SU1254393A1 - Method and apparatus for determining lower bound of dynamic range of piezoaccelerometer - Google Patents

Abstract

The invention relates to a measurement technique and allows to simplify the method. To do this, it is easy to determine the amplitude-frequency characteristic of a signal from a piezo-accelerometer 3 by automatically maintaining a constant amplitude of the disturbing force and continuous sweep in frequency, as well as setting certain values of the amplitudes of oscillations by using a vibration exciter with a sensor 5 dynamic forces. 5 2 sec. f-ly, 2 ill. (L / G 01 4 WITH from Fig 1.

Description

This invention relates to a measurement technique and is intended for calibration of piezo accelerometers.

The aim of the invention is to simplify the method for determining the lower limit of the dynamic range of a piezoaccelerometer, defined by its sensitivity and the intrinsic noise of piezoceramics. Fig. 1 shows a schematic of the device for determining the lower limit of the dynamic range of a piezo-oximeter; in fig. 2 - amplitude-frequency characteristic of the output signal of a piezo accelerometer mounted on the proposed device.

A device for determining the lower limit of the dynamic range of a piezo accelerometer (Fig. 1) consists of a platform 1 rigidly mounted on supports 2, which are displaced relative to the installation positions of the piezo accelerometer 3 and vibration exciter 4 with a sensor 5 of dynamic forces. The piezo accelerometer 3 and the dynamic force sensor 5 are installed in close proximity to each other. The output of the dynamic force sensor is entered as negative feedback into the exciter 6 exciter circuit and connected to its control input.

The lower limit of the piezo-axometer tester under test is determined as follows.

The test piezo accelerometer 3 is mounted on a rigidly fixed platform 1. The platform oscillations are excited in the immediate vicinity of the piezo accelerometer by means of a vibration exciter 4. In the immediate vicinity of the installation sites of the piezo accelerometer and the dynamic force sensor, their output signals are connected to each other by linear dependence, where the coupling coefficient is static deformation of the platform. To maintain the amplitude of the vibration-stimulating force, a constant signal from the output of the dynamic force sensor 5 is fed back to the input of the vibration exciter 4. The frequency of the exciting forces is changed from zero to the frequency of half the first resonance of the platform mounted on supports 2, and measured amplitude -frequency response at the output of the piezo accelerometer (Fig. 2), not 0

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The linear portion of the measured amplitude-frequency characteristic determines the lower limit of the dynamic range of the piezo accelerometer. The nonlinear part of the amplitude-frequency characteristic of a piezo accelerometer is determined by its deviation from the direct (when plotting the amplitude-frequency characteristic on a logarithmic scale using different axes).

Using the invention allows, simply and quickly, in comparison with the prototype, to determine the lower limit of the dynamic range of a piezo accelerometer, firstly by using standard vibration measuring equipment (vibration exciter, dynamic force sensor, compressor designed to connect the dynamic force sensor output to the input vibration exciter); secondly, almost any construction can be used as a platform on rigid supports, while using a prototype it is necessary to use a special platform with complex kinematics. In addition, it is easier to determine the amplitude-frequency characteristic of a signal from a piezo accelerometer by automatically maintaining a constant amplitude of the disturbing force and continuous frequency sweep, and it is also easier to set certain values of the amplitudes of the platform oscillations by using a vibration exciter with a dynamic force sensor.

Formula of invention

1, A method for determining the lower limit of the dynamic range of a piezo-accelerometer, which means that a piezo accelerometer is mounted on a platform, excites platform oscillations, measures the output signals of an accelerometer in a given frequency range, and determines the characteristics of a piezo accelerometer, characterized in that In order to simplify the method, the platform is excited by a concentrated oscillatory force in the installation area of the accelerometer, the frequency of the exciting force is smoothly changed from zero to half the frequency of the first resonance of the platform, the amplitude of the force is kept constant by driving .3

rank, and the lower limit of the dynamic

The range of the piezo accelerometer is determined by the conjugation point of the linear and non-linear sections of the amplitude-frequency characteristic obtained from the output of the piezo accelerometer.

2, A device for determining the lower limit of the dynamic range of a piezo accelerometer, comprising a platform with a vibration exciter mounted on it, rigidly fixed at two points5 displaced

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The installation location of the exciter, characterized in that it introduces an amplitude controlled source of excitation signal and a force sensor installed between the platform and the exciter, the output of the force sensor connected to the control input of the exciter signal, the output of which is connected to the input of the exciter A piezo accelerometer is installed in the installation area of the vibration exciter.

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Editor M. Tsitkina

Compiled by V. Pimenov Tehred I., Popovich

Order 4714/48

Circulation 778

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Production and printing company, Uzhgorod, st. Project, 4

FIG. 2

Proofreader M. Maksimishinets

Subscription

Claims (3)

Claim 1. The method of determining the lower boundary of the dynamic range of the piezoelectric accelerometer, namely, that the piezo accelerometer is installed on the platform, excite platform vibrations, measure the output signals of the accelerometer in a given frequency range and determine the characteristics of the piezo accelerometer according to the measurement results, characterized in that, in order to simplify the method, the platform is excited by a concentrated oscillatory force in the installation area of the accelerometer, the frequency of the exciting force ⁵⁵ smoothly changes from zero to half the beginning of the frequency of the first resonance of the platform, the force amplitude is kept constant by a factor of 1254393, and the lower boundary of the dynamic range of the piezo-accelerometer is determined by the conjugation point of the linear and non-linear sections of the amplitude-frequency characteristic obtained from the output of the piezo-accelerometer. 2, A device for determining the lower boundary of the dynamic range of a piezo-accelerometer, comprising a platform with a vibration exciter installed on it, rigidly fixed at two points offset relative to the installation location of the vibration exciter, characterized in that an exciting source of excitation is introduced into it 5 signal and a force sensor installed between the platform and the exciter, and the output of the force sensor is connected to the control input of the excitation signal source, the output 10 of which is connected to the input of the exciter, and the piezo accelerometer is installed in the installation area of the exciter. Compiled by V. Pimenov Editor M. Tsitkina Tehred I.Popovich Proofreader M. Maximishinets __________. D— * Order 4714/48 Draw 778 Subscription VNIIIPI of the USSR State Committee for Inventions and Discoveries 113035, Moscow, Zh-35, Raushskaya nab., 4/5 Production and printing company, · Uzhhorod, st. Project, 4