SU1679187A1 - Ultrasonic unit for measuring movements - Google Patents

Abstract

The invention relates to a measurement technique and can be used to measure and monitor motion parameters of objects, for example, elements of robotic systems. The aim of the invention is to improve the accuracy of measuring displacements and expanding the range of use by eliminating electromagnetic interference about the signal circuits of the primary displacement transducer, which contains a rectilinear acoustic duct and is equipped with two pairs of reading elements connected in opposite polarity in parallel. The read elements of the first pair are symmetrically located relative to the record element and move along the transducer's sound line together with the record element, and the read elements of the second pair are placed along the edges of the sound line. 3 silt

Description

The invention relates to a measurement technique and can be used to measure and control motion parameters of objects, for example, elements of robot-technical systems.

The aim of the invention is to improve the accuracy of displacement measurement and to expand the range of use by eliminating electromagnetic interference in the signal circuits of the primary displacement transducer.

Figure 1 shows the structural diagram of the ultrasonic displacement meter; Fig. 2 illustrates an exemplary embodiment of a block for measuring time intervals; FIG. 3 shows timing diagrams explaining the operation of an ultrasonic displacement meter.

The ultrasonic displacement meter contains a magnetostrictive displacement transducer 1 in the form of a rectilinear acoustic duct 2 made of a magnetostrictive material, mechanically connected to one of the ends of the acoustic duct 2 acoustic absorber 3 and the tension mechanism 4 of the acoustic duct 2 fixed on the acoustic duct 2 near the acoustic absorber 3 fixed element 5 reading with bias magnet 6, connected to the output of the reading element 5, the amplifier-reader 7, mounted on the working student heel acoustic line 2 the movable member 8 to the recording bias magnet 9 is designed for kinematic connection to a controlled movement of the object, and serially connected single vibrator 10 and the recording amplifier 11, whose output is connected to the input of the movable member 8 entries, the first and second VET

Vi o

00

VI

readout moving elements 12,13 with displacement magnets 14, 15, which are installed at equal distances on opposite sides of the movable recording element 8, a second acoustic absorber 16 and a second fixed reading element 17 with a displacement magnet 18, which are mounted at the second end of the acoustic Zvukovaya 2, the second amplifier-shaper 19 readout and block 20 measuring time intervals.

The first and second movable elements 12, 13 of the readout are combined in opposite polarity and connected to the inputs of the second amplifier-former 19, the first and second fixed elements 5, 17 of the reader are combined in the opposite polarity, and the outputs of the first and second amplifier 7,19 the reads are connected to the corresponding signal inputs of the time interval measuring unit 20, the first control input of which is combined with the input of the one-shot 10 and is intended to give a signal. Starting the ultrasound measure displacement and a second control input 20 measurement time intervals unit for supplying Enable operation signal.

In addition, fmg.1 shows the enable input 21, the output 22 of the request and the start input 23, the first output 24 of the result, the first output 25 of the result control, the second output 26 of the result, the second output 27 of the result control and the output 28 of the synchronization.

The time interval measurement unit 20 can be made of two time measurement circuits 29, 30, the AND 31 element and the OR 32 element (see Fig. 2). The output of the AND 31 serves as the output 22 of the request, the outputs of the time measurement circuits 29,30 serve as the output outputs 24, 26, the control outputs of the specified control units 29, 30 serve as the output 25, 27 of the result control, and the output of the OR element 32 serves as the synchronization output 28. The first control inputs of the circuits 29,30 are combined and serve as the enable input 21 of the unit 20, and the second control inputs of the circuits 29, 30 are combined and serve as the launch 23 of the unit 20.

The signal inputs of the first and second time interval measurement circuits 29, 30 are the first inputs of the block 20.

The meter works as follows.

Initially, the meter is reset (see Fig. 1). When applying a digital signal Resolution (see Fig. 3, a) at output 21 of resolution

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The driver is put into operation. At its output 22, a digital signal is set. A request (see FIG. 3.e) in response to which the user, through the reaction time tp, sends an impulse Start signal (see Fig. 3.6) to input 23, which prepares the unit for operation. 20 and the one-shot 10 starts.

The single-oscillator 10 generates a rectangular video pulse of a Hz recording duration (which can be modulated with a high frequency) and energizes the recording amplifier of the converter 1. At its output, a current recording pulse x is generated that passes through the winding of the movable recording element 8. In the sound duct 2, the magnetoelastic wave STX is excited due to the magnetomechanical transducer. This wave propagates along the conductor in both directions with a phase velocity V.

At some time points, respectively

Ti - lo m PM - loMl

11 V + VxM l2 V + V4 nj

where 10 is the reference distance between the synchro-movable elements 8 and 12.13 of the recording and reading of the primary WFP;

Vx is the target volume displacement velocity, if the direction of the displacement coincides with the direction of propagation of the magnetic elastic wave a along the sound conductor, the magnetoelastic wave A reaches the first and second movable readout elements 12, 13 with bias magnets 9 and induces electrical readout pulses not their outputs t to the input of the second amplifier -former 19 is read, amplified, converted into rectangular video pulses of the readout (see Fig. 3c) and passed to one of the signal inputs of the measuring unit 20. and the velocity Vx of moving an object above a certain initial threshold value determined by the parametric sensitivity of the channel, the value of the difference interval of moving will be

Tx.1 -i | Ti - T2 / - ± P)

which the second time measurement circuit 30 will be converted to the corresponding digital code

Nx.1 - T x., (3)

g where ft is the sampling frequency in the channel measuring the velocity of the object.

