JP6343184B2 - Wear determination apparatus, wear determination method, and wear determination program - Google Patents

Description

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

  2. Description of the Related Art Conventionally, an apparatus for determining whether a tire chain is mounted on a tire of a vehicle using a sensor provided in the vehicle is known. For example, Patent Document 1 discloses a technique for detecting a change in the rotational speed of a wheel and determining whether or not a tire chain is attached based on the detection result.

Japanese Patent Laid-Open No. 7-300067

In the prior art described above, it has not been possible to determine whether or not a tire chain is attached to the vehicle from the outside of the traveling vehicle. That is, for road management in winter, it is necessary to detect whether or not a tire chain is attached to a running vehicle by an external device. For example, road maintenance managers, etc. know the tire chain installation rate on winter roads that require tire chain installation, such as during snowfall, snowfall, road freezing, etc. In order to urge the non-vehicle to be mounted, it is necessary to determine whether or not the tire chain is mounted on the vehicle from the outside of the vehicle.
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 determining whether a tire chain is attached to a vehicle from the outside of the vehicle.

  In order to achieve the above object, the present invention is based on a comparison result between characteristics of front wheel vibration that is vibration excited by a front wheel of a vehicle and characteristics of rear wheel vibration that is vibration excited by a rear wheel of the vehicle. Then, it is determined whether a chain is attached to the front wheel or the rear wheel. That is, when the vehicle travels, vibrations are excited from the wheels mounted on the vehicle to the air, the road surface, and the like, and the vibrations have characteristics reflecting the material and shape of the surface shape of the wheels. In addition, when a tire chain is attached to a vehicle wheel, the tire chain is usually attached to the front or rear drive wheels of the vehicle, and the tire chain is not attached to the other wheel.

  Therefore, when a tire chain is attached to the front wheel or the rear wheel, the front wheel vibration characteristic and the rear wheel vibration characteristic are significantly different. On the other hand, when a tire chain is not attached to the front wheel or the rear wheel, the front wheel vibration characteristic and the rear wheel vibration characteristic are similar. Accordingly, if the characteristics of the front wheel vibration and the characteristics of the rear wheel vibration are compared, it can be determined whether or not the chain is attached to the front wheel or the rear wheel based on the comparison result.

  The front wheel vibration and the rear wheel vibration can be acquired by a vibration sensor provided outside the vehicle, for example, around a road on which the vehicle travels. Therefore, according to the mounting determination device according to the embodiment of the present invention, it is possible to determine whether or not a tire chain is mounted on the vehicle from the outside of the traveling vehicle.

  Here, the front wheel vibration acquisition means only needs to be able to acquire front wheel vibration that is vibration excited by the front wheel of the vehicle. That is, when the vehicle travels on the road surface, vibrations are excited by the front wheels and the rear wheels. Therefore, it is only necessary that the vibrations derived from the front wheels can be detected by the vibration sensor and the front wheel vibrations can be detected based on the output of the vibration sensor. The vibration may be a phenomenon that causes the medium to vibrate. The medium may be air (in this case, the vibration is sound) or may be a road surface, and various media can be assumed.

  The front wheel vibration is vibration excited by the front wheel, but here, the vibration acquired as the front wheel vibration may be vibration excited mainly by the front wheel, and the rear wheel vibration excited by the rear wheel may be It may be included slightly. That is, because the front wheel vibration is vibration derived from the front wheel and the rear wheel vibration is vibration derived from the rear wheel, it is possible to determine whether the tire chain is mounted or not based on the comparison result of both vibrations. It is only necessary to distinguish between vibration and vibration derived from the rear wheel.

  The rear wheel vibration acquisition means only needs to be able to acquire rear wheel vibration that is vibration excited by the rear wheel of the vehicle. That is, the configuration of the rear wheel vibration acquisition unit is the same as the configuration of the front wheel vibration acquisition unit except that the vibration acquisition target is the rear wheel.

  The front wheel vibration and the rear wheel vibration may be acquired separately by each vibration acquisition means, or after a period of vibration including the front wheel vibration and the rear wheel vibration is acquired once, a part of the acquired vibration May be acquired as front wheel vibration and the other part as rear wheel vibration. As the former, for example, vibrations acquired during a period in which it is considered that vibrations mainly derived from front wheels are detected by vibration sensors installed at one or more positions are front wheel vibrations, mainly vibrations derived from rear wheels. It is possible to adopt a configuration that acquires vibrations acquired during a period considered to be detected as rear wheel vibrations. As the latter, the front vibration (early time zone vibration) is acquired as the front wheel vibration from the time series vibration detected by the vibration sensor installed at one place, and the rear vibration (late time zone vibration) is obtained. It is possible to adopt a configuration that acquires as rear wheel vibration.

