JPS61164132A - Vibration testing method - Google Patents

Abstract

PURPOSE:To shorten a vibration testing time, by using random noises, whose frequency band is limited to those necessary for performing the vibration test, out of the oscillation frequencies of an aimed signal as a vibration signal of a prescribed waveform and finding a transfer function to frequency components in the same frequency band. CONSTITUTION:An aimed signal having the aimed waveform of a vehicle A at the location of a detector 5 is determined by measuring the output signal of the detector 5 by adding a vibration signal of a prescribed waveform to the exciter 1 of a system provided with the vehicle A, to which vibrations are added from the exciter 1, and the detector 5 fitted to an optional position of the vehicle A and finding the transfer function of the system. Then an initial excitation signal is found on the basis of the aimed signal and transfer function and added to the exciter 1. In this case, correction of the excitation signal is repeated until the error to the aimed signal of an actually working signal detected 5 at the time converges in a prescribed range. Since it is sufficient to use random noises, whose frequency band is limited to those necessary for performing the test, out of the oscillation frequencies of the aimed signal of the vehicle A as a vibration signal of a prescribed waveform and find a transfer function to the frequency component in the same frequency band, the calculating time is shortened and, accordingly, the testing time is also shortened.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a vibration test method for testing the durability and strength of a test object by applying vibrations similar to actual vibrations to the test object using a vibrator. .

(Prior art) A vibration exciter or the like is used to apply vibrations to an arbitrary point on a test object, such as a vibration exciter. Find a transfer function of the system including this transfer function and a target signal having a target waveform of vibration at the arbitrary point to find an excitation signal to the vibrator, and transfer this excitation signal to the vibrator. , the error of the output signal obtained from the output of the detector with respect to the target signal is determined, the excitation signal is corrected using this error, and this correction is repeated thereafter to adjust the output signal of the detector to the target signal. A vibration test method is known in which the vibration test is conducted under the same conditions as the actual vibration of the test object, for example, the vibration during actual running of a wheel, by bringing the test object closer. Publication No.).

(Problems to be Solved by the Invention) According to the conventional vibration testing method, since there is a large number of data, a memory with a large storage capacity is required, and the test time is increased due to the long calculation time.

The present invention aims to eliminate these conventional inconveniences.

(Means for solving the problems) The present invention includes (1) creating a vibration signal with a predetermined waveform;
(2) A system equipped with a vibrator, a test object to which vibration is applied to the vibrator, and a detector attached to an arbitrary point on the test object to detect the vibration at that point. [Adding the vibration signal of the predetermined waveform to the vibrator, measuring the output signal of the detector at this time, and determining the transfer function of the family system from the vibration signal and the output signal; (3) determining a target signal having a target waveform of vibration at the arbitrary point of the test object; (4) determining an initial excitation signal to the vibrator based on the target signal and a transfer function; (5) applying the initial excitation signal to the vibrator, determining the error of the actual signal received from the detector at that time with respect to the target signal, and correcting the initial excitation signal using the error; (6) adjusting the error within a predetermined range; A3 is a vibration test method in which modification of the excitation signal is repeated until convergence, and the vibration signal of the predetermined waveform is limited to a frequency band necessary for the test among the vibration frequencies of the target signal of the test object. The method is characterized in that a transfer function is determined for a frequency component within the frequency band using the random noise generated by the frequency band.

(Example) First, an example of a vibration testing apparatus used to carry out the vibration testing method of the present invention shown in FIGS. 1 and 2 will be described.

In the drawing, (1) is a vibration exciter, and this vibration exciter (1) is attached to the axle of vehicle A to vibrate vehicle A in the vertical and longitudinal directions. (3) and hydraulic motors (41), (42), and (4a) which are connected to the vibration source device (3) and to the vibration member (2) to vibrate in the vertical and longitudinal directions. , for example, were attached to the left and right sides of the front axle of vehicle A. (5) is a vibration member (2) attached to an arbitrary position of vehicle A, for example, the axle.
A detector (only one is shown in the drawing) that is installed close to the sensor and detects vibrations in the vertical, horizontal, and longitudinal directions. (6) is the detector (5) and the excitation source device (3).
), and is an electronic control unit comprising, for example, a computer, used to carry out the test method of the present invention, which will be described in detail later.

The vibration source device (3), as shown in FIG. (8
By applying a vibration signal or an excitation signal to 1), hydraulic pressure is applied alternately to both sides of the cylinder of the hydraulic motor (41), (42), and (4a), causing the piston to reciprocate in alternating directions. , there is nothing particularly different from the known ones. In addition, (9) is an agumulator, and (IG is a solenoid valve which connects or shuts off the hydraulic motors (41), (42), and (43) to the hydraulic power source.

