RU2039930C1 - Ultrasonic displacement transducer - Google Patents

Abstract

FIELD: measuring equipment. SUBSTANCE: ultrasonic signals are excited in two parallel installed acoustic lines. One of them is used as a cone assembly. Engageable with these acoustic lines are vibration recorder and reader elements, as well as polarizers which transform longitudinal vibrations into torsional ones. One of the polarizers is connected to the object under check. EFFECT: enhanced accuracy. 2 cl, 6 dwg

Description

 The invention relates to measuring and computing equipment, in particular to digital ultrasonic transducers of displacement with a vernier transformation, and is intended for use in robotics and other fields of technology for precision measurement and control of linear movements of an object.

A known ultrasonic displacement transducer containing a magnetostrictive sound pipe, two dampers, a start circuit, two OR elements, a waiting pulse generator, a write pulse generator, a movable recording coil, a stationary read coil, a read amplifier, a pulse shaper, a counter, a time interval to code converter, a block conversion scale control, normalizer, counting trigger, reference frequency generator, one-shot, AND element, second counter, restart count , Decoder, two registers priority encoder, a shift register, setpoint error code, subtraction unit [1]
A known ultrasonic displacement transducer, selected as a prototype, which contains the main and additional magnetostrictive sound ducts, two acoustic absorbers, a stabilizer of tensile forces, two limiters of movement, a recording element, two reading elements, a recording amplifier, two reading amplifiers, a subtraction unit, a pulse shaper, result calculation unit, input and output buses [2]
Known devices have common disadvantages, which are insufficient resistance to the influence of destabilizing environmental factors, reducing their accuracy and sensitivity to movement. Such factors include the dispersion of the velocity of the elastic wave in the sound duct, a change in the ambient temperature, and the influence of acoustic noise.

 The aim of the invention is to increase the accuracy of control of object movements by using structural methods that reduce the sensitivity of the transducer to destabilizing environmental factors.

 This is achieved by the fact that in an ultrasonic displacement transducer containing two parallel mounted sound ducts, a main and an additional damper located at their ends, reading elements are mounted near the sound ducts to one of the sound ducts, a recording element is fixed to the main sound duct and the forming unit is connected to the specified sound ducts signal processing and display, introduced a polarizer mounted on the main sound duct with the ability to move along it and designed to communicate with object, two additional recording elements and one reading element installed on an additional sound duct, a signal generation, processing and indication unit, made in the form of a single vibrator associated with its outputs D-flip-flop, T-flip-flop, RS-flip-flop and counter, and several amplifiers through which all recording and reading elements are connected with the corresponding inputs and outputs of the indicated triggers and counter.

 In addition, the ultrasonic displacement transducer is equipped with two reflective loads fixed at the ends of the sound ducts, and a second and third polarizers fixed at the ends of the additional sound duct.

 In FIG. 1, 2 are block diagrams of an ultrasonic displacement transducer with different methods for exciting elastic waves in magnetostrictive waveguides; in FIG. 3-5 options for the implementation of selective amplifiers-drivers of reading, recording circuits, single-vibrator; in FIG. 6 time diagrams explaining the operation of the ultrasonic displacement transducer.

 An ultrasonic transducer of displacements (Fig. 1) contains a primary magnetostrictive transducer of displacements (MPP), consisting of the main and additional rectilinear magnetostrictive sound ducts 1, 2, the first, second and third acoustic absorbers 3, 4, 5, two limiters 6 of the displacements, the first element 7 of reading, polarizer 8, first and second recording elements 9, 10, second and third reading elements 11, 12, recording amplifier 13, first selective reading reading amplifier 14, first and second recording circuits 15, 16 and the second and third selective reading amplifiers-17, 18, one-shot 19, T-trigger 20, D-trigger 21, RS-trigger 22, the first and second logical elements AND 23, 24, element 25 equivalence, the counter 26 of the result, as well as the control bus 27, the request bus 28, the start bus 29, the result n-bus 30 and the result control bus 31.

