JP2017043147A - Tire determination device, tire determination method and tire determination program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology that can automatically determine a correct tire type mounted to a vehicle even if the vehicle is in travelling.SOLUTION: A tire determination device includes: road surface vibration measurement means for simultaneously measuring road surface vibration in multiple direction due to vehicle travelling; and tire determination means for determining a tire type mounted to the vehicle based on the vibration in multiple direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a tire determination device, a tire determination method, and a tire determination program.

  On roads that can travel at high speed, such as automobile-only roads, travel restrictions may be imposed depending on the weather conditions. There are various types of travel regulations, including tire regulations. For example, in order to prevent slipping due to worsening weather or a decrease in temperature, there may be a restriction that does not allow a vehicle with summer tires to travel. For example, a technique disclosed in Patent Document 1 is known as a tire determination device that determines the type of tire used by a traveling vehicle.

JP 2013-249023 A

The types of tires used by vehicles are broadly divided into winter tires and summer tires, but there can be various types of tires such as different tread patterns even for the same type of tires. Therefore, it is preferable that the type of tire of the running vehicle can be determined based on more various viewpoints.
The present invention has been made in view of the above problems, and an object of the present invention is to provide a technique capable of automatically and accurately determining the type of tire attached to a vehicle even while the vehicle is traveling.

  In order to achieve the above object, in the present invention, road surface vibrations caused by traveling of the vehicle are simultaneously measured in a plurality of directions, and the type of tire mounted on the vehicle is determined based on the measurement result. That is, since the shape and position of the block forming the tread pattern are different between the summer tire and the winter tire, the road surface vibration characteristics are different due to the difference between the two. Therefore, the road surface vibration when the vehicle travels depends on the type of tire, and the type of tire mounted on the vehicle can be determined by analyzing the road surface vibration.

  Specifically, the vibration of the road surface is generated when the tire surface collides with the road surface as the tire rotates. The pattern excitation sound that constitutes the driving sound of a normal vehicle is the sound caused by the impact when the block on the tire surface comes into contact with the road surface. Therefore, the frequency characteristic of the road surface vibration is the frequency characteristic of the pattern excitation sound. It is equivalent.

  The inventor of the present application confirms that the vibration of the road surface has a frequency characteristic equivalent to the pattern excitation sound, while the transfer characteristic of the vibration in the road surface varies depending on the direction and the direction of the transfer characteristic. The analysis revealed that the dependence differs depending on the tire type (summer tire or winter tire).

  It is considered that the main cause of the difference in the direction dependency of the transfer characteristics depending on the tire type is that the material is different between the summer tire and the winter tire. That is, the materials of the summer tire and the winter tire are different from each other. Generally, the summer tire is harder and the winter tire is softer. Accordingly, the winter tire is deformed in various directions, and vibrations having frequency characteristics equivalent to the pattern excitation sound are transmitted in various directions along the road surface in accordance with the deformation in the various directions. On the other hand, since summer tires are not easily deformed, vibrations having frequency characteristics equivalent to pattern excitation sound are not generated due to the deformation (or the intensity is small even if generated). Therefore, in the summer tire, when the tread pattern block collides with the road surface as the tire rotates, vibration in the vertical direction is generated, but vibration in the other direction is hardly generated.

  For this reason, the vibration intensity due to the traveling of the vehicle equipped with the summer tire increases the vibration intensity only in a specific direction, and the vibration due to the traveling of the vehicle equipped with the winter tire increases the vibration intensity in a plurality of directions. Therefore, if the vibration of the road surface due to the traveling of the vehicle is simultaneously measured in a plurality of directions, the type of tire mounted on the vehicle can be accurately determined based on the measurement result.

  Here, in the road surface vibration measuring means, it is only necessary to simultaneously measure the vibration of the road surface transmitted from the vehicle to the road surface during traveling in a plurality of directions. For example, on the road surface of the section within a predetermined distance from the toll gate, It is possible to employ a configuration in which a vibration sensor or the like capable of measuring vibrations in two or more directions is attached and vibrations for each vehicle are simultaneously measured in two or more directions. Various methods can be adopted as a method for attaching the vibration sensor to the road surface. The vibration sensor may be configured to be able to measure vibration by bringing the vibration sensor into contact with the road surface, or the vibration sensor may be embedded in the road surface. The vibration may be measured by the above.

