SU1674058A1 - Relay-pulsed controller - Google Patents

Abstract

This invention relates to an automatic adjustment technique. The purpose of the invention is to improve the accuracy of regulation. The invention makes it possible to increase the control accuracy by combining the three-position control in the zone of "large" mismatches and the pulse control in the zone of "small" mismatches. The three-position regulation deadband is quantized by the number of equations, which depends on the number of time intervals during which the control error signal is in this zone. At the beginning of each time interval, a single pulse is formed, the duration and period of which depends on the basic characteristics of the quality of control on the integral values of the module and the square of the control error signal over the previous time interval. The polarity of a single pulse is set in accordance with the sign of the difference between the current value of the control error signal and its value at the time of the end of the preceding time interval. The number of time intervals is set equal to the number of periods of single pulses. 3 il.

Description

The invention relates to the technology of automatic control of technological processes, in particular, to systems of relay-pulse control of parameters (temperature, humidity, fluid flow, etc.) of technological processes, and can be used for highly precise program movement (positioning) of actuators of automatic control systems. air heaters, boiler rooms and other thermal units and installations.

The purpose of the invention is to improve the accuracy of regulation.

FIG. 1 shows an example of the implementation of a relay-relay regulator; in fig. 2 illustrates an example of the application of the proposed device in a software thermostatting system (temperature control) of an inertial object; in fig. 3a is the transition control curve; b - curves of changes in the values of the normalized (scaled) control error; c - actuator response; (d) Schedule of changes in the position of the regulatory body.

The regulator is arranged as follows (Fig. 1).

(

Vj

 About 01 00

The regulator input is connected to the first input of the adder 1, to the inputs of controlled keys 2 and 3, to the input of the absolute value determination unit 4 and the input of the polarity detector 5, the first output of which is connected to the input of the AND 6 logic element, and AND 7 logic gate. The second inputs of AND 6 and 7 logic gates are combined with the input of the HE 8 logic element and connected to the output of the relay element 9, whose input is combined with the input of the relay element 10, with the input of the recovery unit (value of the control error signal) to the square 11, by the input of electronic switches 12, 13 and connected to the output of the sensor for determining the normalized absolute values of the control error signal 4, the output of the electronic switch 12 is connected via an element of the analog memory 14 and the electronic switch 15 to the first input of the adder 16. The second input of the adder 16 is connected to the output The electronic key 17, whose input is connected via the analog memory element 18 with the electronic key 13 output. To the third input of the adder 16, a constant voltage (+ E) from the source of the reference voltages 19 is supplied. of the normalized regulation error squared 11 is connected via a serial connection circuit of an electronic switch 20, an analog memory element 21 and an electronic switch 22 to a first input of the adder 23, and through a serial connection circuit of an electronic switch 24, an analog memory item 25 and an electronic switch 26 - with the second input of the adder 23, the third input of which is supplied with a constant voltage (+ E) from the source of the reference voltages 19. The second input of the adder 1 is connected via a series circuit of the electronic switch 27 and the element nta analog memory 28 with the output of the electronic key 2. The third input of the adder 1 is connected to the output of the electronic key 29, the input of which through the element of the analog memory 30 is connected to the output of the electronic key 3, the output of the adder 1 is connected to the input of the polarity detector 31, the first input which is connected to the input of the logic element 32 and the second output to the input of the logic element 33. The second inputs of the logic elements 32 and 33 are connected to the output of the pulse duration shaping unit (control actions) 34, the input of which is ithout electronic key 35 with the output of the adder 23. The control input 35 of the electronic key connected to the output of the AND gate 36, a first

the input of which is connected to the output of the logical element HE 8, the second input to the output of the relay element 10, and the third to the output of the pulse shaping unit

(control actions) 37, the input of which is connected to the output of the adder 16. The control inputs of the electronic switches 12, 17, 20, 26, 2 and 29, as well as the reset input of the elements of the analog memory 14 and 21 are connected to the first output of the trigger 38, the second input of which is connected to the control inputs of the electronic switches 13, 15, 22, 24, 27, 3 and to the reset input of the elements of the analog memory 18 and 25. The trigger input 38

connected to the output of the formation of the duration of the period of the pulse impulse control actions 37. The outputs of logic elements 6 and 32 are connected respectively to the first and second inputs

the logical element OR 39, and the outputs of the logical elements And 7 and 33, are connected respectively with the first and second input of the logical element OR 40.

Outputs of logical elements OR 39

and 40 are the outputs of the controller and are intended to control the actuator of the regulator of the automatic regulation system.