 The main and additional sound ducts 1, 2 are fixed parallel to each other in the first and second acoustic absorbers 3, 4. The third acoustic absorber 5 is mounted on the middle part of the additional sound duct 2 and divides it into two independent acoustic paths, supporting and nonius.

 The first concentrated recording element 9 and the second concentrated reading element 11 are fixed on the supporting section of the additional sound duct 2, and the second concentrated recording element 10 and the third concentrated reading element 12 are fixed on the vernier section. The findings of the first and second recording elements 9, 10 are connected to the outputs of the first and second recording circuits 15 and 16, respectively, and the conclusions of the second and third reading elements 11 and 12 are connected to the inputs of the third selective reading amplifiers-shapers 17 and 18.

 The output of the second selective reading driver 17 is connected to the signal input of the first recording circuit 15, the counting input of the result counter 26, and one input of the equivalence element 25. The output of the third selective reading amplifier 18 is connected to the signal input of the second recording circuit 16 and the other input of the equivalence element 25. Its output is connected to the sync input of the D-flip-flop 21, the inverse output of which is connected to the request bus 28, and the direct output is connected to one of the control inputs of the first and second recording circuits 15 and 16. Their other control inputs are connected respectively to the outputs of the first and second elements 23, 24 AND-NOT.

 Some inputs of AND-NOT elements 23, 24 are combined and connected to the sync input of the T-flip-flop 20 and the output of the first selective amplifier-driver 14 of reading, its input is connected to the terminals of the first concentrated reading element 7, mounted on the main sound duct 1 near the first acoustic absorber 3.

 On the working part of the main sound duct 1, a polarizer 8 is fixed, made with the possibility of movement between the limiters 6 and having a kinematic connection with the object. Other inputs of the first and second elements of NAND 23,24 are connected respectively to the direct and inverse outputs of the T-flip-flop 20. Its zero input is combined with a single input of the D-flip-flop 21 and is connected to the inverse output of the one-shot 19. The direct output of the one-shot 19 through the amplifier 13 recording is connected to the main duct 1 and is connected to the zero inputs of the counter 26 of the result and the RS-trigger 22. The bit outputs of the counter 26 of the result are connected to the bus 30 of the result, and the transfer output is connected to a single input of the RS-trigger 22, its output is connected to the bus 31 to The result. The control input of the single-shot 19 is connected to the control bus 27, and its signal input to the start bus 29.

 In addition, the first and second reflective loads 32, 33, the second and third polarizers 34, 35 and the logical element And 36 are additionally introduced into the ultrasonic displacement transducer (Fig. 2). The first reflective load 32 is fixed to the main sound duct 1 from the side of its polarizer 8, and also to one end of the additional sound duct 2. At its other end, a second reflective load 33 is fixed. At the ends of the additional sound duct 2, second and third polarizers 34 and 35 are connected, which are connected to the outputs of the first and second recording circuits 15 and 16, respectively. The output of the first selective reading driver 14 is connected to one input of the And 36 element and a single input of the D-flip-flop 21. The other input of the And-36 element is connected to the direct output of the D-flip-flop 21, and its output with the sync input of the T-flip-flop 20.

Ultrasonic transducer works as follows. When the signal "Resolution" (Fig. 6 a) is sent via the control bus 27, the converter (Fig. 1) is put into operation. A request signal is generated on its request bus 28 (Fig. 6 m), in response to which, after a time t _{p, the} user sends a "Start" signal on the start bus 29 (Fig. 6 b). The one-shot 19 is launched, producing out-of-phase pulsed signals, which are set to the zero state of the T-trigger 20, the RS-trigger 22, the counter 26 of the result and the single state of the D-trigger 21 (Fig. 6 e).

