JP2001165647A - Road surface noise evaluation device - Google Patents

Abstract

(57) [Summary] [Problem] To accurately evaluate a traveling road surface noise based on a road surface shape. SOLUTION: In step 40, based on the road surface amplitude data stored in the data storage unit, a noise amplitude count process for counting how many times the road surface unevenness has a high correlation with the running road surface noise is performed. The noise level is evaluated based on the count number in the processing. In step 44,
The road surface temperature data stored in the data storage unit is fetched, and in step 46, the evaluated noise level is corrected based on the road surface temperature data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a road surface noise evaluation device, and more particularly, to a road surface noise evaluation device for evaluating a noise level when a vehicle is traveling based on a road surface shape.

[0002]

2. Description of the Related Art Conventionally, unevenness of a road surface (particularly, a convex portion) is a source of vibration of tire vibration noise. Therefore, the roughness of the road surface and the noise level during running on the road surface (hereinafter referred to as "road surface running noise level") are reduced. Are known to have a correlation. Therefore, a certain amount of sand having a uniform particle size is spread on the target road surface, and the area covered with sand when the sand no longer spreads (Textur)
e Depth, hereinafter referred to as “TD value”), the road surface roughness is estimated by estimating the road surface roughness, and the road surface roughness is measured by the sand patch method to evaluate the road surface noise. (See FIG. 9).

[0003]

However, the cause of the road running noise is the road surface unevenness whose amplitude (displacement of the road surface unevenness) is within a specific range, and the road surface unevenness having a certain amplitude or less is considered as the road surface running noise. Irrelevant, it has been found that road surface irregularities having a certain amplitude or more have a small relationship with road surface running noise.
In the above-mentioned sand patch method, the average roughness of the road surface is measured, and the road surface running noise is evaluated based on the average roughness. Even if it is, the TD value is changed to affect the evaluation of road surface running noise. That is, the correlation between the TD value and the road surface running noise is low, and the road surface running noise cannot be accurately evaluated. For example, if there is a large unevenness on a part of the road surface, the TD value greatly changes and greatly affects the noise evaluation. However, in reality, the large road unevenness (having an amplitude outside the specific range) affects the noise. Does not give
There was a disadvantage that the reliability of the evaluation based on the TD value was reduced.

The present invention has been made to solve the above problems, and has as its object to provide an apparatus for accurately evaluating road running noise based on a road surface shape.

[0005]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a road surface shape measuring means for measuring a road surface shape, and a correlation between a road surface running noise and a road surface noise measured by the road surface shape measuring device. Extraction means for extracting a convex portion of a high road surface, and evaluation means for evaluating a road surface running noise level based on the number of road surface convex portions extracted by the extracting means,
It comprises.

According to the present invention, since the road surface running noise level is evaluated based on the number of convexities of the road surface having a high correlation with the road surface running noise, it is possible to accurately evaluate the road surface running noise without being affected by the road surface unevenness unrelated to the road surface running noise. Road surface noise level can be evaluated.

According to a second aspect of the present invention, the difference between each of two low points for determining a convex portion in the traveling direction of the road surface and the highest point of the convex portion is determined by the extracting means. Convex portions within the range can also be extracted.

Further, according to the present invention, a road surface temperature measuring means for measuring a road surface temperature, and the road surface running noise level evaluated by the evaluating means is corrected by the road surface temperature measured by the road surface temperature measuring means. And a correction unit that performs the correction. Although the road surface running noise level changes depending on the road surface temperature, according to the present invention, the evaluated road surface running noise level is corrected based on the road surface temperature, so that a more accurate evaluation of the road surface running noise level can be performed. .

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, a road surface noise evaluation apparatus 10 according to the present embodiment includes a road surface shape measuring device 12, a data storage unit 14, a data processing unit 18, and a road surface temperature measuring device 16. The road surface shape measuring device 12 is connected to the data storage unit 14 via the A / D converter 22, and the road surface temperature measuring device 18 is also connected to the data storage unit 14. The data processing unit 18 is connected to the data storage unit 14 and the display unit 20.

