JP2002248915A - Tire condition estimating equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve detection preciseness when the amount of a tire pneumatic pressure state is indirectly detected base on a vehicle wheel speed signal expressing a wheel angular speed. SOLUTION: The equipment that estimates a pneumatic pressure conditional amount of a wheel tire which is fixed to a vehicle is equipped with a wheel speed sensor 10 which detects a wheel speed, namely a wheel angle speed, and outputs a wheel speed signal according to it and an estimation device 20 which estimates the amount of a tire pressure condition based on such a signal. In addition, the estimation device includes a vehicle condition detector 40 which detects a vehicle conditional amount and outputs a signal showing the amount of the vehicle condition according to it and makes a normalization process to normalize estimation of the tire conditional amount using a wheel speed signal based on the amount of the vehicle condition signal outputted from the vehicle condition detection device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for estimating a state of a tire of a vehicle, and more particularly to a technique for estimating the state of the tire based on a wheel speed signal representing an angular speed of a wheel on which the tire is mounted. The present invention relates to improvement of a technique for estimating a state.

[0002]

2. Description of the Related Art Several techniques have been proposed for estimating a state of a tire of a vehicle based on a wheel speed signal representing an angular speed of the wheel on which the tire is mounted.

[0003] One form of this is to provide a wheel speed signal based on the fact that a constant relationship is established between the tire pressure, which is the tire air pressure, the dynamic load radius of the tire, and the wheel speed for the same wheel. Based on this, the tire pressure state quantity is estimated as the tire state. An example of this type of tire pressure state quantity estimation method is disclosed in Japanese Patent Laid-Open No. 6-286436.

Another type is based on the wheel speed signal, based on the wheel speed signal, given the fact that, for the same wheel, a constant relationship holds between the tire pressure and the tire vibration characteristics and the wheel speed vibration characteristics. The state quantity is estimated as a tire state. An example of this type of tire pressure state quantity estimation method is disclosed in Japanese Patent Application Laid-Open No. 7-089304.

[0005]

As is apparent from the above description, when the tire condition is estimated based on the wheel speed signal, that is, when the tire condition is indirectly detected, the tire condition which is the target parameter is used. And the wheel speed signal, which is a basic parameter, are not directly linked to each other, and other parameters are interposed.

Therefore, when the tire condition is indirectly detected, the detection accuracy of the tire condition is more susceptible to the condition of the vehicle including the running condition of the vehicle and the load condition of the wheels, as compared with the case of directly detecting the tire condition. . The state of the vehicle easily acts as a disturbance with respect to the estimation of the tire state.

Therefore, in order to indirectly detect the tire condition with sufficiently high accuracy, it is necessary to effectively remove disturbances at the time of the detection.

[0008]

Based on the above findings, the present invention improves the detection accuracy when indirectly detecting a tire state based on a wheel speed signal indicating an angular speed of a wheel. Was done as an issue,
The following aspects are obtained by the present invention. Each mode is described in the same manner as in the claims, divided into sections, each section is numbered, and described in the form of citing the numbers of other sections as necessary. this is,
In order to facilitate understanding of some of the technical features described in this specification and some of their combinations, the technical features and their combinations described in this specification are limited to the following embodiments. Should not be interpreted as (1) An apparatus for estimating a state of a tire, which is provided in a vehicle provided with a wheel having a structure in which air is sealed under pressure in a tire mounted on the wheel, the wheel speed being an angular velocity of the wheel. , A wheel speed sensor that outputs a wheel speed signal corresponding thereto, a vehicle state amount detecting device that detects a state amount of the vehicle, and outputs a vehicle state amount signal corresponding thereto, and an output from the wheel speed sensor. An estimator for estimating the tire state based on the wheel speed signal obtained, based on the vehicle state quantity signal output from the vehicle state quantity detection device, the estimation of the tire state using the wheel speed signal A tire state estimating apparatus including a unit that performs a normalization process for normalizing.

According to this device, the tire state estimation using the wheel speed signal is normalized based on the vehicle state quantity signal output from the vehicle state quantity detection device. It becomes easy to estimate the state with sufficiently high accuracy.

In this section, the term "tire condition" is interpreted to mean, for example, a state quantity of a tire pressure, which is an air pressure of the tire, or a deformation state of the tire (for example, a rapid deformation occurring in the tire, (Transformation that is difficult or impossible to restore).

In this and other sections, the term "vehicle state quantity" refers to the lateral movement of the load on the vehicle, the longitudinal movement of the load, and the wheel load acting on each wheel as a ground load. , Can be interpreted to mean at least one of the driving torque or driving force of each wheel. (2) The tire state estimation device according to (1), wherein the estimator estimates a state quantity of a tire pressure, which is an air pressure of the tire, as the tire state.

According to this device, the estimation of the tire pressure state quantity using the wheel speed signal is normalized on the basis of the vehicle state quantity signal output from the vehicle state quantity detection device. It is easy to estimate the tire pressure state quantity with sufficiently high accuracy.

In this and other sections, the term "tire pressure state quantity" is interpreted to mean the absolute height of the tire pressure, or to mean the relative height. It is possible.

In the former interpretation, the absolute height of the tire pressure can be represented by a continuous value or a plurality of discrete values. On the other hand, in the latter interpretation, the relative height of the tire pressure is expressed by a distance from a predetermined reference value of the tire pressure, or by a characteristic of whether the tire pressure is higher or lower than the reference value. Or the tire pressure deviates from a reference value or an allowable range. (3) The estimator estimates the tire pressure state quantity based on the wheel speed signal in accordance with at least the relationship established between the tire pressure and the wheel speed for the same wheel (2). The tire condition estimating device according to the paragraph.

If the tire pressure changes, the dynamic load radius of the tire changes, and the wheel speed also changes.

By paying attention to this fact, in the device according to this item, the tire pressure state quantity is estimated based on the wheel speed signal according to at least the relation established between the tire pressure and the wheel speed for the same wheel. Is done. (4) The vehicle is provided with a plurality of wheels,
The wheel speed sensor is provided for each of the plurality of wheels, and the estimator determines a relationship between the plurality of wheel speed signals output from each of the plurality of wheel speed sensors at substantially the same time. The tire condition estimating apparatus according to the above mode (2) or (3), including means for estimating a tire pressure state quantity of each wheel based on the information.

When the tire pressure changes at any one of a plurality of wheels in a vehicle, a difference occurs in the dynamic load radius and the wheel speed of the tire from the tire pressure of other wheels.

By paying attention to this fact, in the device according to the present invention, a plurality of wheel speed signals output at substantially the same time from a plurality of wheel speed sensors respectively provided for a plurality of wheels are provided. The tire pressure state quantity of each wheel is estimated based on the mutual relationship.

According to this device, basically, only the wheel speed sensor is used as the main sensor,
Since the tire pressure state quantity can be estimated, the hardware configuration for the estimation can be easily simplified. (5) the estimator relates to the same type of vehicle state quantity;
At substantially the same time as each other, based on a relationship between a detection value detected by the vehicle state quantity detection device and an estimated value estimated based on a wheel speed signal output from the wheel speed sensor, (2) The tire state estimating device according to the above mode (2) or (3), including a unit for estimating a tire pressure state quantity.

There is an interdependence between the state of the vehicle and the state of the wheels, and if the state of the wheels is known, the state of the vehicle at that time can be estimated.

By paying attention to such a fact, in the device according to this section, regarding the same type of vehicle state quantity, the detection value detected by the vehicle state quantity detection device at substantially the same time as each other is: The tire pressure state quantity of the wheel is estimated based on the relationship with the estimated value estimated based on the wheel speed signal output from the wheel speed sensor. (6) The means according to (5), wherein the means determines that the tire pressure of the wheel is abnormal when the detected value and the estimated value regarding the same type of vehicle state quantity do not match each other. Tire condition estimation device. (7) The plurality of wheels include left and right wheels respectively arranged on the left and right of the vehicle, and the vehicle state quantity detection device includes:
A lateral load displacement sensor for detecting a lateral displacement of a load in the vehicle, wherein the means detects two wheel speed signals output from the wheel speed sensors at substantially the same time with respect to the left and right wheels. Based on the estimated lateral movement amount of the load in the vehicle, when the estimated value differs from the detection value by the lateral load movement amount sensor by a set value or more,
The tire condition estimating apparatus according to item (6), further including a unit that determines that the tire pressure is abnormal with respect to any of the left and right wheels.

