JP4732848B2 - Abnormality determination apparatus and abnormality determination method - Google Patents

Description

  The present invention relates to an abnormality determination device and an abnormality determination method for determining whether or not a tire is abnormal.

  Conventionally, an abnormality determination device that determines whether a tire is abnormal has been provided. For example, there is provided an abnormality determination device that determines that a tire is abnormal when the internal pressure of the tire is equal to or less than a certain value, and notifies the driver by an alarm or the like.

  However, the abnormality determination device does not detect a tire abnormality caused by a factor other than the tire internal pressure. For example, tire abnormalities caused by factors other than the tire internal pressure include peeling between the tread and the belt, between the cords constituting each belt, and between the side rubber and the carcass ply, or the ply cord. And belt cord breakage, tread chunk-out (for example, a state where a block land portion provided on the tread is stripped), and the like. If the vehicle continues to run with these abnormalities occurring, the tires will burst, making the vehicle impossible to run, resulting in a serious accident.

For this reason, there has been proposed an abnormality determination device that determines an abnormality of a tire that occurs due to a factor other than the internal pressure of the tire. For example, an abnormality determination device that measures data relating to a physical quantity including vibration or sound emitted from a tire and compares the measured data with preset data to determine whether or not the tire is abnormal. It has been proposed (for example, Patent Publication 1).
JP 2003-80912 A

  However, in the above abnormality determination device, not only the physical quantity related to the abnormality of the tire but also the physical quantity related to noise other than that is measured, so it is difficult to accurately determine whether or not the tire is abnormal.

  Therefore, the present invention has been made in view of the above points, and an object thereof is to provide an abnormality determination device and an abnormality determination method that can determine with high accuracy whether or not a tire is abnormal.

  In order to solve the above-described problems, the present invention provides a detection unit that detects a physical quantity emitted from a rotating tire, and an adaptive digital filter that extracts a specific signal from a signal corresponding to the physical quantity detected by the detection unit. And weighting means for weighting each of a plurality of specific order component signals among the signals extracted by the adaptive digital filter, and when the sum of the signals weighted by the weighting means exceeds a predetermined threshold, And determining means for determining that the tire is abnormal.

  The present invention provides a detection means for detecting a physical quantity emitted from a rotating tire, an adaptive digital filter for extracting a specific signal from a signal corresponding to the physical quantity detected by the detection means, and an adaptive digital filter. FFT processing means for converting a signal along the time axis into a signal along the frequency axis, and a removal means for removing a signal that does not exceed an envelope substantially passing through the minimum value of each amplitude of the signal converted by the FFT conversion means; And determining means for determining that the tire is abnormal when the sum of the signals of the plurality of specific order components not removed by the removing means exceeds a predetermined threshold.

  In the above invention, there is provided weighting means for weighting each of a plurality of specific order component signals that have not been removed by the removal means, and the determination means is configured such that the sum of the signals weighted by the weighting means is a predetermined threshold value. If it exceeds, it may be determined that the tire is abnormal.

  In the above invention, the weighting means may increase the weighting of the signal of the specific order component as the specific order component increases.

  In the above invention, the weighting means may weight each of the signals of the plurality of specific order components using the tire rotation speed.

  In the above invention, the determination means may set the predetermined threshold used when the tire rotation speed is changed to be larger than the predetermined threshold used when the tire rotation speed is constant.

  According to the present invention, it can be determined with high accuracy whether or not a tire is abnormal.

[First Embodiment]
An abnormality determination device 1 (abnormality determination method) in the present embodiment will be described with reference to the drawings. FIG. 1 is a diagram showing an abnormality determination device 1 in the present embodiment. As shown in FIG. 1, the abnormality determination device 1 is mounted on a vehicle and includes sensors 201 to 204, a detection unit 210, an extraction unit 220, a determination unit 230, and an abnormality output unit 240. ing.

  The sensors 201 to 204 detect a physical quantity emitted from a rotating tire. Each of the sensors 201 to 204 is disposed near the tires 111 to 114. Examples of the physical quantity in the present embodiment include vibration, sound, rotational speed, rotational speed, acceleration, and the like generated in tires and suspension parts such as suspensions.

  The detection unit 210 is a detection unit that detects a signal corresponding to the physical quantity detected by the sensors 201 to 204. The extraction unit 220 extracts a specific signal from the signal detected by the detection unit 210. The determination unit 230 is a determination unit that determines that any of the tires 111 to 114 is abnormal when the signal extracted by the extraction unit 220 exceeds a predetermined threshold. The abnormality output unit 240 is an informing means for informing, when the determination unit 230 determines that one of the tires is abnormal, by outputting a sound or displaying an image / lamp.

  FIG. 2 is a diagram showing an internal structure showing the extraction unit 220 in the present embodiment. As illustrated in FIG. 2, the extraction unit 220 includes a variable sampling circuit 221, an adaptive digital filter 222, and an FFT processing unit 223.

  The variable sampling circuit 221 is a variable sampling unit that samples the input signal x (i) corresponding to the physical quantity detected by the detection unit 210 at a cycle according to the rotation speed of the tires 111 to 114. Specifically, when the rotational speed of the tires 111 to 114 is faster than the reference speed, the variable sampling circuit 221 sets the sampling number of the signal x (i) more than usual (or sets the cycle shorter). When the rotational speed of the tires 111 to 114 is lower than the reference speed, the sampling number of the signal x (i) is set to be smaller than usual (or the period is set to be longer). Thereby, as the rotational speed of the tires 111 to 114 increases, the number of sampling of the signal x (i) increases, and finer sampling is possible, so the apparent number of sampling of the signal x (i) becomes constant. The adaptive control unit 222b described later can extract a specific signal y (i) from the signal x (i) regardless of the rotation speed of the tires 111 to 114. Note that a variable sampling circuit 221 is provided when the adaptive control unit 222b described later extracts a specific signal y (i) from the signal x (i) only when the rotational speeds of the tires 111 to 114 are constant. It does not have to be.