  The road vibration may be measured in a plurality of directions, and the plurality of directions may be selected so that the vibration characteristics are different between the summer tire and the winter tire. In other words, when vibrations in a plurality of directions are measured for each of the summer tire and the winter tire and the vibrations of the two are compared, it is only necessary to select the directions so that they can be distinguished from each other. The number of directions may be plural, but in order to clarify the vibration characteristics in a small number of directions, the directions are preferably orthogonal to each other. In addition, since the analysis target is vibration caused by the traveling of the vehicle, the direction related to the traveling of the vehicle, for example, the direction perpendicular to the road surface, the direction parallel to the traveling direction of the vehicle, the direction perpendicular to the traveling direction of the vehicle, etc. May be the measurement direction of vibration.

  The tire determination means only needs to be able to determine the type of tire mounted on the vehicle based on vibrations in a plurality of directions, and the vibrations in the plurality of directions reflect the types of tires mounted on the vehicle. What is necessary is just to determine the kind of tire by specifying this. The analysis of road vibration can be performed by various methods. The vibration intensity, frequency, profile (waveform), etc. may be analyzed, and the presence or absence of vibration having a predetermined characteristic may be confirmed. This method can be adopted.

  In addition, for example, when vibrations in a plurality of directions are analyzed and it is confirmed that the vibration characteristics in the plurality of directions are characteristics corresponding to a specific tire type, it is determined that a specific tire is mounted on the vehicle. It is good also as composition to do. That is, it is possible to adopt a configuration in which it is determined that a specific type of tire is mounted on the vehicle when vibration components according to the specific type of tire are included in the vibration of the road surface in a plurality of directions due to traveling of the vehicle. is there.

  Furthermore, the tire determination means may be configured to determine the type of tire mounted on the vehicle based on frequency characteristics of vibrations in a plurality of directions. For example, even if the tire determining means determines that the winter tire is mounted on the vehicle when the frequency characteristics of the vibrations in the plurality of directions are frequency characteristics due to traveling of the vehicle on which the winter tire is mounted. good. Here, the frequency characteristic is a relation between the physical characteristic of vibration and the frequency, and may be a relation in which characteristics of the summer tire and the winter tire appear to be distinguishable. Therefore, the relationship between the vibration intensity in a plurality of directions and the frequency is defined, and when the characteristics of the summer tire and the winter tire appear, each characteristic may be defined as the frequency characteristic of the summer tire and the winter tire.

  The frequency characteristics of the summer tire and the winter tire may be defined for both the summer tire and the winter tire, or may be defined for only one of them. If the former, it is determined whether or not the frequency characteristics of vibrations in a plurality of directions are the frequency characteristics of a vehicle equipped with summer tires, and further, the frequency characteristics of vibrations in a plurality of directions equipped with winter tires. It becomes the structure which determines whether it is. In the latter case, it is determined whether the frequency characteristics of vibrations in a plurality of directions are the frequency characteristics of vibrations in a plurality of directions due to traveling of a vehicle equipped with winter tires. If it is not the frequency characteristics of vibrations in a plurality of directions due to traveling, it is possible to adopt a configuration that determines that the frequency characteristics are vibrations in a plurality of directions due to traveling of a vehicle on which a summer tire is mounted. Of course, it is determined whether or not the frequency characteristics of vibrations in multiple directions due to traveling of a vehicle equipped with summer tires, and if it is not the frequency characteristics of vibrations in multiple directions due to traveling of a vehicle equipped with summer tires A configuration may be adopted in which it is determined that the frequency characteristics of vibrations in a plurality of directions caused by traveling of a vehicle equipped with winter tires.

