SU1164748A1 - Device for solving inverse problems of field theory - Google Patents

Abstract

DEVICE FOR REALIZATION OF REVERSE TASKS OF THEORY field containing a memory block, RC grid, converter code - voltage, the output of which is connected to the non-inverting input of a differential amplifier, the inverting input of which is connected to the central node of the RC grid, etc. e with the fact that with. In order to improve the accuracy of the solution, it introduced a block for specifying approximation sections, made in the form of a clock generator, a counter, a reversible counter, a digital-analog converter and a voltage-to-pulse converter, containing a zero-body, an integrator, a comparison unit, an element EXCLUSIVE OR NONE , a multivibrator and a demultiplexer, the first output of which is connected to the summing input of a reversible counter, the output group of which is connected to a group of information inputs of a memory unit and to a group of inputs A digital-to-analog converter whose output is connected to the boundary RC grid node, the differential amplifier output is connected to the first input of the comparison unit and to the input of the zero-body whose output is connected to the integrator's information input to the first input of the EXCLUSIVE OR NON element to the control input of the demultiplexer, the integrator output is connected to the second input of the comparator block, the output of which is connected to the second input of the EXCLUSIVE element with the IPI-NOT, the output of which is connected to the input of the multivibrator, the output of which th connected to the data input of the demultiplexer, the second output of which is connected to the subtraction input of down counter, a group of which the setting input podklyu4; the output generator of the memory unit, the output of the clock generator 4 EO connected to the reset input of the integrator, with the write-read inputs of the memory and cp counting input of the counter, the output group of which is connected to the group of address inputs of the panel and transducer inputs -. l code - voltage.

Description

The invention relates to analog and hybrid computing and can be used to solve inverse problems of heat conduction, gas dynamics, and other problems described by equations of mathematical physics of a parabolic type.

A device is known for. inverse problem solving, containing a functional converter, a DC amplifier, a controlled current source, and an RC grid 0.

However, this device is in its structure a closed control system and is characterized by the presence of a systematic dynamic error, which causes a significant error in solving inverse problems.

The closest to the invention is a device for solving inverse problems, built on the principle of a self-adjusting control system with a reference model, containing a grid model, controllable current sources, a memory unit made on capacitors, a switch, a voltage divider, a comparison unit, integrator and reference voltage source 21.

A disadvantage of such a device is the low accuracy of the solution, the increase of which is associated with large hardware costs. Indeed, in the prototype of the desired function, it is reproduced in the form of a piecewise constant function consisting of a finite number of approximation segments. In this case, in the device, each section of the approximation must have its own storage capacitor. To increase the solution accuracy by increasing the number of approximation plots in the prototype, it is necessary to use a large number of capacitors in the memory block, which entails an increase in the number of analog switches in the switch, control circuits of these keys, and consequently, a decrease in the reliability of the switches. and increase in cost. In addition, the instrumental error increases: the parallel connection of a large number of analog switches with finite resistance in the closed state, an increase in the storage time and a decrease in the information recording time for each capacitor from the memory block — all this leads to a distortion of the solution.

The purpose of the invention is to improve the accuracy of the solution and simplify the device.

