the predicted performance is then computed over the identification interval. The model parameters are adjusted by an optimization routine to improve the model of the plant. Once the model is optimized to the point of diminishing returns, a digital PI or PID controller is designed. The result is that now the machine behaves in a manner that can be easily adjusted to give significantly improved performance. A relatively inexpensive M6800 microcomputer is used for both the on-line model identification, including the error minimizing routines, and for the realization of the series compensating controller. The software used is Motorola 6800 Assembly Language and Motorola Fortran. The method of improved control is being expanded to include the other welding parameters (current and speed of torch travel) and to other methods of control and state reconstruction, such as the linear regulator and the Kalman filter. Performance comparisons between the linear regulator and PID controller are made.

Temperature control method

Abstract: PURPOSE:To make it possible to stabilize a controlling variable and controlled variable in a short time by exercising proportional-differential-integral control when a deviation of a measured temperature from a set temperature is below a fixed value or by exercising ON-OFF control when above the fixed value CONSTITUTION:When a deviation a measured temperature measured by temperature sensor 12 from a set temperature is below a fixed value, solenoid 15 of four- mouth solenoid valve 14 stays unexcited and a heating fluid supplied from conduit 18 is led into heat exchanger 19 under the control of automatic valve 17 to exercise proportional-differential-integral PID control over a heat source On the other hand, the deviation of the measured temperature from the set temperature is above the fixed value, the deviation is detected by temperature regulator 13 to excite four- mouth solenoid valve 14, and consequently while automatic valve 15 is fully opened, an air-pressure signal PID-controlled is led out from four-way solenoid valve 14 As a result, when the temperature deviation decreased below the fixed value, automatic valve 15 is placed in an unexcited state and the PID control system is in effect under ON-OFF control Consequently, a controlling variable and controlled variable can be stabilized in a short time

Optimal self-tuning control systems: Theory and application: Part 1 Introduction and controller design

Abstract: Self- tuning regulators and controllers have proven to be a useful industrial control device. The self- tuning theory upon which these devices are based comprises the two aspects: controller design and system identification. In this first paper the emphasis is on the design, or more correctly, the synthesis, of the controller. In particular, classes of optimal controllers each dependent on a different cost function are discussed. The two most popular controllers- the minimum variance and the generalised minimum variance control laws - are derived in this first part.

Hybrid cascade type aerial tracking system - with one operational amplifier with PID response in inner control loop and microcomputer in outer control loop

Abstract: The hybrid cascade control by microcomputer is for an aerial tracking system and uses, for the internal analog control loop, an operational amplifier, normally designed as a proportional-integral-derivative (PID) controller to speed up the response. The external digital control loop uses a micro-computer with a PID-algorithm so that the entire control system combines fast response with high precision. The manipulated variable is covered by peripheral interface adapter PIA with 16 bits in parallel to provide a high resoln. Such an aerial tracking system requires a min. of space and expenditure.

Fluid flow rate control device

Abstract: PURPOSE:To make it possible to control air flow stably in the measuring range of the air flow meter, by changing the control system from the closed loop to the open loop in case the observation with the air flow detector is much less than its rating CONSTITUTION:The chlorine gas setting value Q F signals which are proportional to the flow rate of raw water are input to the comparator 12 which judges changeover of the loop, the function generator 13 in which characteristics of opening-air flow are stored, and the PI controller 2 which executes the air flow control In case Q F is higher than the projected value to the rating 100%, the changeover mechanism 15 conducts between A and c when the output signal S of the comparator 12 locates the contact of the loop changeover mechanism 15 at the side A, the observation Q F from the detector 6 and the switch 8 becomes feedback value by the controller 2, and the air flow control by the closed loop is executed In case Q F becomes lower than the projected value, the comparator 12 is operated, conducts between B and C, and the generator 13 supplies the opening setting value Ka corresponding to Q F to the opening setting unit 14 Thus the opening control by the open loop is executed without feedback of the air flow observation Q F

Selection system for control parameter

Abstract: PURPOSE:To enable the selection of suitable value without hunting and stable in the dynamic characteristics, by selecting the rate element only, in the system selecting the control parameters in response to the number of sets of the operation units, providing rate, integration and differential oprators. CONSTITUTION:The output signal S2 of the oscillator 1 and the output signal U of the set use analog memory AM2 are inputted to the PID operation unit(rate, integration and differentiation unit) 3, and after the calculation of deviation, one is fed to the adjustment section of the operation unit 3 and another is fed to the multiplier 4. In the multiplier 4, multiplication is made with the gain selection signal from the gain selection signal generators SG1-SGn5, gain selection transfer T06, first order delay unit LAG7, and the rate constant Kp only is corrected with the number of sets of the operation units. The output of the multiplier 4 is added to the preceding section of the operator 4, and the rate constant only among the control parameters is selected to a optimum value and connected to the transfers T1-Tn for adjusters. The analog memories AM1-AMn are connected to the transfers T1-Tn. As a result, stable control system without hunting can be obtained over the entire system.

Dynamic position holding controller for underwater steaming body

Abstract: PURPOSE: To control the position and the bearing of an underwater steaming body by controlling thrust forces through a combination of a position detector and the like with PID controllers, and to reduce the power consumption in generating the thrust forces of thrusters by preventing the exertion of lateral disturbing forces through allowing for bearing deviations arising from disturbances. CONSTITUTION: Outputs of a position setter 500 and the position detector 504 are fed into a position deviation converter 510 through subtractors 506 and 507. Outputs of a bearing setter 501 and a bearing finder 505 are fed into the PD controllers 513, 518, 522, 525 through the subtractor 508, while outputs of a depth setter 502 and a depth meter 503 are fed into the PID controller 527 through a subtractor 509. Outputs of the PD and PID controllers are fed into servo devices to control right and left propellers 03, 06 and bow, stern and vertical thrusters 09, 12, 15. Accordingly, since the thrust forces are automatically controlled by the PD and PID controllers, the position of the steaming body is controlled, and since the control allows for the bearing deviations arising from disturbances, the exertion of lateral disturbing forces can be prevented even when the body receives tidal forces. Therefore, the power consumption in generating the thrust forces can be reduced. COPYRIGHT: (C)1982,JPO&Japio

A new optimization method of pid control parameters for automatic tuning by process computer

Abstract: The method for the optimization of PID control parameters is proposed to aid the tuning operation of field engineers. The control system is restricted to the single-input single-output process, but may have time delay and non-self-regulation property. For the parameter estimation of the process, the characteristic areas are defined. In order to optimize control parameters, a new performance index is defined in the form of the weighted integral of squared error. The closed loop response obtained by the optimal settings has the desired damping factor and the stability margin. The present algorithm is implemented on a DDC system. The field tests carried out by using this system assure us that the method is applicable for the real processes.

Automatic optimum adjustment pid controller

Abstract: PURPOSE:To make invariably the best control possible by preventing a PID controller from changing in adjusting state due to the state of a load, by exercising the best control when the fixed load rate of a controlled system is equal to its input change. CONSTITUTION:In the figure, PID controller 4 for controlled system 3 has gain R, capacity T and delay element L; block 1/R is a proportional control block multiplying output x of system 3 by 1/R, block Tp shows a differentiating circuit, and block 1/Lp is an integrating circuit. Output variation mtheta of unit 4 is input to system 3. Here, block v generates a signal output proportional to the square root of the rate of a load on system 3. When v=v0, the relation between output x of system 3 and input variation m0 is shown by expression 8 and when m0=v0, the best control is exercised. Consequently, the adjusting operation of the controller can be prevented from changing in state due to the change of the load, providing the best automatic control at any time.

Digital control gauge for process control

Abstract: PURPOSE:To obtain a digital control gauge with a high cost performance as well as easy handling, by providing the control operation function of a high degree and then forming the control loop with the single loop CONSTITUTION:Control gauge 2 consists of two sets of PID control function circuits 3 and 4 functioning as the controlling function plus general operation function circuit 5 Input circuit 31 receives cascade input CAS and the set input when the switch is set to remote side R and local side L respectively, and also extracts the deviation of the process variable PV to then send it to velocity-type PID arithmetic circuit 32 The PID operation is given to the deviation signal at circuit 32, and the output is given to integrating circuit 33 for correction Thus the output of circuit 33 is delivered through terminal MV in the form of the operation output when the switch is set to side RA, and the manual operation output is sent to terminal MV when the switch is set to side M respectively Circuit 5 comprises the operation wafers of the small function unit, and then the output terminals are connected based on the fixed connecting table In such way, the high-class control operation function can be realized in a simple way

Ein Verfahren zur Bestimmung der Parameter von PI-, PD- und PID-Reglern / A method for the determination of the parameters of PI, PD, and PID controllers

Abstract: Γ il Zames, G.: Functional analysis applied to nonlinear feedback 1 systems. IEEE Trans. Circuit Theory CT-10 (1963), S. 392-404. 17] Kudrewicz, J.: Application of the functional analysis methods for the investigation of stability of nonlinear electrical systems. Rozprawy Elektro tech. IX (1963), S. 3-50. Π1 Simdberg, I.W.: On the boundedness of solutions of nonlinear integral equations. Bell System Techn. J., 44 (1965), S. 439^153. [4] Corduneanu, C.: Integral Equations and Stability of Feedback Systems. Verlag: Academic Press, New York, London 1973. [5] Hsu, J.C., und Meyer, A.U.: Modern Control principles and applications. Verlag: McGraw-Hill , New York 1968. [6] Sydow, Α.: A Contribution to the Analysis and Synthesis of Discrete-time Systems by Contraction principle. EIK 13 (1977), S. 535-547. [7] Schober, J.: Anwendung funktionalanalytischer Methoden zur Stabilitätsanalyse von Systemen mit verteilten Parametern. Dissertation, Universität Karlsruhe 1978. [8] Miller, R.K.: Nonlinear Volterra Integral Equations. Verlag: W.A. Benjamin, Menlo Park, California 1971. [9] Reiffen, H.-J., Scheja, G., und Vetter, U.: Algebra. Verlag: Bibliographisches Institut, Mannheim, Wien, Zürich 1969.

Extension of the smith predictor

Abstract: An effective means of controlling non-linear systems with time delays by use of a digital computer is presented. A model of the system is required, and an extension of Smith's method is used. The method is demonstrated on an experimental enzyme reactor containing a saturating element and a large delay relative to the time constants of the system. The time optimum control of the experimental system as well as PID control is used to demonstrate the effectiveness of the method.

Feed pump driving turbine controller

Abstract: PURPOSE:To control a driving turbine with high reliability with not many elements of hardware by means that once a failure of a main controller or a differential transformer is detected, a manually operated backup device is applied instead of it for continuously controlling the driving turbine CONSTITUTION:When there appears something wrong with a main controller 4, PI controller 26, differential transformer 24, or others, first a signal of a valve opening fed back to an analog input circuit 29 is differentiated by a differentiator 30 If the result stands outside a specific range, a comparator 31 puts out the signal to an OR circuit 34 An exciting rectifying circuit 27 has a detective function of breaking of wire of the differential transformer and puts out the detected signal to a digital input circuit 32 The signals from the comparator 31 and digital input circuit 32 are put in an OR circuit 34 to form a logical sum, which makes a hand operating backing device 23 change a switch 28 into manual operation A feed pump driving turbine can be successively controlled in safe without need of applicating a double differential transformer