  The mounting determination means only needs to be able to determine whether a tire chain is mounted on the front wheel or the rear wheel based on the comparison result between the characteristics of the front wheel vibration and the characteristics of the rear wheel vibration. That is, comparing the characteristics of the front wheel vibration and the rear wheel vibration, if there is a difference in characteristics due to the tire chain being attached to the front wheel or the rear wheel, the chain is attached to the front wheel or the rear wheel. What is necessary is just to be able to determine that it is. Of course, here, the characteristics of the front wheel vibration and the characteristics of the rear wheel vibration may be compared, and if there is no difference in characteristics, it may be determined that the tire chain is not attached to either the front wheel or the rear wheel. .

  The characteristics of vibration can be analyzed by various factors. For example, vibration intensity, frequency, profile (waveform), and the like may be analyzed, and the presence or absence of vibration having a predetermined characteristic may be confirmed, and various methods can be employed. When analyzing the strength as the vibration characteristic, the mounting determination means determines whether the chain is mounted on the front wheel or the rear wheel based on the difference between the strength of the front wheel vibration and the strength of the rear wheel vibration. It becomes composition. For example, a configuration may be employed in which a difference or ratio in strength is acquired as a difference, and whether or not a chain is attached to the front wheel or the rear wheel based on the difference.

  In this case, various amounts can be adopted as the amount of sample acquired as an analysis target in order to analyze the intensity difference or ratio. For example, the intensity of vibration at a certain time point may be compared, or the intensity within a predetermined period may be compared. The latter may be an integral value of the intensity within the predetermined period, an average value of the intensity within the predetermined period, or whether the intensity is not less than a predetermined value within the predetermined period. Or the number of samples whose intensity is greater than or equal to a predetermined value within a predetermined period. Of course, the analysis related to the strength may be performed based on the strength itself (amplitude of the vibration waveform), or may be performed based on a physical quantity (for example, energy) indirectly indicating the strength.

  It should be noted that the tire chain may be an anti-slip device that causes a difference in the characteristics of vibration excited by the wheel between the state where the tire chain is attached and the state where the tire chain is not attached, and the material and shape are limited. Not. For example, a metal tire chain or a resin tire chain may be used.

  Furthermore, the front wheel vibration acquisition timing acquired by the front wheel vibration acquisition means may be configured to be earlier than the rear wheel vibration start timing acquired by the rear wheel vibration acquisition means. That is, a configuration in which a series of vibrations excited as the vehicle travels is acquired by a vibration sensor installed in one place, front vibrations thereof are acquired as front wheel vibrations, and rear vibrations are acquired as rear wheel vibrations. The front wheel vibration and the rear wheel vibration are not overlapped with each other, and the front wheel vibration and the rear wheel vibration are acquired so that a predetermined time interval exists between the two.

  When acquiring vibration excited by a wheel with one vibration sensor, the intensity of vibration acquired by the vibration sensor increases as the distance between the vibration sensor and the wheel decreases. Therefore, when the distance between the vibration sensor and the front wheel is smaller than the distance between the vibration sensor and the rear wheel, the vibration acquired by the vibration sensor includes a lot of vibration components derived from the front wheel. However, if the distance between the vibration sensor and the front wheel is close to the distance between the vibration sensor and the rear wheel, it is determined whether the vibration derived from the front wheel or the vibration derived from the rear wheel is dominant in the vibration acquired by the vibration sensor. It is difficult to distinguish.

  Such a time zone that is difficult to distinguish is a time zone that includes an intermediate timing between the timing at which the front wheel is closest to the vibration sensor and the timing at which the rear wheel is closest to the vibration sensor, and before and after that timing. Therefore, when comparing the front wheel vibration and the rear wheel vibration, if the front wheel vibration and the rear wheel vibration are acquired after excluding such a time zone, the vibration derived from the front wheel is dominant in the acquired front wheel vibration. Therefore, in the rear wheel vibration after acquisition, the vibration derived from the rear wheel becomes dominant.

