JPH08142841A - Vehicle stability control device - Google Patents

Abstract

PURPOSE: To positively maintain the maneuvering stability of a vehicle even when braking force control is started during travel on the split road surface. CONSTITUTION: The steering angle of the rear wheels RL, RR of a vehicle is controlled by a rear wheel steering angle control means RC according to the operating state of the vehicle detected by an operating state detecting means DS. Whether the vehicle is traveling on the split road surface is judged by a split road surface judging means SD on the basis of a friction coefficient, estimated by a friction coefficient estimating means FE. When braking operation is performed during travel on the split road surface and the braking force control of a braking force control means BC is started, a rear wheel initial control means PC controls in such a way that braking force to the wheel on the high friction coefficient side rises slowly depending on time so as to suppress the generation of yawing moment.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention comprises a braking force control means for controlling a braking force applied to each wheel of a vehicle and a rear wheel steering angle control means for controlling a steering angle of a wheel behind the vehicle. The present invention relates to a vehicle stability control device that maintains steering stability.

[0002]

2. Description of the Related Art Recent vehicles are equipped with a braking force control means and have various control functions such as anti-skid control, traction control, and front / rear braking force distribution control. Furthermore,
It is equipped with a rear wheel steering angle control means, which enables the steering angle control of the wheels behind the vehicle in addition to the conventional front wheel steering function, and has a four-wheel steering function. For example, JP-A-63-3153
The anti-skid control device described in Japanese Patent No. 55 relates to a vehicle having an anti-skid control function and a four-wheel steering function, and controls the steering angle of the rear wheels in a direction that cancels the motion that appears around the vertical axis of the vehicle during brake operation. A device for doing so has been proposed.

Further, Japanese Laid-Open Patent Publication No. 1-172070 has a vehicle equipped with an anti-skid system, which is equipped with an auxiliary steering device for correcting the course of the vehicle at the time of braking. There has been proposed a device that enables safe braking without deflecting the course of the vehicle even when the vehicle is suddenly braked.
In this device, when sudden braking is performed on a straddle road, the brake pressure of the left and right wheels is estimated from the control signal of the brake pressure control solenoid valve, and it is determined from the difference between the brake pressure estimated values of the left and right wheels that it is a straddle road. Based on this, the rear wheels are to be steered by a small angle.

[0004]

In a conventional vehicle having an anti-skid control function, when braking is performed while traveling on a traveling road surface having different friction coefficients (μ) between the left and right wheels of the vehicle, a so-called split road surface. Causes a yaw moment due to the difference in braking force between the left and right wheels, which impairs vehicle stability. As a means for preventing this, so-called select low control is used to adjust the wheel cylinder hydraulic pressure on the road surface with a high friction coefficient of the rear wheels so as to be equal to the wheel cylinder hydraulic pressure on the road surface with a low friction coefficient. According to the select low control, the braking force of the wheels on the high friction coefficient road surface side is not fully utilized, so that the braking distance becomes long. On the other hand, as disclosed in the above-mentioned Japanese Patent Laid-Open No. 63-315355, in a vehicle equipped with a device capable of steering the rear wheels, the cornering force is applied by the steering control of the rear wheels to provide the yaw moment. The braking distance can be shortened because the can be canceled.

However, the control for compensating the yaw moment by the rear wheel steering angle control means as in the above-mentioned prior art is to feed back the result of the vehicle behavior, so that the unstable state occurring at the start of braking is prevented. It is not possible. FIG. 11 shows the situation of the frictional force and the yaw moment when the steering angle control of the rear wheels is performed at the time of braking as described in the above-mentioned publication, and the yaw moment Ts1 generated at the time of braking on the split road surface is countered. Then, the yaw moment Tc1 is applied by the lateral force Fy1 of the rear wheel on the high friction coefficient side. However, the relationship between the braking force and the lateral force at this time is shown in FIG.
As shown in, when the braking force Fx1 is applied to the rear wheel on the high friction coefficient side so that the maximum friction coefficient is obtained, the lateral force F
y1 becomes small. Therefore, the rear wheel steering angle control is not so effective.

In view of the above, the present invention provides a vehicle stability control device having a braking force control means and a rear wheel steering angle control means, which ensures reliable steering control of the vehicle even when the braking force control is started during traveling on a split road surface. The purpose is to maintain sex.

