JP2003165400A - Slip state related amount acquisition device and longitudinal force control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To acquire control parameters suitable for brake fluid pressure control. <P>SOLUTION: A vehicle body deceleration is obtained based on a longitudinal force applied to wheels, and longitudinal force sharing related amounts are acquired based on the vehicle body deceleration and a wheel deceleration. Since the longitudinal force sharing related amounts are not obtained based on a vehicle body speed estimated based on a wheel speed, these amounts can be accurately obtained even during a slip control for all wheels. The longitudinal force sharing related amounts are parameters largely different between those obtained before and after a road surface use μ becomes maximum. Therefore, based on the longitudinal force sharing related amounts, a timing when the road surface use μ becomes maximum can be detected satisfactorily. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a slip state related quantity acquisition device, a longitudinal force control device, and a vehicle body acceleration acquisition device.

[0002]

2. Description of the Related Art Japanese Unexamined Patent Publication (Kokai) No. 5-39021 discloses a slip ratio detecting device for detecting a slip ratio based on a vehicle speed and a wheel speed. Also, (a) road surface utilization μ acquisition means for acquiring road surface utilization μ based on the road surface frictional force detected by the road surface frictional force detection device and the vertical force detected by the vertical force detection device, and (b) that road surface A slip control device is described that includes a brake control unit that controls a brake actuation force based on a change state of a road surface usage μ acquired by a usage μ acquisition means and a slip ratio detected by a slip ratio detection device.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to obtain an appropriate control parameter in a device for controlling longitudinal force, to obtain a control device using the control parameter, and The object is to obtain a vehicle body acceleration acquisition device that acquires a vehicle body acceleration used for one mode of the control parameter. The above problems can be solved by using a slip state related amount acquisition device, a longitudinal force control device, and a vehicle body acceleration acquisition device having the configurations of the following aspects. Similar to the claims, each mode is divided into paragraphs, each paragraph is given a number, and the numbers of other paragraphs are referred to as necessary. This is merely for facilitating the understanding of the technology described in the present specification, and it should not be construed that the technical features described in the present specification and a combination thereof are limited to the following items. Absent. Further, when a plurality of items are described in one section, it is not always necessary to adopt all the items together, and it is possible to take out only some of the items and adopt them.

Of the following aspects, the items (1) to (3) correspond to the items 1 to 3, respectively, and the items (10) and (17) are the items 4 and 4.
Corresponds to 5. Further, the items (18) and (21) correspond to claims 6 and 7, respectively, and the items (23) and (24) correspond to claims 8 and 9, respectively. Further, item (27) corresponds to claim 10, and item (30) corresponds to claim 11.

(1) A wheel speed detecting device for detecting the rotational speed of at least one of a plurality of wheels of a vehicle, and a longitudinal force for detecting a longitudinal force applied to at least one of the plurality of wheels. A detection device, at least a vehicle body speed-related amount related to the speed of the vehicle body acquired based on the longitudinal force detected by the longitudinal force detection device, and at least one of the wheels detected by the wheel speed detection device. A slip state related amount acquisition device including a slip state related amount acquisition unit that acquires a slip state related amount related to a slip state of the wheel based on a wheel speed related amount related to a rotation speed. In the slip state related amount acquisition device described in this section, the slip state related amount is acquired based on the wheel speed related amount and the vehicle body speed related amount based on the longitudinal force. In a state where considerable slip occurs in all wheels, for example, in a state in which slip control is performed for all wheels, the vehicle body speed related amount cannot be accurately acquired based on the rotation speed of the wheels. On the other hand, if the vehicle speed-related amount is obtained based on the longitudinal force, that is, not based on the rotational speed of the wheels, the vehicle speed-related values can be obtained even when a considerable amount of slip occurs on all wheels. The amount can be acquired accurately. Based on the slip state-related amount, for example, it is possible to control the longitudinal force applied to the wheels so that the slip state becomes a desired state. It can be said that the control parameter is suitable for. The slip state-related quantity corresponds to the slip state quantity that represents the slip state of the wheel, the quantity that can estimate the slip status, and the quantity that changes according to changes in the slip status. Obtained based on quantity and. The wheel speed-related amount corresponds to a wheel rotation angular velocity, a rotation angular acceleration, a value obtained by multiplying these by a turning radius (peripheral speed, peripheral acceleration), and the like. Applicable As described above, the vehicle body acceleration can be calculated based on the longitudinal force. Based on the speed, the vehicle speed can be accurately obtained even during the slip control. It is possible to acquire the vehicle speed during slip control without using a special sensor such as a Doppler ground speed sensor. The acceleration in this specification includes positive acceleration when the speed increases and negative acceleration when the speed decreases. Hereinafter, when it is necessary to distinguish negative acceleration from positive acceleration, it is referred to as deceleration, and an increase in the absolute value of negative acceleration is referred to as an increase in deceleration.

(2) The slip state-related quantity acquisition unit relates to a front-rear force-sharing relationship related to the ratio of the front-rear force that the wheels share in the vehicle based on the vehicle body speed-related quantity and the wheel speed-related quantity. The slip state related amount acquisition device according to (1), including a front-rear force sharing related amount acquisition unit that acquires an amount as the slip state related amount. In the slip state related quantity acquisition device described in this section, the front-rear force sharing related quantity of the wheel is acquired based on the wheel speed related quantity and the vehicle body speed related quantity based on the front-rear force. The front-rear force sharing-related amount is an amount related to the ratio of the front-rear force that the wheels share in the vehicle, and the share of the front-rear force of the wheels, the amount that can estimate the share, and the amount that correlates with the share. Etc. are applicable. The front-rear force-sharing related amount can be obtained based on the front-rear force of the entire vehicle and the front-rear force acting on the wheels thereof. It can also be obtained based on the acceleration state (corresponding to the acceleration state) and the rotation state of the wheel (a state represented by a wheel speed related amount, for example, the wheel acceleration state corresponds). Specifically, the ratio of the acceleration of the wheel to the acceleration of the vehicle body, the function value including the ratio, and the like can be adopted as the front-rear force sharing related amount. When the slip of a certain wheel is small and when it is large (for example, when it is close to the locked state), the ratio of the longitudinal force shared by the wheel in the vehicle is smaller when the slip is larger. Therefore, there is a close relationship between the front-rear force sharing related amount and the slip state related amount related to the wheel slip state, and it is considered that the front-rear force sharing related amount is one mode of the slip state related amount. You can The longitudinal force sharing related amount will be described in detail in [Embodiment of the Invention].

(3) A slip state quantity in which the slip state related quantity acquisition unit acquires the slip state quantity of the wheel as the slip state related quantity based on the vehicle body speed related quantity and the wheel speed related quantity. The slip state related quantity acquisition device according to (1) or (2), including an acquisition unit. In the slip state related quantity acquisition device described in this section, the slip state quantity is acquired based on the vehicle body speed related quantity and the wheel speed related quantity. The slip state quantity includes, for example, a slip rate, a difference between a vehicle body speed and a wheel speed (a wheel peripheral speed, which is a value obtained by multiplying a rotational angular speed by a turning radius), a braking slip tendency, and a driving slip tendency strength. The amount to be expressed is applicable.

(4) Any one of the items (1) to (3), wherein the slip state-related quantity acquisition unit includes a vehicle body acceleration calculation unit that obtains a vehicle body acceleration based on the longitudinal force detected by the longitudinal force detection device. The slip state-related quantity acquisition device described in any one of the above. The vehicle body acceleration Gs can be obtained, for example, based on a value obtained by dividing the longitudinal force applied to the entire vehicle (total longitudinal force) by the vehicle weight M. The total longitudinal force Fsx of the vehicle can be the sum of longitudinal forces Fxi applied to each wheel. Gs = (Fsx / M) * g Fsx = (Sigma) Fxi (i = fR, fL, rR, rL) Here, g is a gravitational acceleration. It should be noted that it is not essential to obtain the longitudinal force for all wheels. Based on the longitudinal force applied to some wheels, the longitudinal force applied to other wheels can be estimated. Based on these estimated longitudinal force and the detected longitudinal force, the total longitudinal force can be obtained. The vehicle body acceleration can also be obtained based on a value obtained by dividing the total longitudinal force Fsx by the vertical force Fszi applied to the entire vehicle. Gs = (Fsx / Fsz) · g Fsz = ΣFzi (i = fR, fL, rR, rL) (5) The longitudinal force detection device is provided on each of a plurality of wheels, and the slip state related amount acquisition unit is provided. Is a total longitudinal force applied to the entire vehicle that is the sum of the longitudinal forces detected by the longitudinal force detection devices provided corresponding to the plurality of wheels, and the acceleration for the vehicle body is detected based on the total longitudinal force. (1) to (4) including acceleration calculation unit for longitudinal force
The slip state related amount acquisition device according to any one of items. (6) The longitudinal force detection device is provided corresponding to a part of the plurality of wheels, and the slip state related amount acquisition unit (a) is detected by the longitudinal force detection device. A longitudinal force estimation unit that estimates the longitudinal force applied to other wheels based on the longitudinal force of some wheels, and (b) the longitudinal force of the other wheels and the longitudinal force estimated by the longitudinal force estimation unit. An estimated longitudinal force-corresponding acceleration calculation unit that obtains the acceleration of the vehicle body based on the total longitudinal force applied to the entire vehicle as the sum of the longitudinal force applied to the some wheels detected by the detection device and the total longitudinal force applied to the vehicle The slip state related quantity acquisition device according to any one of (1) to (4), including:
When the front and rear wheels have the same friction coefficient with the road, the front and rear wheels have the same brake actuation amount (fluid pressure of the brake cylinder, drive torque of the brake drive motor, etc.). The relationship (distribution ratio) between the braking force of the front wheels and the braking force of the rear wheels in this case is determined by the vehicle. Therefore, based on the relationship between them and the braking force detected for one of the front wheels and the rear wheels, the braking force applied to the other wheel can be estimated.
The ratio between the braking force of the front wheels and the braking force of the rear wheels becomes substantially equal to the ideal braking force distribution line when the proportioning valve is provided in the hydraulic brake system of the rear wheels. When the proportioning valve is not provided and the same amount of hydraulic pressure is supplied, the ratio is determined by, for example, the size of the diameter of the brake cylinder. In addition, at least one of the brake operating force of the front wheels and the brake operating force of the rear wheels is controlled so that the relationship between the braking force of the front wheels and the braking force of the rear wheels becomes a predetermined relationship. is there. In any case, the relationship between the braking factor amount of the front wheel and the braking factor amount of the rear wheel, the relationship between the braking force of the front wheel and the braking force of the rear wheel, and the braking force of either the front wheel or the rear wheel. Based on and, the other braking force can be estimated.
The same applies to the driving force, and the relationship between the driving factor amount such as the driving torque of the front wheels and the driving factor amount of the rear wheels in a four-wheel drive vehicle is determined by the state of the drive transmission device and the like. The driving force applied to the other driving wheel can be estimated based on the driving force applied to the other driving wheel and the relationship between the driving factor amounts of the front wheels and the driving factors of the rear wheels. When the front-rear force detection device is provided on either one of the front wheels and the rear wheels, it is desirable to provide it on the front wheels or the drive wheels. The front wheel and the rear wheel have a larger braking force than the front wheel, which is important for braking the vehicle body. Further, in the case of a front-wheel drive vehicle or a rear-wheel drive vehicle, if the front-rear force detection device is provided on the drive wheels, both the front-rear force during driving and the front-rear force during braking can be detected. In any case, the acceleration of the vehicle body is calculated based on the longitudinal force of at least one of all the wheels. If only one is provided, the number of front-back force detection devices can be reduced, and the cost can be suppressed.

(7) At least one of the plurality of wheels
Vertical force detection device for detecting a vertical force applied to the vehicle body, and the acceleration of the vehicle body is calculated based on the vertical force detected by the vertical force detection device and the longitudinal force detected by the longitudinal force detection device. The slip state related quantity acquisition device according to any one of items (1) to (6), which includes a vehicle body acceleration calculation unit corresponding to the vertical force obtained by. The vehicle weight can be determined based on the vertical force applied to the wheels. As in the case of the longitudinal force, the vertical force detection device may be provided on each of all wheels or on some wheels. When the vertical force detecting device is provided on some wheels, the vertical force of other wheels can be estimated based on the vertical force and the vehicle attitude (load movement). The vehicle attitude can be directly obtained by a yaw rate sensor, a pitching sensor, a rolling sensor, a vehicle height sensor provided for each wheel, or the like, but can be estimated based on the running state of the vehicle or the like. For example, during straight-ahead braking, the vehicle is in a forward leaning posture, and the degree of forward leaning is greater when the braking force as the longitudinal force is large than when it is small. In this case, the vertical force applied to the front wheels is larger than the vertical force applied to the rear wheels. On the contrary, during the straight-ahead drive, the vehicle is in a backward leaning posture, and the degree of the backward leaning is greater when the driving force as the longitudinal force is large than when it is small. During the turning, the turning outer wheel side is inclined downward and the turning inner wheel side is inclined upward. The degree of the inclination can be acquired based on the turning state. The turning state can be estimated based on the steering angle of the steering wheel and the like. As described above, the vertical force-corresponding vehicle body acceleration calculation unit may include at least one of the detected vertical force-corresponding vehicle body acceleration calculation unit and the estimated vertical force-corresponding vehicle body acceleration calculation unit. (8) The slip state-related quantity acquisition unit includes a vehicle weight-corresponding vehicle body acceleration calculation unit that calculates the acceleration of the vehicle body based on the longitudinal force detected by the longitudinal force detection device and the vehicle weight ( The slip state related quantity acquisition device according to any one of items 1) to 7). The vehicle weight can be, for example, the vehicle body weight, or a value obtained by adding the vehicle body weight and a value obtained by multiplying the standard weight of humans by the standard number of passengers. In the case of a passenger automobile, the weight of the vehicle body is larger than the weight of the occupant, and therefore the vehicle body weight can be the vehicle weight. Further, when the vehicle body acceleration is detected by the acceleration sensor in the state where the disturbance is small, the vehicle weight can be obtained based on the detected vehicle body acceleration and the total longitudinal force. Even if the acceleration sensor uses inertia, it can accurately detect the vehicle body acceleration as long as the disturbance is small. For example, the straight running state of the vehicle can be a state where the disturbance is small.