The adaptive digital filter 222 extracts a specific signal from the signal corresponding to the physical quantity detected by the detection unit 210, and includes a delay unit 222a, an adaptive control unit 222b, and a comparison unit 222c.

  The delay unit 222a delays the signal x (i) output from the variable sampling circuit 221. The delay unit 222a may set the time until the tires 111 to 114 make one rotation as the delay time of the signal x (i). The delay unit 222a may set the delay time of the signal x (i) according to the rotation speed of the tires 111 to 114. The delay unit 222a is provided between the detection unit 210 and the adaptive control unit 222b, but may be provided between the detection unit 210 and the comparison unit 222c.

  The adaptive control unit 222b uses the delayed signal x (i) and the signal E (i) (= R (i) −y (i)) output from the comparison unit 222c to delay the signal x A specific signal y (i) is extracted from (i). Specifically, the adaptive control unit 222b uses the least mean square method, the Newton method, or the steepest method to calculate the coefficient in the adaptive digital filter 222 according to the signal E (i) output from the comparison unit 222c. A specific signal y (i) is output from the signal x (i) by sequentially varying the signal.

  The comparison unit 222c is a signal E (i) that is a difference between the signal R (i) that is the signal x (i) output from the variable sampling circuit 221 and y (i) that is the signal output from the adaptive control unit 222b. Is output. Here, the signal y (i) is a signal (specific signal) synchronized with the rotation of the tires 111 to 114, for example, a signal that is periodically generated due to occurrence of peeling or the like in the tires 111 to 114. The signal E (i) is a signal unrelated to the signal y (i), for example, a signal related to a road surface other than a tire or a vehicle.

  The FFT processing unit 223 is an FFT processing unit that converts the signal y (i) along the time axis output from the adaptive control unit 222b into a signal along the frequency axis. FIG. 3 is a diagram illustrating a signal converted by the FFT processing unit 223 in the present embodiment. As shown in FIG. 3, when the signal y (i) along the time axis is converted into a signal along the frequency axis, the signals of a plurality of specific order components (P1, P2, P3...) Protrude significantly. . Thereby, the determination part 230 mentioned later can pinpoint the abnormality of the tire synchronizing with rotation of the tires 111-114 by using the signal of these specific order components with high precision. Note that the FFT processing unit 223 may convert the signal along the time axis output from the variable sampling circuit 221 into a signal along the frequency axis.

  FIG. 4 shows another example of the extraction unit 220 in the present embodiment, and is a diagram showing the variable sampling circuit 221, the adaptive digital filter 222, and the specific order component extraction unit 224. As shown in FIG. 4, the FFT processing unit 223 may be changed to a specific order component extraction unit 224. Among the parts shown in FIG. 4, the same parts as those shown in FIG. Since the functions of the same reference numerals are the same as those described with reference to FIG. 2, detailed description thereof is omitted here. Note that the adaptive digital filter 222 may not be provided.

  FIG. 5 is a diagram illustrating details of the specific order component extraction unit 224. As illustrated in FIG. 5, the specific order component extraction unit 224 includes bandpass filters 224-1a to 224-1n, execution value calculation units 224-2a to 224-2n, weighting units 224-3a to 224-3n, and And an adder 224-4.

  The band-pass filters 224-1a to 224-1n are specific order component extraction means for extracting a signal of a specific order component from the signal y (i) extracted by the adaptive digital filter 222. Note that the band-pass filters 224-1a to 224-1n may extract a signal of a specific order component from the signal output from the variable sampling circuit 221.

  For example, the band-pass filter 224-1a extracts a signal of the first order component (P1 shown in FIG. 3) from the signal y (i) extracted by the adaptive digital filter 222. Similarly, the band-pass filter 224-1b extracts a second-order component signal (P2 shown in FIG. 3) from the signal y (i) extracted by the adaptive digital filter 222. Signals after the third order component are similarly extracted.

  Thereby, the signal of the specific order component is directly extracted from the signal y (i) without changing the signal y (i) along the time axis extracted by the adaptive digital filter 222 to the signal along the frequency axis. Therefore, the band-pass filters 224-1a to 224-1n can extract the signal of the specific order component earlier than the FFT processing unit 223.

  The execution value calculation units 224-2a to 224-2n calculate the execution values of the signals output from the band-pass filters 224-1a to 224-1n. The execution value calculation units 224-2a to 224-2n may calculate the average value or the square of the signals output from the band-pass filters 224-1a to 224-1n.

  The weighting units 224-3a to 224-3n weight the signals output by the execution value calculation units 224-2a to 224-2n. As a result, the weighting units 224-3a to 224-3n can weight the signal of the specific order component irrelevant to the periodic signal due to the occurrence of separation or the like in the tires 111 to 114, such as zero. It is possible to extract more accurately a periodic signal due to the occurrence of peeling or the like in the tires 111 to 114. The adding unit 224-4 adds the signals output from the weighting units 224-3a to 224-3n.

