JP3214163B2 - Anti-skid control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-skid control device.

[0002]

2. Description of the Related Art In a vehicle equipped with an anti-skid system (ABS), as a control for canceling unnecessary yaw rate generated and improving the stability of the vehicle, a lateral motion of the vehicle, for example, a yaw rate is detected so that a target motion state is obtained. There is one in which different reference speeds are provided for the left and right wheels or the front and rear wheels to control the brake pressure (JP-A-2-68252).

[0003]

However, this one is
When braking on the so-called left / right split μ road, after an unnecessary yaw rate has occurred, the reference speed is changed, and the apparently slipping wheels are slipped, and the brake fluid pressure on the high μ road side is reduced. Then, control is performed to stabilize the vehicle, but the difference between the right and left road surfaces μ is large.For example, when the low μ road side tends to be locked and the brake fluid pressure is maintained by anti-skid control or when the pressure is reduced, the high μ When the roadside slip is very small, a considerably large control gain is required to reduce or maintain the hydraulic pressure by the anti-skid control on the wheels on the high μ roadside. Further, if the control gain is too large, both the wheels tend to be pulled out in the subsequent control, so that the braking force is reduced and the braking force becomes insufficient.

The present invention has been made in view of such a problem. When the anti-skid control is activated on one of the left and right wheels during braking, the anti-skid control is activated in accordance with the yaw rate deviation. By controlling the hydraulic pressure increase speed to change the increase in the brake hydraulic pressure of the wheel that is not running, it is possible to ensure the steering stability of the vehicle when braking on left and right split roads, etc., and also to prevent the braking distance from increasing. It is also intended to be able to plan.

[0005]

According to the present invention, the following anti-skid control device is provided. A control device having an anti-skid device that controls braking fluid pressure to prevent wheel lock so that a wheel slip ratio is maintained at a reference slip ratio, and a yaw rate detection unit that detects a yaw rate generated in a vehicle. A vehicle speed detecting means for detecting a vehicle speed, a steering angle detecting means for detecting a steering angle of a steering device, and a vehicle speed and a steering angle detected by at least the vehicle speed detecting means and the steering angle detecting means, respectively. Target yaw rate setting means for setting a target yaw rate, yaw rate deviation calculating means for calculating a deviation between the generated yaw rate detected by the yaw rate detecting means and the target yaw rate, and anti-skid control operated on one of the left and right wheels. In the case, the anti-skid control is not activated, The pressure increase / retention ratio of the control period, as the yaw rate deviation increases, the anti-skid control unit and a hydraulic lifting speed change control means for reducing (Fig. 1),
And, in the above, when the anti-skid control is operated on one of the left and right wheels, the hydraulic pressure for changing the hydraulic pressure rising speed of the opposite wheel of the left and right wheels on which the anti-skid control is not operated according to the yaw rate deviation. The anti-skid control device includes a reference slip ratio changing unit for performing a rising speed change control and thereafter independently setting a reference slip ratio of the left and right wheels in a direction to reduce the deviation according to the yaw rate deviation. (FIG. 2).

[0006]

According to the present invention, during braking, anti-skid control is performed to prevent the wheels from locking by controlling the brake fluid pressure so that the wheel slip rate is maintained at the reference slip rate. A target yaw rate setting means for setting a target yaw rate based on at least the detected vehicle speed by the vehicle speed detecting means and the steering angle detected by the steering angle detecting means. The yaw rate deviation calculating means calculates the deviation between the yaw rate detected by the yaw rate detecting means and the target yaw rate set as described above, but the hydraulic pressure rise speed change control means operates the anti-skid control on one of the left and right wheels. The anti-skid control is not activated, and the opposite wheels of the left and right wheels are within a fixed hydraulic pressure control cycle. The pressure increase / holding ratio, as the yaw rate deviation increases, smaller.