  Therefore, if the front wheel vibration end timing acquired by the front wheel vibration acquisition means is configured to be earlier than the rear wheel vibration start timing acquired by the rear wheel vibration acquisition means, the front wheel vibration end timing will be Compared with the case after the vibration start timing, it is possible to reliably determine whether or not the tire chain is mounted based on the comparison result between the front wheel vibration and the rear wheel vibration.

  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 mounting determination processing device as described above may be realized alone, applied to a certain method, or used in a state where the same 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 road vibration excited by a vehicle not wearing a tire chain, and (1B) is a diagram showing road vibration excited by a vehicle equipped with a tire chain. It is a block diagram which shows one Embodiment of this invention. It is a flowchart which shows a mounting | wearing determination process. (4A) (4B) is a figure for demonstrating the comparison of a front-wheel vibration and a rear-wheel vibration. (5A) (5B) is a figure for demonstrating the comparison of a front-wheel vibration and a rear-wheel vibration.

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

(1) Principle of wearing determination:
1A and 1B show road vibration detected by a vibration sensor embedded in a predetermined position (for example, a position in a lane, a roadside band, etc., which is a predetermined distance away from a position where a tire contacts) on a traveling road of the vehicle. The horizontal axis represents time, and the vertical axis represents intensity. FIG. 1A shows road vibrations excited by a vehicle not wearing a tire chain, and FIG. 1B shows road vibrations excited by a vehicle equipped with a tire chain. In FIG. 1A and FIG. 1B, the vibration intensity (amplitude) that can be acquired by the vibration sensor is normalized so that the maximum value is 1.

  In the vibration shown in FIG. 1A, the intensity gradually increases as time progresses from left to right on the horizontal axis, and thereafter an intensity increase / decrease pattern that attenuates appears in two places. The preceding pattern Pf in these patterns is the front wheel vibration excited by the front wheel, and the rear pattern Pr is the rear wheel vibration excited by the rear wheel. As shown in FIG. 1A, the front wheel vibration and the rear wheel vibration of a vehicle without a tire chain are similar in magnitude and profile.

  In the example shown in FIG. 1B, the vehicle has a tire chain attached to the front wheels. Even when the tire chain is mounted on the vehicle, the vibration is excited by each of the front wheels and the rear wheels. However, in the example shown in FIG. 1B, the intensity of the front wheel vibration excited by the front wheels to which the tire chain is mounted is The strength of the rear wheel vibration excited by the rear wheel to which the tire chain is not attached is significantly larger. Therefore, the front wheel vibration shown in FIG. 1B maintains a state of high strength over a long period of time compared to the front wheel vibration (pattern Pf shown in FIG. 1A) when the tire chain is not attached.

  Further, in the rear wheel vibration pattern Prb shown in FIG. 1B, since it overlaps with the vibration of the front wheel vibration in the initial stage, it is slightly different from the rear wheel vibration pattern Pr shown in FIG. It is estimated that the vibration is excited with the same tendency of intensity and damping as the rear wheel vibration. When the front wheel vibration and the rear wheel vibration shown in FIG. 1B are compared, they are remarkably different. Therefore, the front wheel vibration and the rear wheel vibration are compared. If there is a significant difference between the two, it can be determined that the tire chain is attached to the front wheel or the rear wheel of the vehicle.

(2) Configuration of wear determination device and wear determination processing:
FIG. 2 is a block diagram showing an embodiment of the wearing determination apparatus 10 of the present invention, and FIG. 3 is a flowchart showing a wearing determination process executed by the wearing determination apparatus 10. Various devices can be connected to the mounting determination device 10 according to the present embodiment via an interface (not shown), and the vibration sensor 40, the display unit 42, and the vehicle sensor 43 are connected to the mounting determination device 10. The vibration sensor 40 is connected to the wearing determination device 10 via the amplifier 41.