In this device, for example, based on the fact that the difference in the dynamic load radius of the tire between the right and left wheels depends on the amount of lateral movement of the load on the vehicle, the two wheel speed signals for the left and right wheels are used to determine A lateral movement amount of the load is estimated, and the estimated value is compared with a value detected by the lateral load movement amount sensor. (8) The plurality of wheels include front and rear wheels respectively arranged before and after the vehicle, and the vehicle state quantity detection device includes:
A front-rear load movement amount sensor for detecting a front-rear load movement amount of the load in the vehicle, wherein the means relates to the front and rear wheels,
At substantially the same time as each other, the forward and backward movement amount of the load on the vehicle is estimated based on the two wheel speed signals output from the wheel speed sensor, and the estimated value is a value detected by the front and rear load movement amount sensor. The tire condition estimating apparatus according to (6) or (7), further comprising means for determining that the tire pressure is abnormal for any of the front and rear wheels when the tire pressure differs by more than a set value.

In this device, for example, based on the fact that the difference in the dynamic load radius of the tire between the front and rear wheels depends on the amount of forward and backward movement of the load on the vehicle, the two wheel speed signals for the front and rear wheels are used. The forward / backward movement amount of the load is estimated, and the estimated value is compared with a value detected by the front / rear load movement amount sensor. (9) The vehicle state quantity detection device includes a vehicle driving force related sensor that detects a driving force of the vehicle or a physical quantity related thereto, and the means includes: a wheel speed signal output from the wheel speed sensor; Based on the vehicle speed that is the traveling speed of the vehicle, the driving force of the vehicle is estimated, and when the estimated value differs from the detection value of the vehicle driving force-related sensor by a set value or more, the tire pressure of the wheel is reduced. The tire condition estimating apparatus according to any one of (6) to (8), including means for determining that the tire is abnormal.

If the tire pressure is assumed to be normal, the dynamic load radius of the tire can be assumed, and if the slip value of the wheel with respect to the road surface is a standard value, the wheel speed and the vehicle speed can be assumed. From this, it is possible to estimate the driving force of the wheels when the tire pressure is normal, and further,
It is also possible to estimate the driving force of the vehicle from the estimated value. Then, when the estimated vehicle driving force is different from the actual vehicle driving force, it is possible to determine that the tire pressure is abnormal.

Based on such knowledge, in the device according to this section, the driving force of the vehicle is estimated based on the wheel speed signal and the vehicle speed, and the estimated value is compared with the value detected by the vehicle driving force related sensor. If the difference is equal to or more than the set value, it is determined that the tire pressure is abnormal. (10) The estimator calculates, for the same wheel, at least the wheel load and the wheel speed signal according to a relationship established between at least the tire pressure, a wheel load acting on the wheel as a ground contact load, and the wheel speed. (2) The tire condition estimating apparatus according to the above mode (2), further comprising means for estimating a tire pressure condition quantity of the wheel based on the condition.

For the same wheel, there is a relationship among tire pressure, wheel load acting on the wheel as a ground contact load, tire dynamic load radius, and wheel speed. For example, under the same wheel load, if the tire pressure changes,
The dynamic load radius changes and the wheel speed also changes. Further, under the same tire pressure, when the wheel load changes, the dynamic load radius changes, and the wheel speed also changes.

By paying attention to such facts, in the device according to this item, the wheel load and the wheel speed signal are related to the same wheel according to at least the relation established between the tire pressure, the wheel load and the wheel speed. , The tire pressure state quantity of the wheel is estimated. (11) The vehicle state quantity detection device includes a wheel load related sensor that detects a wheel load acting on the wheel as a ground contact load or a physical quantity related thereto as the vehicle state quantity, and the estimator relates to the same wheel; At substantially the same time as each other, the tire pressure state quantity of the wheel is estimated based on the relationship between the wheel load related signal output from the wheel load related sensor and the wheel speed signal output from the wheel speed sensor. The tire condition estimation device according to the above mode (2) or (10), including means.

The relationship between the wheel load-related signal output from the wheel load-related sensor and the wheel speed signal output from the wheel speed sensor at substantially the same time with respect to the same wheel changes depending on the tire pressure. .

By paying attention to this fact, in the device according to this section, the tire pressure state quantity of the wheel is estimated based on the relationship between the wheel load related signal and the wheel speed signal for the same wheel.

In this and other sections, the term "physical quantity related to wheel load" includes, for example, a sprung load acting on the axle from the sprung portion of the vehicle, which can be converted into a wheel load. It is. The sprung load is directly detected by a sensor, indirectly detected based on the vertical force or vertical stroke of a suspension that suspends the wheel axle on the vehicle body, or a portion of the vehicle body that is close to the wheel. Can be indirectly detected based on the vehicle height indicating the height from the road surface. Therefore,
The vertical force and the vertical stroke and the vehicle height of these suspensions can be included in the “physical quantity related to the wheel load”. (12) When the relationship between the wheel load-related signal and the wheel speed signal for the same wheel does not coincide with the relationship established when the tire pressure of the wheel is assumed to be normal, The tire condition estimating apparatus according to item (11), including a unit that determines that the tire pressure is abnormal. (13) The vehicle is driven by transmitting the rotational force of a power source as driving force to the wheels via a variable-speed driving force transmission device, and the vehicle state quantity detection device includes: Further, the vehicle includes a vehicle speed sensor that detects a vehicle speed that is a traveling speed of the vehicle, wherein the driving force-related sensor detects a rotation speed sensor that detects a rotation speed of the power source and a speed ratio of the driving force transmission device. A gear ratio sensor, wherein the means includes: a vehicle speed detected by the vehicle speed sensor; a power source rotational speed detected by the rotational speed sensor; a gear ratio detected by the gear ratio sensor; A wheel speed to be detected by the wheel speed sensor when the tire pressure is normal is calculated as a reference wheel speed based on a predetermined slip value as a slip value with respect to a road surface. (2) through (2) including means for determining that the tire pressure is abnormal when the calculated reference wheel speed and the actual wheel speed detected by the wheel speed sensor are different from each other by a set value or more. 12)
The tire condition estimation device according to any one of the above items.

In the vehicle, the rotational force of the power source is used as the driving force.
When the vehicle is driven by being transmitted to the wheels via a variable-speed driving force transmission device, if the vehicle speed, the number of revolutions of the power source, the gear ratio, and the slip value of the wheels with respect to the road surface are determined, the tire If the pressure is normal, the wheel speed to be detected by the wheel speed sensor is determined. If the wheel speed does not match the wheel speed actually detected by the wheel speed sensor, the tire pressure may be abnormal.

Based on such knowledge, in the device according to this item, based on the vehicle speed, the power source rotation speed, the gear ratio, and the set slip value, when the tire pressure is normal, the wheel speed sensor is used. The wheel speed to be detected is calculated as a reference wheel speed, and the calculated reference wheel speed,
If the actual wheel speed detected by the wheel speed sensor differs from the actual wheel speed by a set value or more, it is determined that the tire pressure is abnormal.

In this section, if the "driving force transmission device" is configured to include a transmission and a differential gear, and if only the transmission is capable of shifting, the "speed ratio" in this section is ,
It means the transmission ratio (gear ratio) of the transmission. On the other hand, if the “drive force transmission device” is configured to include a transmission and a differential gear, and the transmission is capable of shifting not only the transmission but also the differential gear, in this section “shift The “ratio” means both the transmission gear ratio (gear ratio) of the transmission and the gear ratio (gear ratio) of the differential gear. (14) The estimator estimates the tire pressure state quantity of the wheel based on the wheel speed signal according to at least the relationship established between the tire pressure and the vibration characteristic of the wheel speed for the same wheel. The tire condition estimating apparatus according to the above mode (2).