As described above, when the anti-skid control is operated on one of the left and right wheels, the hydraulic fluid that changes the brake fluid pressure increase by the yaw rate feedback to the wheel on which the anti-skid control is not operated is changed according to the yaw rate deviation. By controlling the pressure rise speed change, it is possible to secure the steering stability of the vehicle even when braking on a left or right split road, etc., and also to prevent the braking distance from increasing.In this case, As a control for changing the hydraulic pressure rising speed, the anti-skid non-control wheels have a configuration in which the pressure increase / retention ratio within a fixed hydraulic pressure control cycle is reduced as the yaw rate deviation increases, and as a result, the left and right split roads Anti-skid control is not activated when anti-skid control is activated on wheels on the low μ road even during braking The braking fluid pressure rising speed of the wheels on the μ road side can be increased, and if the yaw rate deviation is large, the braking fluid pressure increasing speed can be decreased, and if the yaw rate deviation is small, the braking fluid pressure rising speed can be increased (see FIGS. 5 and 6). In such braking, fine control can be performed so that the braking force on the anti-skid non-controlled wheels can suppress a rapid change in vehicle behavior according to the yaw rate deviation.

In the second aspect of the present invention, in addition to performing the control for changing the hydraulic pressure increasing speed of the anti-skid non-control wheels by the above-described yaw rate feedback at the beginning of braking, the control for changing the reference slip ratio of the yaw rate feedback thereafter is also performed. By doing so, it is possible to more effectively enhance the operability of the vehicle, and it is possible to achieve compatibility with subsequent control.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 3 shows the configuration of an embodiment of the apparatus of the present invention. In the figure,
1L and 1R are the left and right front wheels of the vehicle, 2L and 2R are the left and right rear wheels,
3, a brake pedal; and 4, a tandem master cylinder. In addition, 3a is a booster as a booster of a brake, and 4a is a reservoir. Each wheel 1L,
The wheel cylinders 1R, 2L, and 2R are provided with wheel cylinders 5L, 5R, 6L, and 6R that apply a braking force to each wheel by frictionally holding a brake disk by supplying hydraulic pressure. Each wheel is individually braked when supplied with hydraulic pressure from.

Here, the brake hydraulic pressure (braking hydraulic pressure) system of the braking device will be described. The front wheel brake system 7F from the master cylinder 4 is connected to the pipelines 8F, 9F, 10F and the hydraulic pressure control valves 11F, 12F. Left and right front wheel cylinder 5L,
5R, the rear wheel brake system 7R from the master cylinder 4 is connected to the pipelines 8R, 9R, 10R and the hydraulic pressure control valve 11
R, 12R, left and right rear wheel cylinders 6L, 6R
To reach.

[0011] Hydraulic pressure control valves 11F, 12F, 11R, 12
R is the wheel cylinder 5L of the corresponding wheel,
The brake fluid pressures toward 5R, 6L, and 6R are individually controlled to be used for the anti-skid control of the present invention.
The brake fluid pressure is increased toward the original pressure when the brake fluid pressure is increased to the original pressure when the brake fluid pressure is OFF, and is set to a holding position where the brake fluid pressure when the first stage is ON is not increased or decreased. , 13R, the hydraulic pressure is increased, maintained, and reduced by setting the reduced pressure position to be reduced. The control of these hydraulic pressure control valves is performed by controlling the current (control valve drive current) I _{1 to} I to the solenoid of the corresponding valve from a controller described later.
_Done by ₄ .

The brake fluid pressure in the reservoirs 13F and 13R is returned to the pipes 8F and 8R by the pumps 14F and 14R driven at the time of holding and depressurizing, and is returned to the accumulators 15F and 15R of these pipes. Provide for reuse.

The hydraulic pressure control valves 11F, 12F, 11R, 12
R is turned ON by the controller 20, and OFF control, this controller 20, the wheels 1L, 1R, 2L, signals from the wheel speed sensors 21-24 for detecting the wheel speed V _w1 ~V _w4 of 2R, the steering device steering A signal from a steering angle sensor 25 that detects a steering angle θ of a wheel (not shown);
And a signal from a yaw rate sensor 26 for detecting a yaw rate (d / dt) φ generated in the vehicle.

The signal from the wheel speed sensor is used for calculating the vehicle speed (estimated vehicle speed) when the vehicle speed is applied as a control parameter for setting the yaw rate target value in the yaw rate feedback control in addition to the anti-skid control (ABS control). Can also be used.

