SU781766A1 - Device for determining dynamic characteristics of mechanical systems - Google Patents

Description

one

The image is related to automation, in particular to testing devices, and is intended for dynamic testing of mechanical systems, such as machine tools.

A number of devices are known for determining the dynamic characteristics that provide excitation in a test elastic and constant and alternating force system. The latter is harmoniously varied in a certain frequency range. The displacement arising in the system is measured by a vibration measuring unit, the components of this are determined, displacements, one of which is in phase with force, and the other is shifted by 90 °. Electrical voltages, proportional to these components, are fed to the inputs of a two-coordinate recording device, such as a two-coordinate recorder, which, when the excitation frequency is changed, records the hodograph of the dynamic compliance, i.e., the amplitude-phase frequency response of the elastic system (AFCh). By the form of this characteristic, it is possible to estimate the dynamic quality of the mechanical system under study (vibration resistance), resonance regions, etc. ll.

The closest technical solution to the proposed is

5 a device for determining the dynamic characteristics, comprising a series-connected audio frequency generator, a power amplifier, a vibrator and a force meter, at 10 the corresponding output of the vibrator is connected to the first through a vibration displacement meter, and the output of the force meter to the second input of the vibration meter,

15 outputs of which are connected to the corresponding inputs of the recording unit 2.

A disadvantage of the known devices is that in them the speed

20, the change in the logarithm of the frequency of the alternating force is constant and consistently not related to the rate of change of the components of the vibration displacement. In most of the frequency range (outside the resonance areas), these components are almost unchanged and the stylus pen practically does not move, resulting in a loss of performance. In (region of resonances when

30, the displacement components change dramatically, the recorder pen moves too fast, which reduces the measurement accuracy. Since, in all known devices, the rate of change of the logarithm of the frequency is constant, the determination of the ALFC occurs with low productivity and not with a high enough accuracy.

The purpose of the invention is to improve the accuracy of the device.

This goal is achieved by the fact that the device contains a series-connected measuring device for the rate of change of the components of the vibration and a control unit whose output is connected to the control input of the audio frequency generator, and the inputs of the measuring device for the speed of change for the components of the vibration-displacement are connected to the corresponding outputs of the measuring device for the vibrating movement.

The drawing shows a block diagram of the device.

The device contains a generator of 1.sonic frequencies, an amplifier 2 of a power supply, a vibrator 3, a force meter 4, a vibration meter 5, measuring the movement of the mechanical system under investigation, a vibration meter 6 constituting vibration unit, a recording unit (two-coordinate machine, a slow recording device) 7, a speed meter 8 changes in the components of the vibration displacement and the control unit 9.

The device works as follows.

The output voltage of the sound frequency generator 1 is amplified in the amplifier 2 and supplied to the vibrator 3, which excites a variable force in the elastic system. This force is measured by force meter 4. The vibration displacement excited in an elastic system is measured by a vibration displacement meter 5, the output signal of which is fed to the input of the measurement meter 6 components of the vibration displacement. The output voltage of the gain meter 4 is applied to another input of the same meter. This voltage is proportional to the force exerted. The meter 6 component vibratory displacement produces two yeny Reni

 The current of the current, one of which is proportional to the amplitude of the component of the vibration displacement, is in phase with the force, and the second is the amplitude of the component that is shifted by 90. These voltages are fed to the inputs of the two-coordinate recording device 7, which records the AFC ...

 When the pen of the recorder moves from the point with coordinates X, y to point with coordinates c + dx,

V + dy feather passes the path dS V (diC - + {dl

Therefore, the movement speed of the pen is

s.,. oCf-v (orn - {dTtj ()

On the other hand

dS ds

diu

(2) oC d

de q 1 g f

f is the frequency of the alternating force,

set by generator. A speed meter 8 of the components of the vibratory displacement measures the speeds of% and - and determines the magnitude of dt. OLt

well (1); its output is proportional to the magnitude

to a control unit 9 that controls the rate of change of the logarithm

da

- so that when

d-S generator frequency

increasing f- (due to increasing d .t

d

cLs

decreases as

neither

speed

dc

, j (due to the mind

H

nsheny -) speed - increasing CXCJ .at

is. As a result of this adjustment, according to relation (2), .cis was generated.

automatically maintained

rank dt constant.

Thus, the write speed ds

AFC

appears in the whole range

frequency band is the same, and the rate of change of the logarithm of the frequency of general d4

varies depending

Torah

dt

from the proximity of the elastic system to the resonance, i.e. depending on the size

ranks

U

It follows from the above that the proposed device allows to increase the accuracy and performance of measurements.

Claims (2)

Invention Formula A device for determining the dynamic characteristics of mechanical systems, such as metal-cutting machines, containing a series-connected sound frequency generator, a power amplifier, a vibrator and a force meter, the corresponding output of the vibrator being connected to the first through a vibration meter and the meter measuring output to the second input of the meter The outputs of which are connected to the corresponding inputs. the recording unit, which is so that, in order to improve the accuracy of the device, it contains a series-connected measuring instrument of the rate of change of the components of the vibration and the control unit, the output of which is connected to the control input of the audio frequency generator, And the inputs of the speed meter of variation of the components of the vibration displacement are connected to the corresponding (quim outputs of the measuring instrument of the components of the vibration displacement. Sources of information taken into account in the examination 1 1. Catalog of the Firm Carl Schenk AG, WG, 1976. 2. Analyzer system mod. MS-6965, IHV Zab Co., LTD. Yaponi, FirAoy Avenue (prototype).