  The vibration sensor 40 is embedded in the road R or attached so as to be in contact with the road R so that the vibration of the road R generated by the vehicle traveling on the road R can be acquired. When the vehicle travels on a road around the vibration sensor 40, a signal indicating the road vibration due to the traveling of the vehicle is output from the vibration sensor 40. A signal indicating the vibration is amplified by the amplifier 41 and then input to the control unit 20. The control unit 20 can acquire and analyze a signal indicating the vibration. That is, the control unit 20 generates data (time-series intensity data) indicating the intensity of vibration for each predetermined unit time based on a signal indicating vibration, and records the data in a RAM, which will be described later, as an analysis target. Can do. The vibration sensor 40 detects vibration of the road R excited by the wheels at a predetermined position on the road R on which the vehicle travels (for example, a position in a lane or a roadside band that is a predetermined distance away from a position where the tire contacts). It is buried in an obtainable position.

  The vehicle sensor 43 includes a light source (not shown) and a light receiving unit that receives light output from the light source. The light receiving unit of the vehicle sensor 43 outputs a signal indicating a state where light from the light source is received and a signal indicating a state where light is not received. In the vehicle sensor 43, one of the light source and the light receiving unit is disposed on one side of the road R and the other is disposed on the other side (for example, disposed on the road shoulders on both sides), and the road R is sandwiched between the light source and the light receiving unit. Installed. Therefore, when the vehicle crosses the optical path from the light source to the light receiving unit in the vehicle sensor 43, the light is blocked during the period from the front end to the rear end of the vehicle. The control unit 20 can specify the timing (time) when the front end and the rear end of the vehicle cross the vehicle sensor 43 based on the signal output from the light receiving unit of the vehicle sensor 43. In the present embodiment, the position of the vehicle sensor 43 in the road length direction (direction in which the road R extends) is substantially the same as the position of the vibration sensor 40 in the road length direction. Of course, the configuration of the vehicle sensor 43 is only an example, and a sensor that detects the passage of the vehicle based on a change in the amount of light detected by the light receiving unit (change due to reflected light from the vehicle, etc.) without installing a light source. good.

  The mounting 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 mounting determination program 21 can be executed as one of the programs. In addition, threshold information 30a indicating a threshold for evaluating a comparison result between front wheel vibration and rear wheel vibration is recorded on the recording medium 30.

  The mounting determination program 21 includes a front wheel vibration acquisition unit 21a, a rear wheel vibration acquisition unit 21b, and a mounting determination unit 21c. The front wheel vibration acquisition unit 21a is a program module that causes the control unit 20 to realize a function of acquiring front wheel vibration that is vibration excited by the front wheels of the vehicle. In the present embodiment, the control unit 20 acquires the vibration in the early time zone as the front wheel vibration from the time-series vibration obtained based on the output signal of the vibration sensor 40 installed in one place, and vibrates in the late time zone. Is acquired as rear wheel vibration.

  Specifically, the control unit 20 sequentially acquires data indicating the intensity of time-series vibration based on the output signal of the vibration sensor 40. In this state, when the light receiving unit of the vehicle sensor 43 outputs a signal indicating that the front end of the vehicle has crossed, the control unit 20 executes the mounting determination process shown in FIG. In the mounting determination process shown in FIG. 3, the control unit 20 acquires vibration for one vehicle by the process of the mounting determination program 21 (step S <b> 100).

  In the present embodiment, the control unit 20 detects time-series vibrations in a period from the timing when the front end of the vehicle crosses the light receiving unit of the vehicle sensor 43 to the timing when the rear end of the vehicle crosses the light receiving unit of the vehicle sensor 43. Acquired as vibration for one unit. For this purpose, the control unit 20 determines the timing (time) at which the front end of the vehicle crosses the light receiving unit of the vehicle sensor 43 based on the time measurement result by a timing circuit (not shown) and the output signal of the light receiving unit of the vehicle sensor 43, and the vehicle The timing (time) at which the rear end crosses the light receiving portion of the vehicle sensor 43 is specified. And the control part 20 extracts the vibration of the period from the timing when the front end of the vehicle crossed the light receiving part of the vehicle sensor 43 to the timing when the rear end of the vehicle crossed the light receiving part of the vehicle sensor 43 from the time series vibration. Acquired as vibration for one unit.

  1A and 1B, the timing Tf at which the front end of the vehicle crosses the light receiving portion of the vehicle sensor 43 and the timing Tr at which the rear end of the vehicle crosses the light receiving portion of the vehicle sensor 43 are shown in the graph. Yes. That is, in FIGS. 1A and 1B, the vibration from timing Tf to timing Tr is the vibration Wc for one unit.