The controller 20 includes an input detection circuit,
A microcomputer including an arithmetic circuit, a storage circuit for storing various control programs executed by the arithmetic circuit and arithmetic results, an output circuit for supplying a control signal to the hydraulic pressure control valve, and the like. Perform anti-skid control based on the information. For anti-skid control,
Here, the left and right front wheels 1L and 1R are individually
L and 2R are commonly controlled by a three-channel system, and the braking force is controlled by the brake fluid pressure reduction, holding, and pressure increase modes so that the wheel slip rate is maintained at the reference slip rate during braking. The anti-skid control of each wheel can be performed in the same manner as in a normal three-channel ABS, thereby avoiding locking of the corresponding wheel.

The controller 20 performs anti-skid control to prevent wheel lock in this manner. Furthermore, the controller 20 performs anti-skid control on one of the left and right wheels (front wheel left and right in this example) such as braking on a right and left split μ road. When the skid control operates, the target yaw rate set based on the vehicle speed and the steering angle θ detected by the steering angle sensor 25 and the actual generated yaw rate (d / dt) φ detected by the yaw rate sensor 26 are used. In accordance with the deviation, a hydraulic pressure increase speed change control for changing the hydraulic pressure increase on the opposite wheel side (the other non-ABS wheel of the left and right wheels) on which the anti-skid control is not operated is executed.

Preferably, in accordance with the yaw rate deviation, when the deviation is large, control is performed so as to delay the hydraulic pressure increasing speed. Preferably also, the controller 20 comprises
When the anti-skid control is activated on one of the left and right wheels as the control at the beginning of braking, the hydraulic pressure rise of the opposite wheels of the left and right wheels on which the anti-skid control is not activated is changed according to the yaw rate deviation. After that, in accordance with the yaw rate deviation, control for changing the reference slip ratio for independently setting the reference slip ratios of the left and right wheels in a direction to reduce the deviation is performed. be able to.

In the storage circuit of the controller 20, in addition to the program for executing the above-described control, a control table in which the yaw rate deviation applied to the above-described hydraulic pressure rise speed change control is used as a control parameter (see FIG. 5). , An ABS hydraulic pressure control map using the slip rate and the wheel acceleration as control parameters (see FIG. 8) can also be stored.

FIG. 4 is a flowchart showing an example of a control program including the above-described hydraulic pressure rise speed change control and reference slip ratio change control processing executed by the microcomputer in the controller 20. This program is executed by an operating system (not shown) by a periodic interruption every predetermined time.

In FIG. 4, first, in step S100, based on output signals from the wheel speed sensors 21 to 24, the steering angle sensor 25, and the yaw rate sensor 26, the wheel speed V _Wi (i = 1 to 4). , Steering angle θ and yaw rate (d / dt) φ.

Next, in step S101, estimates the vehicle speed Vcar from the wheel speed V _Wi. In the present embodiment,
V _W1 (left front wheel side), V _W2 (right front wheel side)
And the vehicle speed Vcar is calculated according to the following equation.

Vcar = (V _W1 + V _W2 ) / 2 ---- 1

In the following step S102, a target yaw rate (d / dt) φ _ref is calculated. Here, the steering angle θ read in step S100 and step S10
From the vehicle speed Vcar calculated in 1, obtains a target yaw rate (d / dt) φ _ref according to the following equation.

## EQU2 ## (d / dt) φ _ref = [Vcar / ＶA (1 + KVcar ² )｝] · θ 2 where A is a constant determined by the steering gear ratio of the vehicle, and K is the constant of the vehicle. This is a constant representing the steering characteristic.

[0023] Then, in step S103, calculates the deviation Δ (d / dt) φ of yaw rate (d / dt) φ read in the target yaw rate (d / dt) φ _ref and step S100 of calculating the above. Yaw rate deviation Δ (d
/ Dt) φ is

Δ (d / dt) φ = (d / dt) φ _ref − (d / dt) φ−3

As described above, every time the reading in step S100 is performed, after the respective arithmetic processings in steps S101 to S103 are executed, the operation mode of the anti-skid control is monitored. When it operates on one side of the left and right wheels of the vehicle, the one side wheel performs normal anti-skid control, but the calculated yaw rate deviation Δ (d / d / dt) Control for changing according to φ is performed.

For this reason, it is determined whether or not the anti-skid control is being performed on the left and right wheels in the subsequent determination step S104. In this embodiment, as described above, the anti-skid control is performed simultaneously with the rear wheels (right and left). Common) and three independent front wheel channels. Therefore, it is determined here whether or not the left and right front wheels 1L and 1R are under anti-skid control. The determination during the control in this case is performed, for example, from the time when the first holding or the pressure reduction after the braking is performed.

