Monitor unit for extremal controller

FIELD: physics.

SUBSTANCE: disclosed is a monitor unit for a step extremal control which has an input adder, an adder in an adjustment channel, an input integrator, an integrator the adjustment channel, an input signal memory cell, an output signal memory cell, a signum relay, a relay element with a controlled dead zone, a multiplier, a timer with controlled pulse duration, a switch at the input of the input signal memory cell, a switch at the output of the input integrator and a switch at the input of the output signal memory cell. In order to determine the deviation sign of the controlled quantity at the interval of the k-th step, an estimate is used, which is obtained by integration in the input integrator of the difference, calculated in the input adder, between the current controlled quantity and its value recorded in the input signal memory cell at the end of the k-th step; the direction (sign) of the control action on the k-th step is calculated using the signum relay, which converts the signal at the output of the input integrator, the output signal memory cell in which the sign of the control action on the (k-1)-th step is recorded and a multiplier for signals from outputs of the signum relay and the output signal memory cell; and setup of operation with a specific control object on an optimum pulse duration and pulse ratio is carried out using the timer with controlled pulse duration and the relay element with a controlled dead zone.

EFFECT: high reliability of extremal control circuits.

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The invention relates to automation of technological processes and can be used in extreme regulation of the air flow during fuel combustion in the energy burner on any index or consumption of one commodity flows with simultaneous synthesis of multiple products in a chemical reactor.

The aim of the invention is the introduction of systems of automation of technological processes simple and reliable schemes extreme regulation.

The proposal takes the command block (CB) for the implementation of the algorithm for automatic extreme regulation in the single-loop diagrams with actuators) constant speed, for example of the type IER, mA'am, or IEP, as well as in concatenated schemes with industrial controllers hardware and software systems, for example, type QUINT, KONTAR, ARIES, SIEMENS and others

Figure 1 shows two possible schemes for extreme control using the proposed KB. In figure 1,and shows a single-loop circuit in which KB generates a sequence of pulses to control a constant speed, as in figure 1,b shows the cascade scheme, in which KB adjusts the job stabilizing controller.

For finding the extremum of the proposed CB uses the idea is known in mathematics stepping method [Ivashchenko the SUMMARY. Automatic control. Theory and system elements. M.: Mashinostroenie, 1973. - 606 S.], the essence of which can be shown, for example, for the static characteristics of the optimized object with a parabolic function purpose

In figure 2,and shows a graph of the function (1), which shows that when Δµ_0,k>0, if ΔY_0,k<0, then the next step should continue Δµ_0,k+1>0; and if Δµ_0,n>0 will be that ΔY_0,n>0, then the direction to the optimum must be opposite Δµ_0,n+1<0. This implies a fairly simple expression for the formula that defines the search strategy of optimum in step mode

where the sign "+" for maximization, and the sign "-" for the problem of minimizing. In a neighborhood of the optimum working on the way extreme regulator (AIRE) will always generate oscillations in the control system.

Because of the inertia of the control objects of the action of high-frequency perturbations, noise in the measurement channels, as well as vibrations caused by the work of other regulators, control systems, measurements Y(t) does not correspond to the k-th static state of the managed object Y_0,k.

In the well-known algorithms of extreme regulation for exceptions indicated the data inconsistencies choose a fixed time interval Δτ between steps work ER more time transients in the control object. In low-inertia electric and Electromechanical systems is justified. In thermal control objects in thermal power generation, chemical and other industries in which the control objects have considerable inertia, increasing the time step Δτ reduce the effectiveness of extreme regulation. If the ER together with other regulators of the system (see figure 1) and under the action of high-frequency disturbances and noise in the measurement channel selection fixed time interval Δτ becomes problematic.

From theory of automatic control [( VA automatic control Theory: a Textbook for high schools. - 2nd ed., revised and enlarged extra - M.: MPEI Publishing house, 2004. 400 C., Il.] it follows that, working in one of the shown in figure 1 diagrams, ER should the minimum time to transfer the control object from the initial state in the state in which the indicator of the function being optimized (1) reaches the minimum or maximum value. His work should not lead to the loss of stability of the regulatory system, and the fluctuations in the vicinity of the optimum frequency and amplitude must be technologically acceptable. In figure 2,b shows graphs of transients on the input Y(t) and output u(t) when the transfer control object from one to another stationary state for three values of the parameters mood the ER. It is seen that mode 1 is the most fast. However, for extreme regulator such performance is not justified. With the high speed ER responds to high-frequency disturbances and affects the stability of other regulators of the control system. Mode 3 is unreasonably protracted, and mode 2 is completed in the minimum time without hesitation.

