RU2128358C1 - Automatic control system - Google Patents

Abstract

FIELD: automatic control equipment. SUBSTANCE: device has actuating unit 2 for controlled object 1, control action detector 3, output action detector 4, first and second delay gates 5, 16, first, second, third, fourth and fifth comparison gates 6, 20, 15, 14, 11, first and second models 7, 12, which do not take delays into account, first and second adders 8, 9, first, second and third regulation units 19, 13, 10, first and second extrapolation units 18, 17. EFFECT: possibility to control industrial objects with significant delays in control channel and subjected to random disturbances which conform to arbitrary setting conditions. 1 dwg

Description

в которой L(S) и M(S) - полиномы от S, причем степень полинома L(S) не превышает степень полинома M(S); τ - время транспортного запаздывания. Такого рода системы могут быть использованы при управлении техническими объектами с большими транспортными запаздываниями, в частности объектами, содержащими транспортные конвейеры, отдельные участки производства, взаимосвязанные по сырью и полупродуктам, а также в целом предприятиями с выходом на технико-экономические показатели, которые, как правило, оцениваются с существенной задержкой по отношению к времени производства продукции.The invention relates to the field of automatic control and regulation and can be used to build control systems for technical objects containing significant delays in control channels and subject to the influence of uncontrolled perturbations and random actions that vary according to an arbitrary law. It is assumed that the dynamics of the object is described by the transfer function

in which L (S) and M (S) are polynomials in S, and the degree of the polynomial L (S) does not exceed the degree of the polynomial M (S); τ is the transport delay time. Such systems can be used in the management of technical facilities with large transport delays, in particular, facilities containing transport conveyors, individual production sites interconnected by raw materials and intermediate products, as well as enterprises in general with access to technical and economic indicators, which, as a rule are evaluated with a significant delay in relation to the time of production.

 Known open-loop control system (see book: Ya.Z. Tsypkin. Fundamentals of the theory of automatic systems, M .: Nauka, 1977, p.81, Fig. 6.6), containing a series-connected comparison unit, controller, adder and control object the output of which is connected to the subtracting input of the comparison unit, the other input of which is connected to the input of the correction controller connected by its output to the second input of the adder, moreover, the input of the correction controller and the comparison block receives a setting action, and the output of the object is Rui output value.

 The disadvantage of this system is the low accuracy with respect to objects containing significant delays in the control channels.

 Closest to the proposed technical solution is the regulator (see AS USSR N 855607, class C 05 B 13/02, decl. 04.02.80), containing a series-connected adder, the first comparison unit, a low-pass filter, proportionally an integral control unit, a second comparison unit and a control object model without delay, connected by its output to the adder input, an extrapolator and a delay unit connected in series, the extrapolator input connected to the output of the proportional-integral control unit, output the delay unit is connected to the second input of the second comparison unit, the second input of the adder receives a signal from the output of the control object about an adjustable output value, the second input of the first comparison unit receives a signal about the setting action, and the signal from the output of the extrapolator is the output signal of the controller supplied to the object management. In this regulator, in a model-closed loop, including a model of a control object without delay and a proportional-integral control unit, an exemplary control action for an object without delay is determined, which is then extrapolated to the delay time interval.

 The disadvantage of this regulator is the low accuracy of regulation due to the fact that, firstly, the proportional-integral control unit produces control actions in orientation to the model rather than the natural output of the object, which can differ significantly, and, secondly, not changes in the setting action are taken into account explicitly.

 The objective of the invention is to improve the accuracy of control.

 The task is achieved by the fact that in the automatic control system containing the Executive unit, the control object, the first and second sensors connected in series with the first delay unit, the first comparison unit, the first model of the object without delay, the first adder, the second comparison unit, the first control unit and the first extrapolator, and the output of the executive unit through the first sensor is connected to the input of the first delay unit and to the input of the control object, the output of which is connected through the second sensor to the second the first adder, the output of the first control unit is connected to the second input of the first comparison unit, the output of the control unit is the output of the automatic control system, and the second input of the second comparison unit is the input of the system according to the setting action and the output of the first adder is a model output of the system, according to the invention, the second an adder, a second extrapolator in series, a second delay unit, a third comparison unit, a fourth comparison unit, a second control unit, a second model l of the object without delay, the fifth comparison unit and the third control unit connected by its output to the first input of the second adder, the second input of which is connected to the output of the first extrapolator, and the output is connected to the input of the executive unit, the input of the system is connected by input to the input of the second extrapolator and with the second input of the third comparison unit, the output of the second model of the object without delay is connected to the second input of the fourth comparison unit, the output of the first model of the object without delay is with the second input of the fifth block alignment.