  FIG. 6 illustrates another example of the extraction unit 220 in the present embodiment, and is a diagram illustrating the tracking filter 225. As illustrated in FIG. 6, the extraction unit 220 may include only the tracking filter 225. Of the parts shown in FIG. 6, the same parts as those shown in FIG. Since the functions of the same reference numerals are the same as those described in FIG. 2, detailed description thereof is omitted here.

  The tracking filter 225 extracts a signal of a plurality of specific order components corresponding to the rotation speed measured by the sensors 201 to 204 from the signal extracted by the detection unit 210. For example, when the rotation speed is Akm / h, the tracking filter 225 extracts a signal of a specific order component (for example, Pa1, Pa2, Pa3...) Regarding the rotation speed Akm / h. Similarly, when the rotation speed is Bkm / h, the tracking filter 225 extracts a signal of a specific order component (for example, Pb1, Pb2, Pb3...) Regarding the rotation speed Bkm / h.

  FIG. 7 shows another example of the extraction unit 220 in this embodiment, and is a diagram showing a variable sampling circuit 221, an adaptive digital filter 222, and a synchronous addition unit 226. As shown in FIG. 7, the FFT processing unit 223 may be changed to a synchronous addition unit 226. Of the parts shown in FIG. 7, the same parts as those shown in FIG. Since the functions of the same reference numerals are the same as those described in FIG. 2, detailed description thereof is omitted here. Note that the adaptive digital filter 222 may not be provided.

  The synchronous adder 226 is addition means for sequentially adding the signal per unit rotation extracted by the adaptive digital filter 222 for each unit rotation. Note that the synchronous adder 226 may calculate an average signal per unit rotation based on the sequentially added signals.

  FIG. 8 is a diagram illustrating a signal per unit rotation (for example, per rotation) extracted by the adaptive digital filter 222. When the synchronous addition unit 226 sequentially adds signals per rotation for each rotation, a periodic signal (for example, a signal of a specific order component such as 10 Hz, 20 Hz, or 30 Hz) due to occurrence of peeling or the like in the tires 111 to 114. ) Are added sequentially, while random signals other than the periodic signal cancel each other out. For this reason, the synchronous addition part 226 can extract more accurately the periodic signal (signal of a specific order component) by peeling etc. having occurred in the tires 111-114. The synchronous adder 226 may sequentially add the signal per unit rotation output from the variable sampling circuit 221 for each unit rotation.

  When the signal output from the FFT processing unit 223, the specific order component extraction unit 224, the tracking filter 225, or the synchronous addition unit 226 exceeds a predetermined threshold, the determination unit 230 described above is abnormal in any tire. Judge that there is.

[Second Embodiment]
FIG. 9 is a diagram illustrating the abnormality determination device 1 according to the second embodiment. As shown in FIG. 9, the abnormality determination device 1 in the second embodiment further includes a weighting unit 250 in addition to the abnormality determination device 1 in the first embodiment. Among the parts shown in FIG. 9, the same parts as those shown in FIG. Since the functions of the same reference numerals are the same as those described in FIG. 1, detailed description thereof is omitted here. In addition, the abnormality determination apparatus 1 does not need to include the weighting unit 250 when the weighting units 224-3a to 224-3n illustrated in FIG.

  The weighting unit 250 is a weighting unit that weights each of a plurality of specific order component signals among the signals extracted by the extraction unit 200.

  Here, among the signals extracted by the extraction unit 200, a periodic signal (for example, a signal of a high-order component among a plurality of specific-order component signals) due to occurrence of a failure such as separation in the tires 111 to 114. ) Has a characteristic that it is smaller than the magnitude of the low-order component signal. For this reason, even if there is a periodic signal related to the peeling or the like, the periodic signal may not exceed a predetermined threshold value, and the determination unit 230 accurately determines that the tire having a failure is abnormal. There was a case that could not be done.

  In this embodiment, when the periodic signal includes a plurality of specific order component signals, the weighting unit 250 weights each of the plurality of specific order component signals, so The unit 230 can compare a more appropriate signal of a specific order component (see FIG. 17) with a predetermined threshold value, and can determine more accurately whether or not the tire is abnormal.

In particular, the determination unit 230 assigns a higher weight to the high-order component signal among the plurality of specific-order component signals constituting the periodic signal than the low-order component signal. Thereby, since the signal of the high-order component related to the failure more reliably exceeds the predetermined threshold value, the determination unit 230 can determine with higher accuracy whether or not the tire is abnormal.
Note that the determination unit 230 is not limited to determining that one of the tires is abnormal when the plurality of weighted signals are compared with a predetermined threshold and the signal exceeds the predetermined threshold. In addition, the sum of the weighted signals (or the average value thereof) is compared with a predetermined threshold value, and if the total sum (or the average value thereof) exceeds the predetermined threshold value, one of the tires is abnormal. You may judge. This will be specifically described below.

The determination output value that is the sum of the signals weighted by the weighting unit 250 can be expressed by the following equation.

Vw: rotation speed of tire (wheel), n: specific order, A: signal of specific order component, a: constant
In the present embodiment, the elements that are “weighted” with respect to the signal A of the specific order component are Vw, n, and a as shown in the above formula 1.

  The determination unit 230 compares the determination output value calculated by the above formula 1 with a predetermined threshold, and determines that the tire related to the determination output value is abnormal when the determination output value exceeds the predetermined threshold.

