SU1439412A1 - Method and apparatus for measuring vibration acceleration - Google Patents

Abstract

The invention relates to a measurement technique, namely to means for measuring vibration acceleration, and is intended for use in calibrating vibration measuring transducers of acceleration or vibration testing of products on vibration stands. The aim of the invention is to reduce the measurement time and increase dignity. fidelity of vibration parameters measurement results. The method of measuring the vibration acceleration consists in exciting mechanical vibrations in the object, converting them into a series of contrasting bands moving through a given point, and counting the number of these bands for a time interval, directly proportional to the frequency of the mechanical oscillations excited. To implement this method, the device contains a sinusoidal signal generator, a vibration exciter with a mechanical vibration transducer, a first key and a counter connected in series, a first trigger connected by an output to the second input of the first key, a second key, one input connected to the generator output, and an output through the third key is connected to the input of the reversible counter, the clock generator, the control input connected to the output of the second trigger, and the output to the third key and the first inputs triggers, the fourth key, through which the reset generator § is connected to the countdown input of the reversible counter. The number of bands passing through a given point is converted by the photodiode into electrical pulses. The frequency and level of mechanical oscillations generated by the pathogen are set by the generator of sinusoidal oscillations. A mechanical vibration transducer is installed on the exciter, at the output of which the number of pulses corresponds to the number of contrast bands. The number of pulses is counted by a counter. The time interval for counting pulses is set by a key using a reversible counter, a clock generator, a reset generator, two triggers and three keys. 2c. and 1 z. p. f-ly, 1 ill. U m

Description

The invention relates to a measuring technique, namely to means for measuring vibration acceleration, and is intended for use in calibrating vibration measurement transducers of acceleration or vibration testing of products on vibration stands,

The purpose of the invention is to reduce the measurement range and increase the reliability of measurement results.

The drawing shows a block diagram of a device for measuring vibration acceleration,

The device contains a generator of a sinusoidal signal j; you will excite 2 vibrations with a transducer 3 mechanical oscillations, a third key 4 and a counter 5 connected in series, the first trigger 6, connected to the second input of the first khpoch 4, second key 7, one input connected to the generator output 1, and the output through the third key 8 connected to the input of the direct account of the reverse counter 9, the clock generator 10, the controlling INPUT connected to the output of the second trigger 11 and the output to the third key 8 and the first inputs of both triggers 6 and 11, the fourth key 12, through which the generator 13 of the reset is connected to the input of the countdown of the reversible counter 9.

The method of measuring the vibration acceleration is implemented as follows.

Excited mechanical vibrations transform in a series of points of contrasting stripes through a given point and calculate the number of these bands per unit time.

The dependences of the peak values of the parameters of the sinusoidal mechanical oscillations when measuring their 1 transmitter with a measuring transducer on the wavelength A of the laser, the frequency F of the change of the contrast bands and the frequency f of the oscillations are expressed by the following equations:

Oscillation amplitude

S s

Vibration speed V 2flfSg;

Acceleration of oscillations S,.

Cases further conversions j have

S 41 f4 25 fS 21T f: 2 f V

It is known that

S - - 3 8-f

Claims (2)