The goal is achieved by the fact that in a known device containing a memory block, RC grid, the converter code is voltage, the output of which is connected to the non-inverting input of a differential amplifier, the inverting input of which is connected to the central node of the RC grid, assigning approximation sections, made in the form of a clock pulse generator, a counter, a reversible counter, a digital-analog converter and a voltage to pulse number converter, containing a zero-body, an integrator, a comparison unit, EXCLUSIVE OR NON ment, multivibrator and demultiplexer, the first output of which is connected to the summing input of the reversible counter, the output group of which is connected to the group of information inputs of the memory unit and the group of inputs of the digital-analog converter, the output connected to the boundary node of the CS grid, the output of the differential amplifier is connected to the first input of the comparison unit and to the input of the zero-organ, the output is co-connected to the information input of the integrator, to the first input of the element EXCLUSIVE OR NOT and to the control the demultiplexer input, the integrator output is connected to the second input of the comparator unit, the output of which is connected to the second input of the EXCLUSIVE OR NOT element, whose output is connected to the multivibrator input, the output of which is connected to the information input of the demultiplexer, the second output of which is connected to the subtracting input of the reversible counter, the group of setup inputs of which is connected to the group of outputs of the memory block, the output of the clock pulse generator is connected to the reset input of the integrator. and the write-read inputs of the block in the memory and with the counter input of the counter, the group of outputs of which is connected to the group of address inputs of the memory block and to the group B5SODOV of the converter code - voltage. 3 In FIG. 1 shows a block-cxei device; in fig. 2 - time diagrams of the devices that are used to remove the operation of the device. The device contains RC grid 1, converter 2 code - voltage differential amplifier 3, converter. 4 voltage - the number of pulses, a reversible counter 5, a block of 6 memory, a digital-analog converter 7, a block for setting approximation sections, made in the form of a generator of 8 clocks and a counter 9. Transducer) 4 voltage - the number of pulses contains a null organ 10, an integrator 11, a comparison block 12, an EXCLUSIVE OR NOT 13 element, a multivibrator 14, and a demultiplexer 15. The device works as follows. In accordance with the selected memory block 6, each decision period is divided into intervals by generator pulses 8. Interval number (approximation plots) is equal to the number of cells of block 6, the interval duration is the generator period 8, the generator pulses 8 arriving at the input of the counter 9 are sequentially formed at its outputs the address codes of the memory cells, at the same time serving as unit 6 at this address, and the reset signal of the integrator 11. In the intervals between the pulses of the generator 8, due to the fact that the output of the latter is connected to the inverse input of the recording size of the recording, unit 6 operates in the information recording mode, I enter her data inputs. Information from the outputs of block 6 is sent to. The installation inputs of the reversible counter 5, the outputs of which are connected to the inputs of the digital-to-analog converter 7. The current from the output of the converter is supplied to the node of the grid model 1. The voltage of the internal point of the grid model is compared with the voltage of the differential amplifier 3, The difference (error voltage) is input to the converter 4 voltage - the number of pulses. 484 The converter works in the following way. The error voltage is fed to the first input of the block 12, to the second input of which from the output of the integrator 11 a sawtooth voltage of the same sign is applied. The period is equal to the period of the generator 8. In this case, when the error voltage has a positive sign, on the code of block 12. A pulse appears, the duration of which is proportional to the magnitude of the error voltage, if its sign is negative, then the error voltage value proportional to the duration of the interval between pulses. In order for the control pulse at the input of the multivibrator to be proportional to the absolute value of the error, it is necessary to invert the pulses from the output of block 12 with a negative error voltage sign. This is achieved by switching on the logical element EXCLUSIVE OR NOT 13, one input of which is connected to the output of block 12, and the second with the output of the zero-body 10. The pulses, the duration of which is proportional to the absolute value of the voltage “and errors, from the logic of the logic element 13 are fed to the input of the multivibrator 14, which with the arrival each pulse is triggered and begins to generate its own frequency pulses. The number of pulses of the multivibrator 14 is proportional to the duration of each pulse from the output of the logic element 13, and therefore, proportional to the magnitude of the error voltage. The pulses of the multivibrator 14 are sent to the de-demultiplexer 15, from where, depending on the voltage sign, the errors are sent either to the summing or to the subtracting input of the reversible counter 5, which already contains information on the magnitude of the error voltage at the corresponding time of the previous period solutions. From the output of the revision of the counter, the modified (corrected) code goes to the information inputs of block 6, to the input of which the write output is delivered: the write pulse from the output, generator 8, to the address inputs the address of the corresponding memory cell. Thus, in a single decision period, information accumulates in the cells of block 6.

which, in the next period of the solution, reduces the error between the actual change in voltage at the reference point of the grid model and the necessary law defined by the converter. After a certain number of work cycles, a code will be formed in the cells of block 6, which will provide the required law for changing the desired parameter. If a current is generated at the output of the converter 7, then it is possible to determine the boundary conditions of the second kind - the boundary heat flux. To define boundaries

The conditions of the first kind at the output of the converter 7 should form the corresponding voltage.

The device can be implemented on the modern microelectronic base Integrator, differential amplifier, null-organ - on microchips (m / s) of the K140 series, block 12 - per m / s K554CA2, block 6, reversible counter, counter, generator, multivibrator, demultiplexer, element EXCLUSIVE OR NON - on K155 series microcircuits, digital-to-analog converter on / with K252PA1.

The introduction of the proposed device will provide, in comparison with the prototype, a higher accuracy of resolution and the possibility of long-term storage of information in RAM will allow the device to be used for solving problems in real time, matching it directly with the object under study. In addition, being implemented on discrete elements, the device is more technological in its design and simple to set up.

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Claims (1)

DEVICE FOR DECISION TASKS OF THE FIELD THEORY, containing a memory block, an RC grid, a code-voltage converter, the output of which is connected to a non-inverting input of a differential amplifier, the inverting input of which is connected to the central node of the RC grid, In order to increase the accuracy of the solution, it introduced a block for setting approximation sections made in the form of a clock pulse generator, a counter, a reversible counter, a digital-to-analog converter, and a voltage to number of pulses converter, s null-containing organ, integrator, comparison unit, EXCLUSIVE OR-HE element, multivibrator and demultiplexer, the first output of which is connected to the summing input of the reversible counter, the output group of which is connected to the group of information · inputs of the memory block and to the group of inputs of the digital-analog converter, output which is connected to the boundary node of the RC grid, the output of the differential amplifier is connected to the first input of the comparison apple and to the input of the zero-organ, the output of which is connected to the information input of the integrator, the first input of the EXCLUSIVE OR-HE element and to the control input of the demultiplexer, the output of the integrator 'is connected to the second input of the comparison unit, the output of which is connected to the second input of the EXCLUSIVE OR-NOT, the output of which is connected to the input of the multivibrator, the output of which is connected to the information input of the demultiplexer, the second output of which is connected to the subtracting input of the reversible counter, the group of installation inputs of which is connected to the group of outputs of the memory block, the output of the clock generator * is connected to the input reset of the integrator, with write-read inputs of the memory block and with counting counter input, a group of outputs which is connected to the group of address inputs of the memory block and to the group of inputs of the converter.! The code is voltage. ΤΪ5