When a tire moves on a road surface, the tire vibrates because at least an elastic element is present in the tire. On the other hand, the properties of the elastic element of the tire change with the tire pressure. Further, if the tire vibrates, the wheel speed also vibrates. The tire vibration appears in the wheel speed signal as its vibration. in this way,
There is a relationship between tire pressure and wheel speed.

By paying attention to this fact, in the device according to this section, for the same wheel, at least according to the relationship established between the tire pressure and the vibration characteristic of the wheel speed,
Based on the wheel speed signal, the tire pressure state quantity of the wheel is estimated. (15) The vehicle is provided with a plurality of wheels, the wheel speed sensor is provided for each of the plurality of wheels, and the estimator outputs each wheel speed signal output from each wheel speed sensor. (2) or (14), including a means for estimating the tire pressure state quantity of each wheel independently of the other wheels based on the following.

According to this device, since the tire pressure state quantity of each wheel can be estimated independently of the other wheels, when a plurality of wheels of the vehicle have the same tire pressure simultaneously changing, However, such a tire pressure change can be individually detected for each wheel. (16) A tire model in which the means is a disturbance observer, and a rim side portion and a belt side portion, which are rotatable relative to each other, is connected to each other by at least a torsion spring, is assumed. On the basis of this, a motion system that describes the rotational motion of each wheel is assumed. In the motion system, a change in the spring constant of the torsion spring accompanying a change in the tire pressure of each wheel is regarded as a disturbance to each wheel, and each wheel speed is considered. By using the wheel speed signal output from the sensor as a signal representing the wheel speed on the rim side of each wheel, the disturbance is estimated as one of the state variables of the motion system, whereby the tire of each wheel is The tire condition estimation device according to the mode (15), including a device for estimating a pressure.

A technique for estimating tire pressure using a disturbance observer is disclosed, for example, in Japanese Patent Application Laid-Open No. 2000-238516. (17) The estimator performs the normalization processing in a reflection accuracy reduced state in which the wheel speed signal may not accurately reflect the tire pressure of the wheel. The tire condition estimation device according to any one of the above.

According to this apparatus, even if the wheel speed signal does not accurately reflect the tire pressure of the wheel, the reflection accuracy is reduced, and the tire pressure using the wheel speed signal is obtained by executing the normalization processing. The estimation of the state quantity is obtained regularly, that is, with sufficiently high accuracy. (18) The tire condition estimation device according to (17), wherein the reflection accuracy reduction state includes a state in which the wheel speed signal may not accurately reflect a true dynamic load radius of the tire.

According to this device, even when the reflection speed of the wheel speed signal may not accurately reflect the true dynamic load radius of the wheel, the tire pressure state quantity can be estimated using the wheel speed signal. Is obtained regularly, that is, with sufficiently high precision. Here, the “true dynamic load deformation” is an apparent dynamic load radius, that is, a dynamic load radius (a value obtained by simply dividing a vehicle speed by a wheel speed) which is influenced by a wheel load variation caused by a load movement in a vehicle. And means a dynamic load radius that is not affected. (19) The reflection accuracy reduced state includes an actual wheel load deviation state in which an actual value of a wheel load acting as a ground contact load on the wheel deviates from its normal value by a set amount or more, and the estimator uses the actual wheel load deviation state. (17) or (1) including normalization processing means for performing the normalization processing in the state of load deviation.
8) The tire condition estimating apparatus according to the above mode.

In an actual wheel load deviation state in which the actual value of the wheel load deviates from its normal value by a set amount or more, the true dynamic load radius deviates from the apparent dynamic load radius. Therefore, when estimating the tire pressure state quantity using the relationship between the tire pressure and the dynamic load radius, it is difficult to estimate the tire pressure state quantity with sufficiently high accuracy in the actual wheel load deviation state. is there.

Therefore, in the device according to this section, even in the actual wheel load deviation state, by executing the normalization processing,
Estimation of the tire pressure state quantity using the wheel speed signal,
That is, it is obtained with sufficiently high accuracy. (20) The vehicle state quantity detection device includes a lateral acceleration related sensor that detects a lateral acceleration of the vehicle or a physical quantity related thereto as the vehicle state quantity, and the normalization processing unit outputs an output from the lateral acceleration related sensor. The tire state estimating apparatus according to (19), including means for determining the actual wheel load deviation state based on the obtained vehicle state quantity signal.

The actual wheel load deviation state can be caused, for example, by lateral movement of the load on the vehicle, and the lateral load movement depends on, for example, the lateral acceleration of the vehicle.

Therefore, in the device according to this section, the actual wheel load deviation state is determined based on the lateral acceleration of the vehicle or a physical quantity related thereto.

In this and other sections, the “physical quantity related to lateral acceleration” may include, for example, the steering angle of the steering wheel by the driver, or may include the yaw rate of the vehicle. (21) The vehicle state quantity detection device includes a longitudinal acceleration related sensor that detects a longitudinal acceleration of the vehicle or a physical quantity related thereto as the vehicle state quantity, and the normalization processing unit outputs an output from the longitudinal acceleration related sensor. The tire state estimating apparatus according to (19) or (20), further comprising means for determining the actual wheel load deviation state based on the obtained vehicle state quantity signal.

The actual wheel load deviation state can also be caused by, for example, the longitudinal movement of the load on the vehicle, and the longitudinal load movement depends on, for example, the longitudinal acceleration of the vehicle.

Therefore, in the device according to this section, the actual wheel load deviation state is determined based on the longitudinal acceleration of the vehicle or a physical quantity related thereto.

In this and other sections, the “physical quantity related to the longitudinal acceleration” includes, for example, the driving force of the vehicle, the output of the power source of the vehicle,
Driver's acceleration operation member (eg, accelerator pedal)
, Or the driving force or driving torque of the wheels. (22) The normalization process in which the reflection accuracy reduction state includes a large slip value state in which the slip value of the wheel with respect to the road surface is equal to or greater than a set value, and the estimator performs the normalization process in the large slip value state. The tire condition estimating apparatus according to any one of (17) to (21), including means.

In the case of estimating the tire pressure state quantity assuming an apparent dynamic load radius, if the slip value of the wheel with respect to the road surface deviates from the normal range, the relationship between the peripheral speed of the wheel and the vehicle speed is calculated. Is gone. In this case, the wheel speed, that is, the wheel speed signal does not accurately reflect the apparent dynamic load radius.

Based on such knowledge, in the device according to this section, in a large slip value state where the slip value of the wheel with respect to the road surface is equal to or larger than a set value, the tire pressure state quantity based on the wheel speed signal is estimated. Normalization processing is performed.

In this and the other sections, the term “slip value” can be interpreted to mean, for example, a slip ratio or a slip amount. (23) The vehicle state quantity detection device includes a longitudinal acceleration related sensor that detects the longitudinal acceleration of the vehicle or a physical quantity related thereto as the vehicle state quantity, and the normalization processing unit outputs an output from the longitudinal acceleration related sensor. The tire state estimation device according to (22), further including a unit that determines the large slip value state based on the obtained vehicle state quantity signal.

The large longitudinal acceleration of the vehicle means that the driving force of the wheels, that is, the longitudinal force acting between the wheels and the road surface is large. On the other hand, a large driving force of a wheel generally means that a coefficient of friction between the wheel and the road surface is large, and the coefficient of friction in the linear region thereof is such that a slip value of the wheel with respect to the road surface is small. It increases as it increases. Therefore, it is possible to assume the slip value of the wheel based on the longitudinal acceleration of the vehicle.

Based on such knowledge, in the device according to this section, the large slip value state is determined based on the longitudinal acceleration of the vehicle or the physical quantity related thereto. (24) The vehicle state quantity detecting device includes a driving force related sensor that detects the driving force of the wheel or a physical quantity related thereto as the vehicle state quantity, and the normalization processing unit outputs an output from the driving force related sensor. The tire state estimating apparatus according to (21) or (22), further comprising means for determining the large slip value state based on the obtained vehicle state quantity signal.