To transfer inertial objects from one state to another in minimum time and without interfering with the stability needed for optimal speed-change control action u(t)/dt. Known estimation of the average rate of change of the regulatory impacts in systems with pulse-width stepper control is the duty cycle of the pulse sequence γ. Duty cycle is the ratio of pulse duration τ_andthe total time of the pulse and pause τ_p,

and the time interval Δτ between steps work ER depends on the pulse duration τ_andand duty cycle γ

The proposal KB, which provides the optimal setting for a particular object, the pulse duration τ_andand the duty cycle (the time interval between steps Δτ) or pause duration τ_pin the proposed CB is determined using the integral measure of the deviation to optimize the dummy values Y(t) on the interval of the k-th step

where Y(t) is the current measured value regulated value, Y_k-1the result of the last measurement Y(t) k-l-m step.

In the proposed CB provides the installation limit value of the integral (5) I_max. At each k-th step, when the absolute value |I_k| set value of I_maxin the scheme of KB on the sign of I_kdetermines the direction of movement to the optimum for the next k+l-th step, and then the integral is set to zero. For the next k+l-th step in paginegialle expression (5) is the result of the last measurement Y(t) at the k-th step.

For the set of values of I_maxthe total time of the pulse and pause Δτ_k=τ_and+τ_p=t_k-t_k-1will depend on static and dynamic properties of a particular object management and, accordingly, his reaction to control the impact of ER on the k-th step. As can be seen from the graphs in figure 2,and the sensitivity functions (1) when approaching the optimum is reduced and the time Δτ increases, which has a positive effect on the stability of ER. In addition, integrated assessment of changes in the optimized value filters in the time interval Δτ high-frequency vibration and noise of the measurement channel.

For ER with a specific object with a maximum duty cycle (speed regulatory impacts) in which B is selected, the values of I _max.

Proposals for the application of stepper way extremum in the literature a lot, but publications on schemes for the practical implementation of the algorithm a little. In the patent RU 02168827 H02J 7/35. [Publ. 10.06.2001] published scheme regulating device to control the power energy converters in power systems spacecraft with solar battery containing the scaling amplifier, the first measuring input of the clock generator pulses, the counter dispenser, logical OR and And, trigger, reversible counter and a digital to analogue Converter. The disadvantages are published in this patent extreme regulator should include the complexity of his scheme. He focused on the work in the system of power spacecraft and has limited application. According to the description, the time step is constant and is set by the clock pulses and provides operational dynamic adjustment of the duration of the step.

The closest solution to the proposal KB published in the patent RU 2015522 G05B 13/00. [Publ. 30.06.94], in which the algorithm extreme control inertial object includes a discrete measurement of the output signal of the control object and the results of their analysis - periodic discrete changes the UE is allaudio impact. The object management consistently served first and second different size unchanged trial of exposure and after successive output object corresponding to the above effects of steady-state modes register determine the modes of the output signal, then determine the average of these values of the output signal at a given point in time again served on the control object first trial effect, after which control the current value of the output signal, capture the moment of equality with the previously determined average and as of the time of change of the control action select a value equal to or greater than the difference between the fixed and predetermined points in time, and in the process output object control corresponds to the second trial the effects of steady state control monotony of change of the output signal and when it is being violated resume the implementation of the method, taking the second trial the effects of a new first.

For the practical implementation of this method [patent RU 2015522 G05B 13/00. Publ. 30.06.94] offers extreme regulator, consisting of series-connected pulse element and actuating devices (integrator). Switching element generates and delivers to the input of the integrator series is Yu pulses v(t) in accordance with the control law

where t is time, θ is the pulse duration, T - pulse repetition period; k_ythe deadband of the controller.