If the result of determination in step S104 is that both wheels 1L and 1R are being controlled, in this example of the program, the process proceeds to step S107 via step S106, and the yaw rate deviation Δ (d / dt) will be described later. The setting of the reference slip ratio λ _s is changed in accordance with the above. On the other hand, if only the other wheel (one of the left and right wheels) is being controlled, step S10
5 and the yaw rate deviation Δ (d / dt)
Determine the pressure increase control pattern of the wheels that are not controlled according to the
In step S107, brake fluid pressure control based on the non-controlled wheel side is executed to change the increasing speed of the fluid pressure.

For example, when one wheel starts anti-skid control prior to the other wheel due to braking on a left or right split road surface having a difference between right and left road surfaces μ,
In the process, first, the step S105 side is selected.

First, from step S104 to step S1
In the present step S105, the yaw rate deviation Δ obtained in step S103 will be described.
(D / dt) φ sets a wheel pressure increase control pattern that is not being controlled. In the present embodiment, a control table as shown in FIG. 5 is used, and the control table shows a certain hydraulic pressure with respect to the calculated yaw rate deviation Δ (d / dt) φ value calculated at the time. Pressure increase / holding ratio α within control cycle
To determine.

For example, when the driver performs braking while traveling straight ahead and the master cylinder hydraulic pressure is increased by depressing the brake pedal 3 and this is supplied to the front wheel cylinders 5L and 5R, the road surface is left and right. Assuming that the road is a split μ road, as shown in FIG. 6, when braking is performed on the left and right split road surfaces, anti-skid control is activated on the low μ side wheel (time t ₁ ), whereby the yaw rate (d / dt) φ Occurs, and in a state where the steering is not performed (a state where the steering wheel is held in a neutral state), the yaw rate deviation Δ (d / dt) φ increases. According to Equation 2, when θ = 0 without steering, (d / dt) φ
_ref = 0, and Δ (d / dt) φ = −
(D / dt) φ.

In such a case, in this example of the program, as shown in FIG. 6, when the wheel on the low μ road enters the control area, the hydraulic pressure rising speed of the wheel on the high μ road is reduced. It is. That is, when it is determined that only the other (low μ side wheel) is being controlled (step S104), the pressure is increased based on the calculated value of the yaw rate deviation Δ (d / dt) φ according to the characteristic control table of FIG. / The holding ratio (pattern) is determined, and the speed of increasing the yaw rate is reduced by delaying the pressure increasing speed of the wheel (high μ side wheel) during the non-skid control (from t ₂ to t _{3 in} FIG. 5A). (FIG. 6B), thereby suppressing a rapid change in the vehicle behavior. When the driver performs corrective steering, the vehicle is controlled to further stabilize the vehicle, and
As the yaw rate deviation Δ (d / dt) φ decreases, the pressure increasing speed increases.

In the example shown in FIG. 5, the control table has a value Δ (d /
dt) As φ increases, the value α indicating the pressure increase / holding ratio within the constant hydraulic pressure control cycle decreases and the value Δ (d
/ Dt) The characteristic data is set in a tendency as shown in the drawing so that the value α increases as the value of φ decreases to the predetermined upper limit value. Therefore, for example, step S1
05, the yaw rate deviation Δ (d / dt) φ is a predetermined value Δ (d / dt) φ _A , the value Δ (d / dt)
predetermined value alpha _A showing the pressure increase / holding ratio corresponding to phi _A is to be searched. In this manner, when the anti-skid control of one of the wheels is activated, FIG.
, The pressure increase control pattern of the non-controlled wheel is determined, and the process of step S107 is executed.

In this case, in step S107, pressure reduction, holding, and pressure increase by normal anti-skid control are determined for wheels under anti-skid control according to the ABS control table shown in FIG. While the corresponding hydraulic pressure control valve is driven and controlled in the skid cycle based on the brake hydraulic pressure control for avoiding the wheel lock, the pressure increase control pattern setting of the wheel during the anti-skid non-control in step S105 is performed. When the corresponding hydraulic pressure control valve on the non-controlled wheel side is controlled by the control pattern determined by the following formula, the hydraulic pressure of the non-controlled wheel is controlled so as to increase and maintain the hydraulic pressure without following FIG. Pressure control is performed.