In this device, the large slip value state is determined based on the driving force of the wheel or a physical quantity related thereto. (25) The vehicle state quantity detection device includes a vehicle speed related sensor that detects a vehicle speed that is the traveling speed of the vehicle or a physical quantity related thereto as the vehicle state quantity, and the normalization processing units are substantially the same as each other. Means for determining the large slip value state based on the vehicle state quantity signal output from the vehicle speed related sensor and the wheel speed signal output from the wheel speed sensor at the time (21) to (24). The tire condition estimation device according to any one of the above items.

For example, assuming that the dynamic load radius of the tire is a standard value, it is possible to detect the slip value of the wheel from the vehicle speed and the wheel speed.

Based on such knowledge, in the device according to this section, the vehicle state quantity signal output from the vehicle speed related sensor and the wheel speed signal output from the wheel speed sensor are output at substantially the same time. , The large slip value state is determined. (26) The estimator performs the normalization process by substantially invalidating the wheel speed signal output from the wheel speed sensor with respect to the estimation of the tire pressure state amount in the reflection accuracy reduced state. The tire condition estimation device according to any one of (14) to (25), including a nullification unit.

According to this device, the wheel speed signal is substantially invalidated with respect to the estimation of the tire pressure state quantity in the reflection accuracy reduced state, so that by using the wheel speed signal that does not accurately reflect the tire pressure, It is possible to easily avoid a decrease in the estimation accuracy of the tire pressure state quantity. (27) The estimator is based on the vehicle state quantity signal output from the vehicle state quantity detection device and based on the wheel speed signal output from the wheel speed sensor and the wheel speed signal in the reflection accuracy reduced state. (14) The apparatus according to any one of (14) to (26), further including a correction unit that performs the normalization process by correcting at least one of the calculated values so that the estimation of the tire pressure state quantity is normalized. Tire condition estimation device.

According to this device, in the reflection accuracy reduced state, the estimation of the tire pressure state quantity is normalized by at least one of the wheel speed signal and the calculated value based on the wheel speed signal based on the vehicle state quantity signal. Is corrected as follows.

Therefore, according to this device, the estimation of the tire pressure state quantity using the wheel speed signal is normalized even in the state of reduced reflection accuracy, so that the tire pressure state quantity can be estimated with sufficiently high accuracy. I can do it. (28) The correction means includes: a vehicle speed which is a traveling speed of the vehicle or a physical quantity related thereto, a wheel load acting as a ground load on the wheel or a physical quantity related thereto, a slip value of the wheel relative to a road surface or a related (27) The tire state estimation according to (27), further comprising means for correcting at least one of a wheel speed signal output from the wheel speed sensor and a calculated value based on the wheel speed signal based on at least one of the physical quantities to be performed. apparatus.

The factor that the apparent dynamic load radius of the tire (dynamic load radius that can be easily calculated) deviates from its true dynamic load radius (dynamic load radius that cannot be easily calculated) is the peripheral speed of the wheel. And a wheel load and a slip value of the wheel with respect to the road surface. The peripheral speed of the wheel can be substituted by the vehicle speed or the wheel speed.

Based on such knowledge, in the device according to this section, at least one of the vehicle speed or the related physical quantity, the wheel load or the related physical quantity, and the wheel slip value or the related physical quantity is used. Based on a certain target vehicle state quantity, at least one of the wheel speed signal output from the wheel speed sensor and a calculated value based on the wheel speed signal is corrected, so that the accuracy is sufficiently high regardless of the state of the vehicle. Thus, the tire pressure state quantity is estimated.

In this and other sections, the “physical quantity related to vehicle speed” includes, for example, the peripheral speed of the wheel.
The peripheral speed of the wheel can be acquired by, for example, a product of a wheel speed based on a wheel speed signal and a standard dynamic load radius of the tire.

In this section and other sections, the physical quantities related to the “slip value” include, for example, a driving force or a driving torque of a wheel, and a braking force or a braking torque of a wheel. (29) The vehicle state quantity detection device calculates a vehicle speed, which is a traveling speed of the vehicle, or a physical quantity related thereto, a wheel load acting as a ground load on the wheel, or a physical quantity related thereto, and a slip value of the wheel with respect to a road surface. Or, at least one of the physical quantities related thereto is detected as the vehicle state quantity, and the correcting means detects the wheel speed sensor based on at least one vehicle state quantity detected by the vehicle state quantity detection device. (27) The tire state estimating apparatus according to the above mode (27), comprising means for correcting at least one of the wheel speed signal output from the controller and a calculated value based on the wheel speed signal. (30) The estimator (a) is based on a wheel speed signal output from the wheel speed sensor and the wheel speed signal based on a wheel load acting as a ground load on the wheel during each run of the vehicle. Correcting means for performing the normalization process by correcting at least one of the calculated values; and (b) performing a reference operation for each run of the vehicle during the same run based on the wheel load. The tire state estimating apparatus according to any one of (2) to (29), further comprising: an initialization unit configured to perform the normalization process by initializing the different correction conditions.

The relationship between the tire pressure and the wheel speed changes depending on the wheel load. This is because if the wheel load changes, the dynamic load radius of the tire also changes.

Therefore, when estimating the tire pressure state quantity by paying attention to the relationship between the tire pressure and the dynamic load radius of the tire, the wheel speed sensor outputs the wheel load based on the wheel load during each running of the vehicle. By correcting at least one of the wheel speed signal and a calculated value based on the wheel speed signal, a normalization process can be realized.

Further, during each traveling of the vehicle, it is not indispensable until the absolute value of the wheel load is intentionally specified, and the distance from the wheel load at a certain reference time, that is, the relative value of the wheel load is also determined. Sometimes it suffices.
In this case, for example, the tire pressure at the time of the reference,
Is known independently of the tire state quantity estimation device,
Or when it is possible to make assumptions with high accuracy. For example, it is possible to assume that the tire pressure is normal, ie, a standard value, at the start of each run of the vehicle.

Therefore, during each run of the vehicle, when at least one of the wheel speed signal output from the wheel speed sensor and the calculated value based on the wheel speed signal is corrected based on the wheel load, the same time At the time of reference for driving,
The normalization process can be realized by initializing the above-described correction condition to be performed during the current traveling based on the wheel load.

Based on the above findings, in the device according to this section, during each running of the vehicle, the wheel speed signal output from the wheel speed sensor based on the wheel load and the calculated value based on the wheel speed signal are calculated. The normalization process is performed by correcting at least one of them. Furthermore, the normalization process is also performed by initializing the above-described correction condition that is to be performed during the same round of travel, based on the wheel load, with each start of travel of the vehicle. (31) The vehicle state quantity detection device includes a wheel load-related sensor that detects the wheel load or a physical quantity related thereto, and the initialization unit performs processing based on a vehicle state quantity signal output from the wheel load-related sensor. Means for setting the actual wheel load at the start of each run as a reference wheel load, wherein the correction means is based on a vehicle state quantity signal output from the wheel load related sensor, and Based on the deviation from the set reference wheel load of the actual wheel load sequentially acquired during traveling,
The tire condition estimating apparatus according to (30), further including means for correcting at least one of a wheel speed signal output from the wheel speed sensor and a calculated value based on the wheel speed signal.

[0068]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Some specific embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a block diagram showing a hardware configuration of a tire state estimating device (hereinafter, simply referred to as an “estimating device”) according to the first embodiment of the present invention. The estimating device is mounted on a vehicle and estimates a tire pressure state quantity as a tire state.

The vehicle has an engine (internal combustion engine) as a power source. This engine is associated at its output with a drive transmission. The driving force transmission device is a device that transmits an output (rotational force) of an engine as driving force to a driving wheel among a plurality of wheels of a vehicle. In the present embodiment, the driving force transmission device includes a torque converter, an automatic transmission (hereinafter, abbreviated as “A / T”), and a differential gear (not shown) between the engine and the drive wheels in that order. It is configured by being linked to each other.

