RU2312305C1 - Pickup for measuring deformation of metallic articles - Google Patents

Abstract

FIELD: measuring engineering.

SUBSTANCE: pickup comprises inductive coil. The sections of the winding of the inductive coil that abut against the end of the winding are made of a Z-shaped wire applied on the surface of a dielectric material. The dielectric material has a minimum possible thickness and mounted on the surface of the plate made of a semiconducting material.

EFFECT: expanded functional capabilities.

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Description

The invention relates to automation and computer technology and is intended for use in automation devices for measuring the deformation of metal products.

The technical result is the expansion of the arsenal of technical means for measuring the deformation of metal products.

The inventive sensor for measuring the deformation of metal products, containing an inductor. The sections of the winding of the inductor adjacent to the ends of the winding of the inductor are made in a zigzag fashion on a surface of a dielectric material having a minimum thickness and located on a surface of a plate made of a conductive material.

Known capacitive sensor for measuring deformation (see the description to the AS of the USSR No. 823838, class G01B 7/22. Capacitive sensor for measuring deformation), which contains a fixed main and additional plates made of metal, a movable thin polymer lining, glued to the surface of the element under study in section AB and having a sprayed conductive layer in the aircraft section, which forms the main and additional variable capacitors with the plates.

The projection of the lining on the surface of the element under study overlaps the gluing line and the beginning of the conductive layer. The projection area of the conductive layer of the movable plate on the stationary plates are equal to each other. Conductors are connected to the plates. A plate pressed against them is installed on top of the plates to achieve the unchanged shape of the groove between the plates.

The operation of the sensor is as follows. The transition process due to external influences, propagating, sets in motion the gluing line AB together with the slipping section of the aircraft and the section of the lining both in the longitudinal and transverse directions (due to the existence of the Poisson's ratio). As a result of this, the area of the conductive layer covered by the plate and the distance between the movable and fixed plates change.

The capacity of the main capacitor depends both on the distance between the plates, and on the overlapped area of the conductive layer, and the capacity of the additional capacitor depends only on the distance between the plates.

By subtracting from the readings of the main capacitor the readings of the additional capacitor, the influence of transverse strains on the accuracy of measuring longitudinal strains is eliminated.

In a capacitive sensor for measuring deformations, the measurement of deformations occurs by measuring the capacitances of the primary and secondary capacitors.

In the proposed sensor for measuring the deformation of metal products, the measurement of deformations occurs due to a change in the self-capacitance of the inductor, which is the capacitance distributed along the winding of the inductor.

The closest analogue of the proposed sensor for measuring the deformation of metal products is a device that is a magnetically-controlled strain gauge (see description to AS USSR No. 712652, class G01B 7/24. Magnetically-controlled strain gauge). The magnetically-controlled strain gauge contains a closed-circuit magnetic circuit that is covered by a winding. The magnetic circuit section is intended for fixing on the test object. The magnetic circuit is made of a magnetodielectric with a small modulus of elasticity.

The sensor operates as follows.

To measure the deformations, the sensor is glued onto the object with a patch using glue with low rigidity after drying, for example, using a mass of the same composition as the material of the magnetic circuit. The electrical leads of the winding are connected to a measuring device. When the object is deformed, the section of the magnetic circuit is deformed along with it. This causes a change in the magnetic permeability of the material of the magnetic circuit section, as well as a change in the inductance of the winding, which is taken as a measure of the measured strains.

In a magnetically controlled strain gauge, a measure of the measured strains is a change in the magnetic permeability of the material of the magnetic circuit section, as well as a change in the inductance of the winding (inductance coil).

In the proposed sensor for measuring the deformation of metal products, the measurement of deformations occurs due to a change in the self-capacitance of the inductor, which is the capacitance distributed along the winding of the inductor.

As a device that implements the technical implementation of the proposed sensor for measuring the deformation of metal products, a device that implements a method for measuring the movements of controlled objects (see the description of the patent of the Russian Federation No. 2207498, class G01B 7/00. Method of measuring the movements of controlled objects) can be used, in which the capacitor is excluded, and the function of the acting object is performed by a plate made of a conductive material.

The device of the proposed sensor for measuring the deformation of metal products is illustrated by the following figures:

Figure 1 is a structural diagram of a sensor for measuring the deformation of metal products.

Figure 2 - design of the sensor element for measuring the deformation of metal products.

Figure 3 - section aa Figure 2.

Figure 1 shows a structural diagram of one of the possible options for the technical implementation of the proposed sensor for measuring the deformation of metal products.

The specified device contains an inductor 1, a winding 3 of energy pumping, a winding 4 of information reading, the outputs of which are connected to the inputs of the measuring amplifier 5, the output of which is connected to the input of the comparator 6, the output of which is connected to the sync input of the frequency divider (not shown in Fig. 1) of the shaper 7 time intervals, with the first input of the OR element 8 and with the trigger sync input 9.