  The analysis of the frequency characteristics may be performed by various methods. For example, the tire determination means adopts a configuration that determines the type of tire mounted on the vehicle based on the correlation of the frequency characteristics of vibrations in a plurality of directions. May be. That is, when a winter tire is mounted, vibrations having frequency characteristics equivalent to the pattern excitation sound are transmitted in various directions by the road surface. On the other hand, when summer tires are installed, vibrations in the vertical direction are transmitted to the road surface, and vibrations in other directions are not easily transmitted. Therefore, in the vibration caused by traveling of the vehicle equipped with winter tires, the vibrations in a plurality of directions are similar to each other, while in the vibration caused by traveling of the vehicle equipped with summer tires, the vibrations in the plurality of directions are different from each other. become. Therefore, if the vibration characteristics in a plurality of directions are similar (if there is a correlation), it can be determined as a winter tire, and if not similar (if there is no correlation), it can be determined as a summer tire.

  The correlation of the frequency characteristics may be defined so that the correlation is considered to be stronger as the frequency characteristics are related to each other. For example, the correlation is shown so that the value increases as the frequency characteristics are related to each other. A configuration that defines values can be employed. Further, in this configuration, when the value indicating the correlation is larger than the threshold value, a configuration may be adopted in which the tire determination unit determines that the winter tire is mounted on the vehicle. That is, the larger the correlation value is, the stronger the correlation is. The vibration due to running of a vehicle equipped with winter tires has a strong correlation in frequency characteristics in a plurality of directions, and thus the correlation value increases.

  Therefore, the tire determination means determines that the tire that caused the vibration of the frequency characteristic is a winter tire when the value indicating the correlation of the frequency characteristic is larger than the threshold, and It is possible to determine that the tire that has generated the vibration of the frequency characteristic is a summer tire. Various values can be adopted as the value indicating the correlation. For example, when the frequency characteristic is the vibration intensity for each frequency, the product of Pearson is based on the intensity for each frequency of vibration in a plurality of directions. A configuration in which a correlation coefficient is acquired using a rate correlation coefficient or the like and regarded as a value indicating correlation may be employed.

  Although the case where the present invention is realized as an apparatus has been described above, the present invention can be realized as a method and program for realizing the apparatus and a medium recording the program. In addition, the tire determination processing device as described above may be realized alone, applied to a certain method, or used in a state where the method is incorporated in another device. The idea is not limited to this and includes various aspects. In addition, the implementation mode can be changed as appropriate, such as software or hardware. The software recording medium may be a magnetic recording medium, a magneto-optical recording medium, or any recording medium to be developed in the future.

(1A) is a diagram showing a tread pattern of a summer tire, (1B) is a diagram showing a tread pattern of a winter tire, and (1C) is a diagram for explaining a running sound generated from a running vehicle. (2A) to (2C) are graphs showing frequency characteristics of running sound of a vehicle equipped with winter tires. (3A) to (3C) are graphs showing frequency characteristics of running sound of a vehicle equipped with summer tires. (4A) to (4C) are graphs showing correlations of frequency characteristics of vibrations in a plurality of directions. It is a block diagram which shows one Embodiment of this invention. It is a flowchart which shows a tire determination process.

Here, embodiments of the present invention will be described in the following order.
(1) Principle of tire judgment:
(2) Configuration of tire determination device and tire determination processing:

(1) Principle of tire judgment:
FIG. 1C shows the main components of the running sound of the vehicle. It is known that the tire road noise that occupies most of the traveling sound of the vehicle is mainly composed of the pattern main groove resonance sound and the pattern excitation sound shown in FIG. 1C. Pattern excitation sound is classified as vibration sound, and pattern main groove resonance sound is not classified as vibration sound. That is, the collision between the tire block causing the pattern excitation sound and the road surface causes road surface vibration, but the air column tube causing the pattern main groove resonance sound does not cause the road surface vibration. Therefore, the vibration of the frequency component equivalent to the pattern excitation sound is transmitted to the road surface, and the vibration of the frequency component equivalent to the pattern main groove resonance sound is not transmitted to the road surface.

  FIG. 1A is a typical summer tire tread pattern, and FIG. 1B is a typical winter tire tread pattern. As shown in FIG. 1B, in the winter tire, there are a plurality of blocks B surrounded by a groove Gr extending along the circumference around the rotation axis A of the tire and a groove Gl (lug pattern) intersecting the groove. A tread pattern is formed so as to be lined up. And in the tread pattern of a winter tire, as shown to FIG. 1B, the width | variety of the groove | channel Gr and the groove | channel Gl is approximating, and the depth is also approximating. Further, the groove Gl of the winter tire is wider and deeper than the groove Gl of the summer tire shown in FIG. 1A. On the other hand, in the summer tire, the width of the groove Gl is narrow and shallow.