In the road surface shape measuring device 12, as shown in FIG. 2, a vertical axis (hereinafter referred to as "Z
The laser displacement meter 32 is attached to an "axis", and the displacement of the road surface unevenness is measured while scanning the laser displacement meter 32 in the vehicle traveling direction (hereinafter, referred to as "X direction") on the road surface. When one scan is completed, the laser displacement gauge 32 is moved in a direction transverse to the road surface (hereinafter referred to as “Y direction”), and measurement is performed while scanning in the X direction again. At this time, scanning in the X direction is 0.5 m
The distance is 600 mm at m pitches, and the movement in the Y direction is 5 m
The width is 400 mm with m pitches. Therefore, in the laser displacement meter 32, a range of 600 × 400 mm is the measurement area 34, and scanning of 80 lines is performed. In addition,
The measurement range and the measurement pitch are not limited to these numerical values and can be freely set.

On the other hand, the road surface temperature measuring device 16 measures the road surface temperature in the measurement area 34 described above. The amplitude data indicating the measured displacement of the road surface unevenness (hereinafter referred to as “road surface amplitude data”) and the data of the road surface temperature (hereinafter referred to as “road surface temperature data”) are transmitted and stored in the data storage unit 14.

Next, the details of the road surface noise evaluation processing in the data processing section 18 will be described.

The data processing unit 18 extracts only specific amplitude data (hereinafter referred to as "noise amplitude data") having a high correlation with the road running noise, and evaluates the road running noise level based on the extracted frequency. When the data processing unit 18 receives the amplitude data on the road surface unevenness from the data storage unit 14, the road surface noise evaluation process shown in FIG. 4 starts.

In step 40, based on the road amplitude data stored in the data storage unit 14, a noise amplitude counting process for counting the number of times of road surface unevenness having a high correlation with the road surface running noise is performed. The detailed procedure of the noise amplitude counting process will be described with reference to FIGS.

FIG. 3 shows an uneven state of the road surface measured by the road surface shape measuring device 12. The data axis is displayed on the horizontal axis, the amplitude of the road surface is displayed on the vertical axis, and the amplitude at each point is sequentially plotted along the traveling direction of the road surface. FIG. 5 is a flowchart of a noise amplitude counting process in which the data processing unit 18 counts the number of times of road surface unevenness having a high correlation with the road surface running noise based on the data stored in the data storage unit 14.

First, in step 50, the data number n, the reference maximum value data Dmax, the reference minimum value data Dmin, the amplitude count number C, FLAGα to be set after the amplitude count, and FLAGβ to be set after the amplitude count is cancelled. All are initialized (= 0). Step 5
In step 2, the next data is fetched. In step 54, it is determined whether or not the fetched data is n> N, that is, whether or not all the received data from the data storage unit 14 has been processed. If all data has been processed, the noise amplitude count processing ends.

If there is data to be processed, at step 56, the fetched data Dn is set to the maximum value data Dm.
It is determined whether it is larger than ax. Here, the maximum value Dmax as a reference value is a value that is updated as needed in the later-described steps, and at the time of the first data capture, the captured data Dn = Dmax. Data Dn is Dma
If it is larger than x, then in step 58 the data Dn
It is determined whether or not the difference between the minimum value data Dmin and the minimum value data Dmin is equal to or greater than a minimum value SL of an amplitude (hereinafter referred to as “noise amplitude”) having a high correlation with the road surface running noise. That is, the data Dn is Dmax
When the road surface is larger than the road surface, the road surface is an upward slope, but whether the height difference between the road surface position indicated by the data Dn and the road surface position indicated by the minimum value data Dmin is equal to or greater than the height difference having a high correlation with the road surface running noise. Judge. Note that the minimum value data Dmin as the reference value is a value that is updated as needed in a later-described step, like the maximum value Dmax, and at the time of the first data capture, the captured data Dn = Dmin.

For example, the data of the point shown in FIG.
When the above process is performed, the maximum value Dmax / minimum value D
min is the data value D1 captured at both start points. Therefore, D2 is larger than D1 (= Dmax) (step 56), and D2−D1 ≧ SL
(Step 58).

If the difference between the data Dn and the minimum value data Dmin is not equal to or larger than the SL value, the height difference is an amplitude difference smaller than the noise amplitude and has no correlation with the road running noise. In step 60, the maximum value Dmax is updated to Dn, and step 5
Returning to step 2, the next data is fetched, and the processing from step 54 on is repeated. For example, comparing the height difference between the data D3 at the point in FIG. 3 and the data D2 (Dmin) at the point and the SL value, D3−D2 ≦ SL (step 58). And Dmax = D
3 (step 60), and fetch the next data D4.