Thus, when the control is executed in steps S105 and S107, the yaw rate deviation Δ (d / dt) φ increases in the above-described braking situation on the left and right split roads in FIG. Even in such a case, as the value of Δ (d / dt) φ calculated in step S103 increases, a smaller value is applied as the pressure increase / holding ratio α value accordingly. The pressure increasing speed of the high μ side wheel under control can be delayed, and a sudden change in the initial vehicle behavior can be suppressed. In addition, the correction steering is started, and the difference between the target value and the actual value of the yaw rate, that is, the value Δ ( d /
dt) As φ becomes smaller, the pressure increase speed is increased accordingly. As a result, the hydraulic pressures of the low μ side wheel and the high μ side wheel during the anti-skid control change as shown in FIG. It will change. In FIG. 6, what is indicated by a chain line is
The state of the hydraulic pressure transition when the above-described hydraulic pressure rising speed change control is not performed on the high μ side wheel is shown. In contrast, in the present embodiment, the yaw rate deviation Δ (d
/ Dt) It is possible to finely and appropriately control the hydraulic pressure of the high μ side wheel in accordance with φ.

Then, when the anti-skid control is also activated on the high μ side wheel (time t _{3 in} FIG. 6), the flow is switched from step S104 to step S106, and the hydraulic pressure increasing speed change control is ended. Thus, this control can be performed only at the beginning of braking.

In this way, when the anti-skid control operates on one of the front left and right wheels, the generated yaw rate (d / dt) φ and the target yaw rate (d / d)
t) in response to phi deviation between _{ref Δ (d / dt) φ} , that anti-skid control is a hydraulic lifting speed change control for changing the fluid pressure rise in the opposite wheel does not operate, in a split-road The steering stability of the vehicle at the initial stage of braking can be ensured, and compatibility with prevention of an increase in braking distance can be easily achieved.

[0036] If it is determined that the antiskid control is being both wheels in step S104, the process proceeds to step S106, changes the setting of the reference slip ratio lambda _s depending on the yaw rate deviation Δ (d / dt) φ. Therefore, in the case shown in FIG. 6 in which the hydraulic pressure increasing speed change control is executed as the control at the beginning of braking, and subsequently the anti-skid control is applied to the left and right front wheels, step S107 is executed through step S106. Is done.

Here, the λ _s value is usually set to a certain set value, and when a yaw rate deviation Δ (d / dt) φ occurs, the setting is changed in this step S106, and this is changed in the next step S107. A in processing (anti-skid control)
It is applied as a modified reference value for the slip ratio λ in the case of mode determination according to the BS control table (FIG. 8).

In this embodiment, for the reference slip ratio λ _s , λ _sR for the right wheel side and λ _sL for the left wheel side are determined by the following equations.

Λ _sR = λ _s0 + k ₁ · Δ (d / dt) φ-4

Λ _sL = λ _s0 + k ₂ · Δ (d / dt) φ −5 Here, λ _s0 is an initial value and a normal reference slip ratio (yaw rate deviation Δ (d / dt) When φ is not generated and this is zero, λ _sR , λ _sL = λ _s0 ). K ₁ and k ₂ in the equations are proportional constants in the case of proportional control.

In the above description, each of the front two wheels to be individually subjected to the anti-skid control is targeted. However, the change of the reference slip ratio may be performed only for one wheel. Further, the maximum change amount may be determined and limited. For example, in a case where the avoidance operation is performed while panic braking is performed, the situation is as shown in FIG.

Next, in step S107, step S107
When proceeding from 106, normal decompression, including front left and right wheels, and, if applicable, including the rear two wheels of common control,
Performs anti-skid control using a holding and increasing pressure skid cycle. That is, for each wheel (front right wheel, front left wheel, rear wheel left and right (common)), the slip ratio λ calculated based on the wheel speed value read in step S100 and the wheel acceleration (d
/ Dt) The wheel lock is determined based on V _w , and the brake fluid pressure is reduced, held, and increased to prevent wheel lock and control to keep the reference slip.