The vehicle is provided with wheels on each of the front, rear, left and right sides thereof. The total number of wheels is four. As is well known, each wheel is configured such that air is sealed under pressure inside a rubber tire mounted on a metal wheel.

As shown in FIG. 1, the estimating device includes a wheel speed sensor 10 provided for each wheel. In the figure, "FL" is a front left wheel, "FR" is a front right wheel, and "R".
"L" means the left rear wheel, and "RR" means the right rear wheel.

As is well known, each wheel speed sensor 10 is a sensor that detects an angular speed of each wheel and outputs a wheel speed signal corresponding to the detected angular speed. Specifically, the wheel speed sensor 10 is an electromagnetic pickup, and generates a voltage that changes periodically according to the passage of a large number of teeth formed on the outer periphery of the rotor that rotates with the wheels.

The four wheel speed sensors 10 correspond to those shown in FIG.
Is electrically connected to the estimator 20 as shown in FIG.
The estimator 20 is a device mainly composed of a computer and determines whether or not any one of all the wheels of the vehicle has abnormal tire pressure.

The estimator 20 further includes an alarm 30
Is also connected. The alarm 30 is activated to visually or audibly notify the driver that the tire pressure on at least one wheel of the vehicle is abnormally low. The alarm 30 can be designed to identify the wheels and notify the driver that the tire pressure is abnormally low.

As shown in FIG. 1, the estimator 20 is further connected to a vehicle state quantity detection device 40. The vehicle state quantity detection device 40 employs a configuration adapted to the principle that the estimator 20 performs tire pressure abnormality determination, data selection, and data correction described below. It is configured to include at least one sensor that detects a physical quantity that needs to be referred to for performing various data processing according to the principle.

FIG. 2 shows a specific example of the configuration of the vehicle state quantity detection device 40 in a table format. (1) When it is necessary to detect the amount of lateral load movement When the vehicle state quantity detection device 40 needs to detect the amount of lateral movement of the load on the vehicle, the vehicle state quantity detection device 40 It is configured to include a sensor or a sensor group individually or in combination. (A) a lateral acceleration sensor that detects the lateral acceleration of the vehicle (b) a steering angle sensor that detects the steering angle (rotational operation angle) of the steering wheel of the vehicle by the driver (c) a yaw rate sensor that detects the yaw rate of the vehicle (d) ) Left and right load sensors provided in association with each of the left and right wheels of the vehicle (each load sensor is a wheel load, which is a ground load of each of the left and right wheels, or a load related thereto (for example, from the spring upper portion of the vehicle to the left and right wheels Load acting on each of
(E) Left and right vehicle height sensors provided in association with each of the left and right wheels of the vehicle (each vehicle height sensor is a part of the body of the vehicle that is close to each of the left and right wheels, (2) When it is necessary to detect the longitudinal load movement amount The vehicle state quantity detection device 40 detects the longitudinal movement amount of the load on the vehicle. When necessary, the sensor or the sensor group described in each of the following sections is configured to include individually or in combination. (A) a longitudinal acceleration sensor for detecting the longitudinal acceleration of the vehicle; (b) front and rear load sensors provided in relation to each of the front and rear wheels of the vehicle (each load sensor is a wheel load that is a ground load of each of the front and rear wheels). Or a load associated therewith (eg, a load acting on each of the front and rear wheels from the sprung portion of the vehicle)
(C) Front and rear vehicle height sensors provided in association with each of the front and rear wheels of the vehicle (each vehicle height sensor is a portion of the body of the vehicle that is close to each of the front and rear wheels, (3) A case where it is necessary to detect wheel driving force (or wheel driving torque) The vehicle state quantity detecting device 40 includes a wheel driving force (or When it is necessary to detect the wheel driving torque), the sensor or the sensor group described in each of the following items is configured to be included individually or in combination. (A) an engine speed sensor for detecting an engine speed, and a shift position sensor for detecting a shift position in A / T. (B) An accelerator opening for detecting an accelerator opening which is an operation amount of an accelerator pedal by a driver. (C) a throttle opening sensor for detecting a throttle opening which is an opening of a throttle valve in the engine; a shift position sensor; (d) an engine load sensor for detecting an engine load; and a shift position sensor. Longitudinal acceleration sensor (e) intake manifold load sensor for detecting the load on the intake manifold of the engine, and shift position sensor (f) driving torque sensor for detecting the driving torque acting on the axle of each wheel (4) detecting the wheel load The vehicle state quantity detection device 40 needs to detect the wheel load. When necessary, the sensor or the sensor group described in each of the following items is configured to be included individually or in combination. (A) A wheel-based load sensor provided for each wheel in a vehicle (each wheel-based load sensor detects a wheel load, which is a ground load of each wheel, or a load related thereto (for example, from a spring-up portion of the vehicle to each wheel). (B) a vehicle height sensor for each wheel provided in association with each wheel of the vehicle (each vehicle height sensor for each wheel is close to each wheel of the body of the vehicle) (C) A vertical acceleration sensor for each wheel provided in association with each wheel of the vehicle (the vertical acceleration sensor for each wheel is a sensor for each wheel). FIG. 3 is a flowchart conceptually showing the contents of the tire pressure abnormality determination program stored in the ROM of the computer of the estimator 20. This program is repeatedly executed by the CPU of the computer.

Hereinafter, the contents of this program will be described. First, the principle of the determination by which the estimator 20 determines an abnormal tire pressure will be conceptually described. Next, the failure executed by this program will be described. Judgment and
The data selection and the data correction will be conceptually described, and then the contents of the program will be specifically described with reference to FIG. (1) Determination Principle The estimator 20 determines the detection value detected by the vehicle state quantity detection device 40 and the wheel speed output from the wheel speed sensor 10 at substantially the same time with respect to the same type of vehicle state quantity. The tire pressure state quantity of the wheel is estimated based on the relationship with the estimated value estimated based on the signal.

This determination principle is embodied by employing one or more of the following several types. (A) Lateral Load Movement Reference Type In the case of adopting this type, the estimator 20 sets the wheel speed sensor 1 for the left and right wheels at substantially the same time as each other.
Based on the two wheel speed signals output from 0, the lateral movement amount of the load in the vehicle is estimated, and when the estimated value differs from the detection value by the vehicle state quantity detection device 40 by a set value or more, It is determined that the tire pressure is abnormal in any one of the cases. (B) Front / rear load transfer reference type When this type is adopted, the estimator 20 sets the wheel speed sensor 1 at substantially the same time for the front and rear wheels.
Based on the two wheel speed signals output from 0, the forward / backward movement amount of the load on the vehicle is estimated, and when the estimated value differs from the detection value by the vehicle state quantity detection device 40 by a set value or more, It is determined that any one of the tire pressures is abnormal. (C) Vehicle driving force reference type When this type is adopted, the estimator 20 calculates the combined value (for example, the average value) of the four wheel speeds detected by the wheel speed sensor 10 for each of the four wheels and the vehicle speed. And if the estimated value differs from the actual vehicle driving force detected by the vehicle state quantity detecting device 40 by a set value or more, the tire It is determined that the pressure is abnormal. (2) Failure determination This is a process of determining whether the vehicle state quantity detection device 40 has failed. In this process, for example, when the output signal of the vehicle state quantity detection device 40 does not change for an abnormally long time,
It is determined that 0 has failed. (3) Data selection The estimator 20 determines that the wheel speed signal may not accurately reflect the tire pressure of the wheel, and the reflection accuracy is low.
The data generated based on the wheel speed signal output from the wheel speed sensor 10 is invalidated with respect to the tire pressure abnormality determination. That data is not used for tire pressure abnormality determination. In the present embodiment, the "reflection accuracy reduced state" is defined to mean a state in which the wheel speed signal does not accurately reflect the dynamic load radius of the tire.

