JP2001287633A - Abs controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately grasp a road surface condition to conduct optimum ABS control suitable for the condition. SOLUTION: An ABS control parameter generating circuit 61 generates a parameter for ABS control based on a wheel speed input from a wheel speed sensor 10. A road surface slope estimating circuit 62 estimates a road surface μslope of each wheel based on the wheel speed. A correcting circuit 63 corrects the parameter for the ABS control based on the road surface μ slope input from the road surface slope estimating circuit 62 to be supplied to an ABS control circuit 64. The ABS control circuit 64 controls an ABS hydraulic circuit 40 using the corrected parameter.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ABS control device, and more particularly to an ABS control device that performs ABS control according to the characteristics of individual tires.

[0002]

2. Description of the Related Art A braking force of a tire is generated by a slip between the tire and a road surface. That is, the braking force of the tire is generated by the difference between the speed at which the tire advances (the traveling speed of the vehicle body) and the peripheral speed of the tire.
Normally, in the ABS control, the wheel slip and the wheel deceleration are calculated based on the wheel speed signal, and the increase, holding, and reduction of the brake fluid pressure are controlled in accordance with these to prevent the wheels from being locked.

The characteristics of the frictional force between the tire and the road (so-called μ-S characteristics) are as shown in FIG. AB
When the pressure is increased by the S control, the cycle changes in the directions of arrows X and Y along the μ-S characteristic, and when the pressure is reduced, the cycle slightly decreases in the μ direction (the direction of the arrow Z).

In order to efficiently perform the ABS control using the μ-S characteristics of the tire, when the pressure is increased, the pressure is immediately increased when the slip deviates from the μ peak (arrow X), and the μ is increased.
In the vicinity of the peak, the pressure increase amount is slightly suppressed or maintained, and the time of staying near the μ peak is extended as much as possible.
On the other hand, when the pressure is reduced, it is necessary to immediately return the slip.

However, in the current ABS control, a threshold value for increasing or decreasing the pressure is set so as to conform to the characteristics of general tires. Therefore, the threshold value is not always the optimum value for a certain road surface of a certain tire.

In order to solve such a problem, for example, Japanese Patent Application Laid-Open No. 7-165053 discloses that the frictional force characteristics between a tire and a road surface are estimated to improve the ABS control performance. This technology uses the fact that the wheel acceleration is generated by the difference between the braking torque and the road surface reaction force (the braking force acting on the vehicle) to determine the slip ratio at which the difference between the wheel acceleration and the vehicle deceleration becomes a predetermined value, The target slip ratio is determined in consideration of the offset.

However, since the wheel speed signal contains noise and the vehicle body acceleration is estimated from the wheel speed including the wheel slip, it is difficult to calculate the vehicle body acceleration and the wheel acceleration accurately. is there. Therefore, there is a problem that the tire frictional force characteristics with respect to the road surface cannot be accurately grasped. Furthermore, in the conventional method, ABS
At the time of control, it was not possible to determine what kind of situation on the μ-S characteristic, and as a result, it was difficult to determine whether the pressure should be increased immediately or slowly.

[0008] The present invention has been proposed to solve the above-mentioned problems, and accurately grasps the road surface condition.
An object of the present invention is to provide an ABS control device capable of performing optimal ABS control in that state.

[0009]

According to the first aspect of the present invention,
Wheel speed detecting means for detecting a wheel speed of a wheel, and a road μ gradient estimating means for estimating a road μ gradient that is a gradient of the road μ with respect to the wheel slip speed based on the wheel speed detected by the wheel speed detecting means. , A control parameter generating means for generating control parameters for ABS control, and a road μ gradient estimated by the road μ gradient estimating means,
A control parameter correction unit configured to correct the control parameter generated by the control parameter generation unit; and an ABS control unit configured to perform ABS control based on the control parameter corrected by the control parameter correction unit.