[0007]

In order to achieve the above-mentioned object, the present invention, as shown in the outline of the configuration in FIG. 1, mounts on each wheel FL, FR, RL, RR of a vehicle to apply a braking force. Wheel cylinders Wfl, Wfr, Wrl, Wrr to be added
And a hydraulic pressure generator PG for increasing the brake fluid in response to the operation of the brake pedal BP to apply a brake hydraulic pressure to each wheel cylinder, and a brake interposed between the hydraulic pressure generator PG and each wheel cylinder. A hydraulic pressure control device FV for controlling the hydraulic pressure, wheel speed detection means WS1 to WS4 for detecting the wheel speed of each wheel, and a hydraulic pressure control device FV driven based on the detected wheel speeds of these wheel speed detection means, Braking force control means BC for controlling the braking force applied to each wheel,
The driving state detecting means DS for detecting the driving state of the vehicle and the wheels RL, RR behind the vehicle are supported so that they can be steered.
Rear wheel steering angle control means RC for controlling the steering angles of the wheels RL, RR behind the vehicle based on the detection result of the driving state detection means DS.
In a stability control device for a vehicle, the friction coefficient estimating means FE estimates the friction coefficient of each wheel with respect to a traveling road surface.
And a split road surface determination means SD for determining whether or not the traveling road surface is a split road surface based on the friction coefficient of each wheel estimated by the friction coefficient estimation means FE, and a braking force control means BC.
Split road surface determination means SD at the start of braking force control by
Is determined to be a split road surface, the braking force control means BC is controlled to gradually increase the brake fluid pressure supplied to the wheel cylinder on the high friction coefficient side of the wheels RL, RR on the rear side of the vehicle with the passage of the supply time. The rear wheel initial control means PC for pressing is provided.

The above-described vehicle stability control device further comprises a vehicle body speed estimating means VE for estimating the vehicle body speed of the vehicle based on the detection results of the wheel speed detecting means WS1 to WS4, and the rear wheel initial control means PC is When the speed is high, the wheels RL, R behind the vehicle traveling on the split road surface
Of R, the rising gradient of the brake fluid pressure supplied to the wheel cylinder with the higher friction coefficient is set low, and when the vehicle speed is low, the brake fluid pressure is supplied to the wheel cylinder with the higher friction coefficient of the rear wheels RL and RR. The rising gradient of the brake fluid pressure may be set high.

Further, in the above-described vehicle stability control device, the driving state detecting means DS includes a yaw rate sensor for detecting a yaw rate around the vertical axis passing through the center of gravity of the vehicle, and the yaw rate sensor detects the yaw rate based on the yaw rate sensor. It can be configured to detect operating conditions.

Alternatively, as the operating state detecting means DS,
A front wheel steering angle sensor for detecting steering angles of wheels FL, FR in front of the vehicle is included, and the driving state of the vehicle is detected based on the steering angle detected by the front wheel steering angle sensor and the vehicle body speed estimated by the vehicle body speed estimating means VE. It can also be configured as follows.

[0011]

In the vehicle stability control device having the above structure, when the brake pedal BP is operated, the hydraulic pressure generator PG is operated.
To wheel cylinders Wfl, Wfr, Wrl, Wrr
Brake fluid pressure is supplied to each of the wheels, and each wheel FL, FR,
Although a braking force is applied to RL and RR, a hydraulic pressure control device FV is provided between the hydraulic pressure generator PG and each wheel cylinder.
The hydraulic pressure control device FV is controlled by the braking force control means BC, and the brake hydraulic pressure applied to each wheel cylinder is controlled. In this case,
The wheel speed detection means WS1 to WS4 detect the wheel speed of each wheel, and the braking force control means BC is controlled based on these detected wheel speeds.

