RU2080559C1 - Magnetostriction motion-to-code transducer - Google Patents

Abstract

FIELD: automatic control and measuring equipment. SUBSTANCE: two ultrasonic waves are generated by the ultrasonic pulse exciting element and reference ultrasonic pulse exciting element consisting of two opposite-magnetized magnets positioned at a distance covered by ultrasonic wave during a time period equal to the recording pulse length; the counter is triggered by electromagnetic induction set up by an excitation current pulse, and the offered electronic measuring circuit accomplishes generation of time equivalents and coupling of device with a microcomputer. The position of the object of monitoring is determined according to the algorithm of differential-ratiometric conversion. EFFECT: enhanced accuracy, conversion range and simplified design. 2 cl, 2 dwg

Description

 The invention relates to automation and measuring equipment and can be used to measure and control movements.

Known magnetostrictive displacement transducer containing a sound pipe with a damper, a stationary excitation coil, a recording pulse shaper connected to it, two movable receiving coils with a permanent magnet, a read pulse generator-amplifier associated with it [1]
However, the presence of movable receiving coils makes it difficult to implement a converter for large ranges of movement.

 There is also known a device for converting linear displacement to code [2] comprising a sound pipe, dampers, permanent magnets, excitation and read coils, a time-code converter and a memory register that controls the number of superpositionally connected excitation coils depending on the conversion range. However, the temperature stability of this device is low.

 Closest to the invention in technical essence is a device for converting movement to code / 3, containing a magnetostrictive line, dampers, a permanent magnet rigidly fixed to the object of control, sensors with permanent magnets, amplifiers-shapers, current pulse shaper, RS-triggers, generators counting pulses, counter, memory registers, buffer driver, address decoder, trigger driver, ready signal generator and exchange bus, and serves as information about the measured movement the ratio of the digital code Na to the sum of the digital codes Na and NV multiplied by the scale factor.

 However, the implementation of such a conversion algorithm leads to the appearance of a nonlinearity error due to the presence of an additive error in the time interval corresponding to the Na code due to transients in the sensors, delays in the connecting cables, amplifiers-shapers, electronic circuits for further conversion. In addition, when implementing this device, it is necessary to exclude false triggering of the RS-trigger from electromagnetic interference generated by the excitation current pulse, which leads to hardware complication of the device.

 In addition, due to the attenuation in the magnetostrictive line, the measurement range is limited, because for large ranges, the noise / signal ratio does not allow to achieve high measurement accuracy.

 The aim of the invention is to improve the accuracy, range of conversion and simplify the design of magnetostrictive converters.

 This is achieved by the fact that in a device containing a magnetostrictive line with dampers at the ends, an electro-acoustic transducer, an ultrasonic pulse excitation element containing a permanent magnet rigidly connected to the control object, an amplifier-shaper, a current pulse shaper, a counting pulse generator, a counter, memory registers , a buffer driver, an address decoder, a trigger driver, a ready signal generator and an exchange bus are additionally introduced a mode counter, which direct count input connected to the output of the amplifier-former, the first output with the installation input in the zero state of the counter, and the second and third outputs with inputs for enabling the reading of memory registers, a stationary excitation element of the reference ultrasonic pulse, consisting of two opposite magnetized magnets located at a distance from each other traveled by an ultrasonic wave for a time equal to the duration of the recording pulse, and located at a distance Xb from the electro-acoustic transducer, and into the excitation element is ultrasound Vågå pulse introduced an additional, oppositely magnetized existing permanent magnet, located at a distance from it, it is run by an ultrasonic wave for a time equal to the recording pulse width.

 In FIG. 1 is a block diagram of a magnetostrictive displacement to code converter.

 The transducer contains a magnetostrictive line 1 with dampers 2 at the ends, an electro-acoustic transducer 3, an excitation element of a reference ultrasonic pulse, consisting of fixed permanent magnets 4 and 5, an excitation element of an ultrasonic pulse, consisting of permanent magnets 6 and 7, rigidly connected to the control element, a counter mode 9, a direct count input connected to the output of the amplifier-former 8, a current pulse shaper 12, an output connected to a magnetostrictive line 1, a counter 10, an input directly about the account connected to the output of the counter pulse generator 11, the memory register 13, an information channel connected to the output of the counter 10, the input "record" with the second output of the counter mode 9, the memory register 14, the information channel connected to the output of the counter 10, and the input "record" - with the third output of the mode 9 counter, a start driver 15 connected to the input of the current pulse shaper 12 as well as to the inputs of the zero mode settings of the mode 9 counter, a buffer driver 16 connected to the information input the output outputs of the memory registers 13 and 14, the address decoder 17, the first and second outputs of which are connected respectively to the read permission inputs of the memory registers 13 and 14, the third output with the input of the driver shaper 15, and the fourth output with the first input of the driver for the ready signal 18, the second input which is connected to the third output of the mode 9 counter and the exchange bus 19 (with a microcomputer) connected to the output of the buffer driver 16, the input of the address decoder 17 and the output of the ready signal generator 18.

 The device operates as follows.