At the same time, the recording amplifier 13 is excited. A recording current pulse is generated at its output (Fig. 6 c), which passes into the medium of the main magnetostrictive sound pipe 1 of the MPP and excites an elastic torsion wave (Fig. 6 d) under the polarizer 8, made in the form of an annular magnet, due to the magnetomechanical transformation propagating along sound duct in both directions with a speed of V _cr .

 The outputs of the first concentrated reading element 7 induces a read pulse (Fig. 6 g) due to the influence of the inductive effect, which is converted into a rectangular video read pulse by the first selective reading amplifier amplifier 14. Then it passes through the open second logical element AND-NOT 24, starts (start 1) the first recording circuit 15 and switches the T-trigger 20 to a single state (Fig. 6 g). Switching the T-trigger 20 causes the blocking of the second logical element AND-NOT 24 and the unlocking of the first logical element AND-NOT 23.

The first entry circuit 15 generates a write signal current, which through the first member 9 is centered in the reference branch recording additional acoustic conductor 2 MPP excited longitudinal elastic wave which propagates with a phase velocity V _pr. After a time T ₀ = l ₀ / V _pr, it reaches the second concentrated reading element 11, mounted at a reference distance l ₀ from the first recording element 9, and induces a read signal at its terminals, converting it into a rectangular video pulse by the second selective reading amplifier-driver 17, by which the first recording circuit 15 is restarted.

(1) на время действия разрешающего сигнала по выходу D-триггера 21 (фиг. 6 е). Эти счетные импульсы подсчитываются счетчиком 26 результата (фиг. 6 к) и анализируются элементом 25 равнозначности.In the reference channel of the MPP converter, formed by elements 15, 9, 2, 11, 17, a stable generation of pulses of the reference frequency is established (Fig. 6 h):
f _o

(1) for the duration of the enable signal at the output of the D-trigger 21 (Fig. 6 e). These counting pulses are counted by the result counter 26 (Fig. 6 k) and analyzed by the equivalence element 25.

An elastic wave excited in the main sound pipe 1, propagating towards the first reading element 7, reaches it after the desired time l _{x of the} object (Fig. 6 g).

(2) и им считывается, преобразуясь в прямоугольный видеоимпульс, которым осуществляется запуск (пуск 2) второй схемы 16 записи через открытый первый логический элемент 23 И-НЕ и переключение в исходное состояние Т-триггера 20 (фиг. 6 ж).T _x

(2) and it is read, converted into a rectangular video pulse, which is used to start (start 2) the second recording circuit 16 through the open first logical element 23 AND-NOT and switch back to the initial state of the T-trigger 20 (Fig. 6 g).

(3) где l_н опорное расстояние между элементами 10 и 12 нониусного канала, которые анализируются элементом 25 равнозначности.The vernier channel of the MPP converter, organized by the second recording circuit 16, the second lumped recording element 10, the vernier branch of the additional sound duct 2, the third lumped reading element 12, and the third selective reading amplifier-driver 18 and operating similarly to the MPP reference channel, from this moment goes into mode the generation of pulses of the vernier frequency (Fig. 6 and)
f _n

(3) where l _{n is the} reference distance between the elements 10 and 12 of the vernier channel, which are analyzed by the element 25 of equivalence.

 If the phase of the reference (1) and vernier (3) digital scales coincides (Fig. 6h, i), an impulse signal is generated at the output of the equivalence element 25, which switches the D-trigger 21 to the zero state (Fig. 6 e). This will lead to blocking the operation of the reference and vernier channels of the MPP converter and the input of the result counter 26 will stop the supply of counting pulses of the desired object movement.

(4) где v_пр=1,6 v_кр, Δt=T₀-T_н интервал дискретизации.At the bit output of the counter 26 of the result, the code of the desired displacement will be generated (Fig. 6 k), obtained as a result of the vernier transformation
N _x = 2

(4) where v _ol = 1.6 v _cr , Δt = T ₀ -T _n the sampling interval.