The disadvantage proposed in the patent RU 2015522 G05B 13/00. [Publ. 30.06.94] extreme regulator is that, first, he is working with a constant pulse repetition period, makes a few test steps to determine the optimal period for the current rate of change of the controlled quantity. For inertial object is the rate of change may change, and extreme regulator will constantly adjust, making a lot of trial steps. Secondly, when the adjustment of the pulse repetition period in this extreme regulator uses a sophisticated mathematical calculation of the average value linearization and solving inequalities and equations, which will require considerable computing resources.

To eliminate these disadvantages in this application are invited KB extreme regulator, in which the time interval Δτ between steps is set automatically depending on the rate of change of the controlled quantity, and for stable operation of the ER with a particular inertial object of the regulation proposed in this application CB includes adjusting the pulse duration and the minimum is about interval time step Δτ (duty cycle).

The proposed KB has universal application for single-circuit (see Fig.1,a) and cascade (see figure 1,b) schemes extreme regulation. For this, he has two outputs: discrete output to work with THEM and for analog signal changes correction job stabilizing controller.

Figure 3 shows the structural diagram in the proposal KB extreme controller.

Is KB from the input of the adder 1 and the accumulator in correcting the channel 10, the input of the integrator 2 integrator corrective signal 9, a memory cell of the input signal 3 and the memory cell output signal 7, the Signum relay 4 relay element with adjustable deadband 5, multiplier 6, a timer with adjustable pulse duration 8, the key input of the memory cell of the input signal V1, the output key input of the integrator CL and key input memory output signal CL.

The positive input of the adder 1, the second input of the adder 10 and the contact 1 key V1 is connected to the input of KB, which is connected to the output of the controlled or output adjustment controller in a cascade control scheme. Pin 2 key V1 is connected to the input of the memory cell 3. The output of the memory cell 3 is connected to the negative input of the adder 1. The output of the adder 1 is connected to the input of the integrator 2. The output of the integrator 2 is connected to the input C is the num-relay 4, input relay element 5 and pin 2 key CL. The output of the Signum relay 4 is connected to the first input of the multiplier 4. Relay element 5 is closed by the keys V1, CL and CL. The output of multiplier 4 is connected to the input of the timer 8 and the first contact of the key KL. The first contact of the key CL connected to the input of the memory cell 7. The output of the memory cell 7 is connected with the second input of the multiplier 4. The output of the timer 8 is connected to the input of the integrator 9 is a discrete output KB and the external line is connected with the input trigger THEM. The output of the integrator 9 is connected with the second input of the adder 10. The output of the adder 10 is an analog output KB and cascade control scheme outside line or virtual is connected to the input of a stabilizing controller.

Before turning KB in work in "remote" mode, set the starting values of the signals in the memory cells 3 and 7. In the memory cell 3 and the output of the integrator 9 is set to zero signals y₀=0 and ΔY_q=0. In the memory cell 7 is mounted unit with a positive sign In₀=1. In a cascade control scheme in this mode, the input of stabilizing the Governor is set at start-up circuit the signal from the correction controller.

At the time of switching KB mode "automatic" extreme regulator, as In₀=1, makes the first paragraph is one step in the direction of increasing regulatory impact +I ₀. All subsequent steps are working and dispatched in accordance with the expression (1) in the direction of approach to the extreme.

At the k-th step, the signal from the output of the object of regulation y(t) is fed to the positive input of the adder 1, the first input key KL1 and to the first input of the adder 10. The result of the sum in the adder 1

to the input of the integrator 2. In the expression (6) y_k-1value regulated value memorized in the memory 3 at the time of extreme regulator k-1 steps.

In the interval of time step Δτ=t_k-t_k-1the signal at the output of the integrator y_u(t) changes from zero to a positive or negative direction to a value of the dead zone δ relay element 5

The dead zone δ is set in the relay element is a tuning parameter of extreme regulator. It is optimal in the dynamic setting of ER-specific control object.

At time t_kwhen |y_u(t)|=δ signal at the output of the Signum relay 4 will be determined from the equation

and the signal at the output of the multiplier from the expression

where B_k-1signal from the memory 7, the Z - sign objective optimization, in compliance and with the principle of the stepping method (1), Z=+1 for maximization, and Z=-1 to minimize. At this point, the relay element 5 will conclude the keys V1, CL and CL. Keys V1 and CL opens the inputs of the memory cells 3 and 7. Key KL will reset the signal at the output of the integrator 2and relay element again opens the keys V1, CL and CL.