  Further, the determination unit 230 sets a predetermined threshold value used when the tire rotation speed is changed (when the vehicle is accelerating or braking), when the tire rotation speed is constant (the vehicle travels at a constant speed). Set larger than a predetermined threshold value used in the above case.

  Next, an embodiment of the abnormality determination device 1 to which the above formula 1 is applied will be described with reference to FIGS. In this embodiment, the vehicle is driven at a constant speed or the vehicle is braked suddenly. In this case, tires with protrusions attached thereto (hereinafter referred to as “protrusions with protrusions” as appropriate) for each of the cases where “weighting” using Equation 1 is performed and cases where the “weighting” is not performed. ) Was verified as to whether or not the abnormality could be accurately determined.

  Note that the determination output values shown in FIGS. 10 to 15 are calculated based on the values output by the extraction unit 220 every 1/30 ms, and the calculation results are plotted. This will be specifically described below.

<Conditions for implementation>
In this example, a protrusion was attached to the tire 111 on the right side of the front wheel. The protrusion has a shape of bottom surface: tire circumferential direction length 20 mm × tire width direction length 200 mm, height: 2 mm, top surface; tire circumferential direction length 16 mm × tire width direction length 200 mm. ing.

  In the formula 1, n is 20 and a is 1.0.

<Results>
(1) When the vehicle travels at a constant speed FIG. 10A shows the case where the vehicle travels at a constant speed (Vw) of 120 km / h when “weighting” using the above equation 1 is performed. It is a figure which shows the time change of a determination output value. FIG. 10B is a diagram illustrating a temporal change in the determination output value when the vehicle travels at a constant speed of 120 km / h when the “weighting” using the equation 1 is not performed.

  “PFR” in FIG. 10 indicates a determination output value related to the tire 111 with a protrusion on the right side of the front wheel (with a protrusion). “PFL” in FIG. 10 indicates a determination output value related to the tire 112 (no protrusion) on the left side of the front wheel. The same applies to “PFR” and “PFL” in FIGS.

  As shown in FIG. 10 (a), when the “weighting” using the above formula 1 is performed, the determination output value “PFR” regarding the protruding tire 111 on the right side of the front wheel is a predetermined threshold value (here, 21 dB; Hereinafter, it can be seen that the determination output value “PFR” regarding the tire 112 on the left side of the front wheel does not exceed the constant speed threshold while the constant speed threshold is exceeded. For this reason, the abnormality determination device 1 was able to determine the abnormality of the tire 111 with the protrusion on the right side of the front wheel. The same applies to FIGS. 11 (a) and 12 (a).

  On the other hand, as shown in FIG. 10B, when the “weighting” using the above equation 1 is not performed, the determination output value “PFR” regarding the tire 111 with the protrusion on the right side of the front wheel is at a constant speed. Although there is a portion exceeding the threshold, there is also a portion where the determination output value “PFR” does not exceed the constant speed threshold.

  Also, as shown in FIG. 11 (b), when the vehicle travels at a constant speed of 100 km / h, which is slower than the constant speed in FIG. It can be seen that the determination output value “PFR” related to the tire 111 with the protrusion on the right side of the front wheel does not exceed the constant speed threshold.

  Similarly, as shown in FIG. 12 (b), when the vehicle runs at a slower constant speed of 80 km / h without performing the “weighting” using the above formula 1, the protrusion on the right side of the front wheel It can be seen that the determination output value “PFR” for the attached tire 111 does not exceed the constant speed threshold.

  Accordingly, as shown in FIGS. 10 to 12, when the “weighting” using the above equation 1 is not performed, the determination output value “PFR” for the tire 111 with the protrusion on the right side of the front wheel has a threshold value at a constant speed. In some cases, the abnormality determination device 1 may not be able to accurately determine the abnormality of the tire 111 with the protrusion on the right side of the front wheel.

  On the other hand, when the “weighting” using the above formula 1 is performed, the determination output value “PFR” for the tire 111 with the protrusion on the right side of the front wheel greatly exceeds the threshold value at the constant speed. Was able to accurately determine the abnormality of the tire 111 with the protrusion on the right side of the front wheel.

(2) When the vehicle is braked FIG. 13A shows a determination output value when the vehicle is braked at 0.4 g (g: gravitational acceleration) when “weighting” using the above equation 1 is performed. It is a figure which shows the time change of. FIG. 10B is a diagram illustrating a temporal change in the determination output value when the vehicle is braked at 4 m / s ² when the “weighting” using Expression 1 is not performed. Further, a predetermined threshold (hereinafter referred to as a braking threshold) when the vehicle is braked is a value (here, 400 dB) higher than the constant speed threshold (21 dB).

  As shown in FIG. 13 (a), when the “weighting” using the above equation 1 is performed, the determination output value “PFR” relating to the protruding tire 111 on the right side of the front wheel exceeds the braking threshold. I understand that. The same applies to FIGS. 14 (a) and 15 (a).

  On the other hand, as shown in FIG. 13B, when the “weighting” using the above equation 1 is not performed, the determination output value “PFR” related to the tire 111 with the protrusion on the right side of the front wheel is the braking threshold value. It can be seen that it does not exceed. The same applies to FIGS. 14B and 15B.

  Therefore, as shown in FIG. 10 to FIG. 12, when the “weighting” using the above formula 1 is not performed, the determination output value “PFR” for the protruding tire 111 on the right side of the front wheel exceeds the braking threshold. Therefore, the abnormality determination device 1 cannot accurately determine the abnormality of the protruding tire 111 on the right side of the front wheel.