The code for moving the object (4) is set on the bus 30 of the result, forming a signal "Move". On the request bus 28, a “Request” signal is set (Fig. 6 m), informing the user about the completion of the movement conversion cycle. If there is an overflow of the bit grid 2 ⁿ , where n is the bit depth of the result counter 26 (Fig. 6 k), a signal is generated at its transfer output, which switches the RS-flip-flop 22 to a single state (Fig. 6 l). As a result, a signal "Error" is set on the result control bus 31, indicating the inaccuracy of the received information on the converter buses 30.

On this, the movement conversion cycle is completed and the converter is prepared for the next conversion cycle, which is performed as described. The incident elastic waves in the primary and secondary sound paths 1, 2 of the MPP are absorbed by the first, second, and third acoustic absorbers 3, 4, 5, which maintains a given signal-to-noise ratio of acoustic paths. Limiters 6 movements specify the range of movement l _x polarizer 8 MPP Converter.

 Selective reading amplifiers-shapers 14, 17, 18 (Fig. 3) are made on the basis of a series-connected selective RC amplifier 41, an amplitude limiter 42 and a threshold element 43, which makes it possible to selectively amplify the induced analogue read signals at the terminals of elements 7, 11 , 12 read and convert them into rectangular video pulses of the required amplitude and duration, while ensuring the stable operation of the digital channel of the converter in harsh environmental conditions.

 The first and second recording circuits 15, 16 (Fig. 4) are made on two diode gates 37, 38, an I-HE 39 logic element and a Voltage-Current converter 40. The I-HE 39 logic element serves as a logical key for diode gate signals 37, 38, by which the signal converter 40 is started.

 The one-shot 19 (Fig. 5) contains two AND-NOT logic elements 44, 45 with a timing RC circuit on the elements 47, 48 for setting the duration of the recording signals and an inverter 46.

 Consequently, the use of zero-order elastic torsion waves and the reference and vernier channels for recirculating longitudinal elastic waves, increasing the selectivity of the signal reading circuits of the transducer can increase its resistance to the influence of these destabilizing environmental factors. However, the movement sensitivity and resistance to the influence of the acoustic noise of the converter of FIG. 1 can be increased if its MPP is performed according to the circuit shown in FIG. 2, where the main acoustic path is doubled due to the introduction of a reflective load, and elastic torsion waves are excited in the additional acoustic path.

(5) где l₁ расстояние между элементами 7 и 8 МПП, и считывается с последующим преобразованием в прямоугольный видеоимпульс, который проходит через открытый логический элемент И 36 на счетный вход Т-триггера 20 и переключает его в единичное состояние, а также запускает (пуск 1) первую схему 15 записи, подключенную к одному концу дополнительного звукопровода 2 МПП. Его демпфированная часть подключена к общей шине преобразователя, что позволяет гальванически разделить опорный и нониусный его участки.Distinctive features of the operation of the converter of FIG. 2 are as follows. When an elastic wave is excited in the medium of the main MPP sound path 1 under the polarizer 8, the signal converted to the rectangular video pulse induced at the terminals of the first readout element 7 does not pass through the closed logic element 36 AND to the T-trigger 20 clock input, but switches the D-trigger 21 to a single state This leads to the unlocking of the And element 36 and the recording circuits 15, 16, the removal of the “Request” signal on the request bus 28. Propagating along the sound pipe 1 towards the first reading element 7, the elastic wave reaches through time
T ₁

(5) where l _{1 is the} distance between elements 7 and 8 of the MPP, and is read, followed by conversion into a rectangular video pulse, which passes through the open logical element And 36 to the counting input of the T-flip-flop 20 and switches it to a single state, and also starts (start 1) the first recording circuit 15, connected to one end of the additional duct 2 MPP. Its damped part is connected to the common bus of the converter, which allows galvanic separation of the reference and vernier sections.