 Verification of compliance of the claimed technical solution with the requirements of novelty was carried out taking into account all previously published applications.

The proposed automatic control system is implemented at the inventive level (new communication units between them are introduced) and a new technical result is achieved: the control accuracy in the proposed automatic control system is increased because
- eliminates the sharpness between the model and full-scale output effects due to the introduction of the third regulatory unit;
- are taken into account in explicit form the changes of the setting action, using blocks; the latter is necessary in order to eliminate the influence of changes in the driving influence on the functioning of the third regulatory unit, because the latter perceives them as uncontrolled disturbances.

 The drawing shows a block diagram of an automatic control system.

 The automatic control system contains a control object 1, an executive unit 2, a first 3 and a second 4 sensors, a first delay unit 5, a first comparison unit 6, a first object model 7 without delay, a first 8 and a second 9 adders, a third control unit 10, a fifth unit 11 comparison, the second model 12 of the object without delay, the second control unit 13, the fourth 14 and third 15 comparison units, the second delay unit 16, the second 17 and the first 18 extrapolators, the first control unit 19, the second comparison unit 20, the correction unit 21.

When using the proposed automatic control system in industry for controlling, in particular, flow-transport systems, a control-transport section containing a transport link and an intermediate tank is taken as the control object 1 (see, for example, the book: A. D. Ishchenko. Static and dynamic properties of the agglomeration process, M.: Metallurgy, 1972, p. 82, Fig. 25). The control task is to provide a changing required supply of material in the intermediate hopper. The control action is the consumption of the transported material. Controlled output value - stock (level, mass) of material in the intermediate hopper. The disturbing effect of the process is changes in the consumption of material from the intermediate hopper. Executive unit 2 can serve as a continuous dispenser (see, for example, the book: AD Ishchenko. Static and dynamic properties of the agglomeration process, M.: Metallurgy, 1972, p. 41, Fig. 11), which is a closed system of automatic regulation. The dispenser is controlled by a signal about a predetermined amount of material consumption. The first sensor 3 is, in particular, a conveyor scale (see, for example, Grossman N. Ya., Shnegrov GD Automated weighing and batching systems. M: Mechanical Engineering, 1988, Fig. 177, p. 254). The second sensor 4 is, in particular, a strain gauge whose signal is proportional to the mass of material in the intermediate hopper (see, for example, ibid., Fig. 59 on p. 96). According to the schemes of the monograph Tetelbaum I.N., Schneider Yu.R. The practice of analog modeling of dynamic systems. Reference manual, M .: Energoatomizdat, 1987, the first 5 and second 16 delay blocks are implemented - scheme 1.8.12 on p. 111; extrapolators 17, 18 in the form of a real forcing link - Scheme 1.2.12 on p. 62; the first 7 and second 12 models of the object without delay in the form of an integrator - Fig. 1.3, a. According to the schemes of the monograph by Titz W., Schenk K. "Semiconductor circuitry", M., "Mir", 1982, the following are implemented: the first 8 and second 9 adders - the circuit of Fig. 11.3 on page 138; first 6, second: 10, third 15, fourth 14 and fifth 11 comparison blocks - the diagram of Fig. 11.2 on page 138; the first 19, second 13 and third 10 regulatory blocks in the form of regulators that implement the proportional-integral regulation law - the diagram of Fig. 26.7 on p. 483. The drawing indicates: u - control action; ω is an uncontrolled disturbance; y is the output effect (controlled value); δу ^m - change in model output effect; y ^m - model output effect; δу ^к - corrective action y ^* - defining effect; u ⁱⁿ - exemplary control action.