The estimator 20 sets the “reflection accuracy reduced state”.
Is determined as follows. (A) In the case where the reflection accuracy reduction state includes the actual wheel load deviation state, the estimator 20 determines that the vehicle lateral load movement amount is equal to or greater than the set value and that the vehicle lateral load movement amount is equal to or greater than the set value. When at least one of the conditions is satisfied, it is determined that there is an actual wheel load deviation state in which the actual value of the wheel load deviates from its normal value by a set amount or more. The lateral load moving amount and the longitudinal load moving amount are detected by the vehicle state amount detecting device 40. (B) When the reflection accuracy reduction state includes the large slip value state When the longitudinal acceleration of the vehicle is equal to or greater than the set value, the estimator 20 sets the wheel slip value to the large slip value state where the slip value with respect to the road surface is equal to or greater than the set value. It is determined that there is. The longitudinal acceleration is detected by the vehicle state quantity detection device 40.

The estimated value can be determined to be a large slip value state when the driving force of the wheel is equal to or greater than the set value. The driving force of the wheels is detected by the vehicle state quantity detection device 40.

Further, the estimator 20 assumes that the tire pressure is normal and assumes that the dynamic load radius of the tire is equal to a standard value based on the vehicle speed and the wheel speed signal at substantially the same time. It is possible to calculate the slip value of the wheel when the pressure is normal, and determine that the wheel is in the large slip value state when the calculated slip value is equal to or greater than the set value.

The vehicle speed is detected by the vehicle state quantity detector 40. The vehicle state quantity detection device 40 is configured to detect the vehicle speed by estimating the vehicle speed based on the output signals of the plurality of wheel speed sensors 10 provided on the plurality of wheels, or to directly detect the vehicle speed by a dedicated vehicle speed sensor. It is possible to use a format for detection. (4) Data Correction The estimator 20 checks the vehicle speed, the wheel load, the wheel slip value, and the presence / absence of the A / T shift shock detected by the vehicle state quantity detection device 40 in the reflection accuracy reduced state. Wheel speed sensor 10 based on at least one of
At least one of data generated based on the wheel speed signal output from the controller and a calculated value based on the data.

Specifically, when the estimator 20 performs the correction based on the vehicle speed, the effect of the tread lift that appears to increase according to the vehicle speed does not appear in the corrected data or the calculated value. In order to make the correction, the correction is performed according to a predetermined rule.

When the estimator 20 performs the correction based on the wheel load, the phenomenon that the apparent dynamic load radius of the tire decreases in accordance with the wheel load does not appear in the corrected data or the calculated value. In order to make the correction, the correction is performed according to a predetermined rule.

When the correction is performed based on the slip value of the wheel, the estimator 20 determines that the apparent dynamic load radius of the tire decreases in accordance with the slip value. Is corrected according to a predetermined rule so as not to appear in.

In addition, in this embodiment, in this embodiment,
The reflection accuracy reduced state is classified into two states. The state in which the accuracy of the wheel speed signal reflecting the tire pressure is considerably low and the state in which the wheel speed signal is slightly low are classified. In the present embodiment, data selection is performed in a state where the accuracy of the wheel speed signal reflecting the tire pressure is considerably low, while data selection is performed in a state in which the accuracy of the wheel speed signal reflecting the tire pressure is slightly low. Data correction is performed without being performed.

Next, the contents of the tire pressure abnormality determination program will be described with reference to the flowchart of FIG.

In each execution of this program, first, in step S11 (hereinafter simply referred to as “S11”; the same applies to other steps), the failure determination is performed for the vehicle state quantity detection device 40. Is
Next, in S12, it is determined whether or not the vehicle state quantity detection device 40 is determined to have failed in the failure determination. When it is determined that the vehicle state quantity detection device 40 has failed, the determination in S12 is YES.
, And one execution of this program ends immediately.

On the other hand, if it is assumed that the vehicle state quantity detecting device 40 is not determined to have failed in the failure determination this time, the determination in S12 is NO, and the process proceeds to S13.

In S13, the data selection is performed on data (hereinafter referred to as "wheel speed data") generated based on the wheel speed signals output from the four wheel speed sensors 10. Specifically, it is determined whether the accuracy with which the wheel speed data reflects the tire pressure is considerably low due to the actual wheel load deviation or the large slip value,
If so, it is determined that the current wheel speed data should be invalidated.

Thereafter, in S14, it is determined whether or not the current wheel speed data is determined to be invalid in the data selection. If it is determined that the program should be invalidated, the determination in S14 becomes YES, and one execution of the program is immediately terminated. This eliminates the need for erroneous tire pressure abnormality determination based on wheel speed data having a considerably large error, and normalizes the tire pressure abnormality determination.

On the other hand, if it is not determined that the current wheel speed data should be invalidated, the determination in S14 becomes NO, and the process proceeds to S15.

In S15, the data correction is performed on the current wheel speed data. This data correction is performed based on the detection result by the vehicle state quantity detection device 40 as described above. This eliminates the need for erroneous tire pressure abnormality determination based on wheel speed data having a somewhat large error, and normalizes tire pressure abnormality determination.

Thereafter, in S16, the tire pressure abnormality is determined according to the above-described determination principle by using the current wheel speed data that has been corrected.

Subsequently, in S17, it is determined whether or not at least one of the four wheels is determined to be abnormally low in the tire pressure abnormality determination. If it is not determined that at least one tire pressure of the four wheels is abnormally low, the determination in S17 is NO, and one cycle of the program is immediately terminated.

In contrast, at least one of the four wheels
If it is determined that the two tire pressures are abnormally low, S1
7 is YES, and in S18, the alarm 30
Is turned on, thereby informing the driver that the tire pressure on at least one wheel is abnormally low. This completes one execution of the program.

In addition, in this embodiment, in this embodiment,
Tire pressure state quantity estimation is performed in a vehicle equipped with four wheels (for example, a passenger car),
The present invention can be implemented such that the tire pressure state quantity estimation is performed on a vehicle (for example, a large vehicle) equipped with a larger number of wheels.

[0099] In addition, in this embodiment, the alarm 30 is operated to notify the driver that the tire pressure is abnormally low. For example, the vehicle state quantity detection device 40 fails. Or in this case, the tire pressure determination cannot be performed because the determination in S14 in FIG. 3 is YES and the wheel speed data is invalidated. It is possible to carry out the present invention by operating it to notify the driver.

Next, a second embodiment of the present invention will be described.
However, in the present embodiment, since many elements are common to the first embodiment, only the different elements will be described in detail, and the common elements will be referred to using the same names or reference numerals, thereby giving a detailed description. Is omitted.

In the present embodiment, the estimator 20 is designed to make a tire pressure abnormality determination according to a different determination principle from that in the first embodiment. The principle of the determination is as follows.

That is, the estimator 20 estimates the tire pressure state quantity for the same wheel based on the wheel load and the wheel speed according to the relationship established between the tire pressure, the wheel load and the wheel speed.

More specifically, the estimator 20 assumes a plurality of values for the wheel load, and for each of the plurality of assumed wheel loads, calculates the relationship between the tire apparent dynamic load radius R and the tire pressure P. I remember more than one. The estimator 20 selects one corresponding to the current wheel load from among the plurality of relationships, and determines the tire pressure P corresponding to the current apparent dynamic load radius according to the selected relationship.
The tire pressure P is estimated. Further, when the estimated tire pressure P is lower than the reference value, the estimator 20 determines that the tire pressure P is abnormally low.

Therefore, the estimator 20 eventually determines when the actual relationship between the wheel load and the wheel speed for the same wheel does not match the relationship that holds when the tire pressure on that wheel is assumed to be normal. It is determined that the tire pressure is abnormal.

A plurality of relationships between the dynamic load radius R and the tire pressure P are stored in the ROM of the computer of the estimator 20 as a map in advance. FIG. 4 shows the plurality of relationships in a graph. As is clear from the graphs, the plurality of relationships are set to indicate that the tire pressure P increases as the wheel load increases under the same apparent dynamic load radius R.

However, FIG. 13 representatively shows a plurality of relations when the wheel load is 0, when the wheel load is small, and when the wheel load is large. The relation is stored in the ROM as a map, and one of the plurality of relations is selected and used.

The ROM of the computer of the estimator 20 stores a tire pressure abnormality determination program. This program is different from the tire pressure abnormality determination program of FIG.
Only the part corresponding to S16 is different, and the other parts are common.