(6)
Другая волна, распространяясь в среде основного звукопровода 1 МПП в сторону первой отражающей нагрузки 32, достигает ее, изменяет направление своего движения без смены фазы и формы волны и считывается первым элементом 7 считывания через суммарное время
T₂

(7)
По этому преобразованному сигналу считывания через открытый элемент И 36 переключается Т-триггер 20 в исходное состояние, формируя на своем выходе временной интервал, пропорциональный искомому перемещению l_x объекта
T_x=T₂-T₁=2

(8)
В этот момент запускается (пуск 2) нониусный канал МПП преобразователя, состоящий из второй схемы 16 записи, третьего поляризатора 35, установленный на конце дополнительного звукопровода 2 с первой отражающей нагрузкой 32, третьего элемента 12 считывания и третьего избирательного усилителя-формирователя 18 считывания, формируя импульсы с частотой следования
f_н

(9)
При совпадении фаз опорной и нониусной цифровых шкал преобразователя срабатывает элемент 25 равнозначности и переключает D-триггер 21. Работа опорного и нониусного каналов блокируется. На выходах счетчика 26 результата формируется код искомого перемещения повышенной разрешающей способности
N_x

(10)
Далее процесс преобразования перемещений не отличается от рассмотренного ранее.When a current pulse is supplied to the medium of the reference section of the additional sound duct 2 of the MPP, under the polarizer 34 installed at its end with the second reflective load 33, a torsional elastic wave is excited in the sound duct 2. At the next moment, the elastic wave reaches the second concentrated read element 11 and induces a read pulse at its terminals, which is converted into a rectangular video pulse by the second selective read pickup amplifier 17. On this signal, the first recording circuit 15 is restarted and the result counter 26 is switched. A stable pulse generation is established in the reference channel of the MPP converter with a repetition rate
f _o

(6)
Another wave, propagating in the medium of the main sound duct 1 MPP towards the first reflective load 32, reaches it, changes its direction of movement without changing the phase and waveform and is read by the first reading element 7 after the total time
T ₂

(7)
According to this converted read signal, through the open element And 36, the T-trigger 20 switches to the initial state, forming at its output a time interval proportional to the desired movement l _{x of the} object
T _x = T ₂ -T ₁ = 2

(8)
At this moment, the launch (start 2) of the MPP converter vernier channel is started, consisting of a second recording circuit 16, a third polarizer 35, mounted at the end of an additional sound duct 2 with a first reflective load 32, a third read element 12, and a third selective read pick-up amplifier 18, forming pulse repetition rate
f _n

(nine)
When the phases of the reference and vernier digital scales of the converter coincide, the element of equivalence is triggered 25 and switches the D-trigger 21. The operation of the reference and vernier channels is blocked. At the outputs of the counter 26 of the result, a code of the desired movement of increased resolution is generated
N _x

(10)
Further, the process of transforming displacements does not differ from that considered earlier.

 Thus, the use of torsion elastic wave displacements in the ultrasonic transducer, the vernier transformation method, and a 2-fold increase in the elastic wave propagation base along the MPP acoustic path make it possible to increase the accuracy of control of object movements and the sensitivity to movement.

Claims (2)

 1. ULTRASONIC MOVEMENT CONVERTER, containing two parallel installed sound ducts, the main and additional, dampers installed at their ends, mounted reading elements mounted on the main sound ducts, a recording element fixed to the main sound duct, and a signal processing and indication unit connected to these elements, characterized in that, in order to increase the accuracy of movement control, it is equipped with mounted on the main duct with the ability to move along not o and intended for communication with a moving object, a polarizer mounted on an additional sound duct with two additional recording elements and one read element located between the additional recording elements with a damper, and the signal generation, processing and indication unit is made in the form of a single vibrator associated with its outputs of the D-trigger , T-flip-flop, RS-flip-flop and counter, and several amplifiers through which all the elements of recording and reading are connected with the corresponding inputs and outputs of the three Gere and counter.  2. The Converter according to claim 1, characterized in that, in order to expand the range of controlled movements, it is equipped with two reflective loads fixed at the ends of the main sound ducts, and second and third polarizers fixed at the ends of the additional sound duct.

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