  On the other hand, when the “weighting” using the above formula 1 is performed, the determination output value “PFR” regarding the tire with a protrusion 111 on the right side of the front wheel exceeds the braking threshold value, and therefore the abnormality determination device 1 Was able to accurately determine the abnormality of the tire 111 with the protrusion on the right side of the front wheel.

  Further, the braking threshold used when the vehicle brakes is set to be larger than the constant speed threshold used when the vehicle travels at a constant speed. The reason for this will be described in detail below. Specifically, when the vehicle is braked at a constant speed, a greater weight is applied to the front tire when the vehicle is braked, and the determination output value related to the front tire is further increased.

  For this reason, when the vehicle is braked, if the constant speed threshold value used when the vehicle travels at a constant speed is used as it is as the braking threshold value, not only the tire with the protrusion on the front wheel but also the protrusion As a result, the determination output value regarding the tire without the tire also exceeded the braking threshold value, and the abnormality determination device 1 could not accurately determine the abnormality of the tire 111 with the protrusion on the front wheel.

  However, in this embodiment, when the vehicle is braked, a large weight is applied to the front tire, and the braking threshold is set larger than the constant speed threshold even when the determination output value related to the front tire is large. For this reason, the determination output value for only the tire with the protrusion on the front wheel exceeded the braking threshold value. For this reason, the abnormality determination device 1 can accurately determine the abnormality of the tire 111 with the protrusion on the front wheel even when the vehicle brakes.

  FIG. 16 is a diagram illustrating another example of the abnormality determination device 1 according to the second embodiment. As shown in FIG. 16, another abnormality determination device 1 in the second embodiment further includes a removal unit 260 in addition to the abnormality determination device 1 in the first embodiment. Of the parts shown in FIG. 16, the same parts as those shown in FIG. 1 are denoted by the same reference numerals, and detailed description thereof will be omitted. Note that the input side of the removal unit 260 in this embodiment is connected to the output side of the FFT processing unit 223.

  The removing unit 260 removes a signal (instantaneous value) that does not exceed an envelope that substantially passes through the minimum value of each amplitude of the signal converted by the FFT processing unit 223 (that is, a signal indicating a temporal change in frequency). It is. FIG. 17 is a diagram illustrating an envelope H of the signal converted by the FFT processing unit 223. As shown in FIG. 17, the minimum amplitude A of the P1 order component signal, the minimum amplitude B of the P2 order component signal,..., Approximately pass through the minimum amplitude R of the P18 order component signal. The curve becomes the envelope H.

  FIG. 18 is a diagram illustrating the frequency f1 of the order component of P1 and the vicinity of the frequency f1. As shown in FIG. 18, when the signal (instantaneous value) that does not exceed the envelope H is removed, for example, only the magnitude of L2 out of the magnitude of P1 remains. As a result, signals (instantaneous values) that do not exceed the envelope H are removed, so that signals of a plurality of specific order components (P1, P2, P3,..., P18) that exceed the envelope H (the envelope shown in FIG. 17). Signal from which the portion surrounded by the line H is removed) remains. Since the remaining specific order component signal is a characteristic signal related to a periodic signal due to the occurrence of separation or the like in the tires 111 to 114, the determination unit 230 determines only the remaining specific order component signal. By using this, it can be determined with higher accuracy whether or not the tire is abnormal.

  Here, when the sum (or average value) of signals (instantaneous values) exceeding the envelope H exceeds a predetermined threshold, the determination unit 230 determines that one of the tires is abnormal. Note that the weighting unit 250 described above may weight each of a plurality of specific order component signals that have not been removed by the removal unit 260. Further, the determination unit 230 may determine that one of the tires is abnormal when the sum (or average value) of the signals weighted by the weighting unit 250 exceeds a predetermined threshold.

[Third Embodiment]
FIG. 19 is a diagram illustrating tires 111 to 114 and signals PFR, PFL, PRR, and PRL corresponding to the tires 111 to 114 in the third embodiment. Here, the signal PFR corresponding to the tire 111 is a signal related to the tire 111 and a signal output to the determination unit 230. The signal PFL corresponding to the tire 112 is a signal related to the tire 112 and is a signal output to the determination unit 230. The signal PRR corresponding to the tire 113 is a signal related to the tire 113 and is a signal output to the determination unit 230. The signal PRL corresponding to the tire 114 is a signal related to the tire 114 and is a signal output to the determination unit 230. In addition, the signals PFR, PFL, PRR and PRL corresponding to the tires 111 to 114 include the above-described extraction unit 220 (adaptive control unit 222b, FFT processing unit 223, specific order component extraction unit 224, tracking filter 225, or synchronous addition unit). 226), a signal output from the weighting unit 250 or the removal unit 260. In the present embodiment, the detection unit 210, the extraction unit 220, and the determination unit 230 perform each function for each tire.

  The determination unit 230 is a determination unit that determines that the tire is abnormal when the value of the difference between the two signals output to the determination unit 230 exceeds a predetermined threshold. For example, the determination unit 230 includes two tires (for example, the front tires 111 and 112 or the rear tires 113 and 114) that are rotatably supported on the same axis among the signals output to the determination unit 230. When the difference value (for example, PFR-PFL, or PRR-PRL) of each signal (for example, PFR and PFL, or PRR and PRL) corresponding to 1 exceeds a predetermined threshold, it is determined that the tire is abnormal. To do.