In the embodiment shown in FIG. 2, the following designations are adopted in the diagram of the software for temperature control of an inertial object: 41 — control object (regulation); F (t) - disturbing

impact; 42 - temperature sensor; 43 - software driver, 44 - adder; 45 - regulator; 46 — actuator; 47 - regulatory authority. When the controlled variable is disconnected from the task in one direction or another from the permissible regulation error, pulsed control actions are formed at the controller output (Fig. 3c), which, moving to the actuator, move the regulator towards compensation of disturbances causing this deviation control object. At the same time, in the dead zone of the three-position regulation AH, the value of which is controlled by the setting of the zone of operation of the relay element 9 (Fig. 1), when the error signal of the regulation of the permissible value Dgr determined by the value of the zone of operation of the relay element 10 is exceeded, pulse control is performed. In the range of values of I e (t) IE (/ W2, co) (respectively, le (t) l E (1, "), continuous relay control is performed.

Consider the process of formation of the period, duration and polarity of control actions at those moments of time when the absolute value of the control error | e (t) I An / 2 and the corresponding normalized value le (t) l 1. It is assumed that the normalization of the control error signal carried out with a factor D - Ln / 2. The formation of the duration of the period of the control actions is carried out for all values of e (t). Suppose that in the initial position the trigger 38 is in a single state. Then the electronic keys 13, 15, 22, 24, 27 and 3 will be closed, and the keys 12, 17, 20. 26, 2 and 29 are open. In this case, a constant voltage will be applied to the input of the pulse shaping unit (control actions) 37

U, (, rUi + E. (1)

H

where 1L / le (t) l dt is the voltage value, ti-1

obtained as a result of the integration operation of the absolute values of the control error signal in the previous time interval (period) Tm by the integrating element of the analog memory element 14;

E is a constant voltage coming from a source of reference voltages 19, the value of which can be chosen, for example, from a range of values with a lower limit determined by the inertia of the mechanism used (for example, to compensate for its inertia) and as

1 I (KF Pmax).

where Pmax is the maximum frequency of change of the control error signal;

Kr is a constant coefficient, which, according to the reference theorem, in the temporal representation of continuous signals in discrete form, otherwise the Kotelnikoff theorem, can be specified — Kr 2.

Because of this, the upper limit of the values of this interval can be chosen from the necessary condition for ensuring the equivalence of the representation of a continuous signal by its discrete values, ensuring the adjustment of the control error signal with the least loss of information. In accordance with the values of Ui and E at the output of the block forming the duration of the control actions 37 a pulse of duration will be generated

Ti Kfif | Cf I / le (t) I dt 4- E 1. wi-1

where K is the transfer coefficient of the unit for forming the duration of control actions 37.

During this TI period

5, signals that are equal to the value of the modulus of the error signal of the regulation le (t) l are received through the closed electronic key 13 to the integrating element of the analog memory 18. As a result, for a subsequent period of TI + I, during the time of action of Ti, UIH will be formed. as

h + ti

Un-1- / le (t) l dt, (3)

h

15 Upon expiration of a time interval with a duration equal to TI, the block forming the duration of the pulse following period (control actions) 37 will set the trigger 38 to the zero state.

20 This will cause the electronic keys to switch, namely, the keys 12, 17, 20, 26, 2 and 29 will be transferred from the open to the closed state, the keys 13, 15, 22, 24, 27 and 3 from the closed to the open state .

25 Simultaneously with switching the keys, the voltage value accumulated on the integrator of the analog memory element 18 will be reset (set to zero). When implementing integration with the use of capacitive drives, a reset can be effected, for example, by briefly shorting the capacitive drives of the elements of the analog memory. Accordingly, the following

35, switching the electronic keys will reset the voltage on the integrator of the analog memory element 14. The above-described sequence of operations will be continuously repeated in the functional

40 depending on the change in the control error signal E (t). In this case, at each of the periods Ti, an enabling signal for switching on the electronic signal will be supplied to the input of the logic element 36 from block 37.

45 of the key 35, which commutes the input circuit of the shaping unit for the duration of the pulses of control actions 34. At the time of the end of each period TI and the beginning of the next time interval TI + I, constituting a short time interval (the duration of each of which is mainly determined by the inertia of elemental base), a signal is formed that is sufficient for turning off the electronic key 35. This ensures the synchronization of the operation of the block 37 and the block 34 for forming the pulse duration (control constituent influences) for all the time intervals Ti, 1 ... 1.2.

The process of forming voltages at the input of the pulse duration shaping unit (control actions) 34 is implemented according to a scheme similar to that described at the input of block 37 with the only difference that the shaping of the control pulse duration is carried out in accordance with the value of the estimation of the integral change in the square of the signal control errors le (t) l and in all periods T |, for which Dgr le (t) l Dn / 2. Monitoring of the fulfillment of these conditions is implemented using the AND 36 logic element, controlling the state of the electronic key 35 in accordance with the signals from the pulse shaping unit 37 of the relay elements 9 and 10, controlling respectively the values of Dn / 2 and Dr.

