CN113945264A - Method for estimating noise of automobile actuator - Google Patents
Method for estimating noise of automobile actuator Download PDFInfo
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- CN113945264A CN113945264A CN202111198630.0A CN202111198630A CN113945264A CN 113945264 A CN113945264 A CN 113945264A CN 202111198630 A CN202111198630 A CN 202111198630A CN 113945264 A CN113945264 A CN 113945264A
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- actuator
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- automobile actuator
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01H—MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES
- G01H9/00—Measuring mechanical vibrations or ultrasonic, sonic or infrasonic waves by using radiation-sensitive means, e.g. optical means
Abstract
The invention discloses a method for estimating the noise of an automobile actuator, which comprises the following steps: a. determining a functional relation between a root mean square value and a noise value of a vibration signal of an automobile actuator; b. noise of an automotive actuator product is estimated. According to the invention, the noise of the automobile actuator can be conveniently, quickly and accurately estimated only by measuring the vibration of the automobile actuator product without measuring the noise of the automobile actuator product in a standard acoustic laboratory.
Description
Technical Field
The invention relates to a detection technology of automobile actuator noise.
Background
The automobile actuator mainly refers to a gear train transmission device based on motor control, and the transmission gear train is driven to decelerate through a micro motor to drive an output gear train to rotate, so that a certain rotating speed and torque are output to adjust the rotation of an air conditioner air door or the opening and closing of a cooling water valve. The automobile actuator is mainly applied to aerodynamic management or thermal management of an automobile, and can be installed on assemblies such as an air inlet grille (including an internal grille and an external grille), a spoiler or a cooling water valve of the automobile.
Because the transmission structure of the motor and the gear train has defects and errors in the manufacturing and assembling processes, the vibration of the actuator product is different when the actuator product works with electric loads, and finally, the working noise of different automobile actuators is directly different. Strictly speaking, the operating noise level of an automotive actuator is controlled to be as small as possible. With the development of the automobile industry, especially the appearance and development of electric automobiles, increasingly important attention is paid to the suppression of the working noise of automobile actuator products. The detection of 100% of the noise of automobile actuator products is already used as a necessary condition in the process quality management and control of different actuator products.
The noise of the automobile actuator product is detected and controlled in a harsh acoustic measurement environment (such as a anechoic chamber or a semi-anechoic chamber), a high-precision microphone and data acquisition and analysis equipment, the measurement cost is high, and quick measurement cannot be achieved. At present, most automobile actuator products judge the noise of the products based on the subjective auditory sense of human ears of production line workers, and the noise level of the actuator products cannot be accurately judged due to the influence of human subjective factors.
Disclosure of Invention
The invention aims to provide a method for conveniently, quickly and accurately estimating the noise of an automobile actuator.
The embodiment of the invention provides an estimation method of automobile actuator noise, which comprises the following steps:
a. determining a functional relationship between the root mean square value and the noise value of a vibration signal of a vehicle actuator
Respectively measuring the vibration of the M automobile actuator samples during working by using a laser vibration meter to obtain vibration signals of the automobile actuator samples, then calculating the root mean square value of each vibration signal, respectively measuring the noise values of the M automobile actuator samples in a full anechoic chamber or a semi-anechoic chamber, linearly fitting the root mean square value and the noise value of the vibration signals of the M automobile actuator samples, and determining a functional relation between the root mean square value and the noise value of the vibration signals of the automobile actuator, wherein M is more than or equal to 8;
b. estimating noise of automotive actuator products
The method comprises the steps of measuring vibration of an automobile actuator product during working by using a laser vibration meter, obtaining a vibration signal of the automobile actuator product during working, calculating the root mean square value of the vibration signal of the automobile actuator product, and calculating the noise value n of the automobile actuator product according to a functional relation between the root mean square value and the noise value of the vibration signal of the automobile actuator.