  According to such a feature, the determination unit 230 can determine that any one of the tires is abnormal by comparing a signal related to one tire with a signal related to another tire.

  Next, another process for determining whether or not a tire is abnormal will be described. Here, the determination unit 230 determines and determines any two signals from among the signals output to the determination unit 230 in accordance with the vehicle travel conditions (for example, constant travel, acceleration / deceleration, etc.). It is determined whether or not the tire is abnormal using the value of the difference between the two signals. Specifically, it is as follows.

  The determination unit 230 includes two tires (for example, the front tire 111) that are rotatably supported on the same axis among the signals output to the determination unit 230 when the vehicle is traveling or accelerating / decelerating at a constant speed. And 112, or the subsequent tires 113 and 114) (for example, PFR and PFL, or PRR and PRL) difference values (for example, PFR-PFL or PRR-PRL) exceeded a predetermined threshold value. In the case, it is determined that the tire is abnormal.

  The determination unit 230 also includes a signal PFR (or signal PFL) corresponding to the previous tire 111 (or tire 112) among the signals output to the determination unit 230 when the vehicle is traveling or turning at a constant speed. And the signal PRR (or signal PRL) corresponding to the tire 113 (or tire 114) after being provided in the straight traveling direction of the front tire 111 (or tire 112) (for example, PFR-PRR, When (PFL-PRL) exceeds a predetermined threshold value, it is determined that the tire is abnormal.

Further, the determination unit 230 is a signal corresponding to the previous tire 111 (or tire 112) among the signals output to the determination unit 230 when the vehicle is traveling normally (for example, acceleration / deceleration + turning). Addition of PFR (or signal PFL) and signal PRL (or signal PRR) corresponding to tire 114 (or tire 113) after being provided on the diagonal direction of the preceding tire 111 (or tire 112) (for example, , PFR + PRL, PFL + PRR) exceeds a predetermined threshold value, it is determined that the tire is abnormal.
Next, the other process for determining whether or not the tire is abnormal will be specifically described with reference to FIG. Here, the determination unit 230 determines whether or not the tire is abnormal according to the “vehicle running condition” and the “determination element”.

  FIG. 20 is a diagram illustrating a traveling condition (running state) of the vehicle and determination elements used for determining whether or not the tire is abnormal based on the traveling condition. The vehicle running conditions include vehicle acceleration / deceleration, turning, and normal running (for example, acceleration / deceleration + turning). The determination unit 230 can determine the traveling condition of the vehicle by using an acceleration sensor or the like.

  Further, the determination elements corresponding to the acceleration / deceleration of the vehicle include a determination element A of (PFR-PFL) and a determination element B of (PRR-PRL). Further, the determination elements corresponding to the turning of the vehicle include a determination element A of (PFR-PRR) and a determination element B of (PFL-PRL). Further, determination elements corresponding to normal traveling of the vehicle (for example, acceleration / deceleration + turn) include determination element A of (PFR + PRL) and determination element B of (PFL + PRR).

  When the vehicle accelerates, the determination unit 230 specifies a large determination element among the determination element A of (PFR-PFL) and the determination element B of (PRR-PRL), and the specified determination element is predetermined. If the threshold is exceeded, it is determined that one of the tires is abnormal. For example, when a failure K such as peeling (see FIG. 19) exists in the tire 111, a periodic signal related to the failure K is generated as the tire 111 rotates.

  For this reason, the signal PFR related to the tire 111 is larger than the signal PFL related to the tire 112, and the determination element A (PFR-PFL) is also larger than the determination element B (PRR-PRL). In this case, the determination unit 230 selects the determination element A (PFR-PFL), and determines that the tire 111 is abnormal when the selected determination element A exceeds a predetermined threshold value.

  Further, when the vehicle turns, the determination unit 230 specifies a large determination element of the determination element A of (PFR-PRR) or the determination element B of (PFL-PRL), and the specified determination element If it exceeds a predetermined threshold value, it is determined that one of the tires is abnormal. Further, when the vehicle travels normally (for example, acceleration / deceleration + turn), the determination unit 230 specifies a large determination element of the determination element A of (PFR + PRL) or the determination element B of (PFL + PRR), When the determination element exceeds a predetermined threshold, it is determined that the tire related to the determination element is abnormal.

  Here, the predetermined threshold value is a difference value between signals corresponding to normal tires. For example, when the determination element A of (PFR−PFL) is used, the predetermined threshold value is a signal PFR output to the determination unit 230 when the normal tires 111 and 112 (tires without failure) are used. This is the difference value from the signal PFL. Further, when the determination element B of (PRR−PRL) is used, the predetermined threshold value is a difference between the signal PRR and the signal PRL output to the determination unit 230 when the normal tires 113 and 114 are used. Value. Further, the same applies to the predetermined threshold when other (PFR-PRR), (PFL-PRL), (PFR + PRL), and (PFL + PRR) determination elements are used. The predetermined threshold value may be a preset value, or may be a difference value of each signal corresponding to each normal tire, and may be an average value of the stored difference values. May be.

  According to such a feature, when the vehicle is accelerating, a larger load is applied to the rear tires 113 and 114 than the front tires 111 and 112, and a difference occurs in the wheel speed. Therefore, when the vehicle is accelerating, the determination unit 230 determines whether the rear tires 113 and 114 are abnormal by using the signal PRR and the signal PRL related to the rear tires 113 and 114. (See “Acceleration / Deceleration” and “Decision Element B” shown in FIG. 20).

