JP2001108702A - Bad road determination device and bad road determination method - Google Patents

Abstract

(57) [Summary] [Problem] To quickly and accurately determine whether or not a road is bad. SOLUTION: A wavelet transform is performed on a deceleration G of a vehicle by using a complex function, a time when the phase θ becomes zero from 2π is detected as a time t1 of a first maximum value of the deceleration G, and the phase θ is detected. The time when π is reached is detected as the time t3 of the first minimum value of the deceleration G. The first integral value S1 from the first maximum value of the deceleration G to the value 0 and the second integral value S2 from the value 0 to the first minimum value are calculated, and the ratio (S2 / S3) is calculated. Is determined to be a bad road when the absolute value of is larger than the threshold value. This determination is based on the fact that a change in the deceleration G on a rough road is caused by a vibration component. Since the calculation up to the time of the first minimum value is sufficient, it can be quickly determined whether or not the road is bad. Also, since the time of the first maximum value and the time of the first minimum value are detected using the wavelet transform,
Erroneous detection due to noise or the like can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a rough road determination device and a rough road determination method, and more particularly, to a rough road determination device and a rough road determination method for determining that a vehicle is traveling on a rough road.

[0002]

2. Description of the Related Art Conventionally, as this kind of rough road determination device or method, a starting device for activating an occupant protection device such as an airbag device is used. There has been proposed a device that determines a bad road when the time exceeds a predetermined time (for example, Japanese Patent Application Laid-Open No. H10-67295). In this device, when it is determined that the road is rough, the acceleration value at the time from the peak to the next peak is treated with a small weight, so that the acceleration caused by the rough road when traveling on a rough road is treated. The vibration component is removed.

Further, there has been proposed an apparatus in which a low-frequency low-pass filter process is performed on a signal from a G sensor, and a collision between a rough road and a vehicle is determined based on whether or not a waveform remains after the filter process. .

[0004]

However, when a rough road is determined based on the time from the first peak of acceleration to the next peak, it takes time to detect the peak and the time required to detect the second peak. In other words, it may not be possible to make a quick determination. Further, when a low-pass filter is used, it may take time to make a determination, or a waveform due to collision may be removed by the low-pass filter.

[0005] One of the objects of the rough road determination device and the rough road determination method of the present invention is to quickly determine whether or not the road is rough.

[0006]

Means for Solving the Problems and Functions / Effects The bad road determination apparatus and the bad road determination method of the present invention employ the following means in order to achieve at least a part of the above object.

A bad road determining device according to the present invention is a bad road determining device for determining that a vehicle is traveling on a bad road, and includes deceleration detecting means for detecting deceleration of the vehicle, A first maximum value of the deceleration, and a first maximum value following the first maximum value.
A local minimum value detecting means for detecting a local minimum value, and a first integration from the detected first local maximum value to the deceleration value of 0 when the detected first local minimum value is a negative value. An integral calculating means for calculating a value and a second integral value from when the deceleration becomes the value 0 until the deceleration becomes the first minimum value, and the calculated first integral value and the second integral value The gist of the present invention is to include a rough road determination unit that determines a rough road based on the rough road.

In the rough road judging device of the present invention, the local maximum value detecting means includes a first maximum value of the deceleration of the vehicle detected by the deceleration detecting means and a first maximum value following the first maximum value. Detecting a local minimum value, and when the detected first local minimum value is a negative value, the integration calculating means calculates a first integrated value from the detected first local maximum value to a value of zero deceleration; The deceleration value is 0
And a second integral value until the first minimum value is obtained. Then, the rough road determining means determines the calculated first
A bad road is determined based on the integral value and the second integral value. The determination of a rough road in the rough road determination device of the present invention is based on the fact that a change in deceleration due to a rough road is derived from a vibration component.
That is, since the change in the deceleration due to the rough road is derived from the vibration component, the first minimum value is often negative, and the magnitude is not as large as the first maximum value, but is a certain value. Since the change in deceleration due to the collision does not originate in the vibration component, the first minimum value is rarely negative, and even if a negative value is taken, the magnitude is small.