From this moment begins the next k+1 step regulator. In this step, in the memory cell 3 will contain the value of the signal y_kthat was the subject matter of the regulation at time t_kand in the memory cell 7 is the value of the signal at the output of the multiplier for the same time B_k.

In accordance with expressions (8) and (9) KB implements an algorithm to construct a sequence of pulses according to the following logical functions

At the beginning of each k-th step starts the timer 8. Its output appears and remains on the time interval τ_andthe signal of positive or negative sign ±I_k. This enables the motor to THEM and begins to integrate the integrator 9. The pulse duration τ_andset in the timer 8 and the body is the dynamic adjustment of ER to work on a specific object of regulation. The integrator 9 is a built-in KB analogue THEM a constant speed. He also has the authority settings - the speed of integration S_{and that is selected when configuring the cascade scheme. The result of integration on the interval τandformed in the adder 10 to the signal y(t) and cascade control scheme changes the job of stabilizing the regulator to achieve the goal of extreme regulation.}

The work of the proposed KB is confirmed by the results of a numerical simulation system extreme regulation of the inertial object. Figure 4 shows a structural diagram of the simulated system extreme regulation. Command block ER is configured to search for the maximum.

Figure 5 shows the waveform changes of signals in the circuit KB obtained from simulation work ER in the steady state of the object. Fluctuations occur in the vicinity of the extremum of the object with the transfer function of the linear part of the

and parabolas for the nonlinear part of the

where k=1; T₁=15; T₂=10; τ=1; P₁=0,8; P₂=0,2.

For ER in the simulation were set the following options:

- the dead zone relay element δ=0,5;

the pulse duration τ_and=1,0 C.

Speed THEM S_them=0,1% RO/s (turnaround Time 1000 C.)

Figure 5 shows the graphs constructed by points a, b, C, d, e simulated parabola (8) and static ha is acteristic relay with dead zone δ=0,5.

Figure 6 shows the expanded time work schedule for one step, which shows that the stock regulator pristanovlena 0.1% during 1,0 C.

On the model of the object (7) and (8) is made of simulation tests of extreme control on the time interval 10000 (2,778 hours). Testing is made on a stationary object with the same parameters P₁and R₂when a monotonically increasing parameter while stepwise changing it. 7, 8, 9 shows graphs of signals at the output of the control object y, the output of the linear part of object y_lat the exit of extreme regulator µ and random signal λ_And. For all three modes of simulation carried out in the absence of random perturbations (see Fig.7 and 8,a, 9,a) and the additive supply of centered random function at the entrance of extreme regulator (measurement error) λ_And(see Fig.7,b 8,b 9,b).

1. Command block stepper extreme regulator includes an input adder, the adder in the corrective channel, the input of the integrator, the integrator correction signal, a memory cell of the input signal, the memory cell output signal, Signum-relay, relay element with adjustable deadband, multiplier, timer with adjustable pulse duration, the key input achak the memory of the input signal, the key output of the input integrator, and a key input memory output signal, characterized in that to determine the sign of the deviation of the controlled quantity in the interval k-th step is given by integrating the input integrator calculated in the input adder the difference between the current variable value and its value written in the memory cell of the input signal at the time of the end of the k-1-th step, to calculate the direction (sign) of the regulatory impact on the k-th step is to use the Signum relay that converts the signal at the output of the input integrator, the memory cell output signal, in which a recorded mark regulatory impact on k-1-th step and the multiplier signals from outputs of the Signum relay and a memory cell output signal; and configure it to work with a specific control object on the optimal pulse duration and duty cycle of the pulse sequence used a timer with adjustable pulse duration and relay element with adjustable deadband.

2. The command block according to claim 1, characterized in that can be used as an independent function block when building single-circuit diagrams extreme regulation or dynamic link in the cascade circuits extreme regulation in the communication channel output adjust the regulator with the task of stabilizing controller.

3. The command block according to claim 1, characterized in that it can be performed in a separate device or virtual codes programmable industrial controller.