When the difference between the data Dn and Dmin is equal to or larger than the SL value, Dn can be counted.
Even if the difference between the data Dn and Dmin is equal to or larger than the SL value, there are cases where counting should not be performed. For example, at the point shown in FIG. 3, D6−D5 ≧ SL, but since the road surface at the point continues uphill from the point and does not form unevenness of the road surface, data D6 is counted as noise amplitude data. Should not be. Therefore, in step 62, a count determination process is performed to determine whether Dn should be counted.

As shown in FIG.
In step 80, whether FLAGα to be set after being counted as noise amplitude data is set,
That is, it is determined whether or not the noise amplitude data has already been counted immediately before and whether or not a reset process described later has been performed after the noise amplitude data has been counted. FLAGα
If = 0, the noise amplitude data has not yet been counted or the reset processing has been performed after the noise amplitude data has been counted. Since the data being processed is to be counted, the difference between the data Dn and Dmin is calculated in step 82. It is determined whether or not it is smaller than “2SL” as the maximum value of the noise amplitude having a high correlation with the road running noise, that is, whether or not the difference between the data Dn and Dmin belongs to the noise amplitude range. If the difference between the data Dn and Dmin is smaller than the 2SL value, in step 84, 1 is added to the noise amplitude count number C to make C = C + 1, and FLα as a noise amplitude count flag is set. Set to 1. For example,
In the case of the data D2 at the point in FIG. 4, the noise amplitude has not yet been counted and FLα = 0 (step 8).
0), D2−D1 ≧ 2SL (step 82), the noise amplitude may be counted, so that C = 1 and FLα
= 1 is set (step 84).

In step 80, if FLα = 1, the noise amplitude has been counted and the reset processing has not been performed. Therefore, even if the difference from Dmin exceeds the minimum SL value of the noise amplitude, it is not counted. . That is, it is considered that the road surface between the data Dn-2 to Dn-1 to Dn forms an uphill slope, and does not form an unevenness which is a target of noise. limit,
The count as the noise amplitude is not performed. Conversely, data Dn is obtained by calculating the difference SL value between Dn−2 and Dn−1 and Dn−
Maximum 2SL of noise amplitude by integrating the difference SL value of 1 to Dn
Since the value exceeds the value, it is necessary to cancel the count performed when processing the data Dn-1. So, FL
If α = 1, it is determined in step 86 whether or not FLβ has been set as the canceled FLAG in order to determine whether or not the previous count cancellation processing has been performed. Canceled FL
If FLβ as AG is not set (FLβ =
0), since it is necessary to cancel the previous count, at step 88, C = C-1 and F
Set Lβ = 1. If FLβ has been set as the canceled FLAG, the process proceeds to step 64 without going through step 88 since the previous count has already been canceled. For example, data D6 at the point in FIG.
When processing, the road surface of the point from the point of 2S
Since the amplitude exceeds the L value, the count as the noise amplitude is not performed, and the count performed in the process of D5 is cancelled.

After the end of the count determination processing, step 64
And the maximum value data Dmax and the minimum value data Dmin
Is updated to Dn, the process returns to step 52, the next data is read, and the processing from step 54 is repeated.

In step 56, if Dmax> Dn, since the preceding data Dn-1 to data Dn have a downward slope, they are not counted and are subjected to reset processing in the following procedure.

First, at step 66, it is determined whether or not the difference between the maximum value Dmax and the data Dn is equal to or greater than the reset value RL. Here, the reset value RL means that when the height difference becomes equal to or more than a certain value on a downwardly inclined road surface, the road surface convex portion is set to one.
Assuming that the maximum value data Dmax
And the minimum value data Dmin is replaced with Dn, and FLA
This is a threshold value for initializing (= 0) Gα and FLAGβ, and is determined based on the aforementioned SL value and the like.

If the difference between the maximum value Dmax and the data Dn is equal to or greater than the reset value RL, that is, if Dmax-Dn ≧ RL, in step 68, the maximum value data Dmax and the minimum value data Dmin are replaced with Dn, and FLAGα and A reset process is performed to initialize (= 0) FLAGβ. If Dmax−Dn ≦ RL, the reset process is not performed, and it is determined in step 70 whether Dmin> Dn. If Dmin> Dn, at step 72, Dm
in is updated to Dn, the process returns to step 52, and Dmin <
If it is Dn, the process returns to step 52 without updating Dmin, fetches the next data and repeats the processing from step 54 onward. If the above processing is performed for all the amplitude data, the noise amplitude count processing 40 ends. .