 The device is launched from the third output of the decoder 17 at the command of the microcomputer. Shaper 15 start generates a clock pulse, which starts the shaper 12 of the current pulses and sets the counter mode 9 to zero. The pulse generator 12 generates a current pulse in the magnetostrictive line 1, as a result of which a circular magnetic field is formed around it, which induces an electric pulse in the electro-acoustic transducer 3. After amplification and formation by the amplifier-shaper 8, the signal is fed to the counting input of the mode 9 counter. As a result of this, a high level signal appears at the output of the mode counter 1, which resets the counter 10. As a result of the interaction of the circular magnetic field with the longitudinal magnetic fields of oppositely magnetized constants of the magnets of the excitation element of the reference ultrasonic pulse, two ultrasonic waves arise, which propagate through the sound duct.

 The mechanism for the generation of an ultrasonic wave from the interaction of a circular magnetic field with two oppositely magnetized permanent magnets of an excitation element of an ultrasonic pulse (excitation element of a reference ultrasonic pulse) is shown in the time diagrams of FIG. 2.

 The time diagram “a” shows the shape of the ultrasonic wave obtained by the interaction of a circular magnetic field and a permanent magnet 4 (6).

 The temporal diagram “b” shows the shape of the ultrasonic wave obtained by the interaction of a circular magnetic field and a permanent magnet 5 (7).

 The time diagram "c" shows the shape of the ultrasonic wave obtained by the interaction of the circular field and the excitation element of the ultrasonic pulse (excitation element of the reference ultrasonic pulse).

 The first ultrasonic wave from the excitation element of the ultrasonic pulse, reaching the electro-acoustic transducer 3, is converted into an electric pulse, which is amplified and formed by the amplifier-former 8 and fed to the counting input of the mode counter 9. With the arrival of the signal to the counting input, the mode counter, the signal from output 1 of the mode counter disappears, and the signal from output 2 goes to the “record” input of the memory register 13, as a result of which the digital equivalent of the ultra propagation time is recorded in the memory register 13 ƃ wave from the ultrasonic element driving pulse to the electro-acoustic transducer 3.

The second ultrasonic wave from the excitation element of the reference ultrasonic pulse, having reached the electro-acoustic transducer 3, is also converted into an electric pulse, which is amplified and formed by the amplifier-former 8 and fed to the counting input of the counter of mode 9. With the arrival of the signal to the counting input of the counter of mode 9, the output signal 2 disappears, and the signal from output 3 goes to the “record” input of the memory register 14, as a result of which the digital equivalent of the propagation time of ultrasound is recorded in the memory register 14 a new wave from the excitation element of the reference ultrasonic pulse to the electro-acoustic transducer 3. At the same time, the signal from the third output of the mode 9 counter goes to the second input of the readiness signal generator 18, the first input of which receives the signal from the fourth output of the address decoder 17. The readiness signal generator 18 provides on the bus exchange signal 19 readiness. This means that in the registers 13 and 14 of the memory are written digital codes N _a and N _b .

где X положение объекта контроля;
K- масштабный коэффициент.When forming a microcomputer address on the bus 19, the signal at the first output of the decoder 17 is allowed to read data from the register 13, and the signal at the second output from the register 14. The micro-computer processes the digital codes in accordance with the conversion algorithm, having the form:

where X is the position of the object of control;
K is a scale factor.

 The implementation of such a conversion algorithm eliminates the appearance of a nonlinearity error due to transients in the electro-acoustic transducer, delays in the connecting cables, since the “start” and “stop” pulses are formed when passing through the same transducer nodes. The application of this algorithm provides high repeatability of the static characteristics of the device when the ambient temperature changes, with natural aging and a change in the sound duct.

 The use of two oppositely magnetized permanent magnets in the constructions of the ultrasonic signal excitation element and replacing the excitation of the reference ultrasonic signal can increase the signal amplitude by 40-50% and increase the signal-to-noise ratio, which can significantly increase the accuracy of magnetostrictive displacement transducers and their conversion range.

Claims (2)

 1. Magnetostrictive displacement transducer to code containing a magnetostrictive line with dampers at the ends, an electro-acoustic transducer, an ultrasonic pulse excitation element, rigidly connected to the control object, an amplifier driver, a current pulse generator, a counter pulse generator, a counter, memory registers, a buffer former, address decoder, trigger driver, ready signal generator and exchange bus, the ends of the magnetostrictive line through the dampers being connected respectively Actually with the common bus and the output of the current pulse shaper, the input of which is connected to the output of the start shaper, the input of the direct counter of the counter is connected to the output of the counter pulse generator, and the output is with the information inputs of the memory registers, the outputs of which are connected to the input of the buffer shaper, read permission inputs with the first and the second output of the address decoder, the third output of which is connected to the input of the driver shaper, and the fourth output with the first input of the driver of the ready signal, the output of which is connected to the buses th exchange, also connected to the input of the address decoder and the output of the bus shaper, characterized in that a mode counter is inserted into it, the direct count of which is connected to the output of the amplifier-shaper, the first output with the installation input in the zero state of the counter, and the second and third with the permissions for reading the memory registers, a stationary element for the excitation of the reference ultrasonic pulse, and the counter is started from electromagnetic interference generated by the excitation current pulse, in this case s object is defined as the quotient of the difference codes and the reference measurement interval on the reference code interval multiplied by a scaling factor.  2. The transducer according to claim 1, characterized in that the ultrasonic pulse excitation element and the reference ultrasonic pulse excitation element are made in the form of two oppositely magnetized permanent magnets located at a distance traveled by the ultrasonic wave for a time equal to the duration of the recording pulse.

Images