Next, a vibration test method of the present invention using the apparatus shown in FIGS. 1 and 2 will be explained.

As is clear from the flowchart of the implementation of the method of the present invention shown in FIG.
), and a detector (
5) and a detector (5) corresponding to the Haku exciter (1). To find the transfer function of the system, create random noise as a vibration signal of a predetermined waveform to be added to the excitation 1m (1). (Step ■).

The procedure for creating this random noise will be explained with reference to the flowchart shown in Figure 4.
Based on the phase component shown in Figure 5 (B), for example, the power component shown in Figure (A) ((i) is uniformly distributed between 1π and π using random numbers generated by software. A spectrum in the frequency domain from frequency O to, for example, - localized wave number fM is created (step @).

The actual vibration of a vehicle under test C contains quite high frequency components, so in order to generate a 1F accurate excitation signal, it is necessary to include high frequency components like this J: Including the component increases the calculation time and storage capacity due to the increase in the number of data, and on the other hand, the high frequency components of about 50 Ifz or more have little relation to the durability and ride comfort of the vehicle, so the high frequency components of about 50 Itz or more are exclude,
The analysis is performed in the frequency range up to the upper limit frequency fM, for example, the 501st order.

Next, in step @, this noise is inversely transformed by a fast Fourier transform processor to convert it into the time domain, which is in the representation format inside the CP11, and in step (2), it is converted into a data format that can be output by a DA converter. Conversion and rearrangement are performed, and in step (2) this data is stored in a random noise file. Returning to the flowchart of FIG. 3 again, go to step (a3) to find a transfer function using this random noise. To do this, first, the random noise extracted from the random noise file was generated using a vibrator (
1), and this vibrator (1) vibrates vehicle A 1! , measure the output signals of the detector (5) corresponding to the vibrator (1) and the detector (5) corresponding to the vibrator (1). Next, calculate the transfer function from this measurement data. The above measurements and calculations are performed for the number of vibration exciters (1).The obtained results are stored in the transfer function file.

Next, in step (2), data is read from this file, an inverse transfer function is determined from this data, and is stored in an inverse transfer function file.

In the subsequent steps, initial vibration data for each vibration exciter (1) is created using the inverse transfer function obtained in step (2). In step (2), a target signal having a target waveform of vibration at an arbitrary point on the test object, that is, actual driving data of vibration at an arbitrary point on the vehicle is collected and processed, that is, an actual driving data recorded from a data recorder is processed. Play the data and /
This data is converted into a digital signal using a 10 converter, and this digital signal is sampled into the middle (1-10 units) arc minute of one Fourier transform using a fast Fourier transform processor and stored in an actual running data file. . Next, in step (2), as shown in FIG. 6, the first block of the actual running data is read from the actual running data file, and O
Step 0) Multiply the ramp value that gradually increases from Each is stored in the actual running data file again. After processing this data, step @) reads one block of actual running data y ([) from the actual running data file, and performs a Fourier transform on this data y (t) as follows: Y(f) - F [y(t) ] , step O)
Inverse transfer function matrix Q-1 read from the inverse transfer function file
The initial excitation signal Xff in the C frequency domain is divided using Calculate the initial excitation signal χ([) in the time domain using χ(
t> = F−I [X(f)], Step Q) Multiply this initial excitation signal χ([) by an initial excitation rate of less than 100%.Step 0) Add this multiplied value as the initial excitation signal. Store in the vibration signal file (step (electronic).

This initial excitation rate has a value adapted to the nonlinear system, and by multiplying this initial excitation rate, the initial excitation signal can be set to a low value and gradually approach the actual value by error correction. This enabled the vibration exciter to operate without any problems and without adversely affecting the vehicle.

This initial excitation signal χ(1) is calculated and stored for the number of blocks.

In step (2), one block of initial excitation signals read from this excitation signal file is added to excitation 111 (1) to vibrate the vehicle, and the actual working signal V output from the detector (5) at that time. E (t) was recorded and then the actual running signal y ([) and the actual operating signal y were read from the actual running data file.
The error Δy (t) with E (t) is set at 4 mm. This time domain error signal Δy(t) is temporarily stored in a file,
Next, read out and perform Fourier transformation ΔY(f)=F[Δy
(t)]) and stored in the file again. The above processing is performed for several times. In step (■), the error signal △Y (f) is read from the file, and this error signal △Y (') is ΔY (f)/Y (f)≦E 9
If the condition (predetermined value) is not satisfied, the process moves to step (8).

In step (8), the error signal ΔY is extracted from the file.
(f) for one block, reads the inverse transfer function matrix Q-1 from the inverse transfer function file, and calculates the excitation signal correction (ΔX (f) −G −1・ΔY(f
)), and performs inverse Fourier transform on this correction (ΔX(t
)=F-1[ΔXff)]), then read the excitation signal before correction from the excitation signal file, and add the correction amount to this excitation signal (X (t) −X (t) + ΔX (
t) ). The modified excitation signal is stored in the excitation signal file again.

