SU1649458A1 - Method and device for measuring relative factor of transverse conversion of impedance heads - Google Patents

Description

one

(21) 4435384/10

(22) 03 06 88

(46) 05/15/91. Bul N 18

(72) V.N.Karovetsky, G.N. Semenov,

Y. Smirnov and E.I. Stepanov

(53) 531.768 (088.8)

(56) USSR author's certificate

N 1377642, class G 01 M 7/60, G 01 R 21/00, 1986

(54) METHOD OF MEASUREMENT OF RELATIVE COEFFICIENT OF TRANSVERSE TRANSFORMATION OF IMPEDANCE HEADS AND DEVICE FOR ITS IMPLEMENTATION

(57) The invention relates to a measurement technique and can be used in a vibration measuring technique. The purpose of the invention is to improve the accuracy of measurement of the force impedances by determining

sensitivity of transducers of force and acceleration of impedance heads to the moment acting relative to the lateral axis of the impedance bare legs. Impact heads are influenced by angular harmonic vibration and the normalized dynamic sieve applied to the impedance heads at a point offset from their common axis of symmetry and according to the measured phase difference The parameters of the vibrations and the known displacement of the application point are determined by the moment acting on the force transducer and the acceleration of the impedance heads. In the device for measuring the relative transverse conversion ratio of the impedance heads, there is a U-shaped vibration plate 1 mounted on the base and connected to the vibration table 2, a load 4 and two identical impedance heads 5 and 6 installed

 14

SP

00

between the inner walls of the vibrating plate 1 and the outer walls of the load. In this case, the vibrating plate 1 is connected to the vibrator at a point offset from its axis of symmetry by distance e, and the vibrating transducers 7, 8 of acceleration located on the vibrating plate 1 and the load 4 are set so that their axes of sensitivity are perpendicular to the radius of rotation of the load and plate compactors. The Invention relates to measurement technology.

The purpose of the invention is to improve the accuracy of measuring impedances of force by determining the sensitivity of force transducers and accelerating impedance heads (IG) to the moment of force acting relative to the lateral axis.

FIG. 1 shows the structure of an apparatus for carrying out the method: FIG. 2 - the same, top view.

A device for implementing the presented method contains (Fig. 1) a U-shaped vibratory plate 1, an excitation system of angular harmonic oscillations consisting of a vibrating stand 2 connected by a bolt 3 with a U-shaped vibrating plate 1 at a point offset from its axis symmetry at distance d, load 4, impedance heads 5 and 6, acceleration vibration transducers 7 and 8, located on vibrating plate 1 and load 4, recording devices 9 and 10, connected to acceleration vibration transducers 7 and 8, recording devices 11-14, connected to the converter IG 5 and 6 forces and accelerations, a phase meter 15 connected to recording devices 9 and 10, acceleration vibrating transducers 16 and 17 located on a vibrating plate 1 and a load 4 and compensating the asymmetry of the vibrating plate 1 and a load 4, a computing device 18 to which recording devices 9. 10, 11 and 14 and the phase meter 15. The vibrating plate 1 is fixed in the torsion springs 19 (Fig. 2).

The proposed device for carrying out the method of measuring the relative transverse conversion coefficient of the IG works as follows.

The load 4 is fixed in the vibrating plate 1 by means of IG 5 and 6, which it touches only the side walls, and is located in

The accuracy of determining the sensitivity of the vibration transducers of the force and acceleration of the impedance heads to the moment acting relative to the lateral axis is achieved by an accurate determination of the moment of inertia of the load and allows determining the corresponding systematic errors of measuring the impedances of force in real conditions. 2 sp.f-ly, 2 ill.

suspended state. Vibrating plate 1 and weight 4 are fixed to vibration transducers 7, 8, 16 and 17. Vibrating plate 1 is fixed in torsion springs 19 and connected to rod 3 with vibrating stand 2. Recording devices 9-14, phasometer 15, computing device 18 are connected as shown in FIG. one.