(9) The slip state-related quantity acquisition unit obtains the maximum frictional force-corresponding slip state-related quantity which is the slip state-related quantity when the longitudinal force detected by the longitudinal force detection device is maximum. The slip state related amount acquisition device according to any one of items (1) to (8), including a frictional force corresponding slip state related amount acquisition unit. (10) Vertical force detection device for detecting vertical force applied to at least one of the plurality of wheels, vertical force detected by the vertical force detection device, and vertical force detection device detected by the longitudinal force detection device Road surface utilization μ acquisition device that acquires road surface utilization μ based on longitudinal force and its road surface utilization μ
Based on the road surface utilization μ acquired by the acquisition device and the slip condition related amount acquired by the slip condition related amount acquisition unit, the maximum road surface for obtaining the slip condition related amount capable of maximally utilizing the friction coefficient of the road surface is obtained. The slip state related amount acquisition device according to any one of items (1) to (9), including a use μ-compatible slip state related amount acquisition unit. The coefficient of static friction between the road surface and the tire is determined by the surface shape and material of the road surface and the tire, the surface condition of the road surface at that time, and the like. Normally, braking is performed in a state where the frictional force between the road surface and the tire is smaller than the frictional force corresponding to the static friction coefficient. In other words, the coefficient of friction between the actual road surface and the tire (road surface utilization μ) is usually smaller than the static friction coefficient. Therefore, in the linear region where the slip is small, the frictional force (longitudinal force) between the tire and the road surface increases as the brake operating force increases, and the road surface utilization μ increases. The braking force increases to a friction force according to the static friction coefficient as the brake actuation force increases. The maximum value of the braking force is the friction force according to the static friction coefficient. The braking force is never greater than the frictional force, but the braking actuation force is independent of the braking force. As a result, the braking slip is increased and the wheel is more prone to lock. By utilizing this, it is possible to obtain the maximum value of the braking force, that is, the friction force according to the static friction coefficient, and in that case, the slip state related amount should be the slip state related amount corresponding to the maximum braking force. You can The same is true at the time of driving, and the maximum driving force-corresponding slip state related amount, which is the slip state related amount when the driving force is maximum, can be obtained. The road surface use μ can be obtained by dividing the longitudinal force of the wheel by the vertical force. Therefore,
As in the case described above, the maximum value of the road use μ can be obtained (the static friction coefficient and the maximum road use μ), and the maximum road use μ-corresponding slip state related amount can be obtained. Here, the road surface use μ is maximized when the frictional force of the wheel is maximized, and the maximum road surface use μ compatible slip state related amount and the maximum friction force compatible slip state related amount are the same. . Hereinafter, in the present specification, these are treated in the same manner, and one side includes the other side and the other side includes the one side. Further, as described in [Embodiment of the Invention], the braking force sharing-related amount S and the driving force sharing-related amount S as the longitudinal force sharing-related amounts are The gradient of increase in absolute value becomes large. Therefore, when the longitudinal forces on all the wheels are controlled so that the slip state-related quantities of the respective wheels are the same and are changed according to the solid line in FIG. 7, as described above, the slip state-related quantities are It is possible to acquire the slip state related amount when the road surface use μ is maximum based on the change state of (11) The maximum road use μ-corresponding slip state related amount acquisition unit includes means for detecting that the sign of a differential value of the road use μ with respect to the slip state related amount is switched from positive to negative. Item 10. The slip state related amount acquisition device described in the paragraph. If it is detected that the sign of the ratio of the change amount of the road surface usage μ to the change amount of the slip state related amount is switched from positive to negative, the maximum value of the road surface usage μ can be acquired. Further, for example, the average value of the slip state related amount before and after the change of the sign of the differential value can be set as the maximum frictional force corresponding slip state related amount and the maximum road surface use μ corresponding slip state related amount. (12) A lateral force detecting device that detects a lateral force applied to at least one of the plurality of wheels, and at least a longitudinal force detected by the longitudinal force detecting device and a lateral force detecting device detected by the lateral force detecting device. The slip state related quantity acquisition device according to any one of items (1) to (11), including a turning state estimation unit that estimates the turning state of the vehicle based on the lateral force. According to the slip state related amount acquisition device described in this section, it is possible to acquire the turning state (yaw moment) of the vehicle. Also, the yaw moment can be expressed by the inertia yaw moment and the change amount of the yaw rate,
You can also get a yaw rate.

(13) The longitudinal force detection device is provided on the rotational body side between the wheel that holds the tire and the axle hub, and detects deformation caused by the relative movement of the longitudinal force applied to the wheel. Any one of (1) to (12), which includes a strain sensor for detecting, and at least a communication device capable of supplying information from the rotating body side to the non-rotating body side.
The slip condition related quantity acquisition device described in. In the slip state related amount acquisition device described in this section, since the strain sensor is provided on the rotating body side, information regarding the longitudinal force is transmitted to the non-rotating body side by communication. The same applies to the vertical force detection device and the lateral force detection device that detects the lateral force applied to the tire. Each of the longitudinal force detecting device, the vertical force detecting device, and the lateral force detecting device, or a device including at least one of them can be referred to as a tire acting force detecting device. The tire acting force detection device can also be provided on a suspension arm that supports the wheels on the non-rotating body side. In this case, the communication device becomes unnecessary.

(14) The slip state-related amount acquisition device according to any one of items (1) to (13) and the longitudinal force applied to the wheels of the vehicle are acquired by the slip state-related amount acquisition device. A front-rear force control device including a front-rear force control device for controlling a wheel based on the slip state-related amount. In the longitudinal force control device described in this section, the longitudinal force is controlled based on the slip state related amount. The longitudinal force control device can also be referred to as a tire acting force control device. (15) The front-rear force control device according to item (14), wherein the wheel front-rear force control device includes a brake control unit that controls a front-rear force by controlling a brake provided on the wheel. Whether braking force or driving force is applied to the wheels,
By controlling the brake actuation force, the longitudinal force of each wheel can be controlled. Further, as described above, the brake operating force and the longitudinal force have a proportional relationship in the linear region where the slip is small, but they do not have a proportional relationship in the non-linear region. On the other hand, the longitudinal force control device of this section may be used for control in the linear region or may be used for control in the non-linear region. In any case, the longitudinal force can be controlled by controlling the brake operating force.
The brake may be a friction brake including a pressing device that presses the friction engagement member held by the non-rotating body against the rotating body of the brake that rotates together with the wheels. The friction brake includes a hydraulic brake in which the friction engagement member is pressed against the brake rotating body by hydraulic pressure, an electric brake in which the frictional engagement member is pressed by electromagnetic driving force, and the like. In any case, the braking force is controlled by controlling the pressing force, and the braking control unit includes the pressing force control unit. On the other hand, when the wheels are rotated by the electric motor and the electric motor is provided for each wheel (wheel-in motor), the drive applied for each wheel by the control of the wheel-in motor. The force and the braking force can be controlled independently. In this case, the brake control unit includes the motor control unit. (16) Slip state control in which the longitudinal force control device controls the longitudinal force based on the slip state related amount acquired by the slip state related amount acquisition device so that the slip state is maintained in an appropriate state The longitudinal force control device according to item (14) or (15), which includes a portion. The longitudinal force control device described in this section includes, for example, an antilock control unit and a traction control unit as a slip state control unit. The antilock control and the traction control can be performed based on the slip state related amount. The longitudinal force may be controlled based on the slip state-related amount and at least one of the running state of the vehicle and the driver's intention. For example, the longitudinal force can be controlled so that the slip state-related amount becomes a target value determined by the running state and the driver's intention. The traveling state of the vehicle corresponds to a braking state, a driving state, a turning state, and the like. The driver's intention can be acquired based on the operating state of the driving operation member (for example, a brake operation member, an accelerator operation member, a steering instruction member, etc.) by the driver. (17) The longitudinal force detection device is provided corresponding to a part of the plurality of wheels, and the slip state related amount acquisition device (a) is detected by the longitudinal force detection device. A longitudinal force estimation unit that estimates the longitudinal force applied to other wheels based on the longitudinal force of some wheels, and (b) the longitudinal force of the other wheels estimated by the longitudinal force estimation unit. And a slip state related amount estimating unit for estimating a slip state related amount of another wheel, the front-rear force control device is based on the slip state related amount of the other wheel estimated by the slip state related amount estimating unit. The longitudinal force control device according to any one of (14) to (16), which includes an estimated slip state-related amount corresponding longitudinal force control unit that controls the longitudinal force of the other wheel.

(18) The slip state-related quantity acquisition device is as described in any one of the above items (10) to (13), and the longitudinal force control device acquires the slip state-related quantity. The wheel longitudinal force control device is such that the slip state-related amount acquired by the device is maintained at approximately the maximum road surface use μ-compatible slip state related amount acquired by the maximum road surface use μ-compatible slip state related amount acquisition unit. The longitudinal force control device according to any one of items (14) to (17), including a control device that controls the longitudinal force. In the longitudinal force control device described in this section, the slip state-related amount is maintained at a slip state-related amount corresponding to the maximum road surface use μ. Therefore, the vehicle can be stopped immediately during braking.
The braking distance can be shortened. When driving,
The vehicle body acceleration can be increased, and the vehicle can quickly reach the desired traveling speed. (19) The longitudinal force detection device is provided on each of a plurality of wheels, and the slip state related amount acquisition device is
In order to acquire the slip state related amount of each of all the wheels, the wheel longitudinal force control device, the slip state related amount of each of the plurality of wheels acquired by the slip state related amount acquisition device is substantially the same. The longitudinal force control device according to any one of items (14) to (18), which includes a slip state related amount uniform control unit that controls the longitudinal force of each wheel so that the size of the wheel becomes large. If the slip state-related quantities of all the wheels are controlled to be the same, the tire wear state of each wheel can be made the same. Therefore, the life of the wheels can be made uniform. It is even more effective if the slip state-related amount of each wheel is controlled so as to be the maximum road surface use μ-corresponding slip state-related amount. In addition,
It is possible to control so that the slip state-related quantities of the front wheels and the slip state-related quantities of the rear wheels have different magnitudes, instead of making the slip-state-related quantities of the plurality of wheels all the same. At the time of braking, it is desirable to set the slip state-related amount of the front wheels as the slip state-related amount corresponding to the maximum road use μ. (20) The wheel longitudinal force control device includes a braking demand degree detecting device for detecting a braking demand degree which is a degree of a braking demand by a driver, and the braking demand degree detected by the braking demand degree detecting device is a set level. In the above case, the braking force control unit for controlling the braking force as the longitudinal force is included so that the slip state-related amount is maintained at the maximum road use μ-corresponding slip state-related amount (14) to (19). The longitudinal force control device according to any one of 1. When the degree of braking demand by the driver is equal to or higher than the set level, the high braking demand of the driver can be quickly met if the slip condition-related amount is held at the maximum road surface use μ-corresponding slip condition-related amount. The braking request degree by the driver can be acquired, for example, based on the brake operation state related amount related to the operation state of the brake operation member. For example, if the operating force of the brake operating member is equal to or greater than a set value, and if the operating force is equal to or greater than the set value and the operating speed is equal to or greater than the set speed, the braking request may be equal to or greater than the set level. it can. The braking request degree can be acquired based on a physical quantity corresponding to an operation state such as an operation stroke and a hydraulic pressure of the master cylinder. (21) The wheel longitudinal force control device is a non-linear region in which the road surface use μ does not increase proportionally with an increase in the slip ratio of the wheel, and the slip state related amount corresponds to the maximum road use μ corresponding slip. When the slip state related amount is in the first region which is a value near the state related amount, the change in the longitudinal force is larger than in the second region in which the slip state related amount deviates from the slip condition related amount corresponding to the maximum road use μ by a set value or more The longitudinal force control device according to any one of items (14) to (20), which includes a gentle longitudinal force control unit that reduces the gradient. When the slip state-related amount is in the vicinity of the maximum road surface use μ-corresponding slip state-related amount, control is performed so that the front-rear force is maintained at substantially the same value, and the change in the front-rear force may be small. On the other hand, it is desirable to greatly change the longitudinal force when the slip state-related amount corresponding to the maximum road use μ is separated. The second region may be a region that deviates from the maximum road surface use μ-corresponding slip state related amount in a direction in which the slip ratio increases or a region that deviates in a direction in which the slip ratio decreases.
With this configuration, the slip state-related amount can quickly approach the maximum road surface use μ-corresponding slip state-related amount. In particular, it is desirable to increase the gradient of change in the longitudinal force in the region where the slip ratio is larger than that in the first region. The change gradient of the longitudinal force refers to the amount of change in the longitudinal force with respect to time. (22) In the case where the absolute value of the difference between the slip state related amount and the maximum road surface use μ-compatible slip state related amount (f) is less than or equal to a set value, the wheel longitudinal force control device determines that the slip state related amount is A slip state related amount holding control unit that controls the longitudinal force so as to be maintained at a slip state related amount corresponding to the maximum road surface use μ, and (g) if the absolute value of the difference is equal to or greater than a set value, the slip state The longitudinal force control device according to any one of (14) to (21), including a slip state related amount holding control ending unit for ending the control by the related amount holding control unit. When the deviation is large, it is desirable that the slip state related amount holding control be ended. In this case,
It is desirable that antilock control or traction control be performed, and the slip state related amount holding control termination unit can be referred to as a slip control transition unit.