The above processing is performed for the number of blocks. Step ■ again using the corrected excitation signal obtained in step ■
Steps (2) and (2) are performed, and steps (2), (2), and (2) are repeated until the convergence condition is satisfied.

When the above-mentioned convergence conditions are met, the series of excitation signal modification operations are completed, and it is possible to give the same vibration to the vehicle as the vibration to the vehicle during actual operation in the excitation file. The excitation signal is stored.

The above series of means are implemented in the electronic control units 1 to (1) shown in the first diagram.
6) using a vibration testing device. When this device is activated, an initial excitation signal is first applied to the vibrator (1), and the vehicle A is vibrated by the vibrator (1) in accordance with the initial excitation signal. By subsequently repeating steps (6), (7), and (8), the vibrations are corrected, and finally the vehicle vibrates in the same state as when it is actually running.

For example, when a modified excitation signal stored in the excitation signal file is repeatedly used to simulate the state in which a vehicle travels on a circuit in one consecutive cycle, the excitation signal is the first block of the excitation signal stored in the excitation signal file. Smell-C has an amplitude that gradually increases from zero to a predetermined value, and has an amplitude that gradually decreases to zero in the final block, so it changes from the last block of the previous excitation signal to the first block of the subsequent excitation signal. The vibration waveform where the vibration waveform shifts to is continuous, and therefore, the vehicle A vibrates smoothly and continuously without being subjected to sudden changes in force that would deteriorate the durability of the vibrator and adversely affect the vehicle.

(Effects of the Invention) The present invention includes (1) creating a vibration signal with a predetermined waveform;
(2) A vibrator in a system that includes a vibrator, a test object to which vibration is applied by the vibrator, and a detector that is attached to an arbitrary point on the test object and detects the vibration at that point. adding the vibration signal of the predetermined waveform, measuring the output signal of the detector at this time, and determining a family-based transfer function from the vibration signal and the output signal; (3) at the arbitrary point of the test object; Determining a target signal having a target waveform of vibration = 12
- (4) determining an initial excitation signal to the shaker based on the target signal and the transfer function; (5) applying the initial excitation signal to the shaker and then obtaining the signal from the detector; (6) repeatedly modifying the excitation signal until the error converges within a predetermined range; In the vibration test method, random noise limited to a frequency band necessary for the test among the vibration frequencies of the target signal of the test object is used as the vibration signal of the predetermined waveform, and a frequency within the frequency band is used. Since it is only necessary to find a transfer function for each component, the storage capacity of the memory required to calculate the excitation signal is small, and the oil cylinder time is also short, which has the effect of shortening the vibration test time.

[Brief explanation of the drawing]

FIG. 1 is a diagram of a vibration test device applied to a vehicle implementing the vibration test method of the present invention, FIG. 2 is a diagram of the main parts thereof,
Fig. 3 is a flowchart of the vibration test method of the present invention, Fig. 4 is a flowchart of step ①, and Figs. 5 (^) and (B) show the power distribution and phase distribution with respect to the frequency of random noise. Figure 6 is a flowchart of step ①. (1)... Vibration machine (2)... Vibration member (3)... Vibration source device (4+1 (42) (43)... Hydraulic motor (5)
...Detector (6)...Electronic control conit (8)...Special electromagnetic switching valve Applicant Honda Motor Co., Ltd. Ne1 Figure 5 Japanese Patent Application Laid-open No. Sho G1-164132 (7) Figure 6 ■ ■ QQ-

Claims (1)

[Claims] 1. (1) Creating a vibration signal with a predetermined waveform (2) A vibrator, a test object to which vibration is applied by the vibrator, and mounting at an arbitrary point on the test object. A vibration signal of the predetermined waveform is applied to the vibration exciter in the system equipped with a detector for detecting vibration at the point, the output signal of the detector at this time is measured, and the vibration signal and the output signal are combined. (3) determining a target signal having a target waveform of vibration at the arbitrary point of the test object; (4) determining a transfer function of the system; (4) determining a target signal having a target waveform of vibration at the arbitrary point of the test object; Determining an initial excitation signal (5) Adding the initial excitation signal to the exciter, determining the error of the actual working signal obtained from the detector with respect to the target signal, and correcting the initial excitation signal with the error. (6) In a vibration test method in which the excitation signal is repeatedly corrected until the error converges within a predetermined range, the vibration signal of the predetermined waveform is selected from among the vibration frequencies of the target signal of the test object. A vibration testing method characterized by using random noise limited to a necessary frequency band and determining a transfer function for frequency components within the frequency band.