  On the other hand, when the vehicle is decelerating, a large load is applied to the tires 111 and 112 ahead of the rear tires 113 and 114, and a difference occurs in the wheel speed. Therefore, when the vehicle is decelerating, the determination unit 230 determines whether or not the previous tires 111 and 112 are abnormal by using the signal PFR and the signal PFL related to the previous tires 111 and 112. (See “Acceleration / Deceleration” and “Determining Element A” shown in FIG. 20).

  Further, when the vehicle is turning to the left, a larger load is applied to the outer tires 111 and 113 than the inner tires 112 and 114, and a difference occurs in the wheel speed. Therefore, when the vehicle is turning left, the determination unit 230 uses the signal PFR and the signal PRR related to the outer tires 111 and 113 to determine whether or not the outer tires 111 and 113 are abnormal. It can be determined (see “turn” and “determination element A” shown in FIG. 20).

  On the other hand, when the vehicle is turning to the right, a larger load is applied to the outer tires 112 and 114 than the inner tires 111 and 113, and a difference occurs in the wheel speed. Therefore, when the vehicle is turning to the right, the determination unit 230 uses the signal PFL and the signal PRL related to the outer tires 112 and 114 to determine whether or not the outer tires 112 and 114 are abnormal. It can be determined (see “turn” and “determination element B” shown in FIG. 20).

  Further, even when the vehicle is traveling normally (for example, acceleration / deceleration + turning), the determination unit 230 can determine whether or not the tire related to the normal traveling of the vehicle is abnormal for the same reason as described above ( (See “During normal travel” and “Determination elements A and B” shown in FIG. 20).

  Next, another example of the process for determining whether or not the tire is abnormal will be specifically described with reference to FIG. Here, the determination unit 230 does not specify the “vehicle running condition”, and the tire is abnormal by using the determination element that is the “smallest difference value” of the difference values of two signals related to the tire. It is determined whether or not.

  FIG. 21 is a diagram illustrating vehicle travel conditions (not specified here) and determination elements. In the determination unit 230, the determination element that is the difference value between the two smallest signals among the signals output to the determination unit 230 (for example, min (PFR-PFL, PFR-PRR, PFR-PRL)) is the above-described determination element. When the predetermined threshold is exceeded, it is determined that the tire related to the determination element is abnormal.

  Here, when the vehicle is accelerating, the rear tires 113 and 114 are weighted, and the difference value (PFR−PFL) of each signal related to the front tires 111 and 112 is the difference between the other signals. Smallest compared to the value.

  Therefore, the determination unit 230 uses the smallest difference value (PFR−PFL) as a determination element without specifying whether or not the vehicle is accelerating, thereby determining the tires 111 and 112 (determination) regarding the determination element. It can be determined whether or not the tire related to the element is abnormal.

  On the other hand, when the vehicle is decelerating, the front tires 111 and 112 are weighted, and the difference value (PRR-PRL) of each signal related to the rear tires 113 and 114 is the difference value of each other signal. The smallest compared to. Therefore, the determination unit 230 uses the smallest difference value (PRR-PRL) as a determination element without specifying whether or not the vehicle is decelerating, so that the tires 113 and 114 related to the determination element are abnormal. It can be determined whether or not.

  Similarly, when the vehicle is turning, a weight is applied to the right side or the left side with respect to the traveling direction of the vehicle, and the difference value (PFR-PRR) of each signal related to the tires 111 and 113, or the tire 112 and One of the difference values (PFL−PRL) of each signal relating to 114 is the smallest compared to the difference value of each other signal.

  Therefore, the determination unit 230 does not specify whether or not the vehicle is turning, and uses either (PFR-PRR) or (PFL-PRL) having the smallest difference value as a determination element. It can be determined whether or not the tires 111 and 113 (or the tires 112 and 114) related to the determination element are abnormal.

  Even when the vehicle is traveling normally (for example, acceleration / deceleration + turning), the determination unit 230 determines whether the tire related to the determination element when the vehicle is traveling normally is abnormal for the same reason as described above. Can be determined.

  In addition, the determination unit 230 outputs an average value of signals corresponding to the front tire 111 (or tire 112) and signals corresponding to the rear tire 113 (or tire 114) among the signals output to the extraction unit 220. If there is a difference between the average value and the average value of either one is adjusted to the other average value (so-called offset adjustment), the difference value between the two signals output to the extraction unit 220 is the predetermined value. If the threshold is exceeded, it may be determined that the tire is abnormal.

  Here, a connection for connecting the two axles is provided between an axle that rotatably supports the front tire 111 and the tire 112 and an axle that rotatably supports the rear tire 113 and the tire 114). A member is provided.

  Thereby, since the connecting member is provided, the physical quantity emitted from the front tire 111 (or tire 112) and the physical quantity emitted from the rear tire 113 (or tire 114) are dispersed by the connecting member, etc. The magnitude of the physical quantity will be different.

  Therefore, there is a difference between the average value of the signal PFR (or signal PFL) related to the front tire 111 (or tire 112) and the average value of the signal PRR (or signal PRL) related to the rear tire 113 (or tire 114). May occur.

  Here, by performing the offset adjustment, the determination unit 230 causes the average value of the signal PFR (or signal PFL) regarding the previous tires 111 and 112 and the signal PRR (or the tire 114 (or the tire 114)). The deviation from the average value of the signal PRL) is eliminated. Accordingly, the determination unit 230 can more appropriately calculate the difference value between the signal related to the previous tire and the signal related to the subsequent tire, and can determine with high accuracy whether or not the tire is abnormal. .