  The front wheel vibration acquisition unit 21a is a program module that causes the control unit 20 to realize a function of acquiring front wheel vibration that is vibration excited by the front wheels of the vehicle. The rear wheel vibration acquisition unit 21b is excited by the rear wheels of the vehicle. This is a program module that causes the control unit 20 to realize the function of acquiring rear wheel vibration, which is vibration. In this embodiment, when the vibration for one vehicle is acquired, the control unit 20 acquires the front wheel vibration and the rear wheel vibration by the processing of the front wheel vibration acquisition unit 21a and the rear wheel vibration acquisition unit 21b (step S110). That is, in step S110, the control unit 20 acquires the front part of the vibration for one vehicle as the front wheel vibration by the processing of the front wheel vibration acquisition unit 21a. Further, the control unit 20 acquires the rear part of the vibration for one vehicle as the rear wheel vibration by the processing of the rear wheel vibration acquisition unit 21b.

  Here, the front wheel vibration only includes vibration excited mainly by the front wheel, and the rear wheel vibration only needs to include vibration excited mainly by the rear wheel. Accordingly, the front wheel vibration extracted from the vibration of one vehicle may be vibration in a period earlier than the rear wheel vibration, the start timing of the front wheel vibration is earlier than the start timing of the rear wheel vibration, and the end timing of the front wheel vibration is It may be earlier than the end timing of the rear wheel vibration.

  The end timing of the front wheel vibration and the start timing of the rear wheel vibration can be in various relations. In this embodiment, the end timing of the front wheel vibration is earlier than the start timing of the rear wheel vibration. That is, the control part 20 acquires the vibration of the period which excluded the one part period of the latter period from the first half of the vibration of one vehicle as a front wheel vibration by the process of the front wheel vibration acquisition part 21a. The control unit 20 acquires, as the rear wheel vibration, the vibration during the period excluding the initial period from the latter half of the vibration for one vehicle by the processing of the rear wheel vibration acquisition unit 21b.

  More specifically, in FIGS. 1A and 1B, the first half of the vibration Wc for one vehicle is shown as Wf, and the second half is shown as Wr. The period of front wheel vibration acquired from the first half Wf is F, and the rear wheel vibration The period is indicated as R. As shown in these drawings, in this embodiment, a predetermined period I is formed between the period F of the front wheel vibration and the period R of the rear wheel vibration, and the front wheel vibration and the rear wheel vibration overlap. Parts (parts near the time center of vibration for one vehicle) are not acquired as front wheel vibration and rear wheel vibration. In the present embodiment, the control unit 20 acquires the front wheel vibration by excluding a part of the initial period from the first half of the vibration for one vehicle and the initial part of the vibration for one vehicle. It is acquired as rear-wheel vibration, excluding part of the latter term as well as part of it.

  The mounting determination unit 21c is a program module that causes the control unit 20 to realize a function of determining whether a chain is mounted on the front wheel or the rear wheel based on the comparison result between the characteristics of the front wheel vibration and the rear wheel vibration. It is. In the present embodiment, when the front wheel vibration and the rear wheel vibration are acquired, the control unit 20 acquires a difference between the sum of the strengths of the front wheel vibration and the sum of the strengths of the rear wheel vibrations by the process of the mounting determination unit 21c. (Step S120).

  That is, the control unit 20 adds the intensities of all the samples of the front wheel vibration (acquires the integrated value of the intensity for the period of the front wheel vibration) to obtain the sum of the intensities of the front wheel vibrations. Further, the sum of the strengths of the rear wheel vibrations is obtained by adding the strengths of all the samples of the rear wheel vibrations (acquiring an integrated value of the strengths for the period of the rear wheel vibrations). Then, the control unit 20 acquires the former sum-the latter sum. The sum to be acquired here may be an absolute value.

  As described above, in the state where the tire chain is mounted on the front wheel or the rear wheel of the vehicle, the front wheel vibration and the rear wheel vibration are significantly different, and thus the difference value acquired in step S120 is large. On the other hand, in a state where the tire chain is not mounted on the vehicle, the front wheel vibration and the rear wheel vibration are similar, and thus the difference value acquired in step S120 is small. Therefore, when the difference value acquired in step S120 is larger than the threshold value, a tire chain is attached to the front wheel or the rear wheel of the vehicle, and when the difference value acquired in S120 is equal to or less than the threshold value. It can be determined that the tire chain is not attached to the vehicle.