 The automatic control system operates as follows.

в котором S₇(S), f₁₉(S) - передаточные функции первой модели 7 объекта управления и первого регулирующего блока 19; у^м, у^*, ω - модельное выходное воздействие, задающее воздействие, приведенное неконтролируемое возмущение; S - оператор Лапласа.Model-closed control loop, including the first model 7 of the control object and the first control unit 18, is described by the operational ratio

in which S ₇ (S), f ₁₉ (S) - transfer functions of the first model 7 of the control object and the first regulatory unit 19; y ^m , y ^* , ω - model output action, specifying the effect, reduced uncontrolled disturbance; S is the Laplace operator.

где S₅(s), S₇(s), f₁₀(s), f₁₈(s), f₁₉(s) - передаточные функции блоков системы с соответствующим номером.The exemplary control action u ⁱⁿ obtained in this circuit ^is designed to ensure that the model output action y ^M corresponds to the control action y ^* , and, as can be seen from (1), the model control object does not contain delay. In other words, the exemplary manipulated variable u ^{in the} restored with delay and therefore to extrapolate the current time is entered first extrapolator 18. In addition, to eliminate the differences between the model and full-scale from the ^m output y influences in the third adjusting unit 10. However, it is introduced the fact that the third regulatory unit perceives changes in the driving actions y ^* as uncontrolled disturbances, which negatively affects the accuracy of control. To prevent this from happening, from the input action δy ^{m of the} third control unit 10, the effects of changes in the set action y ^* are eliminated with the help of the correction unit 21. Then the operator ratio with the adequacy of the object model with the output at the full-scale output effect takes the form

where S ₅ (s), S ₇ (s), f ₁₀ (s), f ₁₈ (s), f ₁₉ (s) are the transfer functions of the system blocks with the corresponding number.

As can be seen from (2), the operator S ₂₁ (s) is included only in its first part, which is the transfer function from y ^* to y. Therefore, the characteristics of y ₂₁ (s) do not affect the response characteristics of the control system in response to a disturbance.

где S₇(7)=S₁₂(s); f₁₉(s)=f₁₃(s); S₅(s)=S₁₆(s); f₁₈(s)=f₁₇(s),
то первая часть (2) будет иметь вид

При S₅(s)•f₁₈(s) = 1 в предлагаемой системе обеспечивается высокое качество переходного процесса при изменениях задающего воздействия.If accept

where S ₇ (7) = S ₁₂ (s); f ₁₉ (s) = f ₁₃ (s); S ₅ (s) = S ₁₆ (s); f ₁₈ (s) = f ₁₇ (s),
then the first part (2) will have the form

When S ₅ (s) • f ₁₈ (s) = 1, the proposed system provides a high quality transition process with changes in the setpoint.

At f ₁₈ (s) = 1 there will be an exact correspondence of Smith CAP reactions.

During the operation of the automatic control system, the outputs of the first 3 and second 4 sensors generate signals about the changed current values, respectively, of the control action u (t) and output y (t). The signal u (t) from the output of the first sensor 3 is fed to the input of the first delay unit 5. The signal y (t) from the output of the second sensor 4 is supplied to the second input of the first adder 8 is algebraically summed with the output signal δу ^m (t) of the first model 7 of the control object without delay, as a result, the output signal y ^m (t) of the model control loop is generated, which in the second comparison unit 20, it is subtracted from the driving signal y ^* (t). The signal about the received model error of regulation from the output of the second comparison unit 20 is fed to the input of the first regulatory unit 19, which implements, in particular, a proportional-integral regulation law. The output signal U recovered with delay ⁱⁿ (t-τ) of the first control unit in the first comparison unit 6 is compared with the signal U (t-τ) from the output of the first delay unit 5. The signal about the deviation of U ⁱⁿ (t-τ) from U (t-τ) comes from the output of the first comparison unit 6 to the input of the first model 7 of the control object without delay, the output of which produces a signal δу ^m (t) The first control unit 19 implements in particular, the proportional-integral law of regulation can be tuned, for example, according to the methodology described in the monograph: Kaganov V. Yu., Glinkov GM et al. Fundamentals of the theory and elements of automatic control systems, M.: Metallurgy, 1987, p. 219, oriented to the object without delay. As a result of the functioning of the model control loop, consisting of the first comparison unit 6, the first object model 7 without delay, the first adder 8, the second comparison unit 20 and the first control unit 19, the output of the latter generates a signal U ⁱⁿ (t-τ) of the calculated control, which would provide compensation for the disturbance ω and obtain y (t) = y ^* (t) if it were realized at the moment (t-τ)) instead of the actual U (t-τ). The signal U ⁱⁿ (t-τ) from the output of the first control unit 19 is fed to the input of the first extrapolator 18, where it is extrapolated to the delay time interval τ in the control object. The signal from the output of the first extrapolator 18 is fed through the second adder 9 to the input of the executive unit 2, where it is converted into the control action of the control object 1.