one Then, the outcome of T j, where T is the period of oscillation, can be written 7 V J: These equations indicate that when measuring the amplitude of vibrational oscillations, the pulses F are counted for a time proportional to the period T of the oscillations of the vibrating table; when measuring the speed of oscillations, the pulses F are calculated in; flow constant time interval 7 / L (regardless of the frequency of oscillation); when measuring acceleration, the pulses F are calculated in a time proportional to the oscillation frequency f, Thus, to measure the vibration acceleration, the counting of the number of moving lanes is made over a time interval S directly proportional to the numerical value of the frequency of the excited mechanical vibrations, The measurement is carried out as follows. Excited mechanical vibrations are transformed with the help of an interference transducer, light grid or in another way into a number of moving contrasting bands, The number of bands passing through a given point is detected, for example, by a photodiode, which transform the bands into electrical wires. The frequency and level of mechanical oscillations created by the pathogen 2 are set by the generator 1 of the sinusoidal signal. On the exciter 2, there is a converter of 3 mechanical oscillations; at the output of which the number of pulses corresponds to the number of contrasting bands passing at the installation point one fixing strip. Kojij-pulse quality is counted by counter 5 The pulse count time interval is set by key 4 using a reversing counter 9, a clock generator 10, a reset generator 13; two triggers 6 and 11 and three keys 7, 8 and 2 Dtt of the beginning of the measurement cycle on a second trigger 1 from an external device is fed by a start-up pulse. Trigger 11 opens the second key 7, and; The pulses from the sinusoidal signal generator 1 are fed to the third key 8, and from it to the direct account input of the reversible counter 9. The boom, during which the third key 8 is open, is determined by the clock generator 10 started when the trigger is turned on 1 „ At the end of the clock clock and the clock generator, the duration of which is generally chosen to be 1 s 5, the trigger 11 is turned off, the key 8 is locked and the pulse counting of the generator 1 stops, Upon expiration of the counting time of the RL-oscillator of the generator 1 of the sinusoidal signal in the reversible counter 9, the number corresponding to the frequency of the generator 1 or OR is recorded; which is the same, the frequency of the reproduced vibration. The falling edge of the clock generator 0 triggers the trigger 6, which opens the key 4 for counting the pulses of the converter 3 by the counter 5. Simultaneously, through the key 2, the counter count of the reversing counter 9 receives pulses from the generator 3 of the reset, and the previously recorded number is reset. When the counter 9 is reset, the trigger is turned off & 5, the pulse counting from the converter $ 3 stops and the trigger 11 is turned on, automatically repeats the measurement cycle, Until the end of the next cycle, the number 5 on the counter 5 is displayed corresponding to the vibration acceleration reproduced by the exciter 2. Record in the reverse counter 9 pulses, the number of which always corresponds to the frequency of the reproduced vibrations, and by the SLOW-DUCH reset this  the numbers by the reset generator 13 with a constant frequency before zeroing allow to obtain the pulse counting time of the converter 3, directly pro1 2 portional frequency in the pattern of vibration induced. In order for the indications 5 to correspond numerically to the vibration acceleration, the frequency of the reset generator must be chosen from the condition .i ii f. TO where fj is the frequency of the reset generator, Hz | n is a whole number, chosen in conjunction with the measured frequency response and the required accuracy of measurement. The possibility of directly counting the vibration acceleration of reproducible mechanical vibrations will reduce the time spent on measurements and the time of testing the components of an HF or cap-sounding vibration measuring transducers and also increase the reliability of measurements due to a lawsuit: 1) the frequency of the vibration frequency intent operation: -; and yes, what is the mathematical treatment of the measurement results? about p l invention  - A way to measure the vibration acceleration 5 is that the object is excited by mechanangal oscillations, converting ix to a number of contrasting bands moving across a given point, and counting the number of these bands in a given time interval that differs byM; that, in order to reduce the time and increase the reliability of the measurement results, the time interval selects directly proportional to the numerical value of the frequency of excited mechanical oscillations. 2. "A device for measuring vibration acceleration," containing a series-connected generator of sinusoidal signals, a vibration exciter with a mechanical vibration transducer, and an indicator that is consistent with, c. the purpose of measuring the vibration acceleration, it is equipped with the first key, the output of which is connected to the indicator, the first trigger Mj, the second trigger, a clock generator connected in series with the second key, the third key, A simple counter whose output is connected to the first inputs of both triggers, serially connected by a reset generator and a fourth key, the code of which is connected to the reverse count input of a reversible counter, the output of the first trigger is connected to the second inputs of the fourth and first keys, the output of the sinusoidal signal generator is connected to the first input the second key, and the output of the second trigger - with the second input of the second key and the control input of the clock generator, the output of which is connected to the second input of the third key and rymi inputs of said first and second flip-flops, and vtolnen indicator in the form of the counter with a digital display, 3, the apparatus according to claim 2, characterized in that, in order to shorten the measurement time and increase 4394126 results of reliability, the counter readings correspond to the numerical value of the reproduced acceleration of a given system of units, for which the frequency of the reset generator is chosen from the ratio to f K 10  , where f is the frequency of the reset generator, Hz; the coefficient that accounts for a given system of units; an integer selected depending on the range of the measured accelerations and the required measurement accuracy; distance between contrast bands, µm. K p D