(23) The vehicle includes left and right front wheels, and the longitudinal force detection device includes a left front wheel longitudinal force detection device provided on the left front wheel and a right front wheel longitudinal force detection device provided on the right front wheel. , The longitudinal force control device, the difference between the left front wheel longitudinal force detected by the left front wheel longitudinal force detection device and the right front wheel longitudinal force detected by the right front wheel longitudinal force detection device is greater than or equal to a predetermined set value. In this case, a split road determination unit that determines that the road surface with which the wheel contacts is a split road is included.
The longitudinal force control device as described in any one of (14) to (22). If the slip condition related amount is controlled so as to approach the maximum road surface use μ compatible slip condition related amount, high μ
Among the wheels on the lower side and the wheels on the lower side, the wheel on the higher side has a larger longitudinal force. Therefore, when the difference between the front and rear forces between the left and right front wheels is equal to or greater than the set value, it can be determined that the road is a split road. The front-rear force may be compared between the left and right front wheels or the left and right rear wheels, but the comparison between the left and right front wheels can detect that the road is a split road earlier. (24) The wheel front-rear force control device includes a wheel front-rear force suppression unit that suppresses a front-rear force of a wheel having a larger front-rear force when the split road determination device determines that the road is a split road. The longitudinal force control device as described in the paragraph (23).
In the longitudinal force control device described in this section, the longitudinal force of the wheels on the high μ side in the split road is suppressed. Therefore, the front-rear force difference between the wheel on the high μ side and the wheel on the low μ side becomes small, and it is possible to suppress deterioration in vehicle running stability. Here, for suppressing the longitudinal force, for example, when the longitudinal force increasing mode is set, the increasing gradient can be reduced or the holding mode can be set. When the longitudinal force holding mode is set, it can be gradually reduced. When the longitudinal force reduction mode is set, the reduction gradient can be increased. (25) The longitudinal force control device according to (24), wherein the wheel longitudinal force suppressing unit includes means for suppressing longitudinal force based on a turning state of the vehicle. For example, the longitudinal force of the wheels on the high μ side can be suppressed so that the running stability is maintained at or above the set level. The turning state of the vehicle can be acquired based on the steering angle of the steering wheel, the front wheel steering angle, the yaw rate, the lateral force applied to the wheels, the lateral G of the vehicle, and the like. Further, the yaw moment as the turning state of the vehicle can be estimated based on the longitudinal force applied to each wheel, the lateral force, the wheel base, the tread base, and the like. If estimated based on these, a dedicated sensor or the like for detecting the turning state becomes unnecessary. (26) A lateral force detecting device for detecting a lateral force applied to the wheel, and the wheel based on the lateral force detected by the lateral force detecting device and the longitudinal force detected by the longitudinal force detecting device. The longitudinal force control device according to any one of items (14) to (25), which includes a split road determination unit that determines that the road surface in contact with is a split road. Based on the longitudinal force, lateral force, wheel base, and tread base, the turning state of the vehicle can be estimated. For example, when the steering instruction member is not instructed to steer, the turning state is detected. If so, it can be considered that the vehicle is traveling on the split road. It can be considered that the determination of the split road is performed based on the state of the steering instruction member and the turning state of the vehicle.

(27) (a) A wheel speed detecting device for detecting the rotational speed of at least one of a plurality of wheels of the vehicle,
(b) a longitudinal force detection device for detecting a longitudinal force applied to at least one of the plurality of wheels, and (c) at least acquired based on the longitudinal force detected by the longitudinal force detection device. Based on a vehicle speed related amount related to the speed of the vehicle body and a wheel speed related amount related to a wheel rotation speed acquired based on the rotation speed of the at least one wheel detected by the wheel speed detection device. A front-rear force-sharing related amount acquisition unit that acquires a front-rear force-sharing related amount related to the ratio of the front-rear force that the wheels share in the vehicle, and (d) based on the vehicle body speed related amount and the wheel speed related amount. Then, the slip state related amount acquisition device including a slip state amount acquisition unit that acquires the slip state amount of the wheel, and the longitudinal force applied to the wheel of the vehicle are determined by the longitudinal force sharing related amount and the slip state. Longitudinal force control device which comprises a wheel longitudinal force control device that controls based on the amount. In the longitudinal force control device described in this section, the longitudinal force of the wheel is controlled based on the longitudinal force sharing related amount and the slip state amount. For example, the longitudinal force is controlled based on a control parameter (which can be referred to as a combined control parameter) obtained by combining the longitudinal force sharing related amount and the slip state amount, or a predetermined condition is satisfied. Is controlled based on the front-rear force sharing related amount,
If another condition is satisfied, the control can be performed based on the slip state amount. When it is desirable to use the slip state quantity as the control parameter, control based on the slip state quantity is performed, and when it is desirable to use the front-rear force sharing related quantity as the control parameter, control based on the front-rear sharing measurable quantity is performed. To be done. Specifically, the control based on the longitudinal force sharing related amount is performed in one of the state where the slip state of the wheel is equal to or more than the set state and the state in which it is not, and the control based on the slip state amount is performed on the other side. can do. The longitudinal force control device described in this section can employ the technical features described in any of the above-mentioned items (1) to (26).

(28) Vehicle body acceleration acquisition device, wheel speed detection device for detecting at least one rotation speed of a plurality of wheels of the vehicle, vehicle body acceleration acquired by the vehicle body acceleration acquisition device, and wheel speed A wheel longitudinal force control device that controls the longitudinal force applied to the wheels so that the relation with the wheel acceleration determined based on the rotation speed of the at least one wheel detected by the detection device is a predetermined relation. Front-back force control device including. In the longitudinal force control device described in this section, the longitudinal force is controlled so that the relationship between the wheel acceleration and the vehicle body acceleration has a predetermined relationship. The vehicle body acceleration can be obtained without relying on the longitudinal force detection device. For example, a value detected by an acceleration sensor that detects the vehicle body speed based on inertia can be used. The longitudinal force control device in this section includes (1) to (2
The technical features described in any one of the items 7) can be adopted. (29) Based on the slip state related amount acquisition device according to any one of (1) to (13) and the slip state related amount acquired by the slip state related amount acquisition device, A brake device including a brake control device for controlling a brake. In the brake device described in this section, the brake operating force is controlled based on the slip state related amount. For example, antilock control and traction control can be performed based on the slip state related amount. Further, the control for holding the slip state-related amount at a substantially constant value may be a control separate from the antilock control or the traction control or a control common to at least one part. The turning state of the vehicle can be controlled based on the slip state related amount. The brake device described in this section can adopt the technical features described in any one of (14) to (28).

(30) A longitudinal force detecting device for detecting a longitudinal force applied to at least one of a plurality of wheels of the vehicle, and an entire vehicle based on the longitudinal force detected by the longitudinal force detecting device. A vehicle body acceleration acquisition device including a vehicle body acceleration acquisition unit that acquires the total longitudinal force applied and acquires the acceleration of the vehicle body based on the acquired total longitudinal force. The vehicle body acceleration can also be detected by an acceleration sensor using inertia. However, since the acceleration sensor detects the vehicle body acceleration based on the displacement of the mass caused by the inertial force, the influence of disturbance is large. On the other hand,
According to the longitudinal force detection device, the influence of disturbance is reduced, and therefore the vehicle body acceleration can be accurately detected. The vehicle body acceleration acquisition device described in this section can adopt the technical features described in any of (1) to (13). Further, the vehicle body acceleration acquired by the vehicle body acceleration acquisition device is used for the slip state related amount acquisition device of the items (1) to (13), or the longitudinal force control device of the items (14) to (28). Can be used for

(31) A vertical force detecting device for detecting a vertical force applied to at least one of the plurality of wheels of the vehicle, a change amount of the vertical force detected by the vertical force detecting device, and a wheel base. And a vehicle body acceleration acquisition unit that acquires a vehicle body acceleration based on the height of the center of gravity. Since the moment according to the load movement and the moment according to braking or driving become equal, the vehicle body acceleration can be obtained. The vehicle body acceleration acquired by the vehicle body acceleration acquisition device described in this section is used for the slip state related quantity acquisition device of (1) to (13), or the longitudinal force of (14) to (28). It can be used as a control device.

(32) A wheel speed detecting device for detecting the rotational speed of at least one of the plurality of wheels of the vehicle, and a longitudinal force for detecting a longitudinal force applied to at least one of the plurality of wheels. A detection device, a vehicle speed related amount related to the speed of the vehicle body acquired based on the longitudinal force detected by the longitudinal force detection device, and a rotation speed of the at least one wheel detected by the wheel speed detection device. Based on the wheel speed related quantity related to the slip state related quantity including a slip state related quantity that is a quantity related to the relationship between the wheel speed related quantity and the vehicle body speed related quantity. Quantity acquisition device. The slip state related quantity acquisition device described in this section is (1) to (1)
The technical features described in any of the items 3) can be adopted. Further, it can be used for the longitudinal force control device of the items (14) to (28). (33) A wheel speed detecting device that detects a rotational speed of at least one of a plurality of wheels of a vehicle, and a front-back force detecting device that detects a force in a front-rear direction applied to at least one of the plurality of wheels. , A vehicle speed related amount related to the speed of the vehicle body acquired based on the longitudinal force detected by the longitudinal force detection device, and a rotational speed of the at least one wheel detected by the wheel speed detection device. A speed-related quantity function value acquisition device including a speed-related quantity function value acquisition unit that is a function value with a wheel speed-related quantity. The speed-related quantity function value acquisition device described in this section can employ the technical features described in any of (1) to (13).
Further, it can be used for the control device of the items (14) to (28).

(34) A wheel speed detecting device for detecting a rotational speed of at least one of a plurality of wheels of a vehicle, and a longitudinal force for detecting a longitudinal force applied to at least one of the plurality of wheels. A detection device, a vehicle body speed related amount related to the speed of the wheel acquired based on the longitudinal force detected by the longitudinal force detection device, and a wheel related to the rotational speed of the wheel detected by the wheel speed detection device. A slip state estimating device including a slip state estimating unit that estimates a slip state of the wheel based on a speed-related amount. The slip state estimating device described in this section can employ the technical features described in any of (1) to (13). (35) A longitudinal force detection device that detects a longitudinal force applied to at least one of the plurality of wheels, and a lateral force that detects a lateral force applied to at least one of the plurality of wheels. A detection device, a turning state estimation unit that estimates the turning state of the vehicle based on the longitudinal force detected by these longitudinal force detection devices and the lateral force detected by the lateral force detection device, and the traveling state of the vehicle can be controlled. A vehicle running state control device, comprising: a running state control actuator; and a running state control unit that controls the running state control actuator based on the turning state acquired by the turning state estimating unit. The drive condition control actuator includes
For example, a front wheel steering angle control actuator, a rear wheel steering angle control actuator, a power steering control actuator, a wheel longitudinal force control actuator, and the like are applicable. By controlling the longitudinal force for each wheel, the running state of the vehicle can be controlled. The vehicle running state control device described in this section can be provided in combination with the longitudinal force control device described in any of (14) to (28). The turning state of the vehicle can be controlled by controlling the longitudinal force. (36) If the turning state of the vehicle acquired by the turning state acquisition device is equal to or higher than a set state and the steering instruction member is not in the steering instruction state by the driver, A disturbance detection unit that detects that the vehicle is turning due to a disturbance, and the traveling state control actuator is controlled when the disturbance detection unit detects that the vehicle is turning due to the disturbance. Accordingly, the vehicle traveling state control device according to the item (35), including a turning state suppressing unit that suppresses the turning state. When it is detected that the turning state of the vehicle is equal to or higher than the set state when the steering instruction member is not in the steering instruction state by the driver, the yaw moment can be attributed to disturbance. . In this case, it is desirable that the yaw moment be suppressed by the control of the traveling state control actuator.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION A brake device including a brake control device equipped with a slip state related amount acquisition device according to an embodiment of the present invention will be described below in detail with reference to the drawings. The brake control device according to the present embodiment is also a longitudinal force control device that is an embodiment of the present invention. Further, the slip state related amount acquisition device includes an acceleration detection device which is an embodiment of the present invention. As shown in FIG. 1, the brake device includes a brake pedal 10 as a brake operating member.
A pump device 12 as a power hydraulic source, a master cylinder 14, brakes 20 and 21 including brake cylinders 18 and 19 provided on the left and right front wheels 16 and 17, and left and right rear wheels 24 and 25. Brake cylinder 26,
Brakes 28 and 29 including 27. In the present embodiment, the front wheels 16 and 17 are drive wheels and are front-wheel drive vehicles. Brake 20, 21, 28, 29
Is a friction brake, and the friction engagement member held by the non-rotating body by hydraulic pressure is pressed against the brake rotating body that is rotated together with the wheel, so that the wheels 16, 1
It is a hydraulic brake that suppresses rotation of 7, 24 and 25.

The pump device 12 includes a pump 30, a pump motor 32 that drives the pump 30, and an accumulator 34. The pump 30 pressurizes and discharges the hydraulic fluid in the reservoir 36, and the high-pressure hydraulic fluid discharged from the pump 30 is stored in the accumulator 34.
The hydraulic pressure of the accumulator 34 is the accumulator pressure sensor 3
8, the pump motor 32 is controlled so that the hydraulic pressure detected by the accumulator pressure sensor 38 is maintained within a predetermined set range. A check valve 39 is provided on the discharge pressure side of the pump 30 to prevent the hydraulic fluid from flowing back to the pump 30. Further, the relief valve 40 is provided between the high pressure side and the low pressure side of the pump device 12 to prevent the discharge pressure of the pump 30 from becoming excessive. The pump 30 may be a plunger pump or a gear pump.

The master cylinder 14 is of a tandem type including two pressurizing chambers, and when the brake pedal 10 is depressed, hydraulic pressures of the same height are generated in the two pressurizing chambers. The brake cylinder 26 of the left rear wheel 24 is connected to one pressurizing chamber via a liquid passage 44, and the brake cylinder 18 of the left front wheel 16 is connected to the other pressurizing chamber via a liquid passage 46. .