According to the rough road determination device of the present invention,
Since it is determined whether or not the vehicle is on a rough road by detecting up to the first minimum value, it is possible to determine whether or not the vehicle is on a rough road more quickly than that which detects the second maximum value. Further, since the determination is made based on the difference between the change in the deceleration due to the bad road and the change in the deceleration due to the collision, it is possible to more reliably determine whether or not the road is bad.

In the rough road judging device according to the present invention, the maximum / minimum value detecting means performs a product-sum operation using a predetermined complex function as a basis of integration with respect to the deceleration detected by the deceleration detecting means. Sum operation means, phase operation means for calculating a phase based on the real part and imaginary part of the result of the product-sum operation, and the first maximum value and the first minimum value based on the calculated phase. And a maximum / minimum determination means for determining As a method of detecting the first maximum value and the second minimum value, there is a method based on a differential operation. However, by using this method, that is, a method using a wavelet transform, a product-sum operation is performed without performing a differential operation. And erroneous detection of peaks due to noise and the like can be prevented. In the wavelet transform, since a function localized both in terms of time and frequency is used, the first maximum value and the first minimum value can be quickly detected. As a result, it is possible to more quickly determine whether or not the road is rough. In the rough road determination device of this aspect of the present invention, the local maximum determining unit determines the time when the calculated phase changes from 2π to zero as the first maximum value, and the changed phase becomes π. The time may be determined as the first minimum value.

Further, in the rough road determination device according to the present invention, the rough road determination means includes the first integral value of the second integral value.
When the ratio to the integral value is equal to or more than a predetermined value, it may be determined that the road is bad.

The method for determining a bad road according to the present invention is a method for determining that a vehicle is traveling on a bad road, wherein the first maximum value of the deceleration of the vehicle and the first maximum value are set. Is detected, and when the detected first minimum value is a negative value, the first integration from the detected first maximum value to when the deceleration becomes a value 0 is detected. The gist of the present invention is to determine a bad road based on the value and a second integral value from when the deceleration becomes the value 0 until the deceleration becomes the first minimum value.

In the method for determining a rough road according to the present invention, it is determined whether the road is a rough road by detecting up to the first minimum value. Can be determined. Further, similarly to the bad road determination device of the present invention, the determination is made based on the difference between the change in the deceleration due to the bad road and the change in the deceleration due to the collision. Can be.

In the method for determining a bad road according to the present invention,
The product-sum operation is performed using a predetermined complex function as a basis for integration with respect to the deceleration of the vehicle, and the phase of the real part and the imaginary part of the result of the product-sum operation changes from 2π to zero first. The deceleration may be detected as a first maximum value, and the deceleration when the phase becomes π after the detection of the first maximum value may be detected as a first minimum value. This way,
Since the differential operation is not performed, erroneous detection of the first maximum value or the first minimum value due to noise or the like can be prevented.

[0015]

Next, embodiments of the present invention will be described with reference to examples. FIG. 1 is a configuration diagram schematically showing a configuration of a rough road determination device 20 according to an embodiment of the present invention by functional blocks, and FIG. 2 is a configuration diagram schematically showing a hardware configuration of the rough road determination device 20 of the embodiment. FIG. 3 is an explanatory diagram exemplifying a state in which the rough road determination device 20 of the embodiment is mounted on the vehicle 10. As shown in FIG. 1, the rough road determination device 20 of the embodiment includes a G sensor 22 installed near the center console of the vehicle 10 to detect the deceleration of the vehicle 10, and a signal detected by the G sensor 22. A signal input unit 24 for inputting and smoothing the signal; a local maximum value detecting unit 26 for detecting a first local maximum value of the signal subjected to the smoothing process and a time of a first local minimum value occurring after the first local maximum value And a first integral value from the first maximum value of the signal smoothed by the signal input unit 24 until the signal becomes a value 0 and a second integral value from the time the signal becomes the value 0 to the first minimum value An integral operation unit that computes a value and a bad road determination unit 30 that determines whether the road is a bad road based on the first integral value and the second integral value computed by the integral operation unit 28 are provided.

As shown in FIG. 2, the hardware configuration of the rough road judging device 20 of the embodiment is the same as that of FIG.
Microcomputer 31 configured around 32
It consists of. The microcomputer 31
ROM 34 storing a processing program in addition to the CPU 32
, A RAM 36 for temporarily storing data, and an input processing circuit 38. When the processing program stored in the ROM 34 is activated, the respective units of the rough road determination device 20 of the embodiment illustrated in FIG. 1 function as a single piece of software and hardware.

The bad road judging device 20 according to the embodiment configured as described above is used for performing a pre-process in a starting process of an occupant protection device such as an air bag device mounted on a vehicle. This is because in the activation process of the occupant protection device, first, it is necessary to determine whether a vehicle collision has occurred or the vehicle is traveling on a rough road. Therefore, in the description of the embodiment, the device is configured and described as a rough road determination device for determining a rough road. However, it is needless to say that the device may be incorporated as a part of the occupant protection device. In this case, the microcomputer 31 functions as an electronic control unit of the occupant protection device. In FIG. 3, G sensors 14 and 16, which are attached to the left and right front side members of the vehicle to detect deceleration, detect signals required for the activation process of the occupant protection device.

The signal input unit 24 in the rough road determination device 20 of the embodiment includes a Kalman filter process for removing a high frequency component caused by vibration as a process for smoothing a signal from the G sensor 22 and a movement by a predetermined number of samplings. And moving average processing for calculating an average. In the embodiment, the sampling frequency is set to 2 kHz (0.5 msec as a sampling period), and the number of samplings in the moving average process is set to 10 times.

The local maximum / minimum value detecting section 26 includes a signal input section 24
, The time of the first maximum value and the time of the first minimum value are detected using the wavelet transform on the signal subjected to the smoothing process.
FIG. 4 is a configuration diagram schematically illustrating the configuration of the local maximum / minimum value detection unit 26 using functional blocks. As shown in the figure, the maximum / minimum value detection unit 26 performs a product-sum operation using a predetermined complex function as a basis for integration of the input signal.
And a phase calculator 44 for calculating the phase θ of the magnitude based on the result of the product-sum operation, that is, the real part R and the imaginary part I of the wavelet transform value, and the first phase based on the calculated phase θ A maximum / minimum determining unit 46 for determining the time of the maximum value and the time of the first minimum value is provided. Hereinafter, the principle by which the local maximum value detecting unit 26 can detect the time of the first local maximum value and the time of the first local minimum value will be briefly described.

As a wavelet transform X (a, b) of the time-series signal X (t), a basic wavelet function ψ (t) localized in time and frequency is prepared. After the a-times scale conversion as shown in
This is an expansion exemplified in Expression (2) in which a set of similar functions ψa, b (t) obtained by performing a shift conversion (parallel movement) is a basis function. Note that the scale conversion parameter a has a relationship proportional to the reciprocal of the conversion frequency f.

[0021]

(Equation 1)

In the embodiment, the basic wavelet function ψ
As (t), Gabo shown in the following equation (3) is a complex function in which the imaginary part I is shifted in phase by π / 2 with respect to the real part R.
The r function was used. Here, ωo in the equation (3) is the frequency f
(Ωo = 2πf), and α is also a constant.

[0023]

(Equation 2)

In equation (3), when α = π, Ga
FIG. 5 illustrates a representation of the bor function on the time axis. As shown in the figure, the Gabor function is localized in the range of -T to T on the time axis, and the phases of the waveforms of the real part and the imaginary part are π / π.
It is off by two. The wavelet transform for the time-series signal X (t) is, specifically, a product-sum operation of the time-series signal X (t) and a function that appropriately selects a scale conversion parameter a (ωo in Equation (3)). Become. As a calculation section, a range in which the waveform is localized (a range of -T to T in FIG. 5)
It is. This range is called a window.

The wavelet transform X (a, b) of the time-series signal X (t) by the Gabor function becomes a complex number because the Gabor function is a complex function. FIG. 6 shows the relationship among the real part R, the imaginary part I, the magnitude P, and the phase θ of the wavelet transform X (a, b). The magnitude P is calculated by the following equation (4), and the phase θ is obtained by the equation (5). Here, the size P means a convenient size of the wavelet transform X (a, b), and is a dimensionless quantity. The phase θ is 0 to 0 depending on the magnitude and sign of the real part R and the imaginary part I.
The range is 2π.

[0026]

(Equation 3)

FIG. 7 is an explanatory diagram illustrating the relationship between the time-series signal X (t) and the phase θ (t) of the wavelet transform X (a, b). In the figure, the frequency of the time-series signal X (t) is 50 [Hz] in the section A, 100 [Hz] in the section B,
The section C is 200 [Hz], and the sampling frequency of the time-series signal X (t) is 2 k [Hz]. Phase θ
(T) indicates that the conversion frequency f is set to 1.5 octaves up and down around 125 [Hz], and the frequency range is divided by 1/2 octave, and the width of the window is set to the period T of the conversion frequency f.
(T = 1 / f) twice. In addition, as mentioned above,
The conversion frequency f is ωo in the Gabor function of equation (3).
And ωo = 2πf, the phase θ (t)
Is a calculation using the Gabor function of Equation (3) obtained by substituting a constant ωo determined from the conversion frequency f into the time-series signal X (t).

As shown in the figure, at the phase θ (t) of the conversion frequency f close to the frequency of the time series signal X (t), the time when the amplitude of the time series signal X (t) reaches a maximum (peak) (in the figure). t
At (1, t3, t5), it changes from 2π to zero, and becomes π at the time when the minimum (bottom) occurs (t2, t4, t6 in the figure).
This is explained as follows. Gabo shown in equation (3)
In the r function, the waveform of the imaginary part I is shifted by π / 2 from the waveform of the real part R as illustrated in FIG. Now, consider a case where the conversion frequency f substantially matches the frequency of the time-series signal X (t). When the amplitude of the time-series signal X (t) is the maximum, the waveform of the time-series signal X (t) and the waveform of the real part R of the Gabor function match so as to be superimposed. On the other hand, since the waveform of the imaginary part I is shifted by π / 2, the sum of the products is 0. Therefore, the phase θ is calculated as 2π or zero by the equation (5). By appropriately selecting the signs of the real part R and the imaginary part I in Equation (3), the phase θ (t) can be changed from 2π to zero before and after the maximum.
When the amplitude of the time series signal X (t) is minimal, the waveform of the time series signal X (t) and the waveform of the real part R of the Gabor function are superimposed with different signs, so that the product-sum operation in the real part R is negative. While the sum of products of the imaginary part I also takes the value 0. Therefore, the phase θ is calculated as π by Expression (5). It should be noted that such a relationship does not require that the frequency of the time-series signal X (t) and the transform frequency f of the wavelet completely match each other. It is understood from FIG. 7 that the conversion frequency f may be set.

The time delay td of the detection of the maximum or the minimum is shown in FIG.
As can be seen from the waveform of FIG.
When the waveform overlaps with the waveform of the real part R of the function, it becomes half of the time (operation section) required for the operation, that is, the period T. For example, when the conversion frequency f is 125 [Hz], it is 8 msec. If the purpose is only to detect the maximum or minimum time of the time-series signal X (t), the entire section of the window shown in FIG. A narrow range may be set as the calculation section. In this case, the ratio of the calculation section to the width of the window is referred to as a window coefficient K. FIG. 8 shows the relationship between the window width and the window coefficient K. The relationship between the detection time delay td and the window coefficient K is td = KT. For example, when the conversion frequency f is 125 [Hz] and the window coefficient K is 0.12
In the case of 5, the detection time delay td is 1 msec. When the window coefficient K is reduced in this way, the detection time delay td can be reduced, and the amount of calculation is also reduced.

The conversion frequency f is determined by the rough road determination device 2 of the embodiment.
It is desirable to set the value by performing a rough road running experiment, a collision experiment, or the like using a vehicle on which 0 is mounted. This can be understood from the relationship between the conversion frequency f and the detection sensitivity.
9 and 10 are explanatory diagrams illustrating an example of a relationship between a signal (deceleration signal) detected by the G sensor 22 and a phase θ (t) at the time of a vehicle collision. As can be seen from the figure, the phase θ (t) where the conversion frequency f is high, for example, f = 250 [H
In the phase θ (t) of z], 354 [Hz], the peak time detection becomes sensitive, and a peak that is not considered to be a peak (see the right side of the peak time tp in FIG. 9) is also detected. vice versa,
The phase θ (t) where the conversion frequency f is low, for example, f = 44 [H
In the phase θ (t) of z] and 63 [Hz], the peak time detection becomes insensitive and a peak may not be detected (see peak time tp in FIG. 10). Such a relationship differs depending on the shape and weight of the vehicle. Note that, as can be inferred from the figure, it is considered that the conversion frequency f is appropriate for a passenger car to be about 100 to 150 [Hz]. In the embodiment, 125 [Hz] is used as the conversion frequency f.

The principle of detecting the time of the local maximum and the time of the local minimum in the time-series signal using the wavelet transform has been described above. Maximum / minimum value detection unit 26 of the embodiment
Then, the G sensor 2 smoothed by the signal input unit 24
2 as a time series signal, the time of the first maximum value detected based on the above principle is detected as the time of the first maximum value, and the time of the first minimum value detected after this time is referred to as the first time. It is detected as the time of one minimum value.

Next, the operation of the rough road judging device 20 according to the embodiment, that is, the operation of judging a rough road will be described. FIG. 11 is a flowchart illustrating an example of a rough road determination processing routine executed by the rough road determination device 20 according to the embodiment. This routine is executed when the deceleration exceeds a predetermined value (for example, 2G or 3G) by the G sensor 22.

When the rough road determination processing routine is executed, first, the process waits until the time of the first maximum value in the signal from the G sensor 22 subjected to the smoothing processing is detected (step S1).
00), to calculate the first integral value S1, time integration of the deceleration G from the G sensor 22 is started from the first maximum value time t1 (step S102). Specifically, the time integration of the deceleration G is performed by adding the values of the signals sampled and smoothed from the time t1 of the first maximum value. It goes without saying that the value of the signal may be multiplied by the sampling period and added. The detection of the time of the first maximum value is performed with a delay of a half of the operation section in the wavelet transform.
As described above, if the window coefficient K is set to 0.125, the delay time is 1 msec. Therefore, the integration operation may be performed retroactively to two or three sampling data.

Next, it is determined whether the deceleration G has become equal to or less than 0 before the predetermined time has elapsed (steps S104 and S104).
106). Since the change in the deceleration G on a rough road is considered to be caused by a vibration component, the change usually results in a negative value after a positive value. On the other hand, the change in the deceleration G in a vehicle collision is
Usually, it does not become a negative value because it is not caused by the vibration component.
As a result, if the deceleration G does not become a negative value even after the lapse of the predetermined time, it can be determined that the road is not a bad road. This step S
The processing of steps 104 and S106 is processing for making this determination. If the deceleration G does not become equal to or less than 0 before the elapse of the predetermined time, it is determined that the road is not a bad road (step S120), and this routine is executed. finish. Note that the predetermined time is determined by a damping rate of vibration of the vehicle or the like.

If the deceleration G becomes equal to or less than 0 before the predetermined time has elapsed, the calculation of the time integration is terminated before the time, and the value is set as the first integrated value S1 (step S108). . Then, in order to calculate the second integral value S2, time integration of the deceleration G is started from the time when the deceleration G becomes equal to or less than 0 (step S110). This time integration is performed by an addition process, similarly to the time integration described above. Then, after waiting for detecting the time of the first minimum value (step S112), the time integration of the deceleration G is completed,
The value is set as a second integral value S2 (step S114).
Although a time delay occurs when detecting the time of the first minimum value, it may be performed retroactively to the time when the end of the time integration is detected.

Thus, the first integral value S1 and the second integral value S2
Is calculated, the second integral value S1 with respect to the first integral value S1
The absolute value of the ratio of 2 (S2 / S1) is compared with a threshold value Sref (step S116). As described above, since the change in the deceleration G on the rough road is caused by the vibration component, the first minimum value is generally negative. However, depending on the type of vehicle collision, the first minimum value of the deceleration G may be negative. Therefore, in order to make the determination of the rough road more reliable, the ratio of the integral value is compared with the threshold value Sref. Therefore, the threshold value Sref is used to determine that the change in the deceleration G is due to a bad road more certainly, and is set according to the shape and weight of the vehicle. In the embodiment, the threshold value Sref is
The value is set to 0.3 assuming that the rough road determination device 20 is mounted on a general passenger car.

When the absolute value of the ratio (S2 / S1) of the second integral value S2 to the first integral value S1 is larger than the threshold value Sref, it is determined that the road is rough (step S118), and this routine is terminated and the first routine is terminated. Second integral value S2 with respect to integral value S1
When the absolute value of the ratio (S2 / S1) is equal to or smaller than the threshold value Sref, it is determined that the vehicle is not on a rough road (step S120), and the routine ends.

FIG. 12 is an explanatory diagram illustrating the relationship between the deceleration G and the phase θ in a time series. As shown, the time t1 of the first maximum value of the deceleration G is detected as the time when the phase θ changes from 2π to zero, and the first minimum value t3 is detected as the time at which the phase θ becomes π. Can be. Also,
The time t2 at which the deceleration G takes the value 0 can be detected from the value of the deceleration G itself. Thus, at times t1 to t
3 and the first integral value S1 and the second integral value S of the deceleration G are detected.
2 is determined, and a rough road is determined from the ratio.

According to the rough road determination device 20 of the embodiment described above, the time integral value (the first integral value) of the deceleration G from the time when the deceleration G reaches the value 0 to the time when the deceleration G reaches the value 0 is obtained. Value S
1) and determining a rough road based on the time integral value (second integral value) of the deceleration G from the time when the deceleration G becomes 0 to the time when the deceleration G becomes the first minimum value. it can. As a result, a bad road can be determined more quickly than a bad road that is determined based on the time from the first peak (first maximum value) to the next peak (second maximum value). Moreover, since the wavelet transform is used to detect the time of the first maximum value or the first minimum value, the time until the detection can be shortened. In addition, since the wavelet transform is performed by the product-sum operation and the differential operation is not performed, erroneous detection based on noise can be prevented as compared with the case where the maximum value or the minimum value is determined by the differential operation. Further, according to the rough road determination device 20 of the embodiment, the rough road is determined based on the fact that the change in the deceleration G on the rough road is caused by the vibration component. Can be.

The rough road determination device 20 of the embodiment detects the time of the first maximum value, the time when the deceleration G becomes equal to or less than 0, the time of the first minimum value, the first integral value S1 and the second integral value. Although the calculation of S2 was performed in parallel, when the time of the first minimum value was detected, the time of the first maximum value detected so far or the deceleration G
The first integral value S1 and the second integral value S2 may be calculated using the time at which the value becomes 0 or less, and when the time at which the deceleration G becomes 0 or less is detected, The first integral value S1 is calculated using the detected time of the first maximum value, and the second integral value is calculated using the time when the deceleration G becomes equal to or less than 0 when the time of the first minimum value is detected. S2 may be calculated.

Although the bad road determination device 20 of the embodiment uses the wavelet transform to detect the time of the first maximum value and the time of the first minimum value, the device may not use the wavelet transform.

Although the embodiments of the present invention have been described with reference to the embodiments, the present invention is not limited to these embodiments at all, and various embodiments may be made without departing from the gist of the present invention. Of course, it can be carried out.

[Brief description of the drawings]

FIG. 1 is a configuration diagram schematically showing the configuration of a rough road determination device 20 according to an embodiment of the present invention by functional blocks.

FIG. 2 is a configuration diagram schematically illustrating a hardware configuration of a rough road determination device 20 according to the embodiment.

FIG. 3 is an explanatory diagram exemplifying a state where the rough road determination device 20 of the embodiment is mounted on a vehicle 10.

FIG. 4 is a configuration diagram schematically showing a configuration of a local maximum value detecting unit 26 according to the embodiment by functional blocks;

FIG. 5 is an explanatory diagram exemplifying an expression on a time axis of a Gabor function.

FIG. 6 shows the real part R of the wavelet transform X (a, b)
FIG. 5 is an explanatory diagram showing a relationship among a imaginary part I, a magnitude P, and a phase θ.

FIG. 7 shows a time series signal X (t) and a wavelet transform X
FIG. 3 is an explanatory diagram illustrating a relationship between (a, b) and a phase θ (t).

FIG. 8 is an explanatory diagram showing a relationship between a window width and a window coefficient K.

FIG. 9 is an explanatory diagram illustrating a relationship between a signal (deceleration signal) detected by the G sensor 22 at the time of a vehicle collision and a phase θ (t).

FIG. 10 is an explanatory diagram illustrating the relationship between a signal (deceleration signal) detected by a G sensor 22 and a phase θ (t) at the time of a vehicle collision.

FIG. 11 is a flowchart illustrating an example of a rough road determination processing routine executed by the rough road determination device 20 according to the embodiment.

FIG. 12 is an explanatory diagram illustrating a relationship between a deceleration G and a phase θ in a time series.

[Explanation of symbols]

Reference Signs List 10 vehicle, 14, 16 G sensor, 20 rough road determination device, 22 G sensor, 24 signal input unit, 26 maximum and minimum value detection unit, 28 integration operation unit, 30 rough road determination unit, 3
1 microcomputer, 32 CPU, 34 RO
M, 36 RAM, 38 input processing circuit, 42 product-sum operation unit, 44 phase operation unit, 46 maximum / minimum judgment unit.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kibun Iyoda 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Automobile Co., Ltd. 1 Toyota Central Research Laboratory Co., Ltd.

Claims (6)

[Claims] 1. A bad road determining device for determining that a vehicle is traveling on a bad road, comprising: a deceleration detecting means for detecting a deceleration of the vehicle; and a first maximum of the detected deceleration. A maximum and minimum value detecting means for detecting a value and a first minimum value occurring next to the first maximum value; and when the detected first minimum value is a negative value, the detected first maximum value An integration calculating means for calculating a first integral value until the deceleration becomes a value 0 and a second integrated value from the deceleration becoming a value 0 to the first minimum value; A rough road determination device comprising: a rough road determination unit configured to determine a rough road based on the calculated first and second integral values. 2. The rough road judging device according to claim 1, wherein said maximum and minimum value detecting means uses a predetermined complex function as a basis of integration with respect to the deceleration detected by said deceleration detecting means. Sum calculating means for calculating the sum of the products, phase calculating means for calculating the phase based on the real part and the imaginary part of the result of the sum of the products, and the first maximum value based on the calculated phase. The first
A rough road determination device comprising: a maximum minimum determination unit that determines a minimum value. 3. The local minimum determining means determines when the calculated phase changes from 2π to zero as the first local maximum value, and when the changed phase becomes π, determines the first local minimum value. The bad road determination device according to claim 2, wherein the determination unit is configured to determine that the road is bad. 4. The rough road determining means according to claim 1, wherein the rough road determining means determines that the road is a rough road when a ratio of an absolute value of the second integral value to the first integral value is equal to or more than a predetermined value. The rough road determination device according to the above. 5. A bad road determination method for determining that a vehicle is traveling on a rough road, comprising: a first maximum value of a deceleration of the vehicle; and a first minimum value generated next to the first maximum value. When the detected first local minimum value is a negative value, a first integral value from the detected first local maximum value to the deceleration becomes a value 0, and the deceleration is Value 0
A bad road determination method for determining a bad road based on the second integral value until the first minimum value is obtained after the above. 6. A product-sum operation using a predetermined complex function as a basis of integration with respect to the deceleration of the vehicle, and a phase of a real part and an imaginary part of the result of the product-sum operation is initially set to 2π to zero. 6. The bad road according to claim 5, wherein the deceleration when the phase changes to? Is detected as a first maximum value, and the deceleration when the phase becomes π is detected as the first minimum value after detecting the first maximum value. Judgment method.