The invention has at least the following advantages and characteristics:
1. compared with the prior art, the estimation method provided by the embodiment of the invention has the advantages that the noise of the automobile actuator sample is measured in a standard acoustic laboratory only when the vibration-noise prediction model is established, and the vibration of the automobile actuator product is measured only by using the laser vibrometer when the automobile actuator product is measured, so that the noise of the automobile actuator product can be estimated according to the function relation between the root mean square value and the noise value of the vibration signal of the automobile actuator, which is predetermined, thereby avoiding the defect that the conventional noise measurement method can be realized in a standard acoustic measurement environment, improving the noise detection efficiency of the automobile actuator product, being synchronous with a production line and monitoring and estimating the noise of the automobile actuator product by 100%;
2. the embodiment of the invention monitors and estimates the noise of the automobile actuator by measuring the vibration of the automobile actuator, realizes quantification of the noise of the produced automobile actuator, can quickly estimate the size of the product noise and even predict the change trend of the product noise, further identifies unqualified products, avoids the error and low efficiency caused by subjective auditory sense of human ears and environmental noise, improves the accuracy and convenience of product noise detection, and ensures the product quality.
Drawings
Fig. 1 shows a flow chart of a method for estimating noise of an actuator of a vehicle according to an embodiment of the invention.
FIG. 2 illustrates a vibration signature of a single sample automobile actuator measured in accordance with an embodiment of the present invention.
FIG. 3 illustrates a plot of RMS value of a vibration signal versus time for a single sample automobile actuator in accordance with an embodiment of the invention.
Fig. 4 shows rms versus time for vibration signals of 20 samples of automotive actuators according to an embodiment of the present invention.
Fig. 5 shows a scatter plot of the rms and noise values of the vibration signals of 20 samples of automotive actuators according to an embodiment of the present invention.
Fig. 6 is a schematic diagram showing a fitted straight line of the root mean square value and the noise value of the vibration signal of 20 samples of the automobile actuator according to the embodiment of the present invention.
Fig. 7 shows an error band of the fitted straight line shown in fig. 6.
Fig. 8 shows a schematic view of a vibration measuring mechanism of an automobile actuator according to an embodiment of the invention.
Detailed Description
The method for estimating the noise of the automobile actuator comprises the following steps of:
a. determining a functional relationship between the root mean square value and the noise value of a vibration signal of a vehicle actuator
Respectively measuring the vibration of the M automobile actuator samples during working by using a laser vibration meter to obtain vibration signals of the automobile actuator samples, then calculating the root mean square value of each vibration signal, respectively measuring the noise values of the M automobile actuator samples in a full anechoic chamber or a semi-anechoic chamber, linearly fitting the root mean square value and the noise value of the vibration signals of the M automobile actuator samples, and determining a functional relation between the root mean square value and the noise value of the vibration signals of the automobile actuator, wherein M is more than or equal to 8;
b. estimating noise of automotive actuator products
The method comprises the steps of measuring vibration of an automobile actuator product during working by using a laser vibration meter, obtaining a vibration signal of the automobile actuator product during working, calculating a root mean square value (RMS) of the vibration signal of the automobile actuator product, and calculating a noise value n of the automobile actuator product according to a functional relation between the RMS and the noise value of the vibration signal of the automobile actuator.
The automobile actuator sample piece is a product which is free of defects in the manufacturing process and qualified in the functional test. The automobile actuator product refers to a product obtained by actual production. The noise value is a sound pressure value of the noise.
In this embodiment, when the laser vibration meter is used to measure the vibration of each sample of the automobile actuator and each product of the automobile actuator during operation, the sample of the automobile actuator and the product of the automobile actuator are constrained, only one degree of freedom consistent with the measurement direction of the laser vibration meter is reserved, and a vibration signal Vi within a predetermined time period T is obtained. Preferably, the predetermined time period T ≧ (2T1+2T2), T1 is the positive stroke time of the vehicle actuator, i.e., the time it takes for the output shaft of the vehicle actuator to rotate from the neutral position to the positive limit position, and T2 is the negative stroke time of the vehicle actuator, i.e., the time it takes for the output shaft of the vehicle actuator to rotate from the neutral position to the negative limit position, so that the accuracy of the vibration measurement results can be improved.
Further, after obtaining the noise value n of the automobile actuator product through calculation, estimating the noise level of the automobile actuator product to be between [ n-e1, n + e2], wherein e1 and e2 are respectively a preset lower error limit and an upper error limit.
The operation principle and the operation flow of the method for estimating the noise of the automobile actuator according to the embodiment of the present invention will be described in more detail with reference to a specific embodiment.
Please refer to fig. 1. In this particular embodiment, the method for estimating the noise of the vehicle actuator has the following working flow.