On the other hand, the driving state detection means DS detects the driving state of the vehicle (for example, yaw rate), and the rear wheel steering angle control means RC controls the steering angles of the wheels RL, RR behind the vehicle according to the detection result. It Further, the friction coefficient estimating means FE estimates the friction coefficient of each wheel, and based on this friction coefficient, the split road surface determining means SD determines whether or not the vehicle is traveling on the split road surface. Therefore,
When the braking operation is performed while the vehicle is traveling on a split road surface having different friction coefficients on the left and right sides of the vehicle, and the braking force control by the braking force control means BC is started, the rear wheel initial control means PC
The braking force applied to the wheels on the high friction coefficient side of the rear wheels is controlled so as to gradually rise depending on time. This allows
The generation of a sudden yaw moment at the start of the braking force control can be appropriately suppressed, and the yaw moment can be effectively compensated by the rear wheel steering angle control means RC.

In the vehicle stability control apparatus according to the second aspect, the vehicle body speed estimation means VE estimates the vehicle body speed of the vehicle based on the detection results of the wheel speed detection means WS1 to WS4, and the rear wheel initial control means PC Thus, when the vehicle body speed is high, the rising gradient of the brake fluid pressure supplied to the wheel cylinder with the higher friction coefficient side of the wheels RL, RR behind the vehicle traveling on the split road surface is set low,
When the vehicle speed is low, the wheels RL, RR behind the vehicle
Among these, the rising gradient of the brake fluid pressure supplied to the wheel cylinder on the high friction coefficient side is set high. As a result, the yaw moment at the start of the braking force control can be appropriately compensated.

In the vehicle stability control device according to the third aspect, the yaw rate sensor forming the driving state detecting means DS detects the yaw rate around the vertical axis passing through the center of gravity of the vehicle, and the vehicle operation is performed based on this yaw rate. The condition is detected.

In the vehicle stability control device according to the fourth aspect, the steering angle of the wheel in front of the vehicle is detected by the front wheel steering angle sensor which constitutes the driving state detecting means DS, and the steering angle and the vehicle body speed estimating means VE. The driving state of the vehicle is detected based on the vehicle speed estimated at.

[0016]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 shows an embodiment of the stability control device of the present invention, which comprises braking force control means for controlling the braking force of each wheel and rear wheel steering angle control means for controlling the steering angle of the rear wheels. . First, the braking system will be described. Wheels FL, FR, R
Wheel cylinders Wfl, Wfr, Wr for L and RR respectively
1, Wrr are mounted, and a hydraulic pressure control device FV is interposed in a hydraulic pressure path connecting these wheel cylinders Wfl and the like and the master cylinder MC. Note that the wheel FL indicates the wheel on the front left side as viewed from the driver's seat, hereinafter the wheel FR indicates the front right side, the wheel RL indicates the rear left side, and the wheel RR indicates the rear right side. In the present embodiment, the hydraulic control of the front wheel is performed. Although the front and rear pipes are divided into the system and the hydraulic control system for the rear wheels, so-called X pipes may be used.

The master cylinder MC constituting the hydraulic pressure generator of the present invention is driven according to the operation of the brake pedal BP. The hydraulic control device FV provided between the master cylinder MC and the wheel cylinder Wfl is shown in FIG.
The control portion of L is shown as a representative, and a normally open solenoid valve EV1 and a normally closed solenoid valve EV2 are shown in the hydraulic passage that connects one output port of the master cylinder MC and the wheel cylinder Wrl. As shown in FIG. 3, the discharge side of the pump HP is connected between these and the master cylinder MC. The other wheels have the same structure. The pump HP is driven by a motor FM, and the brake fluid whose pressure has been raised to a predetermined pressure is supplied to the fluid pressure passage. The discharge side hydraulic pressure passage of the normally closed electromagnetic valve EV2 is connected to the pump HP via the reservoir RV, and
Each equipped with a piston and a spring, the solenoid valve EV
The brake fluid, which is recirculated from 2 through the discharge-side hydraulic pressure path, is stored therein, and the brake fluid is supplied to this when the pump HP is operated.