  Furthermore, the material of the summer tire and that of the winter tire are different. In general, the summer tire is harder and the winter tire is softer. Therefore, the winter tire is more easily deformed than the summer tire, and the winter tire block B having a deep groove around the block B is easily deformed isotropically by contact with the road surface, and is parallel to the traveling direction of the vehicle. It can be deformed not only in the direction but also in the direction perpendicular to the traveling direction of the vehicle. On the other hand, a summer tire having a hard surface and a shallow groove Gl is not easily deformed by contact with the road surface, and is less deformed in both the vehicle traveling direction and the vertical direction.

  When the tire surface contacts the road surface and deforms in a direction horizontal to the road surface, vibration having a frequency characteristic equivalent to the pattern excitation sound is transmitted in a direction horizontal to the road surface due to the deformation. Therefore, in a winter tire that can be deformed in the horizontal direction, vibration having a frequency characteristic equivalent to the pattern excitation sound is transmitted in the horizontal direction as the vehicle travels. On the other hand, in summer tires that are difficult to deform, although the vibration of the frequency characteristic equivalent to the pattern excitation sound may occur in the vertical direction due to the collision between the road surface and the pattern as the vehicle travels, the pattern in the horizontal direction The vibration having the frequency characteristic equivalent to the excitation sound is not transmitted (or the intensity is small even if it is generated).

  2A to 2C are graphs showing frequency characteristics of vibration intensity due to traveling of a vehicle equipped with winter tires, and FIGS. 3A to 3C show frequency characteristics of vibration intensity due to traveling of a vehicle equipped with summer tires. It is a graph. The intensity of vibration shown in these graphs is measured by a three-axis vibration sensor (three-axis acceleration sensor) embedded in the road surface. When the traveling direction of the vehicle is the front, each axis is in the vertical direction and the horizontal direction. A triaxial vibration sensor is embedded in the road surface so as to face the front-rear direction. 2A shows the vertical vibration, FIG. 2B shows the horizontal vibration, and FIG. 2C shows the longitudinal vibration. FIG. 3A shows the vertical vibration, FIG. 3B shows the horizontal vibration, and FIG. Directional vibration is shown.

式（１）において、ｆはパターン加振音の周波数（Ｈｚ）、Ｖは車両の車速（ｋｍ／ｈ）、ｎは周方向のブロックＢの個数、Ｒはタイヤの半径（ｍ）である。 In the measurement of these vibrations, the vehicle speed of the vehicle was 50 km / h, the frequency of the pattern excitation sound in the winter tire used for the measurement was around 400 Hz, and the frequency of the pattern excitation sound in the summer tire was around 500 Hz. The frequency of the pattern excitation sound is as shown in the following formula (1).

In Equation (1), f is the frequency (Hz) of the pattern excitation sound, V is the vehicle speed (km / h), n is the number of blocks B in the circumferential direction, and R is the tire radius (m).

  Comparing the strength of vibration in winter tires in each direction based on FIGS. 2A to 2C, although there is a difference in the absolute value of the strength, there is a peak in the frequency region of the pattern excitation sound, and the strength in other frequency regions The profiles are similar to each other. On the other hand, when comparing the intensity of vibration in the summer tire in each direction based on FIG. 3A to FIG. In, the frequency range of the pattern excitation sound does not always have a significantly large intensity. Also, the intensity profiles in other frequency ranges are not similar to each other.

  In order to analyze the similarity of the intensity profiles, the inventor of the present application calculated the correlation coefficient of the vibration intensity in different directions for each of the winter tire and the summer tire. FIG. 4A shows the correlation coefficient between the frequency characteristic of the left and right vibration and the frequency characteristic of the vertical vibration, and FIG. 4B shows the correlation coefficient between the frequency characteristic of the front and rear vibration and the frequency characteristic of the vertical vibration. FIG. 4C shows a correlation coefficient between the frequency characteristic of the vibration in the left-right direction and the frequency characteristic of the vibration in the front-rear direction. In these graphs, the horizontal axis represents the vehicle speed, the vertical axis represents the correlation coefficient, the black circle represents the winter tire, and the white triangle represents the correlation coefficient for the summer tire. That is, here, vibrations generated by traveling at different vehicle speeds are measured in three axial directions, and correlation coefficients of frequency characteristics of vibrations in two directions are acquired and shown in each graph.