Master shut-off valves 50 and 52 are provided in the middle of the liquid passages 44 and 46, respectively. The brake cylinders 18 and 19 of the left and right front wheels 16 and 17 and the brake cylinders 26 and 27 of the left and right rear wheels 24 and 25 are connected by communication passages 54 and 56, respectively. , Communication valves 58, 60 are provided. The master shutoff valves 50 and 52 are normally open valves that are open when current is not supplied to the coil 62, and the communication valves 58 and 60 are normally open valves that are open when current is not supplied to the coil 64. is there. In this state, the hydraulic fluid in the master cylinder 14 causes the left and right front wheels 16, 17, 2
It is supplied to the brake cylinders 18, 19, 26, 27 of 4, 25, and the brakes 20, 21, 28, 29 are operated.

A simulation device 66 is provided in a portion of the liquid passage 46 upstream of the master shutoff valve 52. The simulation device 66 includes a stroke simulator 67 and a simulator opening / closing valve 68, and the stroke simulator 67 is connected to the liquid passage 46 via the simulator opening / closing valve 68. The simulator opening / closing valve 68 is a normally closed valve that is closed when no current is supplied to the coil 69.

The pump device 12 is connected to all the brake cylinders 18, 19, 26, 27 via a liquid passage 72. In addition, the brake cylinders 18, 19, 2
Linear valve devices 80 to 86 as individual hydraulic pressure control valve devices are provided in each of 6 and 27.
Each of the linear valve devices 80 to 86 includes a pressure increasing linear valve 90 and a pressure reducing linear valve 92. A pressure increasing linear valve 90 is provided in the liquid passage 72, and a pressure reducing linear valve 92 is provided in the brake cylinders 18, 19,
It is provided in a liquid passage 94 that connects the reservoirs 36 and 27. By the control of the linear valve devices 80-86,
The hydraulic pressure in the brake cylinders 18, 19, 26, 27 is separately controlled by using the hydraulic fluid of the pump device 12.

The pressure-increasing linear valve 90 and the pressure-decreasing linear valve 92 are normally closed valves, as shown in FIG.
4 and a seating valve 110 including a valve seat 106 and a spring 108. In the seating valve 110, the urging force of the spring 108 acts in the direction in which the valve element 104 is seated on the valve seat 106, and
The differential pressure acting force corresponding to the hydraulic pressure difference between the front and rear of the linear valve and the electromagnetic driving force corresponding to the amount of current supplied to the coil 100 act in the direction of separating the valve 100 from the valve seat 106. Coil 10
When the differential pressure acting force is smaller than the urging force of the spring 108 in the state where no current is supplied to 0, the valve 104
Is kept closed by being seated on the valve seat 106, but when the differential pressure acting force is larger than the biasing force, the valve element 104 is separated from the valve seat 106. When current is supplied to the coil 100, the relative position of the valve element 104 with respect to the valve seat 106 is determined by the relationship between the electromagnetic driving force, the urging force of the spring 108, and the differential pressure acting force. Controlled by power control.

The differential pressure acting force applied to the pressure increasing linear valve 90 is a force corresponding to the pressure difference between the hydraulic pressure of the pump device 12 (the hydraulic pressure of the accumulator) and the hydraulic pressure of the brake cylinder. The force acting on the differential pressure is a force corresponding to the differential pressure between the brake cylinder hydraulic pressure and the hydraulic pressure in the reservoir 36. Since the hydraulic pressure in the reservoir 36 is almost atmospheric pressure, it depends on the hydraulic pressure in the brake cylinder. Will help you. In any case, if the electromagnetic driving force is controlled (the current supplied to the coil 100 is controlled), the hydraulic pressure of the brake cylinder can be controlled.

The linear valve 9 for increasing the pressure in the liquid passage 72
A hydraulic sensor 120 is provided between 0 and the pump device 12. The hydraulic pressure of the hydraulic fluid on the high pressure side of the pressure increasing linear valve 90 is detected by the hydraulic pressure sensor 120. The hydraulic pressure sensor 1 is used as the hydraulic pressure on the high pressure side of the pressure increasing linear valve 90.
If the detected value by 20 is adopted, the influence of the pressure loss between the pump device 12 and the linear valve 90 for pressure increase can be reduced, and compared with the case where the detected value by the accumulator pressure sensor 38 is adopted, Linear valve device 80
The control accuracy of ~ 86 can be improved.

The present hydraulic brake device is controlled by a brake hydraulic pressure control device 150. As shown in FIG. 3, the brake fluid pressure control device 150 includes a CPU 152 and a ROM 1.
The computer mainly includes a computer 54, a RAM 156, an input / output unit 158, and the like. In the input / output unit 158,
The accumulator pressure sensor 38 and the hydraulic pressure sensor 120 described above.
In addition to the master pressure sensors 160 and 162 for detecting the hydraulic pressures in the hydraulic passages 44 and 46, respectively, the brake cylinder 1
Brake hydraulic pressure sensors 164-167 for detecting hydraulic pressures of 8, 19, 26, and 27, and wheels 16, 17, 2 respectively.
Wheel speed sensor 1 for detecting the wheel speed of 4, 25 respectively
69 to 172, a pedal force sensor 174 that detects the pedal force applied to the brake pedal 10, a brake switch 176 that detects whether or not the brake pedal 10 is in an operating state,
An accelerator opening sensor 177 that detects the opening of a throttle valve that is opened and closed according to the operation of an accelerator pedal (not shown), a yaw rate sensor 178 that detects the yaw rate of the vehicle, an acceleration sensor 179 that detects the acceleration applied to the vehicle, and a wheel A tire acting force detection device 180 and the like for respectively detecting the longitudinal force, the vertical force, and the lateral force are connected. Further, the pump motor 32, the coils 100 of the linear valve devices 80 to 86, the electromagnetic opening / closing valves 50, 52,
The coils 58, 60 and 68 are connected to each other via a drive circuit 182. The acceleration sensor 179 detects acceleration using the inertia of the vehicle. The tire acting force detection device 180 does not necessarily have to detect the longitudinal force, the lateral force, and the vertical force, and may at least detect the longitudinal force.

In the present hydraulic brake device, the required brake hydraulic pressure as the required braking force desired by the driver is obtained based on the output signal from the pedal effort sensor 174. Further, the required brake fluid pressure is determined by the master pressure sensors 160, 16
It is also possible to obtain it based on the output signal of 2. In the present embodiment, the tire acting force detection device 180 is provided on each of the wheels 16, 17, 24, 25 and detects the longitudinal force, vertical force, and lateral force applied to the wheels.
Although not shown, the tire acting force detection device 180 includes a detection unit 200 provided on the rotating body side between the wheel holding the tire and the axle hub, and a calculation unit 202 provided on the non-rotating body side, Communication is performed between the detection unit 200 and the calculation unit 202. The detection unit 200 includes a front-back force strain gauge 210, a vertical force strain gauge 212, a lateral force strain gauge 213, a signal processing unit 214, and a transmitter 21.
6, a battery (battery) 218 as a power source, and the like, and the calculation unit 202 includes a receiver 220, a signal processing unit 222, and the like. This acting force detection device 180 has been previously filed by the present applicant and has not been published yet.
Since it is described in detail in the specification of No. 6711, the detailed description is omitted here. The front-back force strain sensor gauge 210, the up-down force strain gauge 212, and the lateral force strain gauge 213 are respectively members that are deformed by relative movement of the detection body provided between the wheel and the axle hub. It is provided. Strain gauge 210 for longitudinal force
Is attached to a member that is deformed by relative movement based on longitudinal force, and the vertical force strain gauge 212 is attached to a member that is deformed by relative movement based on vertical force. Lateral force strain gauge 213 Is attached to a member that is deformed by relative movement based on lateral force.
The signal processing unit 214 includes strain gauges 210, 212, 21.
3 is a signal (information) suitable for communication, and the transmitter 216 includes an antenna and the like. The communication information representing the distortion processed by the signal processing unit 214 passes through the transmitter 216 and the arithmetic unit 20 on the non-rotating body side.
2 is sent.

The calculation unit 202 is provided at a position relatively close to the wheel on the member on the non-rotating body side. In the calculation unit 202, the receiver 220 receives the information transmitted from the detection unit 200, and in the signal processing unit 222, the longitudinal force, the vertical force, and the lateral force are obtained based on the distortion, and the information indicating that is obtained. It is supplied to the brake fluid pressure control device 150. The transmitter 216 provided on the rotating body side, the receiver 220 provided on the non-rotating body side, and the like form a communication unit 224. In addition, the strain gauge is attached to the wheel,
It can be attached to an axle hub. Also,
It is also possible to attach it to a suspension arm that is a non-rotating member that holds the wheels, and if it is attached to the non-rotating member, a communication unit for transmitting and receiving information becomes unnecessary.

During normal braking, the master shutoff valves 50, 52
By closing the brake cylinder 18,
19, 26 and 27 are disconnected from the master cylinder 14. Further, the communication valves 58 and 60 are closed and the simulator opening / closing valve 68 is opened. In this state, the hydraulic pressure in the brake cylinders 18, 19, 26, 27 is controlled by controlling the supply current to the coils 100 of the linear valve devices 80 to 86 by using the hydraulic fluid of the pump device 12, respectively. The supply current to the linear valve devices 80 to 86 is determined so that the brake fluid pressure becomes equal to the required brake fluid pressure desired by the driver. Since the stroke simulator 67 is communicated with the master cylinder 14, it is possible to prevent the stroke of the brake pedal 10 from becoming almost zero.

Further, for example, the antilock control is started when the brake pedal 10 is depressed and a predetermined starting condition such as an excessive braking slip is satisfied. When the vehicle stops, the brake is started. The antilock control is terminated when a predetermined termination condition is satisfied, such as when the pedal 10 is released. In the antilock control, the brake cylinders 18, 19, 26, 2 are the same as in the case of normal braking.
The hydraulic pressure of 7 is controlled by using the hydraulic fluid of the pump device 12 to control the current supplied to the coil 100 of the linear valve devices 80 to 86 so that the braking slip state is maintained in an appropriate state. Further, for example, when the accelerator pedal is depressed and a predetermined starting condition such as excessive driving slip is satisfied, the traction control is started, and when the vehicle speed becomes equal to or higher than the set value, the accelerator pedal is started. The traction control is terminated when a predetermined termination condition such as when the drive slip ratio becomes equal to or less than a set value is satisfied or when the operation of is canceled. In the traction control, as in the case of the antilock control, the brake cylinder 1 of the front wheel which is the driving wheel
The hydraulic pressures of 8 and 19 are controlled by the control of the linear valve devices 80 and 82, so that the drive slip state of the front wheels is maintained at the set state.

When an abnormality occurs in the pump device 12 or the electric system, each electromagnetic control valve is returned to the original position shown in FIG. When the master shutoff valves 50 and 52 are open, the communication valves 58 and
Since 60 is opened, the brake cylinders 18, 1
9, 26 and 27 are communicated with the master cylinder 14. In addition, since the simulator on-off valve 68 is closed, the stroke simulator 66 causes the master cylinder 4 to move.
It is possible to avoid wasteful consumption of the hydraulic fluid by shutting off the valve from 2. Further, since current is not supplied to the coils 100 of the linear valve devices 80 to 86, both the pressure increasing linear valve 90 and the pressure reducing linear valve 92 are closed. The brake cylinders 18, 19, 26, 27 are disconnected from the pump device 12.

During normal braking, if it is detected that the required brake fluid pressure desired by the driver is equal to or greater than the set value and the increasing gradient of the required brake fluid pressure is equal to or greater than the set gradient, high braking is performed. It is considered that there is a request, and Gmax control is performed. The high braking request can also be referred to as a shortest stop distance request. In any case, it is determined that the Gmax control start condition is satisfied, and the Gmax control is started. Gm
As shown in FIG. 8, the ax control is control of the brake fluid pressure that is performed so that the road surface usage μ is maximized. The longitudinal force applied to the wheels is controlled by controlling the brake fluid pressure, but in the present embodiment, the control is performed in a state where the slip is not so large. In other words, the brake fluid pressure is controlled. It is performed within a range in which the longitudinal force can be controlled by. Further, both the braking force as the longitudinal force and the driving force are controlled by controlling the brake fluid pressure. The Gmax control is performed based on the front-rear force sharing related amount as the slip state related amount as the control parameter. The brake fluid pressure is controlled so that the front-rear force-sharing related amount is maintained at the maximum road-use μ corresponding front-rear force-sharing related amount. In addition, in the present embodiment, the control is performed so that the road surface utilization μ is maximized for all wheels. Therefore, the longitudinal force of the entire vehicle can be maximized. The stopping distance can be shortened during braking, and the running speed desired by the driver can be promptly reached during driving. The Gmax control can be referred to as high braking demand control, μmax control, and stop distance shortest control.

The longitudinal force sharing-related amount is acquired based on the vehicle body speed related amount and the wheel speed related amount obtained based on the longitudinal force. Based on the wheel speed related amount and the vehicle body speed related amount, it is possible to acquire the amount related to the ratio of the longitudinal force in the vehicle shared by the wheels. Moreover, the slip state of the wheel can be estimated based on the longitudinal force sharing related amount. In this sense, the front-rear force sharing related amount can be referred to as an estimated slip state related amount. In the present embodiment, the braking force sharing-related amount S as the longitudinal force sharing-related amount, the vehicle body acceleration as the vehicle body speed-related amount is Gv,
When the wheel acceleration as the wheel speed related amount is Gw, the value is given by the formula S = 1-Gw / Gv, and the driving force sharing related amount S as the longitudinal force sharing related amount is expressed by the formula S = Gw. The value is represented by / Gv-1.