The information input of the trigger 9 is connected to the output of the standby multivibrator (not shown in FIG. 1) of the shaper 7 time intervals, and the direct output is connected to the start input of the meter 10 time intervals, the group of information inputs / outputs of which is connected to the computer 11 through the board (in FIG. 1 is not shown) IEEE 488 CARD, installed in the computer 11, and is a public channel (CPC).

The shaper 7 time intervals through the serial communication channel RS-232C is connected to the computer 11, the second input of the OR element 8 is the input 12 of the start of continuous undamped oscillations of the oscillatory circuit, and the open collector output pulled up to the positive output of the supply voltage through the resistor (Fig. 1 not shown), connected to the base of transistor 13, the emitter of which is connected to the “common” power terminal, and the collector is connected to the first terminal of the energy pumping winding 3, the second terminal of which is connected to the positive terminal 14 p Tania.

The inductor 1 contains the middle part 15 and the extreme parts 2 (sections of the winding of the inductor 1 adjacent to the ends of the winding of the inductor 1).

Inductor 1 performs the function of an oscillating circuit.

The extreme parts 2 of the inductor 1 perform a zigzag wire on the surface 19 of the dielectric material 17 (see Fig.2, 3) located on the surface of the plate 16.

The plate 16 is made of the same material as the metal product (not shown in FIGS. 1, 2), for example, carbon steel, and is installed by spot welding on the surface of the metal product (not shown in FIGS. 1, 2). The deformation of the plate 16 repeats the deformation of a metal product (not shown in FIGS. 1, 2).

The dielectric material 17 may be made of glass cement.

The printed conductors of the extreme parts 2 of the inductor 1 located on the surface 19 of the dielectric material 17 are coated on top with a layer of a protective dielectric coating (not shown in FIGS. 2, 3), for example, glass cement.

The middle part 15 of the inductor 1, the energy pumping coil 3 (not shown in FIG. 2) and the information reading coil 4 (not shown in FIG. 2) are performed one above the other by winding the enameled wire onto the cylindrical frame 18 (see FIG. 2 ) made of a polymer material.

The middle part 15 of the inductor 1 and the extreme parts 2 of the inductor 1 are electrically connected to each other.

Measuring amplifier 5 is known from the book. Kofman R., Driskol F. Operational Amplifiers and Linear Integrated Circuits. - M .: Mir, 1979, p.148 and can be performed on standard operational amplifiers of the type KR544UD2. The comparator 6 can be performed on KP554SAZ, and the trigger 9, the element OR 8 and the transistor 13, respectively, K555TM2, K555LE1 and KT3102.

As a shaper of 7 time intervals, a multichannel programmable pulse generator can be used (see the description of the invention to USSR patent No. 1757085, class Н03К 3/64. Multichannel programmable pulse generator). Moreover, all the connections of the generator 11 and the clock inputs of the timers 14 (see the drawing for the description of patent No. 1757085) are broken. One of the three timers 14-1 include in the frequency divider mode. Its synchronization input is used in a device that implements the method as a synchroinput of the shaper 7 time intervals, and the output included in the group of 33-1 outputs is connected to the synchroin of one of the timers 14-2, included in the standby multivibrator mode, the output of the standby multivibrator incoming in the group of outputs 33-2, 7 timeslots are used as the output of the shaper.

A detailed description of the operation of the timers 14-1, 14-2, ... 14-N and the operating parameters in the frequency divider and standby multivibrator modes are described in book. edited by Shakhnov V.A. Directory. Microprocessors and microprocessor sets of integrated circuits. T.1. - M.: Radio and Communications, 1988, p. 76-82.

The device I2-24, described in the book, was selected as a time interval meter. edited by V.A. Kuznetsov Directory. Measurements in electronics. - M .: Energoatomizdat, 1987, p. 351. The computer 11 may be of the type IBM PC.

The operation of the device is as follows.

After turning on the power, the computer program 11 sets, in accordance with the description of the invention to the USSR patent No. 1757085, the operating modes of the timers 14-1, 14-2 (not shown in FIG. 1) of the shaper 7 time intervals. Channel 0 of the timer 14-1 (not shown in FIG. 1) is set to mode 2 — a frequency divider. Channel 0 of the timer 14-2 (not shown in FIG. 1) is set to mode 1 of the standby multivibrator. In this case, the outputs of these channels are set to a single state. Thus, at the information input of the trigger 9 set the level of the logical unit. The inputs of the sample timers 14-1 and 14-2 (not shown in Fig. 1) are fed with logical zero levels that prohibit the operation of timers. The meter 10 time intervals through a public channel using a computer 11 is installed in the mode of measuring the pulse duration.

Then, a single pulse is applied to the trigger input 12 and then to the second input of the OR element 8, for example, from a parallel channel (not shown in FIG. 1) of the computer 11, or by means of the button and time delay. A positive pulse arrives at the base of the transistor 13, which opens the transistor 13, and a current begins to flow through the energy pumping coil 3, which induces an EMF, an electromotive force of induction in the oscillatory circuit, in which electromagnetic oscillations occur.

