CN113945264B - Method for estimating noise of automobile actuator - Google Patents
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- CN113945264B CN113945264B CN202111198630.0A CN202111198630A CN113945264B CN 113945264 B CN113945264 B CN 113945264B CN 202111198630 A CN202111198630 A CN 202111198630A CN 113945264 B CN113945264 B CN 113945264B
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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
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Abstract
The invention discloses a method for estimating 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 the automotive actuator product is estimated. The invention can conveniently, quickly and accurately estimate the noise of the automobile actuator 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 noise of an automobile actuator.
Background
The automobile actuator mainly refers to a gear train transmission device based on motor control, which drives a transmission gear train to reduce speed through a micro motor to drive an output gear train to rotate, and then outputs a certain rotating speed and moment 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 force management or thermal management of an automobile, and can be arranged on an assembly such as an air inlet grille (comprising an internal grille and an external grille), a spoiler or a cooling water valve of the automobile.
Because the motor and the gear train transmission structure have defects and errors in the manufacturing and assembling processes, the vibration of the actuator product is different when the power-on belt is in load work, and the vibration is finally directly expressed as different working noise of different automobile actuators. Strictly speaking, the operating noise level of the vehicle actuator is controlled to be as small as possible. With the development of the automobile industry, especially the appearance and development of electric automobiles, the suppression of the working noise of automobile actuator products is increasingly important. The 100% detection of noise in automotive actuator products has been used as a necessary condition in process quality management and control of different actuator products.
The detection and control of the noise of the automobile actuator product are based on a severe acoustic measuring environment (such as a sound attenuation chamber or a semi-sound attenuation chamber), and the high-precision microphone and the data acquisition and analysis equipment, so that the measuring cost is high, and the quick measurement cannot be realized. Most of the current automobile actuator products are based on subjective hearing of human ears of production line workers to judge the noise level of the products, the noise level is influenced by artificial subjective factors, and the actual noise level of the actuator products cannot be accurately judged.
Disclosure of Invention
The technical problem to be solved by the invention is to provide a method capable of conveniently, rapidly and accurately estimating the noise of an automobile actuator.
The embodiment of the invention provides an estimation method of 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 actuator of a motor vehicle
Measuring vibration of M automobile actuator samples during operation by using a laser vibration meter respectively to obtain vibration signals of the automobile actuator samples, calculating root mean square values of the vibration signals, measuring noise values of the M automobile actuator samples in a full-silencing chamber or a half-silencing chamber respectively, performing linear fitting on the root mean square values and the noise values of the vibration signals of the M automobile actuator samples, and determining a functional relation between the root mean square values and the noise values of the vibration signals of the automobile actuators, wherein M is more than or equal to 8;
b. estimating noise of an automotive actuator product
The vibration of the automobile actuator product during working is measured by a laser vibration meter, a vibration signal of the automobile actuator product during working is obtained, the root mean square value of the vibration signal of the automobile actuator product is calculated, and the noise value n of the automobile actuator product is calculated 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 existing method, the method for estimating the noise of the automobile actuator product only needs to measure the noise of the automobile actuator sample in a standard acoustic laboratory when the vibration-noise prediction model is built, only needs to measure the vibration of the automobile actuator product by using a laser vibration meter when the automobile actuator product is measured, and can estimate the noise of the automobile actuator product according to a predetermined functional relation between the root mean square value of the vibration signal of the automobile actuator and the noise value, so that the defect that the existing noise measurement method can not be realized under the standard acoustic measurement environment is avoided, the noise detection efficiency of the automobile actuator product is improved, the synchronization with a production line can be realized, and the noise of the automobile actuator product can be monitored and estimated by 100%;
2. According to the embodiment of the invention, the noise of the automobile actuator is monitored and estimated by measuring the vibration of the automobile actuator, the noise of the produced automobile actuator is quantized, the size of the product noise can be estimated rapidly, even the change trend of the product noise can be predicted, and further, unqualified products are identified, so that errors and low efficiency caused by subjective hearing of human ears and environmental noise are avoided, the accuracy and convenience of product noise detection are improved, and the product quality is ensured.
Drawings
Fig. 1 shows a flowchart of a method of estimating noise of an automotive actuator according to an embodiment of the present invention.
FIG. 2 illustrates vibration signals measured for a single piece automotive actuator sample according to one embodiment of the present invention.
FIG. 3 illustrates root mean square values of vibration signals versus time for a single piece automotive actuator sample according to one embodiment of the present invention.
Fig. 4 shows root mean square values of vibration signals versus time for 20 automobile actuator samples according to an embodiment of the present invention.
Fig. 5 shows a scatter plot of root mean square values and noise values of vibration signals of 20 automobile actuator samples according to an embodiment of the present invention.