FIG. 5 is a flowchart conceptually showing the contents of the portion corresponding to S16 in FIG. 3 in the tire pressure abnormality determination program according to the present embodiment as a tire pressure abnormality determination routine. In the present embodiment, the tire pressure abnormality determination program is executed by the computer C
The PU repeatedly executes each wheel, and as a result, the tire pressure abnormality determination routine is also repeatedly executed for each wheel.

In each execution of the tire pressure abnormality determination routine, first, in S31, the vehicle load on the current wheel is detected by the vehicle state quantity detection device 40 in S31. Next, in S32, one of the plurality of relationships (see FIG. 4) corresponding to the detected wheel load is selected.

Thereafter, in S33, the wheel speed data for the current wheel, which has been subjected to the data correction in the step corresponding to S15 in FIG.
It is read from the computer RAM of the estimator 20.

Subsequently, in S34, the vehicle speed V is detected by the vehicle state quantity detection device 40. Thereafter, in S35, the value obtained by taking the normal slip ratio of the wheel into the detected vehicle speed V becomes the current wheel speed V _** (**: FL, F
R, RL, RR), the apparent dynamic load radius R of the current wheel is calculated.

Subsequently, in S36, the calculated apparent dynamic load radius R is converted from the tire pressure P according to the selected relationship.

[0113] Thereafter, in S37, the converted tire pressure P is equal to or less than the reference value P ₀ is determined. If it is equal to or less than the reference value P ₀ , the determination is YES, and it is determined in S38 that at least one tire pressure P of the four wheels is abnormal. On the other hand, if the difference is not equal to or _smaller than the reference value P ₀ , the determination is NO, and S
At 39, it is determined that the tire pressures P of all four wheels are normal. In any case, the execution of the tire pressure abnormality determination routine ends here.

It should be noted that, in this embodiment,
For each wheel, the wheel speed V _** is the dynamic load radius R _{** of the} tire.
However, since the conversion is performed using the vehicle speed V in common for the four wheels, it is not essential to actually perform such conversion. In the present embodiment, such conversion is merely performed for convenience of explanation.

As described above, some embodiments of the present invention have been described in detail with reference to the drawings. However, these embodiments are merely examples, and the embodiments described in the above-mentioned section "Means for Solving the Problems and Effects of the Invention" are described. The present invention can be implemented in various modified and improved forms based on the knowledge of those skilled in the art.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a hardware configuration of a tire state estimation device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a variation of the vehicle state quantity detection device 40 in FIG. 1 in a table format.

FIG. 3 is a flowchart conceptually showing the contents of a tire pressure abnormality determination program executed by a computer of an estimator 20 in FIG.

FIG. 4 is a graph for explaining a relationship among an apparent dynamic load radius R, a tire pressure P, and a wheel load, which is referred to when a tire state estimation device according to a second embodiment of the present invention estimates a tire pressure state quantity. is there.

FIG. 5 is a conceptual diagram of a tire pressure abnormality determination routine, particularly a portion related to a tire pressure abnormality determination, in a tire pressure abnormality determination program executed by a computer of an estimator 20 in a tire state estimation device according to a second embodiment. 6 is a flowchart shown in FIG.

[Explanation of symbols]

 Reference Signs List 10 wheel speed sensor 20 estimator 30 alarm 40 vehicle state quantity detection device

Claims (31)