In this embodiment, the brake fluid pressure is controlled (depressurized, maintained, increased) by the ABS control table as shown in FIG. In the figure, a pattern is defined by a reference slip rate and a reference wheel acceleration, respectively, and the calculated slip rate and the wheel acceleration are compared with their respective reference values to control the brake fluid pressure of the corresponding wheel according to the control pattern of the control table. The control of each corresponding hydraulic pressure control valve is performed so as to perform (pressure reduction, holding, pressure increase). That is, in the skid cycle of the ABS, the control is performed such that the brake fluid pressure is maintained for the relevant wheel during braking, when the wheel becomes locked, the pressure is reduced if the wheel is still likely to be locked, and the pressure is increased when the wheel speed is restored and the wheel returns. Then, this is repeated (FIG. 9).

However, in this case,
When the reference slip ratios λ _sR and λ _sL are changed according to 4, the yaw rate deviation Δ (d / dt) φ is changed in a direction to reduce the deviation, and thus the actual yaw rate (d / dt).
As a result of changing and applying the reference value relating to the slip ratio in the ABS control table for the left and right wheels so that φ follows the set target value well, the yaw rate deviation Δ (d / dt)
Anti-skid control is performed in a state in which a left-right differential pressure corresponding to φ is generated, and vehicle behavior control by this is also realized.

At the time of braking, when the processing is executed in step S107 after step S106, the braking fluid pressure is controlled in this manner. Further, as described above, when the corresponding hydraulic pressure control valve is controlled by the control pattern determined by the pressure increase control pattern setting of the wheel during the anti-skid non-control in step S105, FIG. 8 is not followed. When the pressure is increased and maintained, and the operation enters the operation range of the anti-skid control according to FIG. 8, the above-described anti-skid control is continuously performed.

By performing this control, not only the stability during braking on the left and right split μ roads is improved, but also, when turning, when the yaw rate is generated as desired, or when turning inside the turn. Is occurring,
Even if the anti-skid control in which a differential pressure is generated between the left and right hydraulic pressures is operated, there is no problem because the present control is not entered.

In order to prevent the vehicle from becoming unstable due to the occurrence of an unnecessary yaw rate in the vehicle due to the difference between the hydraulic pressure of the high μ side wheel and the hydraulic pressure of the low μ side wheel on the left and right slip road surface,
In order to prevent a differential pressure from being generated between the left and right wheels, control is performed simply according to the control state (pressure reduction, holding, pressure increase) of one wheel so that the hydraulic pressure of the other wheel does not differ. Compared to the case of the system, even in the case of such a system, when the anti-skid is activated on one of the wheels during turning braking, etc., not on the left and right split road surface, control is entered, and yaw rate is generated instead In this embodiment, such a situation is avoided.

In contrast to the control based on only the control of changing the reference slip ratio by the yaw rate feedback, the initial control of the braking is performed by changing the hydraulic pressure rising speed of the non-control wheels by the yaw rate feedback in the initial stage of braking. Can be achieved. Even if the difference between the left and right road surface μ is large, it is possible to cope with it, and it is possible to avoid a tendency for both wheels to release the brake fluid pressure in the subsequent control and to prevent the braking force from becoming insufficient, and according to the control of this embodiment, the left and right split road surface , The steering stability of the vehicle can be secured, and the prevention of the occurrence of yaw rate during the turning braking and the prevention of the increase of the braking distance can be highly compatible.

In this embodiment, the yaw rate deviation Δ
(D / dt) φ is used to change the pressure increase pattern. However, the time T (for example, between t ₁ and t _{2 in} FIG. 6) from the start of the anti-skid control on one side wheel and the yaw rate deviation Δ (d / Dt) φ, it is considered that when T is small, the behavior change is large, and the pressure increasing speed may be further reduced,
Pressure reduction control may be added. In this case, the above T is required as a control parameter in addition to the value of Δ (d / dt) φ.
Alternatively, pressure reduction control is also targeted as a mode of change,
Finer control becomes possible.

In this embodiment, in the reference slip ratio changing process (step S106), the reference slip ratio is changed to a so-called proportional control of the yaw rate deviation Δ (d / dt) φ (Equations 4 and 5).
However, the present invention is not limited to this, and differential control or integral control may be added. Further, when the anti-skid non-controlled wheel enters the anti-skid control by changing the reference slip ratio without entering the hydraulic pressure rise speed change control, there is no problem because the anti-skid control alone can sufficiently secure stability.