According to the present invention, the road surface μ gradient estimating means estimates the road surface μ gradient based on the wheel speed. At this time, it is also possible to estimate what is considered to be substantially equivalent to the road surface μ gradient, such as a torque gradient or a small gain. The control parameter correcting means determines, based on the road surface μ gradient, where the tire is located on the μ-S characteristic, so that the tire is located on the μ peak of the μ-S characteristic at which the grip force of the tire is most exhibited. Next, the ABS control parameters are corrected. In addition, when it is at the μ peak, the control parameter need not be corrected. Then, the ABS control means performs the ABS control using the corrected control parameters. Such ABS control can be performed independently for each wheel provided on the vehicle.

[0011] The control parameter correction means may be configured as follows.
As described above, if the road surface μ gradient estimated by the road surface μ gradient estimating means is larger than the first predetermined value at the time of increasing the ABS brake hydraulic pressure, the pressure increase amount of the ABS brake hydraulic pressure is increased. The control parameters may be corrected as described above. At this time, increasing the pressure increasing amount includes increasing the pressure increasing duty.

[0012] The control parameter correction means may include:
As described above, when the road μ gradient estimated by the road μ gradient estimating means is smaller than the second predetermined value when the ABS brake hydraulic pressure is increased, the pressure increase amount of the ABS brake hydraulic pressure is reduced. The control parameters may be corrected as described above. At this time, reducing the pressure increase amount includes reducing the pressure increase duty.

[0013] The control parameter correcting means may be configured as follows.
As described above, when the road μ gradient estimated by the road μ gradient estimating means is smaller than a third predetermined value, A
The control parameter may be corrected so as to maintain the BS brake hydraulic pressure.

[0014] The control parameter correction means may be configured as follows.
As described, when the road surface μ gradient estimated by the road surface μ gradient estimating means is larger than a predetermined value when the ABS brake hydraulic pressure is reduced, the pressure reduction amount of the ABS brake hydraulic pressure is reduced. Alternatively, the control parameter may be corrected so as to shorten the decompression time. Here, reducing the pressure reduction amount or reducing the pressure reduction time includes reducing the pressure reduction duty.

[0015] The control parameter correction means may be configured as follows.
As described, when the road surface μ gradient estimated by the road surface μ gradient estimating means is smaller than a predetermined value when the ABS brake hydraulic pressure is reduced, the pressure reduction amount of the ABS brake hydraulic pressure is increased. Alternatively, the control parameter may be corrected so as to increase the pressure reduction time. Here, increasing the pressure reduction amount or increasing the pressure reduction time includes increasing the pressure reduction duty.

[0016] The control parameter correcting means may be configured as follows.
As described above, the slip threshold value indicating the start of the pressure reduction of the ABS brake hydraulic pressure may be corrected based on the road surface μ gradient at the time of the start of the pressure reduction estimated by the road surface μ gradient estimating means. Here, the road surface μ gradient at the time of the start of pressure reduction may be the road surface μ gradient immediately before the start of the current pressure reduction, or may be the road surface μ gradient at the time of the start of the previous pressure reduction.

[0017] The control parameter correcting means may be configured as follows.
As described in 1, the slip threshold value indicating the start of pressure increase of the ABS brake hydraulic pressure may be corrected based on the road surface μ gradient at the start of pressure increase estimated by the road surface μ gradient estimating means. Here, the road surface μ gradient at the start of pressure increase may be the road surface μ gradient immediately before the current pressure increase start, or may be the road surface μ gradient at the time of the previous pressure increase start.

[0018] The control parameter correction means may include:
As described in 5, the control parameter generated by the control parameter generation unit may be corrected based on the road μ gradient before the start of the ABS control estimated by the road μ gradient estimation unit.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to FIGS.