First, a description will be given based on the relationship between the braking slip rate during braking and the road surface utilization μ. As shown in FIG. 8, in the linear region where the slip ratio is small and the road use μ increases proportionally with the increase of the slip ratio, the road friction force increases with the increase of the brake fluid pressure, and the road use μ increases. The road surface utilization μ increases to the coefficient of static friction between the road surface and the tire, but does not increase any more. The frictional force becomes maximum when the road surface use μ is maximum, but the vehicle body deceleration becomes maximum when the frictional force of the entire vehicle (total of frictional forces of all wheels) is maximum (a). The braking force sharing-related amount at this time is the maximum road use μ-corresponding braking force sharing-related amount. In the present embodiment, the brake fluid pressure is increased so that the frictional force of all the wheels is maximized at the same time, and is increased with the same gradient for all the wheels. When the brake fluid pressure further increases, the frictional force does not increase any more, but the wheel deceleration increases, so the slip ratio becomes excessive and the locking tendency becomes stronger. This area is a non-linear area in which the road surface utilization μ does not increase proportionally with the increase of the slip ratio (b to c). The same is true during driving, and the relationship between the driving slip ratio and the road surface usage μ is shown in FIG.

The braking force sharing related amount S is represented by the solid line in FIG. 7 and is a negative value. As shown in the figure, it is not the same as the slip ratio, but as is clear from comparison with FIG. 8, it is estimated whether the lock tendency is strong or not according to the longitudinal force sharing related amount. be able to. In the increasing tendency of the braking slip, the wheel deceleration becomes larger than the vehicle body deceleration, and thus becomes a negative value. In the linear region shown in FIG. 8, the wheel deceleration increases as the vehicle body deceleration increases. Therefore, as shown in FIG. 7, the absolute value of the braking force sharing related amount S increases with the vehicle body deceleration. It increases slightly or remains almost constant. However, in a region where the vehicle body deceleration at the beginning of braking is small, the increase gradient of the wheel deceleration is larger than the increase gradient of the vehicle body deceleration, so the absolute value of the braking force sharing related amount gradually increases. At the beginning of braking, the wheel deceleration Gw has a larger increase gradient than the vehicle body deceleration Gv.
These increase in proportion. In this way, in the linear region where the braking slip is small, it is considered that the larger the absolute value of the braking force sharing-related amount, the larger the wheel sharing ratio. Further, when the absolute value of the braking force sharing related amount is small and the change gradient is small, it can be considered that the braking slip is in the linear region.

The vehicle body deceleration has a magnitude corresponding to the sum of the frictional forces between the road surface and the wheels for all wheels, and the frictional force of each wheel is the static friction between the road surface and that wheel. It will never be larger than the size corresponding to the coefficient.
The vehicle body deceleration becomes maximum when the total frictional force of a plurality of wheels becomes maximum. That is, when the friction coefficient of the road surface for all wheels is the same, if the frictional force for all wheels is maximized at the same time by controlling the braking force of each wheel, The power-sharing related amount changes according to the solid line in FIG. 7 (a state in which a predetermined relationship determined by the vehicle is maintained), and the value when the frictional force becomes maximum becomes a. When the braking force sharing related amount becomes a, the sharing ratio of each of the plurality of wheels becomes a predetermined value. After that, even if the brake operating force increases, the frictional force, that is, the vehicle body deceleration does not increase, whereas the wheel deceleration increases. The braking slip suddenly increases and the locking tendency becomes stronger. The deceleration of the vehicle body starts to decrease, and the absolute value of the braking force sharing related amount S rapidly increases (b to c).

On the other hand, when the friction coefficient of the road surface is small for one of the plurality of wheels, if the braking force of all the wheels is increased as in the case where the friction coefficient of the road surface is uniform, Related amount S of braking force of the wheel
The absolute value of increases as indicated by the chain double-dashed line. Since the vehicle body deceleration increases because the frictional force of the other wheels tends to increase, the braking force sharing is increased for that one wheel because the wheel deceleration increases more than the vehicle deceleration increases. The absolute value of the related amount S rapidly increases as compared with the normal case (when the friction coefficient of the road surface is uniform). In this case, even before the vehicle body deceleration becomes maximum, if the increasing gradient of the absolute value of the braking force sharing-related amount S is larger than the increasing gradients of the other wheels, the braking sharing rate for that wheel is increased. You can see that it started to get smaller. Further, it is understood that the slip state of the wheel is closer to the lock state than the other wheels.

As described above, when the absolute value of the braking force sharing-related amount S is large, it is understood that the lock tendency of the wheel is stronger than when the absolute value is small. According to the braking force sharing related amount S, it is possible to estimate the slip state of the wheel, and it can be considered as one mode of the slip state related amount.
Further, the braking force sharing related amount S is an amount in which the change state is significantly different before and after the braking force becomes excessive in relation to the friction coefficient of the road surface. For example, when the braking force of each wheel is controlled so that the frictional force of all wheels is maximized at the same time in the state where the friction coefficient of the road surface is uniform, The change state is significantly different from the latter one. Before the maximum, the absolute value gradually increases as the vehicle deceleration increases, and after the maximum, the vehicle deceleration starts to decrease and the absolute value increase gradient increases. ..
Also, when the friction coefficient of the road surface corresponding to some wheels is clearly smaller than the friction coefficient of the road surface corresponding to other wheels, each wheel should be maximized so that the frictional force of all wheels becomes maximum at the same time. If the braking force of is controlled,
The absolute value of the braking force-sharing related amount S of some wheels increases significantly faster than that of other wheels. for that reason,
According to the braking force sharing related amount, it is possible to accurately detect the time when the vehicle deceleration becomes maximum, the time when the braking force becomes excessive in relation to the friction coefficient of the road surface, etc. Since it can be estimated well, it can be said that the braking force sharing related amount S is suitable for controlling the longitudinal force.
The driving force sharing-related amount as the front-rear force sharing-related amount also changes as shown in FIG. 12, similarly to the braking force sharing-related amount, but in this case, the value is positive.

The vehicle body acceleration can be obtained by dividing the longitudinal force applied to the entire vehicle (total longitudinal force) by the vertical force applied to the entire vehicle (total vertical force). The total longitudinal force Fsx can be the sum of the longitudinal forces Fxi for each wheel. Fsx = ΣFxi = FxfL + FxfR + FxrL + FxrR The vertical force (total vertical force) Fsz applied to the entire vehicle can be the sum of vertical forces Fzi applied to each wheel. This total vertical force is also the vehicle weight M. Fsz = ΣFzi = FzfL + FzfR + FzrL + FzrR Therefore, when the gravitational acceleration is g, the vehicle body acceleration Gv can be obtained according to the equation Gv = (Fsx / Fsz) · g.

As described above, the front-rear force-sharing related amount S as the slip state amount is obtained based on the front-rear force, the vertical force, and the wheel acceleration, and based on the vehicle body speed estimated based on the wheel speed. Not required. Therefore, the front-rear force sharing related amount of each wheel can be accurately acquired. The vehicle weight M can be a vehicle body weight determined by the vehicle type, or a value obtained by adding the vehicle body weight and a value obtained by multiplying the standard human body weight by the standard number of passengers. This is because the human weight is smaller than the vehicle body weight. Further, the vehicle weight M can be obtained based on the total longitudinal force Fsx and the vehicle body acceleration Gv detected by the front-rear G sensor when a front-rear G sensor is provided and a disturbance such as during straight acceleration is small. M = Fsx / Gv The front-rear G sensor normally detects the vehicle body acceleration by utilizing the inertia, for example, based on the displacement of the mass due to the inertia. Therefore, it is easily affected by disturbance. On the other hand, the influence of disturbance can be reduced during straight-ahead braking or straight-ahead driving.

The vehicle body acceleration can also be obtained based on the moment resulting from the load movement amount. The amount of change in the vertical force of the front wheels is ΔFzf, the height of the wheel base and the center of gravity are L and H, respectively, and the weight of the vehicle (total vertical force)
When Fsz is set, the moment resulting from the load movement amount to the front wheels can be equal to the moment according to braking or driving, and therefore the formula ΔFzf · L = Gv · Fsz · H is established. Here, on the left side, the change amount of the vertical force of the front wheels and the change amount of the vertical force of the rear wheels have opposite signs, so that the wheel base may be applied. That is, the left side is
It is also possible to use a value obtained by multiplying the amount of change ΔFzr in the vertical force of the rear wheel by the wheel base. Further, the vehicle body acceleration can be approximated by a value obtained by dividing the longitudinal force for each wheel by the vertical force. Gv ≒ Fxi / Fzi

In the Gmax control, the front-rear force-sharing related amount Sμmax corresponding to the maximum road-surface use μ, which is the front-rear force-sharing related amount when the road surface use μ is maximized, is obtained. As described above, when the brake fluid pressures of all the wheels are increased with a constant gradient, the front-rear force-sharing related amount or the increase gradient at the time when the increase gradient of the absolute value of the front-rear force-sharing related amount suddenly increases. The value at the time when the absolute value slightly increases from the time when abruptly increases is taken as the maximum road utilization μ-corresponding longitudinal force sharing related amount Sμmax. For example, it can be set to a value substantially corresponding to the slip ratio Sa shown in FIG.

The target longitudinal force sharing-related amount can be acquired based on the relationship between the brake fluid pressure and the road surface usage μ. The road use μ can be obtained by dividing the longitudinal force by the vertical force at each wheel. A front-rear force-sharing related amount Sμmax is a front-rear force-sharing related amount at the time when the road surface use μ does not increase with an increase in the brake fluid pressure or a value slightly larger than that. Further, it can also be obtained based on the relationship between the longitudinal force sharing related amount and the longitudinal force (road surface friction force), and the relationship between the brake fluid pressure and the vehicle body deceleration Gv. Furthermore, even if the amount related to front-back force sharing alone,
The target front-rear force sharing related amount can be acquired based on the change in the change state thereof.

In the Gmax control, the brake fluid pressure is controlled so that the actual front-rear force sharing-related amount S approaches the maximum road use μ-corresponding front-rear force-sharing related amount (hereinafter abbreviated as target front-rear force-sharing related amount) Sμmax. Therefore, the control is performed based on the deviation between the actual front-rear force-sharing related amount S and the target front-rear force-sharing related amount Sμmax. During braking, as shown in FIG. 7, when the absolute value of the actual braking force sharing related amount S is smaller than the absolute value of the target braking force sharing related amount Sμmax (the deviation obtained by subtracting the target value from the actual value is positive). Case) is set to the linear pressure increasing mode, and if the deviation is smaller than 0 and is equal to or more than the negative first threshold value, the holding mode is set and is less than the first threshold value and is equal to or more than the negative second threshold value. In the case of, the linear decompression mode is set. If the threshold value is smaller than the second threshold value, normal antilock control is performed. In the anti-lock control, the pressure reducing mode is set to reduce the brake fluid pressure, but the brake fluid pressure is reduced with a larger gradient than when the linear pressure reducing mode is set in the Gmax control.

When the linear pressure increasing mode is set,
The supply current to the pressure increasing linear valve 90 is controlled so that the brake fluid pressure increases at a predetermined gradient, and when the linear pressure reducing mode is set, the pressure reducing linear valve 9
The current supplied to 2 is controlled so that the brake fluid pressure decreases at a set gradient. If the hold mode is set,
The supply current to the linear valve devices 80 to 86 is set to zero. The control mode is determined according to the map shown in FIG. 7, and this map is tabulated and stored in the ROM 1
It is stored in 54.

The Gmax control is started when the above-mentioned high braking request is detected and is ended when a predetermined ending condition is satisfied. The termination condition may be, for example, a case where the required brake fluid pressure is equal to or less than a set value, a vehicle body speed is equal to or less than a set value, or the like. Further, it is also terminated when the antilock control transition condition (which may be the same condition as the antilock control start condition or different condition) is satisfied. During the Gmax control, the hydraulic pressure of the brake cylinders 18, 19, 26, 27 is controlled by the control of the linear valve devices 80-86 as described above.

When it is determined that the road is a split road during the Gmax control, the brake fluid pressure on the wheel on the high μ side is suppressed. The control for the split road (which can be referred to as the high μ side longitudinal force suppression control) is performed. During the Gmax control, the use road surface μ of each wheel is controlled to be maximum (coefficient of static friction between the road surface and the tire). Become. Therefore, when the front-rear force difference between the left and right front wheels is equal to or greater than the set value, it can be determined that the road is a split road. In the case of a split road, the longitudinal force on the high μ side is suppressed. In the present embodiment, when the linear pressure increase mode is set, the pressure increase gradient is reduced, when the holding mode is set, gentle pressure reduction is performed, and when the linear pressure reduction mode is set. The pressure reduction gradient is increased. As a result, the difference between the left and right front and rear forces is reduced, and it is possible to suppress a decrease in traveling stability of the vehicle. Also, if the running stability of the vehicle is on the stable side from the preset setting state,
The split road control is terminated. The fact that the traveling stability of the vehicle is on the stable side of the set state can be determined by, for example, the value detected by the yaw rate sensor 178 becoming equal to or less than the set value.

The Gmax control is performed according to the execution of the Gmax control program shown in the flowchart of FIG.
The Gmax control program is executed every predetermined set time. In step 1 (hereinafter abbreviated as S1; the same applies to other steps), it is detected whether or not the brake switch 176 is in the ON state. ON
If it is detected that the vehicle is in the state of being braked, it is determined in S2 whether or not the Gmax control flag is in the set state. When the Gmax control flag is in the reset state and the Gmax control is not performed, S3
At, it is determined whether or not the high braking request is satisfied, in other words, whether or not there is a Gmax control request. If it is determined that there is a high braking request, Gmax is set in S4 and S5.
The control flag is set and Gmax control is performed. As shown in FIG. 9, the braking force sharing-related amount S is kept at the target braking force sharing-related amount Sμmax, and the vehicle deceleration is kept at the maximum value. This control is performed for all wheels. Further, during the Gmax control, since the Gmax control flag is in the set state, the determination in S2 is YES and S
At 6, it is determined whether the ending condition is satisfied.
When the ending condition is not satisfied, it is determined whether or not the normal antilock control transition condition is satisfied. If neither the end condition nor the antilock control transition condition is satisfied,
In S5, Gmax control is continuously performed. If the ending condition is satisfied, the Gmax control flag is reset in S8. Similarly, when the antilock control transition condition is satisfied, the Gmax control flag is reset in the same manner, but in this case, the antilock control is performed.