It should be noted that the present invention is not limited to the above embodiments and modifications. For example, in the above description, the anti-skid control has been described as having three channels, but it is needless to say that the present invention can also be applied to a four-channel type anti-skid control.

[0050]

According to the present invention, in anti-skid control for controlling brake fluid pressure to prevent wheel lock,
During braking, if anti-skid control is activated on one of the left and right wheels, depending on the deviation between the generated yaw rate of the vehicle and the target yaw rate, the opposite wheel, on which anti-skid control is not activated, must be within a fixed hydraulic pressure control cycle. As the yaw rate deviation increases, the hydraulic pressure rise speed change control can be performed so as to change the hydraulic pressure rise speed by increasing the yaw rate deviation, and the steering stability of the vehicle on the left and right split road surfaces, etc. As a result, it is possible to improve the stability and to appropriately suppress the increase in the braking distance.In braking on left and right split road surfaces, anti-skid control is applied to the wheels on the low μ road side. When activated, the brake fluid pressure rise speed of the wheel on the high μ road side where the anti-skid control is not activated, and if the yaw rate deviation is large, the brake fluid pressure rises If the speed is small and the yaw rate deviation is small, the brake fluid pressure rising speed can be made large, and therefore, in such braking, the braking force on the anti-skid non-control wheels according to the yaw rate deviation can suppress a rapid change in vehicle behavior. In addition, it is controlled finely.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of an anti-skid control device of the present invention.

FIG. 2 is a conceptual diagram of the anti-skid control device of the present invention.

FIG. 3 is a system diagram showing a configuration of an embodiment of the present invention.

FIG. 4 is a flowchart illustrating an example of a control program executed by the controller of the example.

FIG. 5 is a diagram showing an example of a control table applicable to the program.

FIG. 6 is an example of a time chart for explaining the contents of hydraulic control of the left and right wheels by the same program.

FIG. 7 is a time chart showing an example of changing a reference slip ratio.

FIG. 8 is a diagram showing an example of a control table (ABS control map) for anti-skid control.

FIG. 9 is a time chart showing a state of anti-skid control.

[Explanation of symbols]

 1L, 1R Left and right front wheels 2L, 2R Left and right rear wheels 3 Brake pedal 4 Master cylinder 5L, 5R, 6L, 6R Wheel cylinder 11F, 12F, 11R, 12R Hydraulic pressure control valve 20 Controller 21-24 Wheel speed sensor 25 Steering angle sensor 26 Yaw rate sensor

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Naoki Maruko 2 Nissan Motor Co., Ltd. 2 Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Prefecture (56) References JP-A-4-78644 (JP, A) JP-A-3 -86665 (JP, A) JP-A-2-254051 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B60T 8/00-8/96

Claims (2)

(57) [Claims] 1. A control device having an anti-skid device for controlling brake fluid pressure to prevent wheel lock so that a wheel slip ratio is maintained at a reference slip ratio, and detects a yaw rate generated in a vehicle. A yaw rate detecting means, a vehicle speed detecting means for detecting a vehicle speed, a steering angle detecting means for detecting a steering angle of a steering device, and a vehicle speed detected by at least the vehicle speed detecting means and the steering angle detecting means, respectively. Target yaw rate setting means for setting a target yaw rate based on a steering angle; yaw rate deviation calculating means for calculating a deviation between the generated yaw rate detected by the yaw rate detecting means and the target yaw rate; If the skid control is activated, the a Nchisukiddo control is not operating, the opposite wheels of the right and left wheels In the constant hydraulic pressure control cycle
Pressure / holding ratio as the yaw rate deviation increases
An anti-skid control device comprising: a hydraulic pressure rise speed change control means for reducing the pressure. 2. When the anti-skid control operates on one of the left and right wheels,
Anti-skid control is not performed. The hydraulic pressure rising speed is changed to change the hydraulic pressure rising speeds of the opposite wheels of the left and right wheels. Thereafter, the left and right wheels are moved in a direction to reduce the deviation according to the yaw rate deviation. 2. The anti-skid control device according to claim 1, further comprising a reference slip ratio changing means for independently setting the reference slip ratio.