  As shown in FIG. 4A and FIG. 4B, the correlation coefficient between the vertical vibration and the horizontal vibration (left-right and front-back vibration) is mostly 0.4 or less in both the winter tire and the summer tire. There is no correlation. On the other hand, as shown in FIG. 4C, the horizontal coefficient of winter tires, that is, the correlation coefficient between the left and right vibrations and the front and rear vibrations is large. It is around 8. Therefore, in winter tires, it can be said that there is a correlation between left-right vibration and front-back vibration. In summer tires, the correlation coefficient is 0.4 or less, and it cannot be said that there is a correlation between left-right vibration and front-rear vibration.

  The above analysis results indicate that the vibration equivalent to the pattern excitation sound is transmitted in the horizontal direction in the winter tire, and the characteristics are similar in the horizontal direction (left-right direction and front-rear direction). On the other hand, the summer tire shows that the characteristics are not similar in vibrations in a plurality of directions. Therefore, if the road surface vibration caused by the traveling of the vehicle is simultaneously measured in a plurality of directions, the type of tire mounted on the vehicle can be determined based on the measurement result.

(2) Configuration of tire determination device and tire determination processing:
FIG. 5 is a block diagram showing an embodiment of the tire determination apparatus of the present invention, and FIG. 6 is a flowchart showing a tire determination process executed by the tire determination apparatus. Various devices can be connected to the tire determination device 10 according to the present embodiment via an interface (not shown). In the present embodiment, an amplifier 41 and a display unit 42 are connected to the tire determination device 10. In addition, a three-axis vibration sensor 40 is connected to the amplifier 41. The triaxial vibration sensor 40 is a sensor that measures the intensity of vibration in the triaxial direction, and is embedded in the road surface R. In the present embodiment, each axis of the triaxial vibration sensor 40 includes a vehicle traveling direction (front-rear direction) on the road surface R, a vertical direction, and a left-right direction when the vehicle traveling direction is regarded as the front. They are oriented parallel to each other.

  In addition, the tire determination device 10 includes a control unit 20 and a recording medium 30. The control unit 20 includes a CPU, RAM, ROM, and the like (not shown), and can execute a program recorded in the recording medium 30 or the ROM. In the present embodiment, the tire determination program 21 can be executed as one of the programs. In addition, threshold information 30a indicating a threshold (for example, 0.55) for determining whether or not there is a correlation between vibrations in a plurality of directions caused by winter tires is recorded on the recording medium 30.

  The tire determination program 21 includes a road surface vibration measurement unit 21a and a tire determination unit 21b. The road surface vibration measuring unit 21a is a module that causes the control unit 20 to realize a function of simultaneously measuring road surface vibrations caused by traveling of a vehicle in a plurality of directions. That is, when the vehicle travels on the road surface R around the triaxial vibration sensor 40, information indicating the intensity of vibration in the direction along each axis is sequentially output from the triaxial vibration sensor 40. When a signal indicating the intensity of vibration in the direction along each axis is output from the triaxial vibration sensor 40, the signal is amplified by the amplifier 41. When the amplified signal is output from the amplifier 41, the control unit 20 acquires the amplified signal by the process of the road surface vibration measuring unit 21a (step S100).

  The tire determination unit 21b is a module that causes the control unit 20 to realize a function of determining the type of tire mounted on the vehicle based on vibrations in a plurality of directions. In this embodiment, the control part 20 acquires the frequency characteristic of the intensity | strength of the vibration of a some direction by the process of the tire determination part 21b (step S110). That is, the control unit 20 performs a Fourier transform on the time-series vibration intensity acquired by the process of the road surface vibration measuring unit 21a, and acquires a correspondence relationship (that is, frequency characteristics) between the vibration intensity and the frequency. The control unit 20 executes the above process for each of the vibration in the front-rear direction and the vibration in the left-right direction.