At the outputs of the polarity detector 31, signals will be formed which, using the matching circuits of logic elements 32 and 33, form the polarity of the control actions (subtract and add). In this case, the formation of the sign of the control actions will be carried out on the basis of the signal received at the output of adder 1, equal to V (t) Ј (t) - Ј (ST), which is equivalent to continuous tracking of the change in the sign of the rate of change of the control error signal. In addition, due to the magnitude of the hysteresis of the polarity detector 31 and the elements of the analog memory 28 and 30, during the formation of the control actions, the sign of this signal V (t) is memorized at the time of termination of the preceding time interval of the formation of the control actions. And this, in those moments of time

when --it О completely eliminates the loss of information about the magnitude of the mismatch, this contributes to an increase in the accuracy of regulation not only in dynamic, but also in static modes of operation of automatic regulation systems. Thus, the effect of increasing the control accuracy is achieved mainly due to the fact that the number of quantized levels in the dead zone of the three-position control is not predetermined, but is determined in the process of testing the software-specified influences. In this case, the magnitude of the three-position regulation deadband is subjected to quantization, depending on the time during which the error signal

the regulation is in the dead zone of the three-position regulation.

In this device, all parameters of the control actions are determined through the main integral criteria imposed on the quality of regulation. Namely, through the value of the control error and its square. However, these

characteristics of the control quality are monitored at each of the control time intervals, the number and duration of which are determined and adjusted based on the values obtained

estimates that determine the magnitude of the mismatch. In addition, the implementation in the control devices of this method of automatic control is possible based on the use of a minimum

the number of variable parameters (otherwise, customization). For example, based on the choice of the normalizing (scaling) divider as the sole or main body of adjustment. Namely, you can

combine its values and, respectively. its change with the setting of the size of the dead zone of the three-position regulation - DN / 2. As a result of this combination, all other parameters

control device will be associated with the installation of a single parameter - the normalizing divider, since the simultaneous change of the normalizing divider and the dead zone size will entail

directly and indirectly change all other variable parameters. In this case, the degree of dependence of the change in each of the parameters can be separately set, both before putting the regulating device into operation, or directly during the adjustment.

Claims (1)

Claims Relay-pulse controller containing the first and second pulse width formers, the element is NOT, the first and second elements are OR, the outputs of which are respectively the outputs of the controller Slacken and Add, which is equivalent to that. in order to improve the control accuracy, a reference voltage source, two polarity detectors, five AND elements, two relay elements, a squaring unit, a trigger, an absolute value determination unit, three adders, six analog memory elements and thirteen are entered into it. keys, information inputs of the first and second keys are connected to the inputs of the squaring block, the first and second relay elements and with the output of the absolute value determination unit, the input of which is the controller input and connected to the input of the first polarity detector, with the information inputs of the third and fourth keys and the summing input of the first adder, the first subtractive input of which is connected to the output of the fifth key, the information input of which is connected via the first element of the analog memory — to the output of the fourth key; the second subtractive input of the first adder is connected to the output of the sixth key, whose information input through the second the analog memory element is connected to the output of the third key, the output of the first adder is connected to the input of the second polarity detector, the first and second outputs of which are connected to the first inputs of the first and second elements, respectively, the second inputs of which are connected to the output of the first pulse width generator, whose input connected to the output of the seventh key, the information input of which is connected to the output of the second adder, the first input of which is connected to the output of the eighth key, whose information input is connected with the output of the third analog memory element, the information input of which is connected to the output of the ninth key, whose information input is connected to the output of the squaring unit, the second input of the second adder is connected to the output of the tenth key, the information input of which is connected to the output of the fourth analog element the memory, the information input of which is connected to the output of the eleventh key, the information input of which is connected to the output of the squaring block, the third input of the second adder is connected to the output the source reference voltage and the first input of the third adder, the second input of which is connected to the output of the twelfth key, the information input of which is connected to the input of the fifth analog memory element, whose information input is connected to the output of the second key, the third input of the third adder is connected to the output of the thirteenth key, the information input which is connected to the input of the sixth element of analog memory, the information input of which is connected to the output of the first key, the output of the third adder is connected to the input of the second shaper pulse duration, the output of which is connected to the counting input of the trigger and to the first input of the third element And, the second input of which is connected to the output of the second relay element, and the third - to the output an NOT element whose input is connected to the output of the first relay element and to the first inputs of the fourth and fifth elements AND, the second inputs of which are connected respectively to the first and second the outputs of the first polarity detector, and the outputs with the first inputs of the first and second elements OR, respectively, the second inputs of which are connected respectively to the outputs of the first and second elements AND, the control inputs of the first, third, eighth, eleventh and twelfth keys are connected to the inputs Reset the fourth and the sixth elements of analog memory and direct output trigger, the inverse output of which is connected to the control inputs of the second, fourth, sixth, ninth and tenth keys and inputs Reset the third and fifth elements of the analog memory, the control input of the seventh key is connected to the output of the third element I. Output 47 1 t C 42 45 L at  2 Regulation of the Regulator ) )