The solenoid valves EV1 and EV2 are 2-port 2-position solenoid directional control valves, each of which is in the first position shown in FIG. 3 when the solenoid coil is not energized, and the wheel cylinder Wrl communicates with the master cylinder MC and the pump HP. There is. When the solenoid coil is energized, it is in the second position, and the wheel cylinder Wrl is disconnected from the master cylinder MC and the pump HP and communicates with the reservoir RV. These solenoid valves E
V1 and EV2 are connected to the electronic control unit ECU of FIG.
Energization and de-energization of the solenoid coil is controlled according to the braking state of the vehicle, and the brake fluid pressure in the wheel cylinder Wrl is increased, reduced, or maintained. That is, when the solenoid coils of the solenoid valves EV1 and EV2 are not energized, the master cylinder MC and the pump H are added to the wheel cylinder Wrl.
The brake fluid pressure is supplied from P to increase the pressure and communicates with the reservoir RV side to reduce the pressure when energized. If the solenoid coil of the solenoid valve EV1 is energized and the solenoid coil of the solenoid valve EV2 is non-energized, the brake fluid pressure in the wheel cylinder Wrl is maintained. Therefore, so-called pulse pressure increase (step pressure increase) or pulse pressure decrease can be performed by adjusting the time interval of energization / de-energization, and control can be performed so as to gradually increase or decrease the pressure. In this embodiment, a pair of 2-port 2-position electromagnetic switching valve was used, but 3-port 3-position
A position electromagnetic switching valve may be used. Further, the motor FM that drives the pump HP is connected to the electronic control unit ECU, and the drive is controlled thereby.

Wheel speed sensors WS1 to WS4 are provided on the wheels FL, FR, RL, and RR, and these are connected to an electronic control unit ECU, and the rotational speed of each wheel, that is, the number of pulses proportional to the wheel speed. Is inputted to the electronic control unit ECU. Further, a brake switch BS that is turned on when the brake pedal BP is depressed, a yaw rate sensor YS that detects the yaw rate of the vehicle, and the like are connected to the electronic control unit ECU. The yaw rate sensor YS detects a change speed of the vehicle rotation angle (yaw angle) around the vertical axis passing through the center of gravity of the vehicle, that is, a yaw angular speed (yaw rate) γ, and outputs it to the electronic control unit ECU. The yaw rate γ can be calculated based on the wheel speed difference between the driven wheels (front wheels FL and FR in this embodiment), and the yaw rate sensor YS can be omitted.

Thus, during normal brake operation, the wheel cylinder W is driven from the master cylinder MC via the hydraulic pressure control device FV in response to the operation of the brake pedal BP.
The brake fluid pressure is supplied to fl and the like, and various controls such as anti-skid control can be performed as described below. That is, if any of the wheels tends to lock during braking, the control shifts to anti-skid (ABS) control. Then, for example, so-called traction control is performed in order to prevent the wheels RL and RR on the drive wheel side from slipping due to acceleration slip when the vehicle starts, and as a part of that, braking force is applied to the wheels RL and RR. This prevents acceleration slip. The hydraulic control device FV is connected to the electronic control device ECU, and its operation and non-operation are controlled.

On the other hand, the rear wheel steering angle control means is shown in FIG.
As shown in FIG. 5, a steering angle control device SCD is provided between the wheels RL, RR behind the vehicle, and the steering angle of the wheels RL, RR is controlled by a motor SM according to the output of the electronic control device ECU. Has been done. This rudder angle control device SC
A rear wheel rudder angle sensor SSr is attached to D, and wheels RL, R
The actual steering angle of R is detected. The motor SM is drive-controlled based on the rotation amount set by the electronic control unit ECU according to the outputs of the yaw rate sensor YS, the wheel speed sensors WS1 to WS4, the front wheel steering angle sensor SSf, and the rear wheel steering angle sensor SSr.

The structure of the steering angle control device SCD of this embodiment has a rack shaft 60 provided at right angles to the traveling direction of the vehicle as shown in FIG. Is connected to a rear knuckle arm 63 via a ball joint 62. The rack 61 formed on the rack shaft 60 is configured to mesh with a pinion 64 extending in the front-rear direction of the vehicle. A pinion 65 is provided at the tip of the motor shaft of the motor SM, and a gear 66 meshes with the pinion 65 to form a hypoid gear. The hypoid gear transmits the rotation of the motor shaft of the motor SM as the rotation of the gear 66.
The motor SM is configured not to rotate when a rotational force is applied to the gear 66 from the 0 side.

