SU815609A1 - Device for electromagnetic checking metal-article physical characteristics - Google Patents

Description

I

The invention relates to the means of non-destructive electromagnetic quality control of metal products and can be used for the multiparameter control of their physical and mechanical properties.

 A device consisting of a generator of sinusoidal oscillations, a block of overhead transducers, and forces of a body is known. signals, a measuring unit, a fade-sensitive detector (its role is played by a slot amplifier), and a phase-shifter with a gate driver lj.

The disadvantage of this device is the low measurement accuracy in the case of large changes in the gap between the working transducer and the surface of the product under test.

It is also known a device in which the influence of the gap is suppressed by moving the transducer relative to the product in order to maintain the gap constant, i.e. use active

suppression method. At the same time, the module of the multidimensional signal of the converter is minimized. This device contains sinusoidal kshebakv generators at various personal frequencies, a converter (your converter — Compressor-to-Work, switched on using an auxiliary circuit), a signal amplifier, a square detector for generating a multidimensional signal, and an optimizer with an effective mechanism.

In this device, the influence of the aazor is eliminated by the use of a mixer & t of the displacement of the transducer relative to the product in order to maintain the gap clearance.

In devices with active suppression of the influence of an azor, this problem of ycnettrao is solved within wide limits of its magnitude, since there are no fundamental restrictions on the operation of the transducer system. There is no 2j.

The disadvantages of the known device are the fall of the sensitivity of the system to changes in the size of the gap when

approach to the extremum, as well as the need to filter the signal components due to search fluctuations.

These drawbacks with devices with extreme systems are absent in devices with a tracking system.

Closest to the proposed technical entity is a device for electromagnetic control of the physical properties of metal products, containing a series-connected generator unit, a conversion unit. generators, amplifier, processing unit and measuring information, the inputs of which are also connected to the outputs of the generator unit, the indicator connected in series to the unit of phase shifters connected to the outputs of the generator unit, the unit of synchronous detectors and the actuator which is mechanically connected to the converter unit

3

The disadvantage of this device is Zack

The reason is that it is not suitable for solving multi-parameter problems, when the signal of the converter, along with the size of the gap, is influenced by several other factors. This is due to the fact that in a known device for driving a converter, only a single frequency current is used, as a result of which the output signal of the converter unit is two-dimensional, which makes it possible to extract the signal due to the influence of the gap to control the tracking system two influencing factors: a gap and one variable factor (which is a controlled parameter). In the case when the signal is influenced by more than two factors, the dimension of a single-frequency signal is less than the number of influencing factors and, therefore, it is impossible to isolate a signal proportional only to the gap to control the tracking system. So

therefore, this device cannot be set.

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to hurt the error introduced by changes in the gap, when solving a multiparameter problem.

The purpose of the invention is to improve accuracy.

The goal is achieved by the fact that the devices are equipped with a series-connected coefficient block, the inputs of which are connected to the outputs of a block of synchronous detectors, and a summing amplifier, the output of which is connected to an actuator.

In the drawing shows a block diagram of the device.

The device contains a block 1 of a sinusoidal oscillation generator, block 2

converters (compensating and working converters included in the ,, differential circuit), amplifier 3 signals, block 4 of the processing of measuring information, indicator 5, block 6

phase-sensitive synchronous detector®, block 7 of phase shifters, block of 8 coefficients, summing amplifier 9 and actuator 10,

Number of entries for elements 4.6,

7.8.9, as well as the number of generators in block 1, is determined by the number of factors affecting the converter signal. The elements of the device are connected in the following order: generator unit 1, transmitter unit 2, amplifier 3, measuring information processing unit 4 and indicator 5 are connected in series, generator unit 1, generator 7 phase shifters, unit 6 of synchronous detectors, unit

8 coefficients summing amplifier

9 and the actuator Yu, which is mechanically connected to unit 2. In addition, the signal inputs of the synchronous detectors of unit 6 are connected to the output

amplifier 3.

The device works as follows.

The output signal of the generator unit 1, which is the total sum of sinusoidal oscillations of different frequencies, is fed to the converter unit 2. The output signal of block 2 is amplified by amplifier 3. The output signal of amplifier 3 is fed to the signal inputs of block 6 of synchronous detectors, to the reference inputs of which is fed through block 7 of phasers a reference signal from block 1. Signals of block 6 of phase-sensitive synchronous detectors go to block 8 of coefficients. I.

The conditions from which the settable factors are selected in block 8,

° determine the outcome of the fact that the connection of the signal of the electromagnetic converter unit 2 with technological or structural factors determines the stochastic nature of the random distribution

Claims (3)

5 heals of defects and their parameters in the controlled product. Therefore, the coefficients to be set are calculated by the least squares statistical method from the system of normal equations, 7 / M / - // (b // // px //, is the normalized correlation matrix of signals; // PX / is the correlation matrix of the gap with the signal transducer; // p // - matrix-column is normalized with coefficients: coefficients // Matrices // // and are determined theoretically on the basis of the transducer equations and parameters of a random metric or experimentally based on the data of a multifactor experiment. A special technique has been worked out. As a result of processing the signal with these coefficients, the signal is dependent only on the variations of the gap, and the following factors are suppressed. This signal goes to summing amplifier 9, where the signals of the I synchronous detectors of block 6 are summed. The signal goes to the actuator U, which moves the working transducer of unit 2 normally to the surface of the test product. By moving the working transducer of unit 2, it restores equality gap under working and compensating transducers that obviates, control error caused by a change in the gap. The output signal of amplifier 3 is also fed to the input of block 4 by processing the measurement information. The other inputs of block 4 receive signals from the output of block 1. In block 4, a signal is selected that characterizes the value of the parameter being measured. The signal from block 4 is fed to the indicator 5, where it can be recorded or read from the scale. In this way, the introduction of a block of 8 coefficients and a summing accelerator 9 allows, under conditions of simultaneous action on the signal of block 2 of several interfering factors, to eliminate the gap. This, in turn, allows for multi-parameter testing of metal products with high accuracy when changing the gap in a wide range of its values. The formula invented Device for electromagnet i control of physical properties of metal products, containing successively connected, dianennye-generator unit, transducer unit, amplifier, measurement information processing unit, whose inputs are also connected to the outputs of the generator unit, indicator, series-connected phase shifters, connected by inputs with the outputs of the generator unit, the unit of synchronous detectors and the actuator, which is fur: the battery is connected to the converter unit, I distinguish This hem, that, in order to improve accuracy, it is equipped with series-connected coefficient block, whose inputs are connected to the outputs of the sync detector block, and a summing amplifier, the output of which is connected to the actuator. Sources of information taken into account at the exponent 1.Pustynnikszh c. G. and AnisimovS. D. Electronic device for monitoring the heat treatment of steel products. - Electromechanics, 1964, No. 4. 2. Authors certificate of the USSR 249724, cl. Q O1 M 27/80, 1968. 3. Electronics. Proceedings of MEI, 1964, ep. 57, p. 139 (prototype).