FIG. 4A shows that the vibrations excited by the wheels of a vehicle with and without a tire chain are measured many times, and the difference between the sum of the front wheel vibration strength and the rear wheel vibration strength is obtained. This is a created histogram. In the histogram shown in FIG. 4A, the vertical axis represents the frequency, and the horizontal axis represents the difference between the sum of the front wheel vibration intensity and the sum of the rear wheel vibration intensity, and the difference is indicated by the value before normalization of the vibration intensity. ing. In FIG. 4A, the histogram of the vehicle with the tire chain attached is shown as a black rectangle, and the histogram of the vehicle with no tire chain attached is shown as a white rectangle. As shown in FIG. 4A, the histogram of the vehicle with the tire chain attached is distributed on the right side of the graph, and the histogram of the vehicle with no tire chain attached is distributed on the left side of the graph. Accordingly, if the difference in the sum of the strengths is larger than a value of about 7 (× 10 ⁷ ), it can be determined that the tire chain is attached to the front wheel or the rear wheel of the vehicle, and the difference in the sum of the strengths is 7 (× If the value is smaller than about 10 ⁷ ), it can be determined that the tire chain is not attached to the vehicle. In this embodiment, in this way, a threshold value for determining whether the tire chain is mounted or not is defined in advance, and information indicating the threshold value is recorded in advance on the recording medium as threshold information 30a.

  Therefore, the control unit 20 refers to the threshold information 30a by the process of the mounting determination unit 21c, and determines whether or not the difference acquired in step S120 is larger than the threshold (step S130). In step S130, when it is not determined that the difference acquired in step S120 is larger than the threshold value, the control unit 20 determines that the tire chain is not mounted on the vehicle by the processing of the mounting determination unit 21c, and displays on the display unit 42. On the other hand, a control signal is output 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 difference acquired in step S120 is greater than the threshold, the control unit 20 has a tire chain mounted on the front wheel or the rear wheel of the vehicle by the processing of the mounting determination unit 21c. And a control signal is output to the display unit 42 to display the determination result on the display unit 42 (step S150).

  In the above configuration, the front wheel vibration and the rear wheel vibration can be acquired by the vibration sensor 40 installed outside the vehicle. Therefore, it can be determined whether or not the tire chain is attached to the vehicle from the outside of the traveling vehicle. Further, in the above configuration, the front wheel vibration end timing is earlier than the rear wheel vibration start timing, and as shown in FIGS. 1A and 1B, the front wheel vibration period F and the rear wheel vibration period R A predetermined period I is formed between the two. In the predetermined period I, the front wheel vibration and the rear wheel vibration are overlapped, and it is difficult to consider that one of them is dominant. In the present embodiment, since the front wheel vibration and the rear wheel vibration are acquired in a state where the predetermined period I is excluded, it is possible to acquire both vibrations in a state where the characteristics of the front wheel vibration and the rear wheel vibration clearly appear. it can. As a result, by analyzing the difference between the sum of the strength of the front wheel vibration and the sum of the strength of the rear wheel vibration, as shown in FIG. 4A, the vehicle with the tire chain attached and the vehicle with no tire attached are clarified. Can be distinguished. Therefore, it is possible to accurately determine whether the tire chain is attached or not.

(3) Other embodiments:
The above embodiment is an example for carrying out the present invention. As long as it is determined whether the tire chain is attached to the vehicle by comparing the characteristics of the front wheel vibration and the characteristics of the rear wheel vibration, Various embodiments can also be employed. For example, a plurality of vibration sensors 40 may be installed on the road. In this case, a plurality of vibration sensors 40 are embedded in the road width direction, and data that can be analyzed most accurately (for example, data having a large intensity or data having a large difference between the intensity of the front wheel vibration and the rear wheel vibration). ) To determine whether the tire chain is mounted or not mounted.

  Furthermore, a plurality of vehicle sensors 43 may be installed on the road. In this case, a plurality of vehicle sensors 43 are installed in the road length direction, the vehicle speed is specified based on the timing at which the vehicle crosses each sensor, the vehicle length is specified based on the timing at which the vehicle crosses the sensor and the vehicle speed, Based on the vehicle speed and the vehicle length, it is possible to adopt a configuration that specifies a range to be acquired as front wheel vibration or rear wheel vibration from vibrations acquired by the vibration sensor 40.