In the Gmax control, as shown in the flowchart of FIG. 5, first, in S16, it is determined whether or not the target braking force sharing related amount Sμmax for each wheel has already been obtained. If already requested, S17-
At 20, the braking force sharing related amount for each wheel is calculated. The longitudinal force and the vertical force are detected to determine the vehicle body deceleration. Further, the wheel deceleration is obtained by differentiating the wheel speed, and the braking force sharing related amount is obtained based on the vehicle body deceleration and the wheel deceleration. S
At 21, the control mode is determined according to the table represented by the map of FIG. In S22, it is determined whether the split flag is in the set state. If it is in the reset state, it is determined in S23 whether or not the road is a split road. If it is not a split road, the normal Gmax control according to the control mode is performed for each wheel in S24. Depending on the control mode
The brake fluid pressure is controlled.

On the other hand, if it is determined that the road is a split road, the split flag is set in S25, and it is determined in S26 whether the longitudinal force of the left front wheel 16 is greater than the longitudinal force of the right front wheel 17. Is determined. When the front-rear force of the left front wheel 16 is larger, it can be seen that the left front wheel 16 is located on the high μ side.
The brake fluid pressure of the left front wheel 16 is suppressed. On the contrary, when the longitudinal force of the right front wheel 17 is larger, in S28,
The brake fluid pressure of the right front wheel 17 is suppressed. In any case, since the longitudinal force of the wheel on the high μ side is suppressed, it is possible to suppress the yamment and the stability.

When the split flag is set, it is determined in S29 whether or not the ending condition of the split road support control is satisfied. When the running stability of the vehicle is equal to or higher than the set level, such as when the yaw rate is equal to or lower than the set value, the split road support control is ended. The split flag is reset in S30, and normal Gmax control is performed in S24.

On the other hand, the target braking force sharing related amount Sμ
Before max is determined, the rapid pressure increase mode is set in S31, and the target braking force sharing related amount determination routine is executed in S32. Since the high braking request by the driver is satisfied, the pressure increasing linear valve 9 is increased so that the brake fluid pressure is increased at the same preset preset gradient for each of the left and right front wheels 16 and 17, and the left and right rear wheels 24 and 25.
The supply current to 0 is controlled. The brake fluid pressure is increased at the same gradient so that the road surface use μ of each wheel is maximized at the same time. The brake fluid pressure is increased with a larger gradient than when the linear pressure increase mode is set.

In S49 of the target braking force sharing related amount determination routine represented by the flowchart of FIG.
The vertical force is calculated, and the road surface usage μ is calculated in S50. In S51 to 53, as described above, the vehicle body deceleration and the wheel deceleration are calculated, and the braking force sharing related amount S is calculated. In S54, it is determined whether the amount of change in the usage μ is positive (whether the usage μ tends to increase). When it is increasing, it is in the linear region, and the absolute value of the actual braking force sharing related amount S is smaller than the absolute value of the maximum road surface utilization μ-corresponding braking force sharing related amount. In this case, the latest amount of change in the braking force sharing related amount is stored as ΔSA, and the brake fluid pressure increase control in S31 is continuously performed. If the road surface use μ is not increasing, in S56, the change amount ΔS of the actual braking force sharing related amount S is smaller than ΔSA by a set value α (negative value) or more (decrease in braking force sharing related amount). Whether the amount is larger than ΔSA by a set value (−α) or more) is determined. If it is smaller than the set value, the determination is YES, and in S57, the braking force sharing related amount S at that time is stored as the maximum road surface use μ-corresponding braking force sharing related amount Sμmax, and S58.
At, the target braking force sharing related amount determination flag is set. Since it is difficult to obtain the time point a in FIG. 7,
The braking force sharing-related amount S at the time point d, which has decreased to some extent beyond the state a, is set as the maximum road surface use μ-corresponding braking force sharing related amount. The target braking force sharing related amount determination flag is reset when braking is not being performed.

When the road surface use μ is constant and the slip ratio is maintained constant, the braking force sharing-related amount becomes the magnitude shown by the broken line in FIG. 7. In this case, the ratio between the vehicle body deceleration and the wheel deceleration is kept substantially constant.

Further, in the present embodiment, similarly during driving, the driving force sharing related amount S is controlled so as to approach the target longitudinal force sharing related amount Sμmax. In this case, the driving force sharing related amount of the front wheels 16 and 17 is obtained based on the longitudinal force of the front wheels 16 and 17 as driving wheels and the vertical force of all the wheels 16, 17, 24 and 25. In this embodiment, Gmax control is applied to traction control. Traction control is performed when the traction start condition is satisfied. In traction control, the brake fluid pressure is increased when the driving force sharing related amount is large with respect to the target driving force sharing related amount and the locking tendency is strong, and when the driving force sharing related amount is small with respect to the target driving force sharing related amount, the brake fluid pressure is increased. The hydraulic pressure is reduced. As described above, in the present embodiment, the driving force is controlled by controlling the brake fluid pressure, the driving force is reduced as the brake fluid pressure increases, and the driving force is reduced as the brake fluid pressure decreases. The applied driving force is increased.

As shown in FIG. 12, a value d which is slightly larger than the driving force sharing-related amount at the time when the increasing gradient of the driving force sharing-related amount suddenly becomes the target driving force sharing-related amount. In this embodiment, the accelerator opening sensor 177 is used.
When the detected value by is equal to or more than the set value and it is detected that the accelerator pedal is depressed, the target driving force sharing related amount Sμmax is obtained, and the maximum road use μ-corresponding driving force sharing related amount Sμmax determination flag is set. It When the value detected by the accelerator opening sensor 177 is 0, the maximum road surface usage μ-corresponding driving force sharing related amount determination flag is reset.
The traction control is performed according to the execution of the traction control program represented by the flowchart of FIG. In S71, it is determined whether or not the accelerator pedal is depressed, and when it is determined that the accelerator pedal is depressed, it is determined in S72 whether or not the traction control flag is in the set state. If it is not in the set state, it is determined in S73 whether the traction start condition is satisfied, and if it is satisfied, S7 is performed.
At 4, Gmax traction control is performed. If the traction control flag is in the set state, S7
In 5, it is determined whether or not the traction end condition is satisfied. If the traction end condition is not satisfied, the traction control is continuously performed in S74, and if the end condition is satisfied, the traction control is ended. To be made. Each linear valve device 80-86 is returned to its original position. The traction control is performed according to the table represented by the map of FIG. The linear pressure increasing mode is set when the driving force sharing related amount S is larger than the target driving force sharing related amount Sμmax, and the decompression mode is set when the driving force sharing related amount S is smaller than the target driving force sharing related amount Sμmax. .

Maximum road use μ Corresponding front-rear force sharing related amount (S
In the present embodiment, μmax) is obtained when the accelerator opening sensor 177 detects that the accelerator pedal is depressed. On the other hand, the traction start condition is satisfied when the actual slip ratio exceeds the maximum road use μ compatible slip ratio. Will be required.

In S80 of the flowchart of FIG. 11, it is determined whether or not the target driving force sharing related amount Sμmax has already been determined. If determined, S8
No more than 1 is executed. If not yet determined, it is determined in S81 whether or not the accelerator pedal is depressed, and if it is determined that the accelerator pedal is depressed, in S82 to 85, the longitudinal force of the driving wheels,
The vehicle body acceleration Gv is obtained based on the vertical forces of all the wheels, and the driving force sharing related amount S of the drive wheels 16 and 17 is obtained based on the vehicle body acceleration Gv and the wheel acceleration Gw. S8
At 6, it is determined whether the vehicle body acceleration Gv has an increasing tendency, and if it has an increasing tendency, at S87,
The increase amount of the driving force sharing related amount S is obtained and stored as ΔST. The amount of increase in the driving force sharing-related amount S when the driving force is increasing is obtained. When the vehicle body acceleration tends to decrease, it is determined in S88 whether or not the actual increase amount ΔS of the driving force sharing-related amount S is greater than ΔST by a set value β or more.
The determination in S88 is YES, and in S89,
The driving force sharing related amount S at that time is set as the target driving force sharing related amount Sμmax, and the Sμmax determination flag is set in S90. The Sμmax determination flag is reset in S91 when the accelerator pedal is not depressed.

As described above, in this embodiment, the target driving force sharing related amount is obtained when the accelerator opening sensor 177 is in the ON state and the driving force is increasing. Then, when the traction start condition is satisfied, traction control (Gmax traction control) is performed based on the target driving force sharing related amount and the actual driving force sharing related amount. As shown in FIG. 14, the acceleration is kept at the maximum,
Since the road surface usage μ is maximized, the traveling speed desired by the driver can be immediately achieved. Further, the target driving force sharing related amount is set as the maximum frictional force corresponding driving force sharing related amount. The maximum frictional force-corresponding driving force sharing related amount is acquired based on the vehicle body acceleration and the driving force sharing related amount, and in this case, it is not necessary to obtain the road use μ.

It should be noted that the Gmax traction control can be performed when the driver's acceleration request is large. For example, when the accelerator opening is equal to or larger than the set value and the increasing gradient of the accelerator opening is equal to or larger than the set gradient, the acceleration demand is strong, that is, the maximum acceleration demand is detected, and the Gmax traction control is performed. To be done. Further, also in the Gmax traction control, the split road determination and the split road correspondence control can be performed. Further, in the above embodiment, during the traction control, the linear pressure increasing mode is set when the actual driving force sharing-related amount is larger than the target driving force sharing-related amount. Although the gradient is set to be constant, the pressure increase gradient may be set to be larger when the actual driving force sharing related amount is far from the target driving force sharing related amount than when it is small. In addition, Gmax for traction control
Although the case where the control is applied has been described, the Gmax control may be performed separately from the traction control. For example, when the driving force sharing-related amount exceeds the maximum frictional force driving force sharing-related amount, an increase in the driving force can be suppressed by controlling the driving source. When the drive source includes the engine, the throttle valve opening can be maintained or reduced, and when the drive source includes the electric motor, the output torque of the electric motor can be constant or suppressed.

As described above, in this embodiment, S17 to S2 of the Gmax control program of the brake fluid pressure control device 150.
0, S49, 51 to 53, S82 to 85 are stored and executed, and the slip state related amount acquisition unit is configured. The slip state related amount acquisition unit is also a front-back force sharing related amount acquisition unit. In addition, the brake fluid pressure control device 15
The road surface utilization μ acquisition device is configured by a portion that stores S49 and S50 of 0, an execution portion, and the like.
Maximum road surface usage μ depending on the part that stores
A corresponding slip state related amount acquisition unit is configured. further,
Brake fluid pressure control device 150, linear valve device 80-
A longitudinal force control device is constituted by 86 and the like. The longitudinal force control device is also a wheel longitudinal force control device. Figure 7 of them
The gentle front-back force control unit is configured by a portion that stores the table represented by the map, a portion that executes the linear pressure reduction control, the holding control, and the like. Also, the left and right front wheels 16, 1
7, a portion that stores S23 of the tire acting force detection device 180 and the brake fluid pressure control device 150, a portion that executes S23, and the like constitute a split road determination unit, and the linear valve devices 80 and 82 and S26 to 28. The front-back force suppression unit is configured by a part that stores, a part that executes, and the like. Furthermore, S1 of the brake fluid pressure control device 150
A vehicle body acceleration acquisition unit is configured by a portion for storing 8, 51, and 83, a portion for executing the portion, and the like.

Even in the antilock control, Gmax
Controls can be applied. Alternatively, the antilock control may be performed based on the braking force sharing related amount instead of the slip ratio.

Further, in the above embodiment, the tire acting force detecting device 180 is provided on all four wheels, but it may be provided only on the left and right front wheels 16, 17. Front wheel 1
The front-rear force of the rear wheel can be obtained based on the front-rear force applied to Nos. 6, 17 and the relationship between the front-rear force of the front wheel and the front-rear force of the rear wheel. If the longitudinal force is smaller than the maximum frictional force with the road surface and the brake fluid pressure and driving force of each wheel are the same, a predetermined amount of force is set between the front and rear forces of the front and rear wheels. The relationship is maintained. The tire acting force detection device 180 may be provided on the rear wheels, but if the tire acting force detection device 180 is provided on the front wheels, it is possible to detect earlier that the road is a split road. Further, during braking, the front wheels have a greater frictional force, which is important. Furthermore, because the front wheels are the drive wheels,
If it is provided on the front wheels, both braking force and driving force can be detected.

Here, the case where the braking force as the longitudinal force is required will be described. As shown in FIG. 15, S9
The front wheel braking force is read in 1 and the rear wheel braking force is estimated in S92. Since the proportioning valve is not provided in the brake device in the present embodiment, the ratio of the braking force of the front wheels to the braking force of the rear wheels is set. Therefore, the braking force of the rear wheels can be obtained based on these ratios and the braking force of the front wheels.
In S93, the vehicle total braking force is obtained by adding the detected front wheel braking force and the estimated rear wheel braking force, and in S94, the vehicle body deceleration is obtained by dividing the vehicle total braking force by the vehicle weight stored in advance. .