  Next, the control part 20 acquires the correlation coefficient which shows the correlation with the frequency characteristic of the vibration of the front-back direction, and the frequency characteristic of the vibration of the left-right direction by the process of the tire determination part 21b (step S120). That is, the control unit 20 uses a known correlation coefficient calculation method such as the Pearson product moment correlation coefficient to show the correlation between the frequency characteristic of the vibration in the front-rear direction and the frequency characteristic of the vibration in the left-right direction. Get the number.

  Next, the control part 20 determines whether a correlation coefficient is larger than a threshold value by the process of the tire determination part 21b (step S130). In other words, the control unit 20 identifies the threshold with reference to the threshold information 30a. And the control part 20 compares the correlation coefficient acquired by the process of step S120, and a threshold value, and determines whether a correlation coefficient is larger than a threshold value.

  If it is not determined in step S130 that the correlation coefficient is greater than the threshold value, the control unit 20 determines that a summer tire is mounted on the vehicle by the processing of the tire determination unit 21b, and controls the display unit 42 with a control signal. And the determination result is displayed on the display unit 42 (step S140). On the other hand, when it is determined in step S130 that the correlation coefficient is greater than the threshold, the control unit 20 determines that a winter tire is mounted on the vehicle by the processing of the tire determination unit 21b, and displays the display unit 42. The control signal is output to display the determination result on the display unit 42 (step S150). According to the above processing, it is possible to automatically and accurately determine the type of tire without relying on visual observation.

  The above embodiments measure the vibration in the horizontal direction on the road surface generated by the traveling of the vehicle, and the type of tire mounted depending on whether or not the correlation coefficient of the vibration intensity is determined to be greater than a specific threshold value. It is an Example which determines. However, the above-described embodiment is an example for carrying out the present invention. As is clear from FIGS. 2 and 3, strong vibration due to pattern excitation sound is generated in the vertical direction around 500 Hz by the tread pattern of the summer tire (FIG. 3A). ), The strength in the left-right direction (FIG. 3B) and the front-rear direction (FIG. 3C) has characteristics different from those of winter tires, and the tires are mounted on the basis of the vibration of the road surface in these directions. It is possible to determine the type of tire.

  In addition, various factors may be added to the analysis.For example, the vibration of winter tires is mainly the same frequency as pattern excitation sound, and the vibration of summer tires is mainly the same frequency as main groove resonance sound. You may consider that it is.

DESCRIPTION OF SYMBOLS 10 ... Tire determination apparatus, 20 ... Control part, 21 ... Tire determination program, 21a ... Road surface vibration measurement part, 21b ... Tire determination part, 30 ... Recording medium, 30a ... Threshold information, 40 ... Triaxial vibration sensor, 41 ... Amplifier 42 ... Display section

Claims (6)

Road surface vibration measuring means for simultaneously measuring the vibration of the road surface due to traveling of the vehicle in a plurality of directions;
Tire determination means for determining the type of tire mounted on the vehicle based on the vibrations in the plurality of directions;
A tire determination device comprising: The tire determination means determines the type of tire mounted on the vehicle based on frequency characteristics of the vibrations in the plurality of directions.
The tire determination device according to claim 1. The tire determination means determines the type of tire mounted on the vehicle based on the correlation of the frequency characteristics of the vibrations in the plurality of directions.
The tire determination apparatus according to claim 1 or 2. The tire determination means determines that a winter tire is mounted on the vehicle when the value indicating the correlation is greater than a threshold value.
The tire determination device according to claim 3. A road surface vibration measuring step for simultaneously measuring vibrations on the road surface in a plurality of directions due to traveling of the vehicle;
A tire determination step of determining the type of tire mounted on the vehicle based on the vibrations in the plurality of directions;
The tire judgment method containing. A road surface vibration measurement function for simultaneously measuring the vibrations of the road surface due to vehicle travel in a plurality of directions;
A tire determination function for determining the type of tire mounted on the vehicle based on the vibrations in the plurality of directions;
Tire judgment program that makes the computer execute.

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