  Furthermore, the method for comparing the characteristics of the front wheel vibration and the rear wheel vibration is not limited to the above-described embodiment, and various methods can be adopted, and the vibration intensity, frequency, profile (waveform), etc. An analysis target may be used, or the presence or absence of vibration having a predetermined characteristic may be confirmed, and various methods may be employed. Furthermore, the vibration medium is not limited to the road R, and air (in this case, vibration is sound) may be used, or the contact sound between the road R and the sensor may be acquired as vibration excited by the wheels.

  When comparing the strength, the ratio of the sum of the front wheel vibration strength and the sum of the rear wheel vibration strength may be analyzed. Such a configuration can be realized by acquiring the ratio of the sum of the strengths of the front wheel vibration and the sum of the strengths of the rear wheel vibration in step S120 in the same configuration as the above-described embodiment. Of course, in this case, the threshold value used for the determination in step S130 is a threshold value set in advance so that the wearing and non-wearing of the tire chain can be distinguished by the ratio of the strength sums.

  FIG. 4B is a histogram created by measuring the vibrations of a vehicle with and without a tire chain many times and obtaining the ratio of the sum of the front wheel vibration strength and the sum of the rear wheel vibration strength. . In the histogram shown in FIG. 4B, the vertical axis represents frequency, and the horizontal axis represents the ratio of the sum of the front wheel vibration intensity and the sum of the rear wheel vibration intensity. Also in FIG. 4B, the histogram of the vehicle with the tire chain attached is shown as a black rectangle, and the histogram of the vehicle with no tire chain attached is shown as a white rectangle. As shown in FIG. 4B, the histogram of the vehicle with the tire chain attached is distributed on the right side of the graph, and the histogram of the vehicle with no tire chain attached is distributed on the left side of the graph. Accordingly, if the ratio of the sum of strength is larger than a value of about 2.5, it can be determined that the tire chain is attached to the front wheel or the rear wheel of the vehicle, and the ratio of the sum of strength is a value of about 2.5. If it is smaller, it can be determined that the tire chain is not attached to the vehicle.

  In FIG. 4B, when the tire chain is mounted, it is mounted on the front wheel, and the former / the latter is obtained as the ratio of the sum of the front wheel vibration strength and the sum of the rear wheel vibration strength. When the ratio value is equal to or greater than the threshold value, it is determined that the tire chain is attached. When the latter / the former is acquired as the ratio of the sum of the front wheel vibration strength and the sum of the rear wheel vibration strength, it is determined that the tire chain is attached when the ratio value is equal to or less than the threshold value. become. Furthermore, if the ratio is set so that the larger of the sum of the front wheel vibration intensity and the rear wheel vibration intensity is a numerator, the tire chain is mounted when the ratio value is equal to or greater than the threshold value. It is determined that

Further, the lengths of vibrations to be the front wheel vibration and the rear wheel vibration are not limited to the lengths as in the above-described embodiment. For example, as shown in FIGS. 1A and 1B, the configuration may be such that the vibration of the first half Wf of the vibration Wc for one vehicle is acquired as the front wheel vibration and the vibration of the second half Wr is acquired as the rear wheel vibration. FIG. 5A is a diagram showing, as a histogram, the difference in the sum of the intensities when the vibration of the first half Wf is acquired as the front wheel vibration and the vibration of the second half Wr is acquired as the rear wheel vibration. Even in this example, as shown in FIG. 5A, if the difference in the sum of strength is larger than a value of about 7 (× 10 ⁷ ), it is determined that the tire chain is attached to the front wheel or the rear wheel of the vehicle. If the difference in the sum of the strengths is smaller than a value of about 7 (× 10 ⁷ ), it can be determined that the tire chain is not attached to the vehicle.

  Further, FIG. 5B shows, as a histogram, the ratio of the sum of the intensities when the vibration of the first half Wf of the vibration Wc for one vehicle is acquired as the front wheel vibration and the vibration of the second half Wr as the rear wheel vibration. It is a figure. Even in this example, as shown in FIG. 5B, if the ratio of the sum of strengths is larger than a value of about 2.25, it can be determined that the tire chain is attached to the front wheel or the rear wheel of the vehicle. If the ratio of the sum of the strengths is smaller than a value of about 2.25, it can be determined that the tire chain is not attached to the vehicle.