(First Embodiment) The present invention can be applied to, for example, an ABS control device 1 having the configuration shown in FIG. The ABS control device 1 includes a wheel speed sensor 10 (10FL, 10FR, 10FR) that detects the wheel speed of each wheel.
RL, 10RR), a stop switch 11 for detecting that the brake pedal is depressed, and an electronic control unit (hereinafter, referred to as “ECU”) 20 for controlling the entire device.
For performing brake control according to the control of the ECU 20
And an S hydraulic circuit 40.

The ECU 20 amplifies the signal from the wheel speed sensor 10 (21FL, 21FR, 21R).
L, 21RR), an amplifier 22 for amplifying a signal from the stop switch 11, an input port 23 for converting an input signal into a signal that can be internally processed, a CPU 24 for performing predetermined arithmetic processing, a control program, and the like. ROM to store
25, a RAM 26 for temporarily storing signals, and a TMR 27
And an output port 28 for converting an output signal into a predetermined format.
And an amplifier 2 for amplifying and outputting a signal from an output port
9 to 36.

The CPU 24 operates in accordance with the control program stored in the ROM 25, and stores a signal input through the input port 23 in the RAM 26. And C
The PU 24 estimates the road μ gradient and generates and further corrects control parameters for ABS control. And CP
U24 sets the ABS in accordance with the corrected control parameters.
A signal for performing control is output from the output port 28 and the amplifier 29.
To the ABS hydraulic circuit 40 through.

The ABS hydraulic circuit 40 includes a solenoid SOL
1 to SOL8 are provided. A
Specifically, as shown in FIG. 2, the BS hydraulic circuit 40 includes a master cylinder 42 that generates a hydraulic pressure corresponding to the depression force of the brake pedal 41, and a solenoid SOL1 that increases, decreases, and holds the hydraulic pressure of the brake fluid. SOL8, a reservoir 43 (43F, 43R) for temporarily storing the brake fluid, and a pump 4 for pumping the brake fluid stored in the reservoir 43
4 (44F, 44R), a motor 45 serving as a driving force for the pump 44, and a wheel cylinder 46 (46FL, 46FR, 46RL, 46FL, 46FR, 46RL,
46RR) and check valves 47 to 50 for suppressing the inflow of high-pressure brake fluid in a predetermined direction.

The solenoid SOL1 and the solenoid SOL
2, Solenoid SOL3 and Solenoid SOL4, Solenoid SOL5 and Solenoid SOL6, Solenoid SOL
7 and the solenoid SOL8 are respectively connected in series via a hydraulic passage. One set of these solenoids SOL connected in series is connected on one side to the master cylinder 42 and on the other side to the reservoir 43.

Solenoids SOL1, SOL3, SOL
5, a hydraulic passage for supplying brake fluid is provided between each port of SOL7. Check valves 47 to 50 for preventing high-pressure brake fluid from flowing from the port on the wheel cylinder 46 side to the port on the master cylinder 42 side are provided in these hydraulic pressure passages. Wheel cylinder 46FL, 46FR, 4
6RL and 46RR are connected to connection points X, Y, Z and V of two solenoids SOL connected in series via hydraulic passages, respectively.

The reservoir 43 stores brake fluid returned from the wheel cylinder 46 in the pressure reduction control mode. The pump 44 is driven by the motor 45 when the ABS control is being performed, pumps up the brake fluid stored in the reservoir 43, and supplies the brake fluid to the master cylinder 42 via a check valve.

The above-described ECU 20 provides an arbitrary solenoid SOL to the ABS hydraulic circuit 40 having such a configuration.
To control (increase / decrease / hold) the fluid pressure of an arbitrary wheel cylinder 46 to control the braking torque of a desired wheel.

Such an ABS control device 1 is functionally configured as shown in FIG. That is, AB
The S control device 1 includes a wheel speed sensor 10 and a wheel speed sensor 1
An ABS control parameter generation circuit 61 that generates an ABS control parameter based on the wheel speed from 0; a road μ gradient estimation circuit 62 that estimates the road μ gradient of each wheel based on the wheel speed; A correction circuit 63 for correcting an ABS control parameter based on the ABS control, and an ABS for controlling the ABS hydraulic circuit 40 using the corrected parameter.
And a control circuit 64. The ABS control parameter generation circuit 61, the road gradient estimation circuit 62, the correction circuit 6
3. The ABS control circuit 64 corresponds to the CPU 24 described above.