The signal about the setting action y ^{* is} supplied to the correction unit 21, where first, using the second extrapolator 17, the second delay unit and the third comparison unit 15, a signal is generated about the error of the extrapolation of the setting effect. Then, according to expression (3), the effect of this error is determined, for which the output signal of the third comparison unit 15 is converted into a model-closed circuit, including the second object model 12 without delay, the second control unit 13 and the fourth comparison unit 14. The second control unit 13 implements the same regulation law, with the same tuning factors as the first control unit 19.

The output signal of the second model 12 of the object without delay is subtracted from the output signal δу ^{м of the} first model 7 of the object without delay in the fifth block 11 of comparison and the signal of the received difference is fed to the input of the third control block 10. In the third control block 10 is implemented, in particular, in proportion integral law of regulation. Its tuning coefficients can be selected according to the method described in the above monograph Kaganova V.Yu., Glinkova G.M. and others in orientation to an object with a delay of τ. The output signal of the third control unit 10 is summed in the second adder 9 with the output signal of the first extrapolator 18.

 Thus, in the proposed automatic control system, due to the introduction of new blocks and connections, the accuracy of control is increased; uncontrolled disturbances are effectively compensated and changes in the driving action are worked out. At the same time, the “isolation” of the circuits of the servo and stabilizing control was carried out.

 To assess the effectiveness of the proposed automatic control system, the model of this system and the prototype system were tested. The tests were carried out for conditions when the control object has a delay in the control channel and the inertia or integrator properties. Tests have shown that for this class of objects, the application of the proposed system provides an increase in control accuracy by 10-25% in comparison with the prototype system.

 Industrial applicability.

 The present invention can be used in the construction of control systems for metallurgical facilities, for example, by-product coke and blast furnace production.

Claims (1)

 An automatic control system comprising an exposure control sensor connected by an output through a first delay unit to a first input of a first comparison unit connected by an output to an input of a first object model without delay, connected by an output to a first input of a first adder connected by a second input to an output of an output exposure sensor, and output - with the first input of the second comparison unit, the second input of which is the input of the system's driving influence, the output of the second comparison unit is connected to the input of the first blocking output, the output of the first control unit is connected to the second input of the first comparison unit and to the input of the first extrapolator, an actuator, characterized in that the second adder, the second delay unit, the third, fourth and fifth comparison units, the second control unit, the second a model of the object without delay, a third control unit, a second extrapolator, the input of which is combined with the second input of the second comparison unit and with the first input of the third comparison unit, and the output of the second extrapolator is it is connected through the second delay unit to the second input of the third comparison unit, connected by the output to the first input of the fourth comparison unit, connected by the output to the input of the second control unit, connected by the output to the input of the second model of the object without delay, connected by the output to the second input of the fourth comparison unit and to the first the input of the fifth comparison unit connected by the second input to the output of the first model of the object without delay, and the output to the input of the third regulatory block connected by the output to the first input ohm of the second adder connected by the second input to the output of the first extrapolator, and the output to the input of the actuator, the output of which is combined with the input of the control action sensor and is the system output, which serves to connect the control input of the control object, the input of the output action sensor is the system input, used to connect the output of the control object, the output of the first adder is the output of the model output of the system.