S1: randomly selecting 20 automobile actuator products manufactured under the condition of consistent production conditions as automobile actuator samples;
s2, respectively measuring the vibration of the automobile actuator sample piece during power-on work by using a Doppler laser vibration meter, obtaining a vibration signal Vi within the time length T of 10S, and then calculating the root mean square value RMS (Vi) of the obtained vibration signal within the time length T, wherein the calculation formula is as follows:
wherein Vi is a vibration signal measured by the Doppler laser vibrometer. T is the measurement period (i.e., the duration described above), and N is the total number of sampling points (i.e., measurement points) within the measurement period T.
Preferably, in the present embodiment, a trapezoidal integration algorithm is used to replace the sum of squares obtained by discrete accumulation in the above formula, so as to reduce errors and improve the model accuracy. Fig. 2 shows a vibration signal of one of the samples of the vehicle actuator. Fig. 3 shows a plot of rms value of a vibration signal of one of the samples of the vehicle actuator versus time in accordance with an embodiment of the present invention. Fig. 4 shows rms versus time for vibration signals of 20 samples of automotive actuators according to an embodiment of the present invention. Table 1 shows RMS values of vibration signals of 20 automobile actuator samples at a time period T of 10 s.
| Sample # | RMS(Vi) | Sample # | RMS(Vi) |
| 1 | 0.0130 | 11 | 0.0103 |
| 2 | 0.0130 | 12 | 0.0163 |
| 3 | 0.0136 | 13 | 0.0137 |
| 4 | 0.0143 | 14 | 0.0156 |
| 5 | 0.0138 | 15 | 0.0202 |
| 6 | 0.0163 | 16 | 0.0152 |
| 7 | 0.0215 | 17 | 0.0192 |
| 8 | 0.0197 | 18 | 0.0117 |
| 9 | 0.0211 | 19 | 0.0235 |
| 10 | 0.0202 | 20 | 0.0127 |
TABLE 1
When the Doppler laser vibrometer is used for measuring the vibration of an automobile actuator sample, the automobile actuator sample is placed in a three-dimensional Cartesian coordinate system, two 5 degrees of freedom perpendicular to the vibration measurement direction are fixed under the consistent measurement environment and condition, and only one degree of freedom consistent with the measurement direction of the laser vibrometer is reserved for measuring the vibration.
S3, measuring the sound pressure (db (A)) of the noise of 20 automobile actuator samples in the full anechoic chamber or the semi-anechoic chamber respectively, wherein the front and back measuring environments and the measuring conditions are ensured to be consistent; table 2 shows the results of noise measurement of 20 samples of the automobile actuator at a measurement period T of 10 s.
| Sample # | db(A) | Sample # | db(A) |
| 1 | 31.82 | 11 | 31.91 |
| 2 | 32.05 | 12 | 32.18 |
| 3 | 32.07 | 13 | 31.95 |
| 4 | 32.02 | 14 | 32.05 |
| 5 | 31.94 | 15 | 32.37 |
| 6 | 32.36 | 16 | 32.08 |
| 7 | 32.46 | 17 | 32.32 |
| 8 | 32.33 | 18 | 31.88 |
| 9 | 32.37 | 19 | 32.34 |
| 10 | 32.52 | 20 | 32.15 |
TABLE 2
S4: a scatter plot of RMS values of vibration signals and sound pressures db (A) of noise for 20 samples of automobile actuators is shown in FIG. 5. Fitting the root mean square value and the noise value of the vibration signals of 20 automobile actuator samples through least square normals to obtain a functional relation between the root mean square value RMS and the noise value n of the vibration signals of the automobile actuator, wherein the functional relation is as follows:
noise value n (db (a)) 31.36+48.93 RMS (vibration signal)
The results of the linear fit are shown in FIG. 6.
S5: measuring the vibration of a newly produced automobile actuator product during power-on work by using a Doppler laser vibration meter, obtaining a vibration signal within a time length T, calculating a root mean square value (RMS), and substituting the RMS into the functional relation to estimate the noise magnitude, for example, when the RMS of the vibration signal is equal to 0.018, substituting into the functional relation:
the noise level (db (a)) is estimated at n-31.36 + 48.93-0.018-32.24 db (a).
And S6, comparing the estimated noise value with the given noise control threshold value for the given noise control index, and rapidly judging whether the noise of the automobile actuator product meets the quality control index.