The ABS control parameter generation circuit 61
As the parameters for the BS control, pressure reduction start slip threshold S1_0, pressure increase start slip threshold S2_0, pressure reduction start wheel acceleration threshold G1_0, pressure increase start wheel acceleration threshold G2_0,
The pressure reducing duty ratio D1_0, the pressure increasing duty ratio D2_0,
The decompression time T1_0 is generated, and these parameters are supplied to the correction circuit 63.

The road surface μ gradient estimating circuit 62 estimates the road surface μ gradient of each wheel based on the wheel speed of each wheel detected by the wheel speed sensor 10, and supplies the road surface μ gradient to the correction circuit 63. A detailed description of the road surface gradient estimating circuit 62 will be described later.

The correction circuit 63 initializes the parameters generated by the ABS control parameter generation circuit 61, corrects the control parameters using the road μ gradient, and selects an operation mode. The ABS control circuit 64
The hydraulic pressure of the brake fluid is controlled for the ABS hydraulic circuit 40 according to any one of the operation modes of the “pressure reduction mode”, the “pulse pressure reduction mode”, and the “pulse pressure increase mode”.

(Configuration of Road Surface Estimation Circuit 62)
The road μ gradient estimating circuit 62 will be described. The road μ gradient estimating circuit 62 according to the present embodiment calculates the μ gradient when only the road disturbance ΔTd is input to the wheel resonance system as the vibration input.

As shown in FIG. 4, the road surface μ gradient estimating circuit 6
Reference numeral 2 denotes a pre-processing filter 71 for detecting a wheel speed vibration Δω1 of each wheel as a response output of a wheel resonance system receiving a road surface disturbance ΔTd from a wheel speed ω1 of each wheel detected by the wheel speed sensor 10. Transfer function identification circuit 72 for identifying the transfer function of each wheel that satisfies the wheel speed vibration Δω1 obtained by using the least square method, and the friction coefficient μ between the tire and the road surface based on the identified transfer function. A μ gradient calculating circuit 73 for calculating a gradient for each wheel.

The pre-processing filter 71 is a band-pass filter that passes only a frequency component in a certain band around a frequency expected to be the resonance frequency of the wheel resonance system, or a high-band frequency component including the resonance frequency component. It can be constituted by a high-pass filter or the like that passes only the light. This band-pass filter or high-pass filter fixes a parameter that defines frequency characteristics to a constant value.

The output of the pre-processing filter 71 is
It is assumed that the DC component has been removed. That is, the wheel speed ω
Only the wheel speed vibration Δω1 around 1 is extracted.

Here, the transfer function F (s) of the pre-processing filter 71 is

[0037]

(Equation 1)

It is assumed that Where ci is the coefficient of the filter transfer function and s is the Laplace operator.

Next, an operation formula on which the transfer function identification circuit 72 depends is derived. In the present embodiment, the calculation of the pre-processing filter 71 is included in the calculation of the transfer function identification circuit 72 and executed.

First, the transfer function to be identified is road surface disturbance Δ
A second-order model in which Td is an excitation input, and the wheel speed vibration Δω1 detected by the pre-processing filter 71 at this time is a response output. That is,

[0041]

(Equation 2)

Assume the following vibration model. Here, v is observation noise included when observing the wheel speed signal.
By transforming equation (2), the following equation is obtained.