When a metal product is deformed (not shown in FIGS. 1, 2), the plate 16 deforms, tensile or compressive stress acts on the dielectric material 17 (the thickness of the dielectric material 17 changes) and the extreme parts 2 of the inductor 1 (the overlap area of the extreme parts 2 of the coil changes inductance 1 and plate 16 made of a conductive material (two capacitively connected capacitances between the extreme parts 2 of the inductance coil 1 are changed)).

As a result, the intrinsic capacitance of the inductor 1, which is the capacitance distributed along the winding of the inductor 1, is changed by changing the capacitive coupling, the capacitance, between the extreme parts 2 of the inductor 1, the capacitance and frequency of oscillation of the oscillatory circuit.

The inductor 1 can be made so that the inductance of the middle part 15 of the inductor 1 is much larger than the inductance of the extreme parts 2 of the inductor 1. In this case, the change in the frequency of oscillation of the oscillatory circuit during deformation of the plate 16 is determined by the change in the intrinsic capacitance of the inductor 1 , which is the capacitance distributed along the winding of the inductor 1.

The frequency of the resonant oscillations of the oscillatory circuit is measured by taking information from the coil 4 of the read information. The terminals of the read coil 4 are connected to the direct inputs of the measuring amplifier 5, which amplifies the signal. Then the signal from the output of the measuring amplifier 5 is fed to the direct input of the comparator 6, to the inverse input of which a reference voltage is supplied. From the output of the comparator 6, positive rectangular signals are fed to the first input of the OR 8 element (a logic zero level is being sent to the second input of the OR 8 element at this time), the clock input of the driver 7 time intervals and to the sync input of the trigger 9. From the output of the OR 8 element, rectangular pulses arrive to the base of the transistor 13, upon opening of which a current flows through the energy pumping coil 3, upon changing which an induction emf arises in the oscillating circuit, under the action of which currents appear in the oscillating circuit, with the direction of the current in the inductor 1 in each half-cycle of the oscillation of the oscillatory circuit. Moreover, in the positive half-cycle of oscillations in the oscillatory circuit, energy is pumped during an increase in current in the energy pumping coil 3, and in the negative half-cycle of oscillations, energy is pumped during a decrease in current in the energy-pumping coil 3, since energy transfer occurs at the moment of change in current in the coil 3 paging energy.

Thus, continuous undamped resonant vibrations with energy pumping at certain points in time are excited in the oscillatory circuit, the amplitude of oscillations is increased at these moments, these oscillations are converted into digital form and the oscillation frequency of the oscillatory circuit is determined.

Next, the computer program 11 supplies from the start block (not shown in FIG. 1) to the enable inputs of the timers 14-1, 14-2 (not shown in FIG. 1) the logic unit levels and allows their operation. In this case, one of the timers of group 14-1 (not shown in FIG. 1), set to the frequency divider mode, starts dividing the input frequency coming from the output of the comparator 6 to the sync input of the shaper 7 time intervals by the number n set using the computer program in the channel counter 0 timer (not shown in Fig.1). At the output of this timer (not shown in FIG. 1), at the end of the count, a negative pulse is generated each time, the duration of which is equal to the length of the frequency period of the input signal coming from the output of the comparator 6. From the output of the frequency divider (not shown in FIG. 1), the signal arrives to the synchronization input of the timer of the group of timers 14-2 (not shown in FIG. 1) of the time slot generator 7, which operates in the standby multivibrator mode, and starts the waiting multivibrator due to the negative input pulse difference (in Fig. 1 azan), the output of which is set to the level of logical zero. This logical zero is fed to the information input of trigger 9, which, on the positive edge of the pulse coming from the output of comparator 6, is set to zero and forms the beginning of a time interval, which begins to measure 10 time intervals. The waiting multivibrator (not shown in FIG. 1) of the shaper 7 time intervals decrements the number recorded in its counter (counts the number of negative pulses arriving at its sync input from the output of the divider (not shown in FIG. 1) frequencies) and, upon receipt of a given number of pulses, sets its exit to the level of a logical unit. In this case, according to the first positive differential pulse coming from the output of the comparator 6 to the trigger input of trigger 9, trigger 9 is set to a single state and forms a closure of the measurement of the time interval for the meter 10 time interval. The trigger 9 is necessary in order to eliminate the influence of the time delays of switching along the edges when the counters are triggered (not shown in FIG. 1) of the shaper 7 time intervals. Formed by the trigger 9 and measured by the meter 10 time intervals, the time interval is read through the public channel using computer programs 11 and the magnitude of the frequency of oscillations in the oscillatory circuit is determined by measuring the time interval in which a predetermined number of oscillation period of the oscillatory circuit fits.

Then, using the computer program 11, the amount of deformation of the metal product (plate 16) is determined, for which the functional relationship between the vibration frequency of the oscillatory circuit and the deformation of the plate 16 is stored in the memory of the computer 11.

Claims (1)

A sensor for measuring the deformation of metal products containing an inductor, characterized in that the sections of the winding of the inductor adjacent to the ends of the winding of the inductor are zigzag on a surface of a dielectric material having a minimum thickness and located on a surface of a plate made of a conductive material.

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