  Further, various methods other than the above-described examples can be adopted as the method for acquiring the front wheel vibration and the rear wheel vibration. After the vibration for one vehicle is acquired, the front wheel vibration and the rear wheel vibration are acquired from the vibration. The front wheel vibration and the rear wheel vibration may be acquired separately. Further, the lengths of the front wheel vibration and the rear wheel vibration can be specified based on various indexes. For example, it is a period before and after the timing when the front wheel and the rear wheel are closest to the vibration sensor 40, and the vehicle travels for a distance corresponding to one rotation of the tire (for the half rotation of the tire before and after the closest timing). It is possible to adopt a configuration that acquires vibrations during a period corresponding to (period) as front wheel vibrations and rear wheel vibrations. Of course, if it is clear from the wheelbase that the vehicle travels for the distance of one rotation of the tire, it is possible to shorten each period so that the periods do not overlap based on the wheelbase etc. good.

  Furthermore, it is possible to determine whether the tire chain is mounted or not by paying attention to each of vibrations excited by the wheels with the tire chain mounted and vibrations excited by the wheels not mounted. For example, if the evaluation criteria that can distinguish the characteristics of the vibration excited by the wheel with the tire chain and the characteristics of the vibration excited by the wheel not attached are determined in advance, each of the front wheel vibration and the rear wheel vibration It is possible to determine whether or not a tire chain is attached to the front wheel and the rear wheel. As the evaluation criteria, various criteria according to various characteristics can be adopted. For example, for the front wheel vibration and the rear wheel vibration, the threshold value to be compared with the sum of the vibration strengths and the vibration strength are predetermined values. A configuration in which a threshold value for the number of samples as described above is set in advance can be employed. In other words, when the sum of the vibration intensity is greater than or equal to the threshold value, the configuration for determining that the tire chain is attached to the wheel, or when the number of samples whose vibration intensity is greater than or equal to the predetermined value is greater than or equal to the threshold value, It is possible to adopt a configuration that determines that a tire chain is attached to the vehicle.

DESCRIPTION OF SYMBOLS 10 ... Wear determination apparatus, 20 ... Control part, 21 ... Wear determination program, 21a ... Front wheel vibration acquisition part, 21b ... Rear wheel vibration acquisition part, 21c ... Wear determination part, 30 ... Recording medium, 30a ... Threshold information, 40 ... Vibration sensor 41 ... Amplifier 42 ... Display unit 43 ... Vehicle sensor

Claims (5)

Front wheel vibration acquisition means for acquiring front wheel vibration which is vibration excited on the road surface by the front wheel of the vehicle;
Rear wheel vibration acquisition means for acquiring rear wheel vibration which is vibration excited on the road surface by the rear wheel of the vehicle;
Mounting determination means for determining whether a tire chain is mounted on the front wheel or the rear wheel based on a comparison result between the characteristics of the front wheel vibration and the characteristics of the rear wheel vibration;
A wearing determination device comprising: The wearing determination means includes
Based on the difference between the intensity of the front wheel vibration and the intensity of the rear wheel vibration, it is determined whether a tire chain is attached to the front wheel or the rear wheel.
The wearing determination device according to claim 1. The end timing of the front wheel vibration acquired by the front wheel vibration acquisition means is:
It is a timing earlier than the start timing of the rear wheel vibration acquired by the rear wheel vibration acquisition means.
The wearing determination device according to claim 1 or 2. A front wheel vibration acquisition step of acquiring front wheel vibration which is vibration excited on a road surface by a front wheel of the vehicle;
A rear wheel vibration acquisition step of acquiring rear wheel vibration which is vibration excited on the road surface by the rear wheel of the vehicle;
A mounting determination step of determining whether a tire chain is mounted on the front wheel or the rear wheel based on a comparison result between the characteristics of the front wheel vibration and the characteristics of the rear wheel vibration;
Wear determination method including A front wheel vibration acquisition function for acquiring front wheel vibration, which is vibration excited on the road surface by the front wheels of the vehicle;
A rear wheel vibration acquisition function for acquiring rear wheel vibration which is vibration excited on the road surface by the rear wheel of the vehicle;
An attachment determination function for determining whether a tire chain is attached to the front wheel or the rear wheel based on a comparison result between the characteristics of the front wheel vibration and the characteristics of the rear wheel vibration;
Wear determination program that causes a computer to execute.

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