[0043]

(Equation 3)

First, the equation obtained by multiplying equation (3) by the preprocessing filter of equation (1) is discretized. At this time, Δω1, ΔT
d and v are discretized data Δω1 (k), ΔTd (k), v (k) sampled at every sampling period Ts.
(K is a sampling number: k = 1, 2, 3,...). The Laplace operator s can be discretized using a predetermined discretization method. In the present embodiment, 1
As an example, let it be discretized by the following bilinear transformation. Note that d is a one-sample delay operator.

[0045]

(Equation 4)

Further, since the order m of the pre-processing filter is desirably 2 or more, in the present embodiment, m is set to 2 in consideration of the calculation time, whereby the following equation is obtained.

[0047]

(Equation 5)

In order to identify the transfer function from each data of the wheel speed vibration Δω1 based on the least square method,
The equation is modified as follows to be in the form of a linear function with respect to the parameter to be identified. Note that “T” is the transposition of a matrix.

[0049]

(Equation 6)

In the above equation, θ is a parameter of the transfer function to be identified.

The transfer function identification circuit 72 estimates the unknown parameter θ by applying the least square method to each data obtained by sequentially applying the detected discretized data of the wheel speed vibration Δω 1 to the equation (9). , Thereby identifying the transfer function.

Specifically, the detected wheel speed vibration Δω1
Into discrete data Δω (k) (k = 1, 2, 3,...)
The data is sampled at N points, and the parameter θ of the transfer function is estimated using the following equation of the least square method.

[0053]

(Equation 7)

Here, the crowned amount of the symbol "$" is defined as the estimated value.

The above-mentioned least square method may be operated as a sequential least square method for obtaining the parameter θ by the following recurrence formula.

[0056]

(Equation 8)

Here, ρ is a so-called forgetting coefficient, which is usually set to a value of 0.95 to 0.99. At this time, the initial value is

[0058]

(Equation 9)

It is sufficient to set

As a method for reducing the estimation error of the least square method, various modified least square methods may be used.
In the present embodiment, an example will be described in which an auxiliary variable method, which is a least square method in which auxiliary variables are introduced, is used. According to the method,
At the stage when the relationship of the expression (9) is obtained, the parameters of the transfer function are estimated using the following expression with m (k) as an auxiliary variable.

[0061]

(Equation 10)

The sequential operation is as follows.

[0063]

[Equation 11]

The principle of the auxiliary variable method is as follows.
Substituting equation (9) into equation (15) gives

[0065]

(Equation 12)

If the auxiliary variable is selected so that the second term on the right side of equation (19) becomes zero, the estimated value of θ matches the true value of θ. Therefore, in the present embodiment, as auxiliary variables,
ζ (k) = [− ξy1 (k) −ξy2 (k)] T is calculated by the equation error r
The one delayed so as not to have a correlation with (k) is used. That is,

[0067]

(Equation 13)

It is assumed that Here, L is a delay time.

After identifying the transfer function as described above,
In the μ gradient calculation circuit 73, the physical quantity related to the road surface μ gradient D0 is

[0070]

[Equation 14]

Is calculated. When the physical quantity related to the road μ gradient D0 can be calculated by the equation (21), for example,
When the physical quantity is small, it can be easily determined that the friction characteristics between the tire and the road surface are in a saturated state.

In the road surface μ gradient estimating circuit 62 described above, in the pre-processing filter 71, the parameter defining the frequency characteristic of the band-pass filter or the high-pass filter is fixed to a constant value. You may make it change according to the parameter identified by 72. That is, the transfer function identification circuit 72
An adaptive circuit for changing the characteristics of the pre-processing filter 71 according to the parameters identified in (1) may be further provided.
In the second mode of the first embodiment of Japanese Patent Application Laid-Open No. 11-78843 (FIG. 9)
Etc.)).

The road μ gradient estimating circuit 62 identifies the transfer function of the wheel resonance system and calculates the road μ gradient when the excitation torque ΔT 1 is input to the wheel resonance system as an excitation input. (A first mode of the third embodiment of JP-A-11-78843 (see FIG. 13 and the like)).