Fig. 6 shows a schematic diagram of a fitted straight line of root mean square values and noise values of vibration signals of 20 automobile actuator samples according to an embodiment of the present invention.
Fig. 7 shows the error band of the fitted straight line shown in fig. 6.
Fig. 8 shows a schematic view of a vibration measuring mechanism of an automotive actuator according to an embodiment of the present invention.
Detailed Description
According to the embodiment of the invention, the method for estimating the noise of the automobile actuator 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 actuator of a motor vehicle
Measuring vibration of M automobile actuator samples during operation by using a laser vibration meter respectively to obtain vibration signals of the automobile actuator samples, calculating root mean square values of the vibration signals, measuring noise values of the M automobile actuator samples in a full-silencing chamber or a half-silencing chamber respectively, performing linear fitting on the root mean square values and the noise values of the vibration signals of the M automobile actuator samples, and determining a functional relation between the root mean square values and the noise values of the vibration signals of the automobile actuators, wherein M is more than or equal to 8;
b. estimating noise of an automotive actuator product
The vibration of the automobile actuator product during working is measured by a laser vibration meter, a vibration signal of the automobile actuator product during working is obtained, a root mean square value (RMS) of the vibration signal of the automobile actuator product is calculated, and a noise value n of the automobile actuator product is calculated according to a functional relation between the root mean square value and the noise value of the vibration signal of the automobile actuator.
The automobile actuator sample should be a product that is defect free in the manufacturing process and acceptable in 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 automobile actuator sample and each automobile actuator product during operation, the automobile actuator sample and the automobile actuator product are constrained, and only one degree of freedom consistent with the measurement direction of the laser vibration meter is reserved, so as to obtain the vibration signal Vi within the predetermined time period T. Preferably, the predetermined time period T is equal to or longer than (2t1+2t2), T1 is a positive travel time of the vehicle actuator, that is, a time taken for the output shaft of the vehicle actuator to rotate from the intermediate position to the positive limit position, and T2 is a negative travel time of the vehicle actuator, that is, a time taken for the output shaft of the vehicle actuator to rotate from the intermediate position to the negative limit position, so that accuracy of the vibration measurement result can be improved.
Further, after the noise value n of the automobile actuator product is obtained through calculation, the noise level of the automobile actuator product is estimated to be between [ n-e1, n+e2], and e1 and e2 are respectively a preset lower error limit and an upper error limit.
The working principle and working procedure of the method for estimating the noise of the automobile actuator according to the embodiment of the invention will be described in more detail with reference to a specific implementation.
Please refer to fig. 1. In this particular embodiment, the method workflow for estimating the noise of the vehicle actuator is as follows.
S1: randomly selecting 20 automobile executor products manufactured under the condition of consistent production conditions as automobile executor samples;
s2, respectively measuring vibration of a sample piece of the automobile actuator during power-on operation by using a Doppler laser vibration meter, obtaining a vibration signal Vi within a time period T=10s, and then calculating a root mean square value RMS (Vi) of the vibration signal within the obtained time period T, wherein the calculation formula is as follows:
Wherein Vi is the vibration signal measured by the Doppler laser vibration meter. T is the measurement period (i.e., the duration described above), and N is the total sampling point (i.e., the measurement point) during the measurement period T.
Preferably, in this embodiment, a trapezoidal integration algorithm is used to replace the discrete accumulation squaring sum in the above formula, so as to reduce errors and improve model accuracy. Fig. 2 shows the vibration signal of one of the vehicle actuator samples. Fig. 3 shows root mean square values of vibration signals of one of the automobile actuator samples versus time according to an embodiment of the present invention. Fig. 4 shows root mean square values of vibration signals versus time for 20 automobile actuator samples according to an embodiment of the present invention. Table 1 shows RMS values for a vibration signal of 20 automobile actuator samples with a duration of t=10s.
| 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 vibration meter is used for measuring the vibration of the automobile actuator sample, the automobile actuator sample is placed in a three-dimensional Cartesian coordinate system, and under the consistent measurement environment and conditions, two 5 degrees of freedom perpendicular to the vibration measuring direction are fixed, and only one degree of freedom consistent with the laser vibration meter measuring direction is reserved for measuring the vibration.
S3, measuring sound pressure (db (A)) of noises of 20 automobile actuator samples in a full-silencing chamber or a half-silencing chamber respectively, wherein the consistency of front and rear measuring environments and measuring conditions is ensured; table 2 shows the noise measurement results when the measurement period of 20 automobile actuator samples was t=10s.
| 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 pressure db (a) of noise for 20 automobile actuator samples is shown in fig. 5. The root mean square value and the noise value of the vibration signals of 20 automobile actuator samples are linearly fitted through a least square method, and the functional relation between the root mean square value RMS and the noise value n of the vibration signals of the automobile actuator is obtained as follows:
Noise value n (db (a))=31.36+48.93 rms (vibration signal)
The linear fitting results are shown in fig. 6.