[Claims] 1. An apparatus for estimating a state of a tire provided on a vehicle having a wheel configured such that air is sealed under pressure in a tire mounted on the wheel, wherein the angular velocity is the angular velocity of the wheel. A wheel speed sensor that detects a wheel speed and outputs a wheel speed signal according to the wheel speed; a vehicle state amount detection device that detects a state amount of the vehicle and outputs a vehicle state amount signal according to the wheel speed sensor; An estimator that estimates the tire state based on the wheel speed signal output from the vehicle state quantity signal output from the vehicle state quantity detection device, the tire state using the wheel speed signal A tire state estimation device including a unit that performs a normalization process for normalizing the estimation. 2. The tire state estimating device according to claim 1, wherein the estimator estimates a state quantity of a tire pressure, which is an air pressure of the tire, as the tire state. 3. The estimator estimates the tire pressure state quantity based on the wheel speed signal in accordance with at least a relationship established between the tire pressure and the wheel speed for the same wheel. Item 3. A tire condition estimation device according to item 2. 4. The vehicle, wherein a plurality of the wheels are provided on the vehicle, wherein the wheel speed sensors are provided for each of the plurality of wheels, and wherein the estimators are respectively provided from the plurality of wheel speed sensors. The tire condition estimating device according to claim 2 or 3, further comprising means for estimating a tire pressure condition amount of each wheel based on a mutual relationship between a plurality of wheel speed signals output at substantially the same time. 5. The detection device according to claim 1, wherein the estimator detects a detection value detected by the vehicle state quantity detection device at substantially the same time with respect to the same type of vehicle state quantity, and a wheel speed output from the wheel speed sensor. The tire condition estimating device according to claim 2 or 3, further comprising: a unit configured to estimate a tire pressure state quantity of the wheel based on a relationship with an estimated value estimated based on the signal. 6. The apparatus according to claim 5, wherein said means includes means for determining that the tire pressure of said wheel is abnormal when said detected value and said estimated value relating to the same kind of vehicle state quantity do not coincide with each other. The described tire condition estimation device. 7. The vehicle according to claim 7, wherein the plurality of wheels include left and right wheels respectively disposed on the left and right sides of the vehicle, and the vehicle state quantity detection device includes a lateral load movement amount sensor that detects a lateral movement amount of a load on the vehicle. The means for estimating a lateral movement amount of a load in the vehicle based on two wheel speed signals output from the wheel speed sensors at substantially the same time with respect to the left and right wheels. The tire state estimating apparatus according to claim 6, further comprising: a unit that determines that the tire pressure is abnormal with respect to one of the left and right wheels when the detected value differs from a value detected by the lateral load movement amount sensor by a set value or more. . 8. The vehicle according to claim 8, wherein the plurality of wheels include front and rear wheels respectively disposed in front and behind the vehicle, and the vehicle state quantity detection device includes a front and rear load movement amount sensor that detects a front and rear movement amount of a load in the vehicle. The means for the front and rear wheels, at substantially the same time as each other, based on two wheel speed signals output from the wheel speed sensor, estimates the amount of forward and backward movement of the load in the vehicle, the estimated value The tire condition according to claim 6 or 7, further comprising means for determining that the tire pressure is abnormal with respect to one of the front and rear wheels when the detected value differs from the value detected by the longitudinal load movement amount sensor by a set value or more. Estimation device. 9. The vehicle state quantity detecting device includes a vehicle driving force related sensor for detecting a driving force of the vehicle or a physical quantity related thereto, and the means includes: a wheel speed signal output from the wheel speed sensor; Based on the vehicle speed, which is the traveling speed of the vehicle,
A method comprising: estimating a driving force of the vehicle, and determining that the tire pressure is abnormal with respect to the wheel when the estimated value differs from a value detected by the vehicle driving force-related sensor by a set value or more. The tire condition estimation device according to any one of claims 6 to 8. 10. The wheel load and the wheel speed signal for the same wheel according to a relationship established between at least the tire pressure, a wheel load acting on the wheel as a ground contact load, and the wheel speed. 3. The tire condition estimating device according to claim 2, further comprising: means for estimating a tire pressure condition amount of the wheel based on the above. 11. The vehicle state quantity detection device includes a wheel load-related sensor that detects a wheel load acting on the wheel as a ground load or a physical quantity related thereto as the vehicle state quantity, wherein the estimator uses the same wheel. At substantially the same time as each other, based on the relationship between the wheel load related signal output from the wheel load related sensor and the wheel speed signal output from the wheel speed sensor, the tire pressure state quantity of the wheel is determined. The tire state estimating device according to claim 2 or 10, further comprising an estimating unit. 12. The method according to claim 11, wherein the relation between the wheel load-related signal and the wheel speed signal for the same wheel does not coincide with a relation established when the tire pressure of the wheel is assumed to be normal. The tire condition estimating device according to claim 11, further comprising means for determining that the tire pressure of the wheel is abnormal. 13. The vehicle state quantity detection device, wherein the vehicle is driven by transmitting a torque of a power source as a driving force to the wheels via a variable speed driving force transmission device. Further includes a vehicle speed sensor that detects a vehicle speed that is a traveling speed of the vehicle, wherein the driving force-related sensor determines a speed ratio of the driving force transmission device and a rotation speed sensor that detects a rotation speed of the power source. A speed ratio sensor for detecting, a vehicle speed detected by the vehicle speed sensor,
The tire pressure is normal based on a power source rotation speed detected by the rotation speed sensor, a speed ratio detected by the speed ratio sensor, and a predetermined slip value as a slip value of the wheel with respect to a road surface. In the case of, the wheel speed to be detected by the wheel speed sensor is calculated as a reference wheel speed, and the calculated reference wheel speed and the actual wheel speed detected by the wheel speed sensor are different from each other by a set value or more. 13. The tire state estimating device according to claim 2, further comprising a unit that determines that the tire pressure is abnormal in such a case. 14. The estimator calculates the tire pressure state quantity of the wheel based on the wheel speed signal according to at least the relationship established between the tire pressure and the vibration characteristic of the wheel speed for the same wheel. The tire condition estimating device according to claim 2, which estimates. 15. The vehicle, wherein a plurality of the wheels are provided on the vehicle, the wheel speed sensors are provided for each of the plurality of wheels, and the estimator outputs each wheel output from each wheel speed sensor. 15. The tire condition estimating device according to claim 2, further comprising means for estimating a tire pressure condition amount of each wheel independently of other wheels based on a speed signal. 16. A tire model in which the means is a disturbance observer, and a rim side portion and a belt side portion rotatable relative to each wheel are connected to each other by at least a torsion spring. Based on the model
A motion system that describes the rotational motion of each wheel is assumed,
In the motion system, a change in the spring constant of the torsion spring accompanying a change in the tire pressure of each wheel is regarded as a disturbance to each wheel, and a wheel speed signal output from each wheel speed sensor is used as the rim side portion of each wheel. 16. The tire condition estimation of claim 15, including using the signal representing the wheel speed of the vehicle to estimate the disturbance as one of the state variables of the motion system, thereby estimating the tire pressure at each wheel. apparatus. 17. The method according to claim 2, wherein the estimator performs the normalization process in a state where the reflection speed of the wheel speed signal may not accurately reflect the tire pressure of the wheel. The tire condition estimation device according to any one of the above. 18. The tire condition estimating apparatus according to claim 17, wherein the reflection accuracy reduction state includes a state in which the wheel speed signal may not accurately reflect a true dynamic load radius of the tire. 19. The reflection accuracy reduction state includes an actual wheel load deviation state in which an actual value of a wheel load acting as a ground contact load on the wheel deviates from a normal value thereof by a set amount or more, and the estimator includes: 19. The tire condition estimating device according to claim 17, further comprising a normalization processing unit that performs the normalization process in the actual wheel load deviation state. 20. The vehicle state quantity detection device includes a lateral acceleration related sensor for detecting a lateral acceleration of the vehicle or a physical quantity related thereto as the vehicle state quantity, and the normalization processing unit includes the lateral acceleration related sensor. 20. The tire state estimating apparatus according to claim 19, further comprising: means for determining the actual wheel load deviation state based on a vehicle state quantity signal output from the vehicle. 21. A longitudinal acceleration related sensor for detecting the longitudinal acceleration of the vehicle or a physical quantity related thereto as the vehicle state quantity, wherein the normalization processing means includes the longitudinal acceleration related sensor. 21. The tire state estimating device according to claim 19, further comprising means for determining the actual wheel load deviation state based on a vehicle state quantity signal output from the vehicle. 22. The reflection accuracy reduction state includes a large slip value state in which a slip value of the wheel with respect to a road surface is equal to or greater than a set value, and the estimator performs the normalization process in the large slip value state. 17. A method according to claim 17, further comprising:
2. The tire condition estimation device according to claim 1. 23. The vehicle state quantity detecting device includes a longitudinal acceleration related sensor for detecting the longitudinal acceleration of the vehicle or a physical quantity related thereto as the vehicle state quantity, and the normalization processing unit includes the longitudinal acceleration related sensor. 23. The tire state estimating apparatus according to claim 22, further comprising: means for determining the large slip value state based on a vehicle state quantity signal output from the vehicle. 24. The vehicle state quantity detection device includes a drive force related sensor for detecting a drive force of the wheel or a physical quantity related thereto as the vehicle state quantity, and the normalization processing unit includes the drive force related sensor. 23. The tire state estimating apparatus according to claim 21, further comprising means for determining the large slip value state based on a vehicle state quantity signal output from the vehicle. 25. The vehicle state quantity detection device includes a vehicle speed related sensor that detects a vehicle speed that is a traveling speed of the vehicle or a physical quantity related thereto as the vehicle state quantity, wherein the normalization processing units are substantially equal to each other. And means for judging the large slip value state based on the vehicle state quantity signal output from the vehicle speed related sensor and the wheel speed signal output from the wheel speed sensor at the same time. The tire condition estimation device according to any one of the above. 26. The normalization process, wherein the estimator substantially invalidates a wheel speed signal output from the wheel speed sensor with respect to the estimation of the tire pressure state quantity in the reflection accuracy reduced state. The tire condition estimating device according to any one of claims 14 to 25, further comprising an invalidating unit that performs the following. 27. A wheel speed signal output from the wheel speed sensor and the wheel speed signal based on the vehicle state amount signal output from the vehicle state amount detection device in the reflection accuracy reduced state, 27. The correction method according to claim 14, further comprising: a correction unit that performs the normalization process by correcting at least one of the calculated values based on the normalization process so that the estimation of the tire pressure state quantity is normalized. Tire condition estimation device. 28. The correction means, comprising: a vehicle speed which is a traveling speed of the vehicle or a physical quantity related thereto, a wheel load acting on the wheel as a ground contact load or a physical quantity related thereto, a slip value of the wheel relative to a road surface or 28. The tire condition according to claim 27, further comprising means for correcting at least one of a wheel speed signal output from the wheel speed sensor and a calculated value based on the wheel speed signal based on at least one of a physical quantity related thereto. Estimation device. 29. The vehicle state quantity detection device, comprising: a vehicle speed that is a traveling speed of the vehicle or a physical quantity related thereto;
The wheel load acting on the wheel as a ground load or a physical quantity related thereto, and at least one of a slip value of the wheel with respect to a road surface or a physical quantity related thereto is detected as the vehicle state quantity. Means for correcting at least one of a wheel speed signal output from the wheel speed sensor and a calculated value based on the wheel speed signal based on at least one vehicle state amount detected by the vehicle state amount detection device. The tire condition estimation device according to claim 27. 30. The estimator comprising: (a) a wheel speed signal output from the wheel speed sensor and a wheel speed signal output from the wheel speed sensor based on a wheel load acting on the wheel as a ground load during each run of the vehicle. Correction means for performing the normalization process by correcting at least one of the calculated values based on: (b) a reference time for each run of the vehicle,
30. An initialization means for performing the normalization processing by initializing the condition of the correction to be performed during the same traveling based on the wheel load.
The tire condition estimation device according to any one of the above. 31. The vehicle state quantity detection device includes a wheel load related sensor for detecting the wheel load or a physical quantity related thereto, and the initialization unit outputs a vehicle state quantity signal output from the wheel load related sensor. Based on a vehicle state quantity signal output from the wheel load related sensor, and a means for setting the actual wheel load at the start of each run as a reference wheel load. Based on the deviation of the actual wheel load sequentially acquired during the same traveling from the set reference wheel load, a wheel speed signal output from the wheel speed sensor and a calculated value based on the wheel speed signal are calculated. 31. The tire condition estimating device according to claim 30, further comprising a unit that corrects at least one of them.