sh

Set at frequency f

2

vibrations

Ka

Kc

which is transmitted via vibrating stand 2 and stock 3 to vibrating plate 1, which makes angular oscillations about an axis that passes through the axes of torsion springs 19. Measured amplitudes of signals from the outputs of vibration transducers 7 and 8, force and acceleration transducers of IG 5 and 6, measure the difference phases between signals of vibration transducers 7 and 8. With the help of measured values, the sensitivity of transducers of force and acceleration of IG to moment are determined by the expressions

IV

M

for vibroconverter acceleration IG and Ucftj

-shchg)

for the vibration transducer of IG forces, where Ua (t), Uc (t) are the output signals of the vibration transducers of acceleration and IG forces;

M (t) I Gmax Sin (+ V) moment

force acting relative to the lateral axis of the IG;

I is the moment of inertia of the load, relative to the lateral axis;

P V (An 2, / Ar 2 I An Ar, „

Emax - (-) + (-) - - -cosSP

- amplitude of angular acceleration; Arsln (p

Y - arctg

/ AG & T

rr (-) cosp

- phase shift of the generated moment of force;

gp, yy - the distance from the axis about which the angular motion takes place, to the acceleration vibration transducers, which determine the parameters of vibration;

An, Ar are the output signals of acceleration vibration transducers, which determine vibration parameters;

(p is the phase difference between the signals of acceleration vibration transducers;

coscological frequency of vibration.

The most favorable mode of operation is the mode in which the phase difference between the signals of vibration transducers 7 and 8 is 180 °, in this case

those. the value of the moment of force at the given An, Ar, rn, yy max. In order to obtain such a regime, one should change the frequency and find its value at which (p 180 ° (redundant mode).

The proposed method and device for its implementation in comparison with the known ones allow determining the sensitivity of the force transducers and I / IT acceleration to the moment and, thus, determine the corresponding systematic errors in the measurement of the force impedances under real conditions.

Claims (2)

1. Method for measuring the relative transverse conversion ratio of impedance heads, which implies that the impedance heads are subjected to harmonic vibration and normalized dynamic force, the vibration parameters, the output signals of the acceleration transducers and the forces of the impedance heads, and the phase difference between the harmonic vibration and the normalized force are measured. dynamic force, distinguished by the fact that, in order to improve the accuracy of measuring impedances of force by determining the sensitivity For the moment acting relative to the lateral axis of the impedance heads, the transducers of force and acceleration of the impedance heads use angular harmonic vibration as the 5th harmonic vibration, and force is applied at a point offset from the symmetry axis of the heads, according to the measured phase difference, the vibration parameters and the known value displacement of the point of application of the normalized dynamic force, determine the moment acting on the force transducers and acceleration of the impedance heads, and the sensitivity and coefficient nt poperech5 Foot of converter power and acceleration impedance heads at the time is calculated by a certain relationship. 2. A device for measuring the relative transverse conversion ratio of impedance heads, containing a U-shaped vibrating plate mounted on the base and connected to a vibrator, a load, acceleration vibration transducers, spread on the load and a U-shaped vibrating plate, recording devices connected to the vibrating transducers and transducers of force and acceleration of each impedance head, and a phase meter, the inputs of which are connected to vibration transducers through appropriate recording devices, and the load through ie identical to the impedance of the head, located on either side, is attached to the inner sides 5 U-shaped vibrating plates, characterized in that, in order to improve the accuracy of measuring impedances of force, due todetermining the sensitivity of acceleration converters and the strength of impedance heads to 0, the moment acting relative to the lateral axis of the impedance heads, the U-shaped vibrating plate is connected to the vibrator at a point offset from its axis of symmetry, and the axis of sensitivity of the accelerating vibrator is perpendicular to the radius of rotation of the load and vibrating plate. four FIG. 2