As shown in FIG. 2, the electronic control unit ECU is a microcomputer C including a processing unit CPU, a memory ROM, a RAM, an input port IPT, an output port OPT, etc. which are connected to each other via a bus.
Equipped with MP. The wheel speed sensors WS1 to WS
4. Output signals from the brake switch BS, the yaw rate sensor YS, etc. are input through the amplifier circuit AMP to the input port IP respectively.
The processing unit CPU is configured to be input from T. Further, from the output port OPT, via the drive circuit ACT, the hydraulic pressure control device FV and the steering angle control device S.
The control signal is output to the CD. In the microcomputer CMP, the memory ROM stores a program corresponding to the flowcharts shown in FIG. 5 and subsequent figures, the processing unit CPU executes the program while an ignition switch (not shown) is closed, and the memory RAM stores the program. Temporarily stores variable data required for execution of.

In the present embodiment configured as described above, a series of processing such as anti-skid control is performed by the electronic control unit ECU, and when the ignition switch (not shown) is closed, FIGS. Execution of the program corresponding to the flowchart of 7 starts. First, in FIG. 5 showing the main routine, in step 101, the microcomputer CMP is initialized and various calculated values are cleared. Next, at step 102, the detection signals of the wheel speed sensors WS1 to WS4 are read, and
The detection signal of the yaw rate sensor YS is read, and the wheel speeds VwFL, VwFR, VwRL and VwRR of the four wheels are calculated in step 103 based on the former detection signal.

Next, the routine proceeds to step 200, where it is judged whether or not the anti-skid control start condition is satisfied. If the start condition is satisfied and it is judged that the anti-skid control is started, the anti-skid control is executed at step 300. Transition. Details of the process in step 200 are shown in FIG.
Will be described later with reference to. When it is determined in step 200 that the anti-skid control start condition is not satisfied, the routine proceeds to step 400, where it is determined whether or not the traction control start condition is satisfied. If this start condition is satisfied, traction control is performed in step 500, and if not satisfied, the process returns to step 102. Then, upon completion of each of the above controls, the process returns to step 102.

On the other hand, in this embodiment, the rear wheel steering angle control operation is performed as shown in the flowchart of FIG.
That is, first, after initialization is performed in step 111,
In step 112, the wheel speed sensors WS1 to WS4
The detection signal of is read and the yaw rate sensor Y
The detection signal of S, the steering angle of the front wheels FL and FR detected by the front wheel steering angle sensor SSf, and the actual steering angle of the rear wheels RL and RR detected by the rear wheel steering angle sensor SSr are Is read. Subsequently, the routine proceeds to step 113, where the wheels FL ahead of the vehicle detected by the front wheel steering angle sensor SSf,
Based on the steering angle of FR and the estimated vehicle speed calculated based on the outputs of the wheel speed sensors WS1 to WS4, the target steering angles of the rear wheels RL and RR are set, and according to the detected yaw rate γ of the yaw rate sensor YS. Will be corrected. next,
In step 114, the deviation between the target rudder angle and the actual rudder angle (initial value is 0) is calculated, and step 1 is performed based on this deviation.
At 15, the motor SM of the steering angle control device SCD is duty-controlled, and the wheels RL and RR are driven so that the steering angle becomes the target steering angle. Therefore, in the present embodiment, the yaw moment that may occur during braking is also actuated by the steering angle control device SCD so as to cancel it, and compensation operation is performed.

Further, in the present embodiment, when the anti-skid control start determination is made in step 200 of FIG. 5 described above, as shown in FIG. 7, for the wheel on the higher friction coefficient side of the wheels RL, RR behind the vehicle. Rear wheel initial control is performed. That is, in step 201, it is determined whether or not the brake switch BS is on, and if it is off, the process returns to the main routine and proceeds to step 400 in FIG. 5, but if it is on, proceeds to step 202. In step 202,
The road surface friction coefficient μ is estimated based on the wheel speed VwRL calculated in step 103, and based on the value of the road surface friction coefficient μ, it is determined in step 203 whether the road surface is a split road surface. If it is not a split road surface, normal anti-skid control is performed in step 300 of FIG. 5, but if it is determined to be a split road surface, in step 204, the wheel on the high friction coefficient side of the wheels RL, RR behind the vehicle is selected. The pulse pressure increase control is performed for a predetermined time, and the pressure is gradually increased while the stability of the vehicle behavior is not impaired. If it is determined in step 205 that the yaw rate γ has become equal to or greater than the predetermined value K1 and the vehicle has started to become unstable, then in step 206, the wheel cylinder hydraulic pressure is once held. Go to step 300.