In consideration of the influence of the error in model fitting on modeling, the present embodiment further introduces an error band into the fitted straight line, as shown in fig. 7, parallel dotted lines on the upper and lower sides of the fitted straight line respectively pass through the point with the largest variance in the numerical direction of the fitted straight line, and the upper error limit in the present embodiment is 0.2, and the lower error limit is 0.18, so that when the RMS of the vibration signal is equal to 0.018, the estimated value n of the noise level (db (a)) is between [32.06, 32.44 ].
In the present embodiment, the measurement of the vibration signals of the sample automobile actuator and the product automobile actuator is realized based on the vibration measuring mechanism shown in fig. 8.
Please refer to fig. 8. The laser vibration meter 1 is installed on the portal frame 5 and is positioned right above the positioning tool. The measuring direction of the laser vibrometer 1 is the vertical direction. The laser vibration meter 1 is used for measuring the vibration of the automobile actuator sample piece 9 or the automobile actuator product and obtaining a vibration signal of the automobile actuator sample piece 9 or the automobile actuator product.
The positioning tool is used for restraining and positioning the automobile actuator sample piece 9 or the automobile actuator product, and only one degree of freedom which is consistent with the measuring direction of the laser vibration meter is reserved. In the embodiment, the positioning tool comprises a positioning seat 2, the positioning seat 2 is provided with a positioning cavity 20 which is opened upwards, and the shape of the positioning cavity is matched with the shape of an automobile actuator (the shape of an automobile actuator sample piece is the same as that of an automobile actuator product). The side of the positioning socket 2 is provided with an opening 21, and the opening 21 is used for exposing an electric interface of an automobile actuator sample or an automobile actuator product placed in the positioning cavity 20.
By adopting the method for estimating the noise of the automobile actuator, the noise of the automobile actuator product can be estimated only by measuring the vibration of the automobile actuator product without measuring the noise of the automobile actuator product in a standard acoustic laboratory, so that the noise detection efficiency of the automobile actuator product is improved, and the accuracy of a product noise detection result can be ensured.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (5)
1. A method for estimating noise of an automobile actuator is characterized by comprising the following steps:
a. determining a functional relationship between the root mean square value and the noise value of a vibration signal of a vehicle actuator
Respectively measuring the vibration of the M automobile actuator samples during working by using a laser vibration meter to obtain vibration signals of the automobile actuator samples, then calculating the root mean square value of each vibration signal, respectively measuring the noise values of the M automobile actuator samples in a full anechoic chamber or a semi-anechoic chamber, linearly fitting the root mean square value and the noise value of the vibration signals of the M automobile actuator samples, and determining a functional relation between the root mean square value and the noise value of the vibration signals of the automobile actuator, wherein M is more than or equal to 8;
b. estimating noise of automotive actuator products
The method comprises the steps of measuring vibration of an automobile actuator product during working by using a laser vibration meter, obtaining a vibration signal of the automobile actuator product during working, calculating the root mean square value of the vibration signal of the automobile actuator product, and calculating the noise value n of the automobile actuator product according to a functional relation between the root mean square value and the noise value of the vibration signal of the automobile actuator.
2. The method of claim 1, wherein the noise level of the vehicle actuator product is estimated to be between [ n-e1, n + e2], and e1 and e2 are the lower and upper error limits, respectively.
3. The method for estimating the noise of the automobile actuator according to claim 1, wherein when the vibration of each sample of the automobile actuator and each product of the automobile actuator during operation is measured by a laser vibrometer, the sample of the automobile actuator and the product of the automobile actuator are constrained, and only one degree of freedom which is consistent with the measurement direction of the laser vibrometer is reserved to obtain the vibration signal Vi within the predetermined time period T.
4. The method of estimating noise of an automotive actuator as claimed in claim 3 wherein said predetermined time period T ≧ (2T1+2T2), T1 is the positive travel time of the automotive actuator, i.e., the time taken for the output shaft of the automotive actuator to rotate from the neutral position to the positive limit position, and T2 is the negative travel time of the automotive actuator, i.e., the time taken for the output shaft of the automotive actuator to rotate from the neutral position to the negative limit position.
5. The method for estimating noise of an automobile actuator according to claim 1, wherein a least square method is used to perform straight line fitting on the root mean square value and the noise value of the vibration signals of the M automobile actuator samples.
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