If the determined vehicle deceleration is used as the vehicle deceleration in S18 and S51, the slip state related amount is similarly determined based on the vehicle deceleration and the brake hydraulic pressure is controlled. According to the present embodiment, it is possible to reduce the number of tire acting force detection devices and reduce costs. Further, a portion of the brake fluid pressure control device 150 that stores S92, a portion that executes S92, and the like constitute a longitudinal force estimation unit. In the present embodiment, S2
A portion storing 0, 53, a portion for executing, and the like constitute a slip state related amount estimation unit, and a portion storing S21, S24, a portion for performing, etc., configure an estimated slip state related amount corresponding longitudinal force control unit. It will be. In addition,
As for the vertical force, the vertical force of the rear wheel can be estimated based on the detected vertical force of the front wheel. For example, the vertical force of the rear wheel can be estimated based on the amount of change in the vertical force of the front wheel, that is, the amount of movement of the load. Further, for the rear wheels, a control mode similar to the control mode determined based on the slip state-related amount of the front wheels can be set.

Further, in the above embodiment, the braking force as the longitudinal force is controlled on the basis of the longitudinal force-sharing related amount. However, the longitudinal force-sharing related amount and the slip state as the slip state-related amount are controlled. It can be controlled based on both the quantity and the quantity. In the present embodiment, Gmax control is performed based on the longitudinal force sharing related amount,
Antilock control is performed based on the slip state amount. In the state where the slip ratio is large and close to the locked state, for example, in the region where the slip ratio is equal to or more than the set value Sc in the case shown in FIG. 8, the slip state amount indicates the wheel slip state rather than the longitudinal force sharing related amount. It can be expressed accurately and is considered to be suitable for controlling the braking force.

First, the slip state quantity will be described.
The slip state amount in the present embodiment is obtained based on the wheel speed and the vehicle body speed acquired based on the longitudinal force. The slip state amount S is represented by S = (VM-VW) / VM during braking, and by S = (VW-VM) / VM during driving. Here, VW is a value obtained by converting the wheel speed into a vehicle body speed, and is a value obtained by multiplying the rotational angular velocity by the turning radius of the wheel. VM is a vehicle speed calculated based on the longitudinal force. Each of these slip state quantities S is a negative value, but the relationship shown in FIG. 8 is satisfied between the absolute value of the slip state quantity and the road surface usage μ. The slip state amount S can also be expressed as a positive value. For example,
The slip state amount S during braking can be represented by S = (VW-VM) / VM, and the slip state amount S during driving can be represented by S = (VM-VW) / VM.

The longitudinal force applied to each wheel is detected by the tire acting force detecting device 180, and the total thereof is obtained in the same manner as in the above embodiment. Fsx = ΣFxi In the present embodiment, as shown in FIG. 19, when the brake operation is started (for example, the brake switch 17
A value ΔFsx = Fsx−Fsx0 obtained by subtracting the total front-rear force Fsx0 when 6 is switched from the OFF state to the ON state) to the total front-rear force Fsx at the time when the vehicle speed is estimated is used. Here, Fsx0 is represented by the formula Fsx0 = ΣFxi0 = FxfL0 + FxfR0 + FxrL0 + FxrR0. In this way, the amount of increase in the longitudinal force from the steady state is used as the longitudinal force. Since the total front-rear force Fsx is not always 0 in the steady state, the total front-rear force in the steady state is subtracted from the total front-rear force at the time when the vehicle speed is estimated. Brake switch 178
It is normal that no hydraulic pressure is generated in the wheel cylinders of the wheels at the time when is switched from the OFF state to the ON state, and it is considered that the braking force is not substantially applied. You can Brake switch 1
The trigger is that the switch 78 is switched from the OFF state to the ON state, which is a steady state as in the case of the normal traveling state. The vehicle body acceleration αM is obtained by dividing the total difference between the longitudinal forces (hereinafter, simply referred to as longitudinal force) by the vehicle body weight M. αM = ΔF / M

The vehicle body speed VM is V ₀ when the vehicle body speed is V ₀ at the start of estimation, for example, when the brake switch 176 changes from the OFF state to the ON state (this vehicle body speed is a value estimated based on the wheel speed). Can be adopted)) according to the equation VM = V0 + ∫αMdt. The estimation of the vehicle body speed VM can be started at the time when the antilock control is started. This is because the antilock control is performed based on the slip state amount S as described above. In this case, the vehicle speed when the antilock control is started is adopted as the initial value V0. However, when the antilock control is started, the slip ratio is usually considerably large, so it is preferable to adopt the vehicle body speed in the state where the slip ratio is relatively small as the initial value V0.

Further, it is not essential to directly adopt the value of the vehicle body speed VM obtained according to the above equation.
For example, a value combined with the vehicle body speed V _G estimated based on the output value αG of the acceleration sensor 179 can be adopted. By using the output value αG of the acceleration sensor 179, the vehicle body speed VG is obtained according to the equation VG = V0 + ∫αGdt. By combining these vehicle body speeds VM and VG, for example, the value obtained according to the equation V = a · VM + (1-a) · VG can be adopted as the vehicle body speed. The ratio a in this case can be a preset value or a variable value. For example, it may be a value determined based on the degree of reliability of the vehicle body speed or a value determined based on the degree of noise.
Specifically, the vehicle body speed with less noise or the frequency with which noise is generated can be set as the vehicle body speed with higher reliability. The value can be set such that the weighting becomes large. The noise occurrence frequency can be represented by the number of times when the noise becomes equal to or higher than a set value within a set time. The noise is represented by dαG / dt and dαM / dt, respectively. For example, when it is determined that the output value from the acceleration sensor 179 has a larger noise, dαG / dt> dαM / dt is smaller than that otherwise. , The value of the ratio a is increased, and the weighting of the vehicle body speed VG is decreased.

The noise is obtained by differentiating the acceleration α, not the second-order differentiation of the vehicle body speed V. Therefore, the state of noise can be detected more accurately than in the case where the vehicle body speed V is subjected to the second-order differentiation. The above circumstances can be similarly applied during driving. However, during driving, the accelerator pedal is often slightly operated even in a steady state (during constant speed traveling). Even in this case,
An increase amount ΔFsx of the longitudinal force Fsx from the longitudinal force Fsx0 in the steady state is used as the longitudinal force. In the steady state, even if the accelerator pedal is operated, it can be considered that the acceleration was almost zero.

In the present embodiment, the wheel longitudinal force control program shown in the flowchart of FIG. 16 is executed every set time. Although this wheel longitudinal force control program partially overlaps with the Gmax control program shown in the flowchart of FIG. 4, the same step numbers are given to those portions and description thereof will be omitted. When the brake switch 176 is in the ON state, it is determined in S101 whether the antilock control flag is set. If the antilock control flag is not set, S
At 102, the slip state amount S is read and S1
At 03, it is determined whether the antilock start condition is met. As described above, when the slip state amount S is equal to or larger than the value corresponding to the set value Sc (the value of the slip state amount S corresponding to the case where the slip ratio is the set value Sc), it is considered to be satisfied. If the antilock start condition is not satisfied, the steps related to Gmax control are executed after S2.

When the antilock control start condition is satisfied, the antilock control flag is set in S104, and the antilock control is performed in S105. The antilock control is performed according to the antilock control table represented by the map shown in FIG. The anti-lock control table is well known, and one of the pressure increasing mode, the slow pressure increasing mode, the holding mode, the pressure reducing mode, and the rapid pressure reducing mode is selected based on the slip state amount S and the wheel acceleration. To be selected. During the antilock control, in S106, it is determined whether or not the end condition is satisfied. If the end condition is not satisfied, the antilock control is continuously performed,
When the ending condition is satisfied, the antilock control flag is reset in S107. On the other hand, when the brake switch 176 is OFF, the Gmax control flag and the antilock control flag are reset in S108.

The slip state quantity S is acquired by executing the slip state quantity acquisition program shown in the flowchart of FIG. The slip state amount acquisition program is
It is repeatedly executed at preset time intervals. S1
Brake switch 176 is turned on at 10, 111
It is determined whether or not the vehicle is in the state and whether the state is switched from the OFF state to the ON state. When the brake switch 176 is switched from the OFF state to the ON state, S11
At Nos. 2 and 113, the estimated vehicle body speed V0 is calculated based on the wheel speeds, and the total Fsx of the longitudinal forces of the wheels is calculated. The estimated vehicle body speed can be acquired, for example, based on the maximum value of the four wheel speeds. In the ON state of the brake switch 176, the slip state amount S is obtained in S114 to 117 as described above.

In the above-described antilock control, the linear valve device 80-
86 is controlled. Further, the determination as to whether or not the antilock control start condition is satisfied is also made based on the slip state amount S. As described above, in the present embodiment, the antilock control is performed based on the slip state amount S acquired based on the vehicle body speed based on the longitudinal force.
Therefore, even if the slip control is performed for all the wheels, the slip state of the wheels can be accurately acquired, and thus the antilock control can be favorably performed. In the present embodiment, the brake ECU 1
A slip state amount acquisition unit is configured by a part that stores and executes a slip state amount acquisition program represented by the flowchart of FIG.

In the above embodiment, it is determined whether or not the start condition of the antilock control is satisfied based on whether or not the slip state amount S is a value corresponding to the set value Sc or more. However, it is also possible to make the determination based on whether or not the front-rear force sharing related amount is equal to or greater than the set value (the value corresponding to the above-mentioned set value Sc). Further, the Gmax control can also be performed based on the slip state amount. Since the contents of Gmax control are the same as in the above embodiment, S
A case of obtaining μmax will be described. The vehicle body deceleration αM is obtained in steps S49 to 51 in the flowchart of FIG. 20, and the slip state amount S is obtained in steps S121 to 123.
Is calculated according to the above equation. In S124, the change gradient (differential value) of the road surface usage μ with respect to the slip state amount S is obtained, and in S125, it is determined whether the value obtained by multiplying the previous differential value and the current differential value is positive or negative. When the road use μ is increasing, the sign of the value obtained by multiplying the previous differential value and the current differential value is positive, but the road use μ
Reaches the maximum value and decreases slightly, the multiplied value becomes negative. The road use μ can be obtained by dividing the longitudinal force by the vertical force at each wheel. In S126, the average value of the slip state amount S in that case for two times is obtained, and the slip state amount Sμ corresponding to the maximum road surface use μ is obtained.
It is considered as max. The control based on the slip state amount S can be applied to the case where the Gmax control is performed independently and the case where the antilock control is performed independently. The control based on the slip state amount can be similarly applied to the control of the driving force as the longitudinal force.

Further, the vehicle body acceleration αM obtained based on the longitudinal force is compared with the detection value αG detected by the acceleration sensor 179, and the estimated vehicle body speed V obtained based on the longitudinal force.
An abnormality of the acceleration sensor 179 can be detected by comparing M with the estimated vehicle body speed VG obtained based on the detection value αG of the acceleration sensor 179. As described above, the total longitudinal force applied to the vehicle is obtained as the total longitudinal force for each wheel, but it is rare that all of the tire acting force detection devices 180 provided on each wheel are abnormal. . In the present embodiment, a value larger than the difference estimated to occur when one of the four tire acting force detection devices 180 is abnormal is set as the set value, and the difference in the vehicle body deceleration and the difference in the estimated vehicle body speed are set. If the values are larger than the set values, the acceleration sensor 179 is estimated to be abnormal.

The abnormality detection program shown in the flow chart of FIG. 21 is executed every predetermined set time. In S151 to 154, the vehicle body acceleration αM is obtained based on the longitudinal force, the detection value αG by the acceleration sensor 179 is obtained, and the absolute value ΔαGM of these differences is obtained. Further, the estimated vehicle body speeds VM and VG are obtained respectively, and the absolute value ΔVGM of the difference between them is obtained.
In S155, it is determined whether ΔαGM is greater than or equal to the set value β1. If the set value is β1 or more,
If it is determined in S156 that the acceleration sensor 179 is abnormal and is smaller than the set value β1, it is determined in S157 whether ΔVGM is equal to or larger than the set value β2. If it is smaller than the set value β2, the acceleration sensor 1
79 is considered normal. If the value is equal to or greater than the set value β2, the acceleration sensor 179 is determined to be abnormal in S158. In this case, the output value of the acceleration sensor 179 is corrected in S159. αG = αG ± Δα Thus, in this embodiment, the same physical quantity is 2
Since they are acquired by three different methods, the abnormality of the acceleration sensor 179 can be detected by comparing these. Further, there is also an advantage that it is possible to always detect, not only at the time of initial check.

Further, by using the tire acting force detecting device 180 provided for each wheel, the turning state of the vehicle can be estimated. In the present embodiment, as shown in FIG. 22, the steering ECU 302 and the steering angle sensor 300 are further connected to the input unit 158 of the brake ECU 150. Steering ECU
A steering control actuator 304 is connected to 302. The steering control actuator 304 is
In the present embodiment, a device for steering the rear wheels,
The rear wheels are steered by an amount determined based on the steering angle of the steering wheel and the vehicle speed. When the steering angle is large, the steering angle is made smaller than when the steering angle is small, but when the vehicle body speed is large, the steering angle is made smaller than when it is small. The yaw rate estimation program represented by the flowchart of FIG. 23 is executed every predetermined set time. In S201, the longitudinal forces FxfL, FxfR, FxrL, FxrR and lateral forces FyfL, FyfR, F applied to the wheels are determined.
yrL and FyrR are obtained, and in S202, the yaw moment MJ applied to the vehicle is calculated by the formula MJ = (FxfL + FxfR) .Lf- (FxrL + FxrR) .Lr +
It is determined according to (FyfL-FyfR) * Tf / 2 + (FyrR-FyrL) * Tr / 2. Here, Lf, Lr, Tf and Tr are
These are the distance from the center of gravity to the front and rear wheels (Lf + Lr corresponds to the wheel base), and the tread bases for the front and rear wheels. Next, in S203, the yaw rate is estimated. The yaw moment MJ applied to the vehicle can be expressed by the product MJ = Jy · Δγ of the yaw moment of inertia Jy and the change amount Δγ of the yaw rate γ. Therefore, the change amount Δγ of the yaw rate γ is obtained from these equations. Can, yaw rate γ
Γ = ∫Δγdt The yaw rate γ can be estimated by integrating the change amount Δγ of

At S204, it is determined whether the yaw moment MJ is larger than the set value X and the steering angle θ detected by the steering angle sensor 300 is substantially zero. If the determination is NO, a normal control command is output to the steering ECU 302 in S205.
The steering ECU 302 steers the rear wheels under the control of the normal steering control actuator 304. On the other hand, if the determination is YES, it is determined that the yaw moment MJ is caused not by the driver's intention but by disturbance, and in S206, a disturbance response control command is output to the steering ECU 302. .
The steering ECU 302 steers the rear wheels so as to suppress the yaw moment MJ caused by the disturbance.
In this way, the yaw rate can be estimated based on the longitudinal force and the lateral force. Further, in the present embodiment, since it is configured to detect whether or not the yaw moment is caused by the disturbance, if the yaw moment is detected as caused by the disturbance, the yaw moment is detected. Can be suppressed. Further, there is an advantage that the turning state can be acquired even without the yaw rate sensor 178.