In step 204, as shown in FIG. 8, the wheel cylinder hydraulic pressure for the wheel on the higher friction coefficient side of the rear wheels RL, RR is gentle as shown by the solid line with respect to the original rising gradient shown by the broken line. The pulse pressure increase control is performed so as to exhibit a different rising slope. That is, the braking force applied to the wheel on the high friction coefficient side is controlled so as to gradually increase depending on time. As a result, the braking force is suppressed as shown by Fx2 in FIG. 9, for example, and a large lateral force Fy2 is obtained accordingly. Therefore, according to this embodiment, a large yaw moment Tc2 is obtained as shown in FIG. 10 as compared with the conventional device shown in FIG. 11, and the large yaw moment Ts2 at the start of braking on the split road surface is reliably canceled. . Thus, the steering angle control device S
The CD provides effective compensation for the yaw moment generated on the split road surface.

Further, in step 204, when the vehicle body speed is high, the rising gradient of the brake fluid pressure supplied to the wheel cylinder with the higher friction coefficient side of the rear wheels RL, RR is set low, and the vehicle body speed is low. If the rising gradient of the brake fluid pressure supplied to the wheel cylinder on the high friction coefficient side is set to be high during the above condition, the yaw moment can be compensated more effectively according to the change in the vehicle body speed.

[0030]

Since the present invention is configured as described above, it has the following effects. That is, in the vehicle stability control device according to the present invention, as described in claim 1, when the split road surface determination means determines that the split road surface is the split road surface at the start of the braking force control by the braking force control means, the rear wheel initial control means determines. Since the brake fluid pressure supplied to the wheel cylinder on the high friction coefficient side of the wheels behind the vehicle by controlling the braking force control means is configured to gradually increase in accordance with the passage of the supply time, the split road surface The steering stability of the vehicle can be reliably maintained even when braking is started.

In the vehicle stability control device according to the second aspect, the rear wheel initial control means is a wheel having a higher friction coefficient among the wheels behind the vehicle traveling on the split road surface when the vehicle body speed is high. Set the rising gradient of the brake hydraulic pressure supplied to the cylinder low, and set the rising gradient of the brake hydraulic pressure supplied to the wheel cylinder of the wheel behind the vehicle with the higher friction coefficient higher when the vehicle speed is low. Therefore, even when braking on the split road surface is started, the yaw moment is appropriately compensated according to the change in the vehicle body speed, and the steering stability of the vehicle can be more reliably maintained.

In the vehicle stability control device according to the third aspect of the invention, the driving state detecting means is configured to detect the driving state of the vehicle based on the yaw rate detected by the yaw rate sensor. The operating state of can be detected.

In the stability control device for a vehicle according to a fourth aspect of the present invention, the driving state detecting means includes the driving state of the vehicle based on the steering angle detected by the front wheel steering angle sensor and the vehicle body speed estimated by the vehicle body speed estimating means. Is configured to detect, it is possible to easily detect the driving state of the vehicle.

[Brief description of drawings]

FIG. 1 is a block diagram showing an outline of a vehicle stability control device of the present invention.

FIG. 2 is an overall configuration diagram of an embodiment of a vehicle stability control device of the present invention.

FIG. 3 is a configuration diagram showing a part of an example of a hydraulic control device according to an embodiment of the present invention.

FIG. 4 is a sectional view showing a part of an example of a steering angle control device according to an embodiment of the present invention.

FIG. 5 is a flowchart showing a process for braking force control in one embodiment of the present invention.

FIG. 6 is a flowchart showing processing of rear wheel steering angle control according to an embodiment of the present invention.

FIG. 7 is a flowchart showing a process of determining whether to start anti-skid control in an embodiment of the present invention.

FIG. 8 is a graph showing a control state of the wheel cylinder hydraulic pressure of the rear wheels in the embodiment of the present invention.

FIG. 9 is a graph showing a relationship between a braking force and a lateral force during general vehicle braking.

FIG. 10 is a plan view showing a relationship between a braking force and a lateral force at the time of steering the rear wheels of the split road surface traveling vehicle according to the embodiment of the present invention.

FIG. 11 is a plan view showing a relationship between a braking force and a lateral force when steering rear wheels of a conventional split road vehicle.