Further, when the excitation torque ΔT 1 is input to the wheel resonance system as the vibration input, the road μ gradient estimating circuit 62 calculates the transfer function of the wheel resonance system from the detected vibration input and the response output. The identification may be performed (the first mode of the fourth embodiment of JP-A-11-78843 (see FIG. 16 and the like)).

In addition, the road μ gradient estimating circuit 62 selects only the response signal which is a periodic signal from the response signals,
The transfer function of the wheel resonance system may be identified based on the selected response output, and the μ gradient may be calculated (Japanese Patent Laid-Open No.
-Fifth embodiment of Japanese Patent Publication No. 78843 (see FIG. 18 and the like).

In the example described above, the response output to the wheel resonance system including the friction characteristics between the tire and the road surface is detected in response to the vibration input, and the transmission characteristic of the wheel resonance system from the vibration input to the response output is detected. Representing at least a physical quantity relating to the ease of slipping between the tire and the road surface by a vibration model including as an unknown element of the wheel state, based on the vibration model, an unknown element that substantially satisfies at least the detected response output. It is an estimate.

The present invention is not limited to this,
The parameters of the physical model representing the unsprung resonance characteristics may be identified from the wheel speed signal, and the road surface μ gradient may be calculated as a physical amount for estimating a physical amount related to the ease of slip between the road surface and the wheels from the identified parameters ( Refer to the column of embodiments of Japanese Patent Application No. 10-281660).

In the above-described example, the road surface μ gradient is calculated as a physical quantity relating to the ease of slipping between the road surface and the wheels. However, the present invention is not limited to this. The gradient of the braking torque (the braking torque gradient), the gradient of the driving torque with respect to the slip speed (the driving torque gradient), and the minute vibration may be obtained.

That is, the braking torque gradient and the driving torque gradient may be calculated based on the time-series data of the wheel speed detected at every predetermined sample time (see Japanese Patent Application Laid-Open No. 10-114263 (see FIG. 1 and the like). )).

Further, based on the time-series data of the wheel deceleration detected at every predetermined sample time and the time-series data of the brake torque or the physical quantity related to the brake torque detected at every predetermined sample time, A braking torque gradient may be calculated (see Japanese Patent Application Laid-Open No. H10-114263 (FIG. 2,
See FIG. 3 etc.)).

Further, the braking force is minutely excited at the resonance frequency of the vibration system composed of the vehicle body, the wheels, and the road surface, and the minute resonance frequency component of the wheel speed with respect to the minute amplitude of the braking force when the braking force is minutely excited. A minute gain, which is an amplitude ratio, may be calculated (Japanese Patent Laid-Open No. 10-114263 (see FIG. 4 and the like)).

(Main Routine 1) A of such a configuration
When performing the ABS control, the BS control device 1 specifically executes the processing from step ST1 to step ST13 shown in FIG.

Each circuit is first initialized as shown in FIG. 5 (step ST1). When a signal is input to each sensor (step ST2), the wheel speed sensor 10
Calculates the wheel speed (step ST3). The ABS control parameter generation circuit 61 calculates the wheel acceleration DVw (step ST4), the estimated vehicle speed (step ST5), and the actual slip ratio S based on the wheel speed (step S).
T6) Generate ABS control parameters.

The road surface gradient estimating circuit 62
Based on the wheel speed of each wheel from 0, the road surface μ of each wheel
The gradient is estimated (step ST7), and the road μ gradient is supplied to the correction circuit 63.

After the processing in step ST7, the correction circuit 63
Performs the initial setting of the ABS control parameters (step ST8). Here, the correction circuit 63 specifically executes a subroutine process from step ST21 to step ST25 shown in FIG.