Next, at step 42, the noise level is evaluated based on the count number in the above-described noise amplitude count processing. As shown in FIG. 6, there is a correlation between the number of noise amplitudes and the noise level, and as a result of the experiment, it is understood that the noise level is almost proportional to the number of noise amplitudes. Therefore, the noise level is evaluated based on the numerical value obtained by the experiment and the above-described noise amplitude count.

At step 44, the road surface temperature data stored in the data storage unit 14 is fetched.
The estimated noise level is corrected based on the road surface temperature data. Generally, it is known that the noise level changes depending on the road surface temperature. As a result of the experiment, as shown in FIG.
It can be seen that the noise level of the frequency of 800 Hz decreases as the temperature increases. Therefore, the estimated noise level is corrected based on the numerical value obtained by the experiment.

In step 48, the noise level data obtained by the correction is output to the display unit, and the road surface noise evaluation processing in the data processing unit 18 ends. The display unit 20 displays the content of the received noise level data.

According to the present embodiment, only the noise amplitude having a correlation with the road surface running noise is extracted based on the road surface shape, and the road surface running noise level is evaluated based on the number of extractions. The noise level can be evaluated.
Further, since the above-mentioned evaluated road surface running noise level is corrected based on the road surface temperature data, the road surface running noise can be more accurately evaluated.

[0032]

As described above, according to the present invention, only the convex portions of the road surface having a high correlation with the road surface running noise are extracted based on the road surface shape, and the road surface running noise level is determined based on the extracted number. Since the evaluation is performed, it is possible to provide a road surface noise evaluation device capable of accurately evaluating the noise level.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a road surface noise evaluation device according to the present invention.

FIG. 2 is a diagram showing a schematic configuration and a measurement area of a road surface shape measuring instrument in the present embodiment.

FIG. 3 is a diagram showing an uneven state of a road surface.

FIG. 4 is a flowchart of a road surface noise evaluation process according to the embodiment.

FIG. 5 is a flowchart of a noise amplitude count process in the present embodiment.

FIG. 6 is a flowchart of a count determination process in the present embodiment.

FIG. 7 is a diagram illustrating an example of the relationship between the number of times of noise amplitude and road surface running noise.

FIG. 8 is a diagram showing a relationship between road surface temperature and road surface running noise.

FIG. 9 is an explanatory diagram of a road surface shape measurement by a sand patch method.

[Explanation of symbols]

 12 Road surface shape measuring device (road surface shape measuring means) 14 Data storage unit 16 Road surface temperature measuring device (road surface temperature measuring unit) 18 Data processing unit 40 Noise amplitude count processing

Continuing from the front page (72) Inventor Hiroshi Ito 41 Toyota-Chuo R & D Co., Ltd., 41-Cho, Yojimichi, Nagakute-cho, Aichi-gun, Aichi Prefecture (72) Inventor Haruhiko Nishimura 1-Toyota-cho, Toyota-shi, Toyota-shi Toyota Motor In-house F-term (Reference) 2F065 AA45 AA49 CC40 DD04 FF40 GG04 HH04 HH13 JJ03 MM06 MM16 MM26 QQ21 QQ28 UU05 UU06 2F069 AA51 AA60 BB24 DD08 DD19 GG04 GG06 GG07 GG15 GG35 GG39 GG58 GG39 GG58

Claims (3)

[Claims] 1. A road surface shape measuring unit for measuring a road surface shape, an extracting unit for extracting a convex portion of a road surface having a high correlation with road surface running noise from a road surface shape measured by the road surface shape measuring unit, An evaluation means for evaluating a road surface running noise level based on the extracted number of road surface protrusions; 2. The extracting means extracts a convex portion in which a difference between each of two low points for determining the convex portion in the traveling direction of the road surface and the highest point of the convex portion is within a predetermined range. The road surface noise evaluation device according to claim 1, wherein: 3. A road surface temperature measuring unit for measuring a road surface temperature, and a correcting unit for correcting the road running noise level evaluated by the evaluating unit on the basis of the road surface temperature measured by the road surface temperature measuring unit. The road surface noise evaluation device according to claim 1 or 2, wherein: