JP2001260855A - Different-diameter wheel judging device and brake hydraulic pressure control device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a different-diameter wheel judging device for allowing the judgement of a different-diameter wheel even if both right and left wheels have different diameters, and a brake hydraulic pressure control device using the same. SOLUTION: The different-diameter wheel judging device comprises wheel speed detecting means a1, a2, a3, a4 for detecting the wheel speeds of front side right and left wheels and rear side right and left wheels, a straight run judging means (d) for judging the straight running condition of a vehicle, a wheel speed comprising means (c) for comparing the wheel speeds of the front side right and left wheels with the wheel speeds of the rear side right and left wheels, after detected by the wheel speed detecting means a1, a2, a3, a4, when the straight running condition is judged by the straight run judging means (b), and a different-diameter wheel judging means (d) for judging the existence of a different-diameter wheel in the vehicle in accordance with the comparison result of the wheel speed comparing means (c).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a different-diameter wheel judging device for judging a different-diameter wheel in a vehicle and a brake fluid pressure control device using the different-diameter wheel determining device.

[0002]

2. Description of the Related Art Conventionally, as a different-diameter wheel determining device, for example, a device described in Japanese Patent Application Laid-Open No. Hei 8-99626 “Vehicle Control Device” is known. This conventional example includes a plurality of wheel speed sensors for detecting rotation speeds of three or more wheels including at least left and right wheels of a vehicle, wheel speed calculation means for calculating a wheel speed based on a detection signal of the wheel speed sensor, Discriminating means for discriminating the presence or absence of different-diameter tires on the left and right wheels using the calculated wheel speeds; and A selecting means for selecting the wheel on which the wheel is mounted, and using the remaining wheel speed excluding the wheel speed of the wheel selected by the selecting means on the basis of the wheel speed of one of the front wheel and the rear wheel. Correction coefficient calculating means for calculating a correction coefficient for correcting a deviation between a reference wheel speed and the other wheel speed to be corrected, and the correction using the correction coefficient calculated by the correction coefficient calculating means. versus Correction calculating means for correcting the wheel speed to be used to eliminate the wheel speed deviation between the front and rear wheels, and excluding the wheel speed of the wheel selected by the selecting means, and calculating the corrected wheel and the reference wheel speed. An estimated vehicle speed calculating means for calculating an estimated vehicle speed based on the speed and control means for controlling a controlled object in the vehicle using the estimated vehicle speed.

[0003]

However, in the conventional different-diameter wheel determination device, as described above, the presence or absence of the mounting of the different-diameter tire in the vehicle is determined based on the wheel speeds of the left and right wheels. Therefore, there are the following problems. In other words, when a different diameter tire having a smaller diameter than the standard tire mounted on the vehicle is mounted, in addition to a case where a different diameter tire such as a tempered tire is mounted as a spare tire when the tire is punctured, for example, In some cases, both the left and right front wheels are replaced with tires with smaller diameters than the standard tires.If both the left and right wheels are small in diameter, whether or not different diameter tires are installed for the wheel speed of the left and right wheels According to the determination method, it is determined that the different-diameter tire is not mounted. As a result, an incorrect estimated vehicle speed including the wheel speed of the different-diameter tire is calculated, and the brake fluid pressure control is performed based on the incorrect estimated vehicle speed. Will be performed.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has a different-diameter wheel determining apparatus and a different-diameter wheel determining apparatus capable of determining a different-diameter wheel even when both right and left wheels have different diameters. It is an object of the present invention to provide a brake fluid pressure control device using a diameter wheel determination device.

[0005]

In order to achieve the above-mentioned object, the different-diameter wheel determining apparatus according to the first aspect of the present invention has a structure shown in FIG.
As shown in the claim correspondence diagram, wheel speed detecting means a1, a2, a3, a4 for respectively detecting the wheel speeds of the front left and right wheels and the rear left and right wheels, and straight running judgment for judging the straight running state of the vehicle. Means b and each of the front left and right wheels and the rear left and right wheels detected by the wheel speed detection means a1, a2, a3, and a4 when the straight running determination means b determines that the vehicle is running straight. The wheel speed comparing means c for comparing the wheel speeds, and the different diameter wheel determining means d for determining the presence of the different diameter wheels in the vehicle based on the comparison result by the wheel speed comparing means c.

According to a second aspect of the present invention, in the above-mentioned first and second embodiments, the wheel speed comparing means (c) determines an average wheel speed of the front left and right wheels and the rear left and right wheels. Calculating the ratio of the wheel speed of each wheel to the front wheel side left and right wheels and the rear wheel side left and right wheels by comparing the respective wheel speeds, the different diameter wheel determination means d
However, the wheel whose ratio calculated by the wheel speed comparing means c is equal to or less than a predetermined value is determined as a wheel having a different diameter.

According to a third aspect of the present invention, in the above-mentioned first and second embodiments, the wheel speed comparing means (c) determines an average wheel speed of the front left and right wheels and the rear left and right wheels. Ratio calculating means for calculating a ratio of the wheel speed to the wheel speed of each wheel, and a first difference value for calculating a difference value between a first largest ratio and a third largest ratio among the ratios calculated by the ratio calculating unit. Calculating means for determining, when the difference value calculated by the first difference value calculating means exceeds a predetermined value, a ratio between the second largest ratio and the third largest ratio among the ratios calculated by the ratio calculating unit; A second difference value calculating means for calculating a difference value; if the difference value calculated by the first difference value calculating means is equal to or less than a predetermined value, it is determined that there is no different-diameter wheel; When the difference value calculated by the second difference value calculation means is equal to or less than a predetermined value, Only the wheel having the second largest ratio is determined to be a different-diameter wheel, and when exceeding a predetermined value, both wheels of the first and second largest ratio wheels are determined to be different-diameter wheels. Diameter wheel determination means d is configured as a means.

According to a fourth aspect of the present invention, there is provided a brake fluid pressure control device using a different-diameter wheel determining device, wherein a wheel speed detecting means for detecting wheel speeds of front left and right wheels and rear left and right wheels, respectively, Straight running judgment means for judging a state, and the respective wheel speeds of the front left and right wheels and the rear left and right wheels detected by the respective wheel speed detecting means when the straight running judgment is made by the straight running judgment means. And a different-diameter wheel determining device for determining the presence of a different-diameter wheel in the vehicle based on the result of comparison by the wheel speed comparing device. When a different-diameter wheel is determined by the different-diameter wheel determining means of the wheel determining device, a slip ratio determination criterion is determined based on the wheel speeds of the remaining normal wheels excluding the wheel speeds of the wheels determined to be the different-diameter wheels. Become pseudo Means comprising pseudo body speed calculating means for calculating body speed, and correcting means for correcting the wheel speed of a wheel determined to be a different diameter wheel by the different diameter wheel determining means to a detected wheel speed value of a normal wheel. And

[0009]

In the different-diameter wheel determining apparatus according to the first aspect of the present invention, when the straight traveling determination unit determines that the vehicle is traveling straight, the wheel speed comparing unit detects the front wheel side detected by each wheel speed detecting unit. The wheel speeds of the left and right wheels and the rear left and right wheels are compared, and based on the result of the comparison of the wheel speeds, the different diameter wheel determination means determines the presence of the different diameter wheels. As described above, by determining the wheels having different diameters based on the comparison results of the wheel speeds of the front left and right wheels and the rear wheel left and right wheels, the case where both the left and right wheels have different diameters is included. Thus, it is possible to determine up to two wheels having different diameters. Also, when determining the different diameter wheels, first, it is determined whether or not the vehicle is in a straight running state, so that an erroneous determination of the different diameter wheels during turning of the vehicle can be prevented. Become.

According to a second aspect of the present invention, there is provided a different-diameter wheel judging apparatus according to the first aspect, wherein the different-diameter wheel judging means calculates the front left and right wheels and the rear wheels calculated by the wheel speed comparing means. Since the wheels having a ratio of the average wheel speed of the left and right wheels to the wheel speed of each wheel being equal to or less than a predetermined value are determined as the different-diameter wheels, the different-diameter wheels can be reliably determined.

According to a third aspect of the present invention, in the different-diameter wheel determining apparatus according to the first aspect, the traveling state is determined by the straight traveling determining means, and each wheel speed detecting means is determined by the wheel speed comparing means. When comparing the wheel speeds of the front left and right wheels and the rear wheel left and right wheels detected in the above, first, the average wheel speeds of the front wheel left and right wheels and the rear wheel left and right wheels and the wheel speed of each wheel are calculated by the ratio calculating means. If the difference between the first and third ratios calculated by the first difference value calculation means is equal to or smaller than a predetermined value, the different diameter wheel is calculated. If it is determined that there is no value, and if the value exceeds the predetermined value, there is a possibility that one or two different diameter wheels exist, and then the second difference value calculation means sets the ratio calculated by the ratio calculation means. The second largest ratio and the third The difference value between the listening ratio, when said difference value is when more than a predetermined value only wheels of large proportions in the first is determined to be a different-diameter ring, exceeds the predetermined value 1
A determination is made that both wheels of the second and second largest ratio wheels are different diameter wheels. Therefore, different diameter wheels up to two wheels can be accurately determined.

In the brake fluid pressure control device using the different-diameter wheel determining device according to the present invention, when the vehicle is determined to be in the straight traveling state by the straight traveling determining device, the wheel speed comparing device determines each wheel speed detecting device. The detected wheel speeds of the front left and right wheels and the rear left and right wheels are compared, and based on the comparison result of the wheel speeds, the different diameter wheel determining means determines the presence of the different diameter wheels. When the different-diameter wheels are determined by the different-diameter wheels determining means, the pseudo-vehicle-speed calculating means calculates the pseudo-vehicle speed based on the wheel speeds of the remaining normal wheels excluding the wheel speeds of the wheels determined to be different diameter wheels. The calculation of the pseudo vehicle speed, which is a criterion for determining the slip ratio, is performed, and the correcting means corrects the wheel speed of the wheel determined to be a different diameter wheel to the detected wheel speed value of the normal wheel. Therefore, including the case where both the left and right wheels have different diameters,
Since it is possible to determine up to two wheels of different diameters, and because the wheel speed of the different diameter wheels is used for control in a state where the wheel speed is corrected to the wheel speed of the normal wheels, the appropriate brake fluid including the wheels with different diameters is used. Pressure control can be performed.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a configuration diagram showing a brake fluid pressure control device using a different-diameter wheel determination device according to an embodiment of the present invention. In the drawing, reference numeral 1 denotes a vehicle, 2 (2FL (front wheel left), 2
FR (front wheel right), 2RL (rear wheel left), 2RR (rear wheel right)) are wheels, 3 is a wheel speed sensor, 4 is a longitudinal acceleration sensor, 5 is a lateral acceleration sensor, and ECU is a control unit.

FIG. 2 is a flow chart showing an outline of a control for judging whether or not to start the wheel speed correction processing of the different diameter wheels in the control operation of the control unit of the brake fluid pressure control device. , In step 101,
It is determined whether or not the vehicle is traveling straight and traveling at a constant speed (determination of conditions for determining the different diameter wheels). If the determination is YES, the process proceeds to step 102;
Then, in step 102, it is determined whether or not a different-diameter wheel exists (a different-diameter wheel determination). If YES, the wheel speed of the different-diameter wheel is corrected. NO
If it is, the process returns to step 101.

Next, the contents of the control for determining the straight traveling constant traveling state (determining the conditions for starting the different diameter wheel discrimination) in step 101 of FIG. 2 will be described with reference to the flowchart of FIG.
In step 201, based on the detection pulse signal from each wheel speed sensor 3, each wheel 2 (2FL (front wheel left), 2FR
(Front wheel right), 2RL (rear wheel left), 2RR (rear wheel right) wheel speed VW (VWFL (front wheel left), VWFR (front wheel right), VW
RL (rear wheel left), VWRR (rear wheel right)), and determines whether or not these wheel speeds VW are constant. If YES, proceed to step 202; if NO, proceed to step 202. This ends the flow. That is, in a state where the vehicle speed of the vehicle is not constant and the wheel speed is changing, the determination of the different diameter wheel cannot be performed accurately. In such a case, the different diameter wheel determination control is not started.

In step 202, it is determined whether or not the absolute value of the acceleration / deceleration of each of the wheel speeds VW is less than a predetermined threshold value α1, and if YES, proceed to step 203, and if NO, Ends the flow. That is, when the amount of change in the wheel speed is large, such as when the vehicle is traveling on a rough road, the determination of the different-diameter wheel cannot be performed accurately. In such a case, the different-diameter wheel determination control is not started.

In step 203, it is determined whether or not the absolute value of the longitudinal acceleration of the vehicle detected by the longitudinal acceleration sensor 4 is less than a predetermined threshold value α2. , NO, this ends the flow. That is, when the amount of change in the wheel speed is large, such as when the vehicle is accelerating or braking, the determination of the different-diameter wheel cannot be performed accurately. In such a case, the different-diameter wheel determination control is not started.

In step 204, it is determined whether or not the absolute value of the lateral acceleration of the vehicle detected by the lateral acceleration sensor 5 is less than a predetermined threshold value α3, so that the vehicle is running straight. If YES (during straight running), the process proceeds to step 205, and if NO (during turning), the flow is ended here. That is,
When the vehicle is turning, there is a difference in the wheel speeds of the left and right wheels, and it is not possible to accurately determine the different-diameter wheels. In such a case, the different-diameter wheel determination control is not started.

In step 205, the pseudo vehicle speed VI
(The wheel speed VW (VWFL (front wheel left), V
WFR (front wheel right), VWRL (rear wheel left), VWRR (rear wheel right)
It is determined whether or not the value obtained by filtering the select high vehicle speed is constant.
Then, if NO, the flow is terminated. That is, at the stage before the pseudo vehicle body speed VI is stabilized, the determination of the different-diameter wheels cannot be performed accurately. In such a case, the different-diameter wheels determination control is not started.

In step 206, the pseudo vehicle speed V
It is determined whether or not I exceeds a predetermined threshold value α4,
If the determination is YES, the process proceeds to step 207. If the determination is NO, the flow ends. That is, the pseudo vehicle speed VI
Is low (for example, 20 km /
h), the determination of the different-diameter wheel cannot be accurately performed due to the influence of noise. In such a case, the different-diameter wheel determination control is not started.

In step 207, a predetermined time (for example,
It is determined whether or not 0.2 seconds has elapsed. When a predetermined time has elapsed, the routine proceeds to step 208, where the different diameter wheel determination control is started.

Next, steps 102 and 103 in FIG.
The details of the control of the different-diameter wheel determination / correction processing in will be described based on the flowchart of FIG. In step 301, the wheel speed VWFL of each wheel 2FL, 2FR, 2RL, 2RR,
The average value VWAVE of VWFR, VWRL, VWRR is calculated, and in the subsequent step 302, the average value VWAVE of the wheel speed is calculated.
Different diameter ratio I of each wheel 2FL, 2FR, 2RL, 2RR
KFL, IKFR, IKRL, IKRR are calculated, and in the following step 303, the different diameter ratios of the respective wheels are arranged in descending order (different diameter ratio 1st, different diameter ratio 2st, different diameter ratio 3st, different diameter ratio 4st). After that, the process proceeds to step 304.

In step 304, it is determined whether or not a difference value between the first and second different diameter ratios 1st and 3st exceeds a predetermined threshold value β1. When the answer is YES, there is a possibility that one or two different diameter wheels exist, so the process proceeds to step 306 and NO
If, the routine proceeds to step 305, where it is determined that there is no different-diameter wheel, and then the flow is terminated.

In step 305, it is determined whether or not the difference value between the second largest diameter ratio 2st and the third largest diameter ratio 3st exceeds a predetermined threshold value β2. When YES, the first largest different diameter ratio 1st
It is determined that the two wheels having the second largest different diameter ratio 2st have different diameters, and the routine proceeds to step 308, where the two-wheel different diameter correction control is performed. It is determined that only one wheel having a diameter ratio of 1st has a different diameter,
Proceeding to step 307, one-wheel different diameter correction control is performed.

That is, in the one-wheel different-diameter wheel correction control in step 307, a correction rate of 1 is obtained by the following equation.
A correction is made to match the wheel speed increased by the different diameter to the standard wheel speed. Correction rate 1 = Different diameter ratio 1st-Different diameter ratio 2st

In the two-wheel different diameter wheel correction control in step 308, the correction rate 2-1 and the correction rate 2
-2 is required. Correction rate 2-1 = Different diameter rate 1st-Different diameter rate 3st Correction rate 2-2 = Different diameter rate 2st-Different diameter rate 3st

Then, the correction rate 2-1 is multiplied by the wheel speed VW of the different diameter wheel having the first largest diameter difference rate 1st, and
By multiplying the wheel speed VW of the different diameter wheel having the second largest different diameter ratio 2st by the correction rate 2-2, a correction is made to adjust the wheel speed increased by the different diameter to the standard wheel speed.

When there is a different-diameter wheel, the wheel speed of the different-diameter wheel is corrected as described above, and the wheel speed VW of the wheel 2 determined to be the different-diameter wheel is excluded. The calculation of the pseudo vehicle speed VI is performed on the basis of the wheel speed VW, and each wheel 2 is calculated based on the pseudo vehicle speed VI and the wheel speed VW of each wheel 2 including the wheel 2 whose wheel speed has been corrected. Is calculated while calculating the pressure reduction threshold value λ. Based on the result of comparison between the slip rate S of each wheel 2 and the pressure reduction threshold value λ, each wheel 2
Brake pressure control (pressure reduction / holding / re-pressure increase control) is performed.

As described in detail above, the embodiment of the present invention has the following effects. That is, by determining the different diameter wheels based on the comparison result of the respective wheel speeds VW of the front left and right wheels 2FL, 2FR and the rear left and right wheels 2RL, 2RR, both the left and right wheels have different diameters. In some cases, it is possible to determine up to two wheels having different diameters.

Further, the wheel speeds VWFL, VWFR, VWFL, VWFR of the front left and right wheels 2FL, 2FR and the rear left and right wheels 2RL, 2RR
Based on the average value VWAVE of VWRL and VWRR as a reference, a wheel having a different diameter ratio obtained by comparing the average value VWAVE with each wheel speed is larger than the different diameter ratio of the other wheels is determined as a different diameter wheel. Thus, the different-diameter wheel can be reliably determined.

In determining a different diameter wheel, first, a difference value between the first different diameter ratio 1st and the third largest different diameter ratio 3st exceeding the predetermined threshold value β1. After determining whether or not there is a possibility that one or two different diameter rings exist, the different diameter ratio is the second largest diameter ratio 2st and the third largest different diameter ratio 3st. By determining whether one or two different diameter wheels are present depending on whether or not the difference value from the difference exceeds a predetermined threshold value β2, it is possible to accurately determine different diameter wheels up to two wheels. Will be able to

In determining the different-diameter wheels, first, a determination is made as to whether the vehicle is traveling straight and is traveling at a constant speed (determination of a different-diameter wheel discrimination start condition). This makes it possible to prevent wheel determination, thereby preventing malfunction of brake fluid pressure control and improving reliability.

Further, in the brake fluid pressure control device according to the embodiment of the present invention, when the different-diameter wheels are determined as described above, the remaining wheel speeds VW of the wheels 2 determined as the different-diameter wheels are excluded. Is calculated based on the wheel speed VW of the normal wheel of the vehicle, and the wheel speed VW of the wheel 2 determined to be a different-diameter wheel is determined as the detected wheel speed value of the normal wheel. Is performed, it is possible to determine up to two wheels of different diameters, including the case where both the left and right wheels have different diameters, and the wheel speed of the different diameter wheels is Since it is used for the control in a state corrected to the wheel speed, it is possible to perform appropriate brake fluid pressure control including a wheel having a different diameter.

Although the embodiments of the present invention have been described in detail with reference to the drawings, the specific configuration is not limited to these embodiments, and design changes may be made without departing from the scope of the present invention. The present invention is also included in the present invention.
For example, in the embodiment of the present invention, the example in which the lateral acceleration sensor is used as the straight traveling determination means has been described, but a steering sensor can be used.

[0035]

As described above, according to the first aspect of the present invention,
In the different diameter wheel determination device described in the, wheel speed detection means for detecting the wheel speed of the front wheel left and right wheels and the rear wheel side left and right wheels, respectively, straight traveling determination means for determining the straight traveling state of the vehicle, Wheel speed comparing means for comparing each wheel speed of the front left and right wheels and rear wheel left and right wheels detected by each of the wheel speed detecting means when the straight running determining means determines that the vehicle is running straight; Different diameter wheel determining means for determining the presence of different diameter wheels in the vehicle based on the result of comparison by the wheel speed comparing means, and means provided for different diameter wheels including both right and left wheels having different diameters. The effect that it is possible to determine up to two diameter wheels is obtained. Also, when determining the different diameter wheels, first, it is determined whether or not the vehicle is in a straight running state, so that an erroneous determination of the different diameter wheels during turning of the vehicle can be prevented. Become.

According to a second aspect of the present invention, in the different-diameter wheel determining apparatus according to the first aspect, the wheel speed comparing means determines an average wheel speed of the front left and right wheels and the rear right and left wheels. The front wheel side left and right wheels and the rear wheel side left and right wheels are configured to compare the respective wheel speeds by calculating the ratio of the wheel speeds of the respective wheels, and the different diameter wheel determination means is calculated by the wheel speed comparison means. By adopting means configured to determine a wheel whose ratio is equal to or less than a predetermined value as a different-diameter wheel, it is possible to reliably determine a different-diameter wheel.

According to a third aspect of the present invention, in the different-diameter wheel determining apparatus according to the first aspect, the wheel speed comparing means determines an average wheel speed of the front left and right wheels and the rear right and left wheels. Ratio calculating means for calculating the ratio of each wheel to the wheel speed, and first difference value calculation for calculating the difference between the first and third largest ratios among the ratios calculated by the ratio calculating means. Means, and when the difference value calculated by the first difference value calculation means exceeds a predetermined value, the difference between the second largest ratio and the third largest ratio among the ratios calculated by the ratio calculation means. A second difference value calculating means for calculating a value, if the difference value calculated by the first difference value calculating means is equal to or less than a predetermined value, it is determined that there is no different-diameter wheel, and if the difference value exceeds the predetermined value, 1 when the difference value calculated by the second difference value calculation means is equal to or less than a predetermined value. It is determined that only the wheels having a large ratio to the eyes are different-diameter wheels, and when the value exceeds a predetermined value, both wheels of the first and second largest ratio wheels are determined to be different-diameter wheels. By adopting the means that constitutes the diameter wheel determination means, it is possible to accurately determine up to two different diameter wheels.

According to a fourth aspect of the present invention, there is provided a brake fluid pressure control device using the different-diameter wheel determination device, wherein wheel speed detection means for detecting wheel speeds of the front left and right wheels and the rear left and right wheels, respectively, Straight running judgment means for judging a state, and the respective wheel speeds of the front left and right wheels and the rear left and right wheels detected by the respective wheel speed detecting means when the straight running judgment is made by the straight running judgment means. And a different-diameter wheel determining device for determining the presence of a different-diameter wheel in the vehicle based on the result of comparison by the wheel speed comparing device. When a different-diameter wheel is determined by the different-diameter wheel determining means of the wheel determining device, a slip ratio determination criterion is determined based on the wheel speeds of the remaining normal wheels excluding the wheel speeds of the wheels determined to be the different-diameter wheels. Become pseudo Means comprising pseudo body speed calculating means for calculating body speed, and correcting means for correcting the wheel speed of a wheel determined to be a different diameter wheel by the different diameter wheel determining means to a detected wheel speed value of a normal wheel. As a result, it is possible to determine up to two wheels having different diameters, including the case where both the left and right wheels have different diameters, and the wheel speeds of the different diameter wheels are corrected to the wheel speeds of the normal wheels. Since it is used for control in the state, it is possible to obtain an effect that appropriate brake fluid pressure control including wheels of different diameters can be performed.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a brake fluid pressure control device using a different-diameter wheel determination device according to an embodiment of the present invention.

FIG. 2 is a flowchart showing an outline of a determination control as to whether or not to start a wheel speed correction process for different-diameter wheels in a control operation of a control unit of the brake fluid pressure control device.

FIG. 3 is a flowchart showing the content of a different diameter wheel discrimination start condition determination control in the control operation of a control unit of the brake fluid pressure control device.

FIG. 4 is a flowchart showing the content of a different diameter wheel determination / correction process control among control operations of a control unit of the brake fluid pressure control device.

FIG. 5 is a diagram corresponding to claims.

[Explanation of symbols]

 Reference Signs List 1 vehicle 2 wheel 3 wheel speed sensor 4 longitudinal acceleration sensor 5 lateral acceleration sensor ECU control unit

Claims (4)

[Claims] A vehicle speed detecting means for detecting wheel speeds of front left and right wheels and a rear wheel left and right wheels; a straight running judgment device for judging a straight running state of the vehicle; A wheel speed comparison means for comparing each wheel speed of the front wheel left and right wheels and a rear wheel left and right wheel detected by the wheel speed detection means when determined to be in a state; A different-diameter wheel determining device that determines the presence of a different-diameter wheel in a vehicle based on the different-diameter wheel determining device. 2. The wheel speed comparison means calculates the ratio of the wheel speed of each wheel to the average wheel speed of the front left and right wheels and the rear wheel left and right wheels, so that the front wheel left and right wheels and the rear wheel left and right wheels are calculated. Each of the wheel speeds is configured to be compared, and the different-diameter wheel determination unit is configured to determine a wheel whose ratio calculated by the wheel speed comparison unit is equal to or less than a predetermined wheel as a different-diameter wheel. The different-diameter wheel determination device according to claim 1, wherein: 3. The wheel speed comparison means calculates a ratio between an average wheel speed of the front left and right wheels and a rear wheel left and right wheel and a wheel speed of each wheel. First difference value calculating means for calculating a difference value between the first largest ratio and the third largest ratio among the calculated ratios, and the difference value calculated by the first difference value calculating means exceeds a predetermined value The time is 2 of the ratios calculated by the ratio calculation means.
Second difference value calculating means for calculating a difference value between the third largest ratio and the third largest ratio, and if the difference value calculated by the first difference value calculating means is equal to or less than a predetermined value, the different diameter wheel It is determined that there is no wheel, and if the difference value exceeds the predetermined value, when the difference value calculated by the second difference value calculation means is equal to or less than the predetermined value, it is determined that only the wheel having the first largest ratio is a different diameter wheel, 2. The different-diameter wheel determining means is configured to determine that both wheels of the first and second largest ratios are different-diameter wheels when a predetermined value is exceeded. The different-diameter wheel determination device according to any one of the above. 4. A straight travel determination means for detecting the wheel speeds of the front left and right wheels and the rear left and right wheels, a straight travel determination means for determining a straight travel state of the vehicle, and a straight travel by the straight travel determination means. A wheel speed comparison means for comparing each wheel speed of the front wheel left and right wheels and a rear wheel left and right wheel detected by the wheel speed detection means when determined to be in a state; And a different-diameter wheel determining device that determines the presence of a different-diameter wheel in the vehicle based on the different-diameter wheel determination device. A pseudo vehicle speed calculating means for calculating a pseudo vehicle speed serving as a criterion for determining a slip ratio based on the wheel speeds of the remaining normal wheels excluding the wheel speeds of the wheels determined to be the different diameter wheels; Judge Brake fluid pressure control device, characterized in that by being and a correcting means for correcting the detected wheel speed values of the normal wheel wheel speed of the wheel it is determined that different-diameter ring.