S5: measuring vibration of a newly produced automobile actuator product during power-on operation by using a Doppler laser vibration meter, obtaining a vibration signal within a time period T, calculating a root mean square value (RMS), and substituting the vibration signal into the functional relation to estimate the noise level, for example, substituting the vibration signal into the functional relation when the RMS of the vibration signal is equal to 0.018:
an estimated value n=31.36+48.93×0.018=32.24 db (a) of the noise level (db (a)).
S6, for a given noise control index, comparing the estimated noise value with a given noise control threshold value, and rapidly judging whether the noise of the automobile actuator product meets the quality control index.
Considering the influence of the error in model fitting on modeling, this embodiment introduces an error band into the fitted straight line, and as shown in fig. 7, parallel dashed lines on the upper and lower sides of the fitted straight line respectively pass through the points with the maximum variance from the numerical direction of the fitted straight line, and in this embodiment, the upper error limit is 0.2 and the lower error limit is 0.18, so when the RMS of the vibration signal is equal to 0.018, the estimated value n of the noise magnitude (db (a)) is between [32.06, 32.44 ].
In the present embodiment, the measurement of the vibration signals of the automobile actuator sample and the automobile actuator product is realized based on the vibration measuring mechanism shown in fig. 8.
Please refer to fig. 8. The laser vibration meter 1 is arranged on the portal frame 5 and is positioned right above the positioning tool. The measurement direction of the laser vibration meter 1 is the vertical direction. The laser vibration meter 1 is used for measuring vibration of an automobile actuator sample 9 or an automobile actuator product and obtaining a vibration signal of the automobile actuator sample 9 or the automobile actuator product.
The positioning tool is used for restraining and positioning the automobile actuator sample 9 or the automobile actuator product, and only one degree of freedom consistent with the measurement direction of the laser vibration meter is reserved. In this embodiment, the positioning fixture includes a positioning seat 2, where the positioning seat 2 has a positioning cavity 20 that is opened upward, and the shape of the positioning cavity is adapted to the shape of the automobile actuator (the shape of the automobile actuator sample is the same as the shape of the automobile actuator product). The side of the positioning seat 2 is provided with an opening 21, the opening 21 being used for exposing an electrical interface of a car actuator sample or car actuator product placed in the positioning cavity 20.
By adopting the method for estimating the noise of the automobile actuator, disclosed by the embodiment of the invention, the noise of the automobile actuator product can be estimated 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 the noise detection result of the product can be ensured.
It will be apparent to those skilled in the art that various modifications and variations can be made to the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention also include such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.
Claims (5)
1. A method for estimating noise of an automotive actuator, comprising the steps of:
a. determining a functional relation between a root mean square value and a noise value of a vibration signal of an actuator of a motor vehicle
Measuring vibration of M automobile actuator samples during operation by using a laser vibration meter respectively to obtain vibration signals of the automobile actuator samples, calculating root mean square values of the vibration signals, measuring noise values of the M automobile actuator samples in a full-silencing chamber or a half-silencing chamber respectively, performing linear fitting on the root mean square values and the noise values of the vibration signals of the M automobile actuator samples, and determining a functional relation between the root mean square values and the noise values of the vibration signals of the automobile actuators, wherein M is more than or equal to 8;
b. estimating noise of an automotive actuator product
The vibration of the automobile actuator product during working is measured by a laser vibration meter, a vibration signal of the automobile actuator product during working is obtained, the root mean square value of the vibration signal of the automobile actuator product is calculated, and the noise value n of the automobile actuator product is calculated 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 estimating noise of an automotive actuator according to claim 1, wherein the noise level of the automotive actuator product is estimated to be between [ n-e1, n+e2], e1 and e2 being a preset lower error limit and upper error limit, respectively.
3. The method for estimating noise of an automobile actuator according to claim 1, wherein when vibration of each automobile actuator sample and each automobile actuator product during operation is measured by a laser vibration meter, the automobile actuator sample and the automobile actuator product are restrained, only one degree of freedom in accordance with the measurement direction of the laser vibration meter is reserved, and a vibration signal Vi within a predetermined period of time T is obtained.
4. A method for estimating noise of an automotive actuator according to claim 3, wherein the predetermined time period T is equal to or longer than (2t1+2t2), T1 is a positive travel time of the automotive actuator, i.e., a time taken for an output shaft of the automotive actuator to rotate from a neutral position to a positive limit position, and T2 is a negative travel time of the automotive actuator, i.e., a 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 automotive actuator according to claim 1, wherein the root mean square value of the vibration signals of the M automotive actuator samples and the noise value are fitted by a least square method.
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