The turning state of the vehicle can be controlled by using the brake device. In this case, the turning state is controlled by the control of the brake control actuator composed of the linear valve devices 80 to 86, and this brake control actuator also serves as the steering control actuator. Further, in S29 in the above-described embodiment, whether the ending condition of the split road support control is satisfied or not is the longitudinal force of the wheel,
It is also possible to make the determination based on the estimated yaw rate estimated based on the lateral force. Further, the determination that the road is a split road can be made based on the estimated yaw rate. If the yaw moment is generated when the steering angle θ is substantially 0 during braking, the road can be regarded as a split road. On the contrary, the turning state estimation device according to the present embodiment can be adopted separately from each of the above embodiments.
Further, the suppression of the yaw moment caused by the disturbance can be performed only during the automatic traveling.

Further, based on the estimated yaw rate and the value detected by the yaw rate sensor 178, the abnormality can be detected. The abnormality detection program of FIG. 24 is executed every predetermined set time. S250 ~ S25
In 2, the yaw rate is estimated as in the case above. In S253, the absolute value Δγ of the difference between the detected value γ by the yaw rate sensor 178 and the estimated yaw rate γM is obtained, and in S254, it is determined whether or not the set value β3 or more. If the set value is β3 or more, S
At 255, the yaw rate sensor 178 is determined to be abnormal. As in the case of the above embodiment, the set value β3 is set to a value larger than the difference caused by one abnormality in the tire acting force detection device 180. The information indicating the abnormality of the yaw rate sensor 178 may be output to the steering ECU 302. If the determination in S254 is no, in S256, the absolute value of the yaw moment is greater than 0, and
It is determined whether the steering angle θ detected by the steering angle sensor 300 is substantially zero. If the determination result is YES, in S257, it is searched whether or not there is a longitudinal force or lateral force of each wheel whose magnitude is 0. If there is zero of the longitudinal force and the lateral force, the tire action force detection device 180 is determined to be abnormal in S258. When the determination in any of S254 and S256 is NO, it can be determined as normal. When the absolute value of the yaw moment is larger than 0, the acting force of all tires should be larger than 0. Therefore, it is possible to determine that the tire acting force detection device 180 having an acting force of 0 is abnormal.

Further, in the above embodiment, the brake is a hydraulic brake which is operated by hydraulic pressure, but the brake may be an electric brake which is operated by an electric actuator. In this case, the braking force is controlled and the longitudinal force is controlled by controlling the electric actuator. Further, in the hydraulic brake device, the individual hydraulic control valve devices 80, 82, 84, 86 provided corresponding to each wheel may include electromagnetic opening / closing valves instead of linear control valves. In this case,
The change gradient of the brake fluid pressure can be controlled by controlling the duty of the electromagnetic opening / closing valve.

Furthermore, it is not necessary to apply the Gmax control both during braking and during driving, but it may be applied in either case. In addition, the road surface use of all wheels μ
Although the brake fluid pressure is controlled so as to be maximized, it may be controlled so that the road surface use μ of the front wheels is maximized. The road surface use μ of the rear wheels may not be the maximum. Further, it is not essential that the split road control be performed. Further, the vehicle body acceleration may be obtained by an acceleration sensor using inertia. Also in this case, the vehicle body acceleration can be estimated more accurately during the Gmax control than when the vehicle body speed is estimated based on the wheel speed. Further, in the above-described embodiment, the longitudinal force is controlled by controlling the brake fluid pressure, but the driving force may be controlled by controlling the driving source. The present invention can also be applied to a brake control device in which the brake actuation force is controlled so that the actual deceleration approaches the target deceleration desired by the driver.

In addition, the present invention can be carried out in the modes described in [Problems to be Solved by the Invention, Means for Solving Problems and Effects], as well as various modifications and improvements based on the knowledge of those skilled in the art. can do.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a brake device including a slip state related amount acquisition device, a longitudinal force control device, and a vehicle body acceleration acquisition device according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view of a linear valve device included in the brake device.

FIG. 3 is a circuit diagram showing a brake fluid pressure control device included in the brake device.

FIG. 4 is a flowchart showing a braking Gmax control program stored in a ROM of the brake fluid pressure control device.

FIG. 5 is a flowchart showing the contents of S3 of the braking Gmax control program.

FIG. 6 is a flowchart showing a part of the braking Gmax control program.

FIG. 7 is a control table stored in a ROM of the brake fluid pressure control device.

FIG. 8 is a diagram showing a relationship between a slip ratio and road surface usage μ.

FIG. 9 is a diagram showing an example of control by the brake fluid pressure control device.

FIG. 10 is a flowchart showing a part of a driving Gmax control (Gmax traction control) program stored in a ROM of the brake fluid pressure control device.

FIG. 11 is a flowchart showing a maximum frictional force-corresponding driving force sharing related amount determination program stored in a ROM of the brake fluid pressure control device.

FIG. 12 is a control table stored in a ROM of the brake fluid pressure control device.

FIG. 13 is a diagram showing a relationship between a slip ratio and road surface usage μ.

FIG. 14 is a diagram showing an example of control by the brake fluid pressure control device.

FIG. 15 is a flowchart showing another part of the Gmax control program stored in the ROM of the brake fluid pressure control device.

FIG. 16 is a flowchart showing a longitudinal force control program stored in a ROM of the brake fluid pressure control device according to another embodiment of the present invention.

FIG. 17 is an antilock control table stored in a ROM of the brake fluid pressure control device.

FIG. 18 is a flowchart showing a slip state amount acquisition program stored in a ROM of the brake fluid pressure control device.

FIG. 19 is a diagram showing a change state of a wheel speed and a vehicle body speed in a brake device including the brake fluid pressure control device.

FIG. 20 is a flowchart showing a maximum road surface utilization μ-corresponding slip state amount acquisition program stored in a ROM of the brake fluid pressure control device.

FIG. 21 is a flowchart showing an abnormality detection program stored in the ROM of the brake fluid pressure control device which is still another embodiment of the present invention.

FIG. 22 is a diagram showing the periphery of a brake fluid pressure control device that is another embodiment of the present invention.

FIG. 23 is a flowchart showing a yaw rate estimation program stored in a ROM of the brake fluid pressure control device.

FIG. 24 is a flowchart showing an abnormality detection program stored in a ROM of the brake fluid pressure control device.

[Explanation of symbols]

18, 19, 26, 27 Brake cylinder 80-86 Linear valve device 150 Brake fluid pressure controller 179 G sensor 180 Tire acting force detector

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) B60T 8/72 B60T 8/72 G01M 17/007 G01M 17/00 E (72) Inventor Keisuke Seto Toyota, Aichi Prefecture Toyota-cho, Toyota-shi F-term in Toyota Motor Corporation (reference) 3D046 BB23 BB25 BB28 HH00 HH02 HH05 HH16 HH22 HH26 HH36 HH46 HH48 JJ06 LL02 LL05 LL23 LL29 LL37 LL50

Claims (11)

[Claims] 1. A wheel speed detection device for detecting a rotational speed of at least one of a plurality of wheels of a vehicle, and a front-back force detection for detecting a longitudinal force applied to at least one of the plurality of wheels. A device, at least a vehicle speed related amount related to the speed of the vehicle body acquired based on the longitudinal force detected by the longitudinal force detection device, and a rotation of the at least one wheel detected by the wheel speed detection device. A slip state related amount acquisition device including a slip state related amount acquisition unit that acquires a slip state related amount related to a slip state of the wheel based on a wheel speed related amount related to speed. 2. A front-rear force-sharing related amount relating to a ratio of front-rear force that the wheels share in a vehicle, based on the vehicle body speed-related amount and the wheel speed-related amount, by the slip state-related amount acquiring unit. The slip state related amount acquisition device according to claim 1, further comprising: a front-rear force sharing related amount acquisition unit that acquires the slip state related amount. 3. A slip state quantity acquisition unit for acquiring the slip state quantity of the wheel as the slip state related quantity based on the vehicle body speed related quantity and the wheel speed related quantity. The slip state related quantity acquisition device according to claim 1 or 2, including a part. 4. A vertical force detection device for detecting a vertical force applied to at least one of the plurality of wheels, a vertical force detected by the vertical force detection device, and a vertical force detection device for detecting the vertical force. Road surface utilization μ acquisition device that acquires road surface utilization μ based on the calculated longitudinal force, and road surface utilization μ acquired by the road surface utilization μ acquisition device
And a slip condition related amount acquired by the slip condition related amount acquisition unit, a slip condition related amount capable of maximally utilizing the friction coefficient of the road surface is obtained. Claim 1 including and
The slip state-related quantity acquisition device according to any one of claims 1 to 3. 5. The slip state related quantity acquisition device according to claim 1, and the wheel is added to the wheel based on the slip state related quantity acquired by the slip state related quantity acquisition device. A front-rear force control device including a front-rear force control device for controlling a front-rear force, wherein the front-rear force detection device is provided corresponding to a part of the plurality of wheels, and the slip state-related Quantity acquisition device, (a) a longitudinal force estimation unit that estimates the longitudinal force applied to other wheels based on the longitudinal force of the some wheels detected by the longitudinal force detection device, and (b) the longitudinal force A slip state-related amount estimation unit that estimates a slip state-related amount of the other wheel based on the longitudinal force of the other wheel estimated by the force estimation unit, and the wheel longitudinal force control device has the slip state. Related amount Based on the slip state related quantity of other wheels estimated by tough, the other of the longitudinal force control device including an estimated slip condition related quantity corresponding longitudinal force control unit for controlling the longitudinal force of the wheel. 6. The slip state-related quantity acquisition device according to claim 4, wherein the longitudinal force applied to the wheels of the vehicle is approximately the maximum road surface when the slip state-related quantity acquired by the slip state-related quantity acquisition device is approximately the maximum road surface. A front-rear force control device comprising: a wheel longitudinal force control device that controls so as to maintain the maximum road surface use μ-compatible slip state related amount that is the slip state related amount acquired by the use μ corresponding slip state related amount acquisition unit. 7. The wheel longitudinal force control device is a non-linear region in which the road surface utilization μ does not increase proportionally with an increase in the slip ratio of the wheel, and the slip state-related amount is the maximum road surface utilization μ. When the slip condition related amount is in the first region which is a value near the corresponding slip condition related amount, the longitudinal force is more than in the second region where the slip condition related amount deviates from the maximum road use μ corresponding slip condition related amount by a set value or more. The longitudinal force control device according to claim 6, further comprising: a gentle longitudinal force control unit that reduces a change gradient of the longitudinal force. 8. The vehicle includes left and right front wheels, and the longitudinal force detection device comprises: (c) a left front wheel longitudinal force detection device provided on the left front wheel; and (d) a right front wheel longitudinal force provided on the right front wheel. The front-rear force control device includes a detection device, and the difference between the front-rear force of the left front wheel detected by the front-rear force detection device of the left front wheel and the front-rear force of the right front wheel detected by the front-rear force detection device of the right front wheel is predetermined. The longitudinal force control device according to any one of claims 5 to 7, further comprising a split road determination unit that determines that a road surface in contact with the wheel is a split road when the set value is equal to or more than the set value. 9. A front-rear force suppressing section for suppressing a front-rear force of a wheel having a larger front-rear force when the wheel front-rear force control device determines that the split road is on a split road. The longitudinal force control device according to claim 8 including. 10. A wheel speed detecting device for detecting the rotational speed of at least one of a plurality of wheels of a vehicle, and (b)
A longitudinal force detection device that detects a longitudinal force applied to at least one of the plurality of wheels; and (c) at least a vehicle body obtained based on the longitudinal force detected by the longitudinal force detection device. A vehicle based on a vehicle speed related amount related to a speed and a wheel speed related amount related to a wheel rotation speed acquired based on a rotation speed of the at least one wheel detected by the wheel speed detection device. In the front-rear force-sharing related amount acquisition unit for acquiring the front-rear force-sharing related amount related to the ratio of the front-rear force shared by the wheel, (d) at least, based on the vehicle body speed related amount and the wheel speed related amount. A slip state related amount acquisition device including a slip state amount acquisition unit that acquires the slip state amount of the wheel, and at least the front-back force applied to the wheel of the vehicle A longitudinal force control device including a wheel longitudinal force control device that controls based on a related amount and the slip state amount. 11. At least one of a plurality of wheels of a vehicle.
Longitudinal force detection device that detects the longitudinal force applied to the vehicle, and the total longitudinal force applied to the entire vehicle based on the longitudinal force detected by the longitudinal force detection device, and the acquired total longitudinal force A vehicle body acceleration acquisition device including a vehicle body acceleration acquisition unit that acquires the vehicle body acceleration based on the above.