(Parameter Initial Setting) The correction circuit 63
For the wheels to be controlled, the pressure reduction start slip threshold S
1_0, a pressure increase start slip threshold S2_0, a pressure decrease start wheel acceleration threshold G1_0, a pressure increase start wheel acceleration threshold G2_0, a pressure decrease duty ratio D1_0, a pressure increase duty ratio D2_0, and a pressure decrease time T1_0 are set (step ST21). Note that, if necessary, only some of the parameters may be used. Then, the correction circuit 63 determines whether or not the road surface μ gradient value K of the wheel to be controlled is equal to or less than a predetermined value K1 (K ≦ K1) (step ST22). The predetermined value K1 is a value indicating whether the road surface is a low μ road. That is, (K ≦ K1)
, The road surface is a low μ road.

The correction circuit 63 sets (K) in step ST22.
If ≦ K1), the following calculation is performed (step ST23).

S1_0 ← S1_0−S1_1 S2_0 ← S2_0−S2_1 G1_0 ← G1_0 + G1_1 G2_0 ← G2_0 + G2_1 D1_0 ← D1_0 + D1_1 D2_0 ← D2_0_D1_T1 It's getting closer. Therefore, the pressure reduction start slip threshold S1_0 and the pressure increase start slip threshold S
By reducing the value of 2_0, the wheel slip is not increased too much and the wheel grip is maintained. For the same reason, by increasing the pressure reduction start wheel acceleration threshold value G1_0 and the pressure increase start wheel acceleration threshold value G2_0, increasing the pressure reduction duty ratio D1_0, decreasing the pressure increase duty ratio D2_0, and further increasing the pressure reduction time T1_0, The wheel slip is not increased. It should be noted that not only the correction for all seven parameters as described above, but also the correction for only arbitrary parameters may be performed.

The correction circuit 63 determines in step ST22
When (K ≦ K1) is denied, or in step ST2
3 is completed, it is determined whether the road surface μ gradient K is equal to or greater than a predetermined value K2 (K ≧ K2) (step ST2).
4). The predetermined value K2 is a value indicating whether the road surface is a high μ road. That is, when (K ≧ K2), the road surface is a high μ road.

Then, the correction circuit 63 determines in step ST2
When (K ≧ K2) is affirmed in step 2, the following calculation is performed (step ST25).

S1_0 ← S1_0 + S1_2 S2_0 ← S2_0 + S2_2 G1_0 ← G1_0-G1_2 G2_0 ← G2_0-G2_2 D1_0 ← D1_0-D1_2 D2_0 ← D2_0 + D2_2_1T2 There is still room to the limit. Therefore, by increasing the values of the pressure reduction start slip threshold S1_0 and the pressure increase start slip threshold S2_0 in this manner, it is possible to make full use of the grip force of the wheels and to quickly decelerate. For the same reason, the decompression start wheel acceleration threshold value G1_
0 and increasing the pressure increase start wheel acceleration threshold value G2_0, decreasing the pressure reduction duty ratio D1_0, increasing the pressure increase duty ratio D2_0, and further shortening the pressure reduction time T1_0, thereby maximizing the use of the wheel grip force. Can be.

As in step ST23, not only the correction for all seven parameters as described above, but also the correction for only arbitrary parameters may be performed.

Then, the correction circuit 63 determines in step ST2
When (K ≧ K2) is denied in step 5, or in step ST
When the process of step S25 is completed, the process exits this subroutine process and proceeds to step ST9 of the main routine shown in FIG.

(Main Routine 2) Returning to the main routine, the ABS control circuit 64 determines whether the ABS control is being performed (step ST9). If the ABS control is being performed, it is determined whether the ABS control has been completed. (Step ST1
0). When the ABS control has been completed, the process returns to step ST2. When the ABS control has not been completed, the process returns to step ST1.
Proceed to 2.

The ABS control circuit 64 determines in step S
When it is determined in T9 that the ABS control is not being performed, it is determined whether the ABS control has been started (step ST11). AB
The S control circuit 64 proceeds to step ST12 when the ABS control is started, and returns to step ST2 when the ABS control is not started.