The generated code (3) - speed code - from the outputs of the circuit 30 is fed to the output 26 of the result. If this result

coincides with the result of the adjacent measurement (i.e., Nx-1 Nx.i + 1), then a digital signal is output from the output 27 of the circuit 30 (see Fig. 3, g) Duplication 2.

Upon completion of the conversion, a digital signal Query 2 is formed at the first output of circuit 30 (see Fig. 2), the signal input of circuit 30 is blocked, the AND 31 logic element is opened. At the second output of the circuit 30 the digital pulse signal Sync 2 is formed at the next moment (Fig .3, d), coming through the element OR 32 on the output 28 of the synchronization.

In the following time points, respectively

Tz

J1 + lc

t l2 + lo

T4 g

(four)

h is V where li, la are the distances between elements 8 and 5, 17 of writing and reading, the magnetoelastic waves a reach the stationary first and second elements of 5.17 readings. Electrical read signals will be induced at their outputs, converted by the first read amplifier 7 into right-angle video pulses. As a result, the required difference time interval is formed at its output, carrying information about the current position of the object

Jllnb /

Tkh.2 Tz - T4

(five)

These signals start and stop the first time measuring circuit 29 of the measuring unit 20, at the outputs of which the object position code is generated at the next momelt.

Nx.2 Tx.2f2. (6)

where f2 is the sampling frequency over the object position measurement channel.

The resulting code (6) - the position code - goes to output 24. If there is a parity with an adjacent result, then a digital signal Duplication 1 is generated at the output 25 of the result control, at the end of the measurement cycle of the Nx.2 value the circuit 29 produces a digital pulse signal Synchronization 1 arriving at the output 28 of the synchronization (see fig.Z.d) through the element 32 OR. At the other output of the circuit 29, a digital signal is generated. The request passes through the open element 31 And to the output 22 (Fig. 3.e). The signal input of circuit 29 is blocked.

The cycle of the meter is completed on this. The next cycle is initiated by the user.

The meter is switched to the blocking mode when the signal is removed.

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Permission to input 21 controls. In this mode, the meter does not respond to Run signals.

Acoustic absorbers 3, 16, mounted at the ends of the rectilinear sound duct 2, dampen the incident magnetoelastic waves and prevent the formation of reflected waves, perceived by the signal circuits of the transducer 1 as interference signals. To provide the required signal-to-noise ratio, stabilize the wave resistance and increase the rigidity, the duct 2 is mechanically stretched in the longitudinal direction with the help of the tension mechanism 4.

The parallel connection of readout elements 12, 13 and 5, 17 in the opposite polarity increases the resistance of the meter to electromagnetic interference and provides higher metrological characteristics of measurements on both channels. The measurement accuracy of the channels is established by selecting the sampling frequency fi, f2 within the resolution of the acoustic path. The use of time measurement circuits 29, 30 allows one to selectively set the sensitivity for each measurement channel and thereby expand the functionality of the meter.

Claims (1)

Invention Formula An ultrasonic displacement meter containing a magnetostrictive displacement transducer in the form of a rectilinear acoustic duct made of a striction material, mechanically connected with one of the acoustic duct acoustic absorbers and the tension mechanism of the acoustic duct. mounted on the duct near the acoustic absorber fixed reading element with bias magnet, connected to the output of the read element, amplifier reading shaper mounted on the working section of the duct movable writing element with bias magnet, which is kinematically connected to the object under controlled movement and connected in series with a single vibrator and amplifier recording, the output of which is connected to the input of the movable recording element, characterized in that, in order to increase Determining the accuracy of measuring displacements and expanding the field of use, it is equipped with first and second movable read elements with bias magnets, which are installed at equal distances on opposite sides of the movable recording element, a second acoustic absorber and a second stationary read element with a bias magnet, which are mounted at the second end of the acoustic sound duct, the second read amplifier, and the unit for measuring time intervals, the outputs of the first and second moving elements the readings are combined in the opposite polarity and connected to the inputs of the second amplifier-reader, the outputs of the first and second fixed readout elements are combined in the opposite polarities, the outputs of the first and second ycitel reader shapers are connected to the corresponding signal inputs of the time interval measurement unit, the first control input of which is combined with the one-vibrator input and intended to send a signal to start the ultrasonic displacement meter, and the second control input of the time interval measurement unit It is intended to give a signal to enable operation. 1 AND upgraded ,; blocking 29 23 Launch t t Vx 2228 2116 Phi $ .2 Ch.2 JTL Sync. X .Inquire and Blocking Tkh-G thirty Zslros I m “H. t Vx-7 P JITI .P X Jl Duplication 2 R