[Explanation of symbols]

 BP Brake pedal BS Brake switch YS Yaw rate sensor SCD Steering angle control device SSf Front wheel steering angle sensor SSr Rear wheel steering angle sensor MC Master cylinder HP pump Wfr, Wfl, Wrr, Wrl Wheel cylinder WS1 to WS4 Wheel speed sensor FR, FL, RR , RL wheels

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Masanobu Fukami 2-1-1 Asahi-cho, Kariya City, Aichi Prefecture Aisin Seiki Co., Ltd. (72) Inventor Jun 2-1-2 Asahi-cho, Kariya City, Aichi Prefecture Aisin Seiki Co., Ltd. Incorporated (72) Inventor Takayuki Ito 2-1, Asahi-cho, Kariya city, Aichi Prefecture Aisin Seiki Co., Ltd. (72) Inventor Yoshiharu Nishizawa 2-1-1 Asahi-cho, Kariya city, Aichi Prefecture Aisin Seiki Co., Ltd. ( 72) Inventor Shingo Sugiura 2-1-1 Asahi-cho, Kariya-shi, Aichi Aisin Seiki Co., Ltd. (72) Inventor Norio Yamazaki 2-1-1 Asahi-cho, Kariya-shi, Aichi Aisin Seiki Co., Ltd. (72) Inventor Akio Sakai 2-1-1 Asahi-cho, Kariya city, Aichi Prefecture Aisin Seiki Co., Ltd.

Claims (4)

[Claims] 1. A wheel cylinder mounted on each wheel of a vehicle for applying a braking force, and a hydraulic pressure generator for increasing a brake fluid in response to an operation of a brake pedal to apply a brake fluid pressure to each of the wheel cylinders. A hydraulic pressure control device that is interposed between the hydraulic pressure generation device and each of the wheel cylinders to control the brake hydraulic pressure, a wheel speed detection unit that detects a wheel speed of each wheel, and the wheel speed. A braking force control unit that drives the hydraulic pressure control device based on the wheel speed detected by the detection unit and controls the braking force applied to each wheel.
A driving state detecting means for detecting a driving state of the vehicle and a rear wheel for supporting a wheel behind the vehicle in a steerable manner and controlling a steering angle of the wheel behind the vehicle based on a detection result of the operating state detecting means. In a vehicle stability control device including a steering angle control means, a friction coefficient estimating means for estimating a friction coefficient of each wheel with respect to a traveling road surface, and traveling based on the friction coefficient of each wheel estimated by the friction coefficient estimating means. Split road surface determination means for determining whether or not the road surface is a split road surface, and when the split road surface determination means determines that the road surface is a split road surface when the braking force control means starts the braking force control, the braking force control means is controlled to control the vehicle. The rear wheel initial control that gradually increases the brake fluid pressure supplied to the wheel cylinder on the higher friction coefficient side of the rear wheels as the supply time elapses. Stabilizer control apparatus for a vehicle, characterized in that it comprises means. 2. A vehicle body speed estimating means for estimating a vehicle body speed of the vehicle based on a detection result of the wheel speed detecting means, wherein the rear wheel initial control means controls the split road surface when the vehicle body speed is high. Of the wheels behind the running vehicle, the rising gradient of the brake fluid pressure supplied to the wheel cylinder on the high friction coefficient side is set low, and when the vehicle body speed is low, the high friction coefficient side of the wheels behind the vehicle is set. 2. The stability control device for a vehicle according to claim 1, wherein the rising gradient of the brake fluid pressure supplied to the wheel cylinder is set high. 3. The driving state detecting means includes a yaw rate sensor for detecting a yaw rate around a vertical axis passing through the center of gravity of the vehicle, and the driving state of the vehicle is detected based on the yaw rate detected by the yaw rate sensor. The stability control device for a vehicle according to claim 1, wherein the stability control device is configured. 4. A vehicle body estimated by the vehicle body speed estimating means and a steering angle detected by the front wheel steering angle sensor, wherein the driving state detecting means includes a front wheel steering angle sensor for detecting a steering angle of a wheel in front of the vehicle. The stability control device for a vehicle according to claim 1, wherein the driving state of the vehicle is detected based on a speed.