It is a figure which shows the abnormality determination apparatus in 1st Embodiment. It is a figure which shows the extraction part in 1st Embodiment (the 1). It is a figure which shows the signal converted by the FFT process part in 1st Embodiment. It is a figure which shows the extraction part in 1st Embodiment (the 2). It is a figure which shows the extraction part in 1st Embodiment (the 3). It is a figure which shows the extraction part in 1st Embodiment (the 4). It is a figure which shows the extraction part in 1st Embodiment (the 5). It is a figure which shows the signal output to the synchronous addition part in 1st Embodiment. It is a figure which shows the abnormality detection apparatus in 2nd Embodiment (the 1). It is a figure which shows the time change of the determination output value in an Example. It is a figure which shows the time change of the determination output value in an Example. It is a figure which shows the time change of the determination output value in an Example. It is a figure which shows the time change of the determination output value in an Example. It is a figure which shows the time change of the determination output value in an Example. It is a figure which shows the time change of the determination output value in an Example. It is a figure which shows the abnormality detection apparatus in 2nd Embodiment (the 2). It is a figure which shows the signal converted by the FFT process part in 2nd Embodiment. It is a figure which shows the frequency of the order component of P1, and its peripheral frequency in 2nd Embodiment. It is a figure which shows the signal regarding each tire and each tire in 3rd Embodiment. It is a figure which shows the driving condition and determination element of the vehicle in 3rd Embodiment (the 1). It is a figure which shows the driving condition and determination element of the vehicle in 3rd Embodiment (the 2).

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Abnormality determination apparatus, 111-114 ... Tire, 200 ... Extraction part, 201-204 ... Sensor, 210 ... Detection part, 220 ... Extraction part, 221 ... Variable sampling circuit, 222 ... Adaptive digital filter, 222a ... Delay part, 222b ... Adaptive control unit, 222c ... Comparison unit, 223 ... FFT processing unit, 224 ... Band bus filter, 225 ... Tracking filter, 226 ... Synchronous addition unit, 230 ... Signal determination unit, 230 ... Determination unit, 240 ... Abnormal output unit , 250 ... weighting unit, 260 ... removal unit

Claims (5)

Detection means for detecting a physical quantity emitted from a rotating tire;
An adaptive digital filter for extracting a specific signal from a signal corresponding to the physical quantity detected by the detection means;
Weighting means for weighting each of a plurality of signals of a specific order component among signals extracted by the adaptive digital filter;
Determination means for determining that the tire is abnormal when the sum of the signals weighted by the weighting means exceeds a predetermined threshold ;
The adaptive digital filter is:
A delay unit in which a delay time of the signal is set according to the rotation speed of the tire;
An adaptive control unit for extracting a specific signal from the delayed signal;
A comparator that outputs a difference between the signal before being delayed and the specific signal extracted by the adaptive controller;
With
The adaptive control unit extracts the specific signal based on the delayed signal and the difference signal output by the comparison unit,
The weighting unit performs weighting such that the periodic signal is extracted with respect to a signal of a specific order component irrelevant to the periodic signal among the extracted specific signals.
An abnormality determination device characterized by the above. Detection means for detecting a physical quantity emitted from a rotating tire;
An adaptive digital filter for extracting a specific signal from a signal corresponding to the physical quantity detected by the detection means;
FFT processing means for converting a signal along the time axis extracted by the adaptive digital filter into a signal along the frequency axis;
Weighting means for weighting each of a plurality of signals of specific order components among the signals converted by the FFT processing means;
Removing means for removing a signal that does not exceed an envelope substantially passing through the minimum value of each amplitude of the signal of the specific order component weighted by the weighting means ;
Determination means for determining that the tire is abnormal when the sum of signals from which signals that do not exceed the envelope exceed the predetermined threshold ,
The adaptive digital filter is:
A delay unit in which a delay time of the signal is set according to the rotation speed of the tire;
An adaptive control unit for extracting a specific signal from the delayed signal;
A comparator that outputs a difference between the signal before being delayed and the specific signal extracted by the adaptive controller;
With
The adaptive control unit extracts the specific signal based on the delayed signal and the difference signal output by the comparison unit,
The weighting means increases the weighting of the signal of the specific order component as the specific order component increases.
An abnormality determination device characterized by the above. Said weighting means, the abnormality determination apparatus according to claim 1 or claim 2, wherein the weighting for each signal of said plurality of specific order component using a rotational speed of the tire. The said determination means sets the said predetermined threshold value used when the rotational speed of the said tire changes larger than the said predetermined threshold value used when the rotational speed of the said tire is constant, or characterized by the above-mentioned. The abnormality determination device according to claim 2 . Detecting a physical quantity emitted from a rotating tire;
Extracting a specific signal from a signal corresponding to the detected physical quantity;
Weighting each of a plurality of specific order component signals of the extracted signals;
Determining that the tire is abnormal if the sum of the weighted signals exceeds a predetermined threshold ;
In the step of extracting the specific signal,
The delay time of the signal is set according to the rotation speed of the tire,
The difference between the signal before being delayed and the specific signal extracted by the adaptive control unit is output,
The specific signal is extracted based on the delayed signal and the difference signal;
In the weighting step, weighting is performed such that the periodic signal is extracted with respect to a signal of a specific order component unrelated to the periodic signal.
An abnormality determination method characterized by the above.

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