The correction circuit 63 executes a process of correcting a parameter for selecting a control mode (step ST1).
2). The correction circuit 63 specifically executes the processing from step ST31 to step ST38 of the subroutine shown in FIG. The road surface μ gradient at the start of the previous pressure reduction is K1 and the road surface μ gradient at the start of the previous pressure increase is K2.

(Parameter correction) The correction circuit 63 determines that the road surface μ gradient K1 at the start of the previous pressure reduction is equal to or greater than a predetermined value K3 (K1
.Gtoreq.K3) (step ST31).
When 1 ≧ K3), the pressure reduction start slip threshold S1 is set to S1_
The correction is increased by 3 (step ST32). In this case, as shown in FIG. 8, the road surface μ gradient when decompression was started at the decompression start slip threshold value S1 was high,
There is still room for wheel grip. Therefore, by largely correcting the decompression start slip threshold S1,
The peak of the μ-S characteristic is used effectively.

In step ST31, the correction circuit 63 sets (K
If (1 ≧ K3) is denied, or if the process of step ST32 is completed, it is determined whether or not the road surface μ gradient K1 at the time of starting the previous pressure reduction is equal to or less than a predetermined value K4 (K1 ≦ K4) (step ST33). ). The correction circuit 63 determines that K1 ≦ K4
When affirmative, the pressure reduction start slip threshold S1 is set to S1_
Correction is made smaller by 4 (step ST34). In this case, as shown in FIG. 9, the road surface μ gradient when the pressure reduction was started at the pressure reduction start slip threshold S1 was low,
In the μ-S characteristic, the peak has been reached or has already exceeded the peak. Therefore, the decompression start slip threshold S1
Is corrected so as not to exceed the μ peak of the μ-S characteristic.

The correction circuit 63 sets (K) in step ST33.
When 1 ≦ K4) is denied, or when the process of step ST34 is completed, it is determined whether or not the road surface μ gradient K2 at the start of the previous pressure increase is equal to or more than a predetermined value K5 (K2 ≧ K5) (step S34). ST35). The correction circuit 63 calculates (K2 ≧ K
If affirmative, the pressure increase start slip threshold S2 is set to S
The correction is made larger by 2-3 (step ST36). In this case, as shown in FIG.
2, the road surface μ gradient when the pressure increase was started was high, and the wheel slip recovered more than necessary. Therefore, the pressure increase start slip threshold value S2 is largely corrected so that the brake fluid pressure is not inadvertently increased.

The correction circuit 63 sets (K) in step ST35.
When 2 ≧ K5) is denied, or when the process of step ST36 is completed, it is determined whether or not the road surface μ gradient K2 at the start of the previous pressure increase is equal to or smaller than a predetermined value K6 (K2 ≦ K6) (step). ST36). The correction circuit 63 calculates (K2 ≦ K
If affirmative, the pressure increase start slip threshold S2 is set to S
Correction is made smaller by 2_4 (step ST37). In this case, as shown in FIG.
2, the road μ gradient when pressure increase was started was low, and wheel slip was not yet recovered. Therefore,
By correcting the pressure increase start threshold value S2 to a small value, the wheel slip is reliably recovered.

Then, the correction circuit 63 proceeds to step ST3.
When (K2 ≦ K6) is denied in step 7, or in step S
When the process of T37 is completed, the process exits the subroutine and
The process proceeds to step ST13 of the main routine shown in FIG.

Note that S1_3 and S1_ used in the correction are used.
It is preferable that the values of 4, S2_3 and S2_4 be values corresponding to K1 and K2. In addition, the decompression start slip threshold S1
When correcting the pressure increase start slip threshold S2, it is preferable to make these widths substantially constant. Therefore, when the pressure reduction start slip threshold S1 is corrected to be larger than the slip, the pressure increase start slip threshold S2
Is preferably corrected so as to increase the slip.

The correction circuit 63 replaces the road surface μ gradient K1 at the start of the previous pressure reduction with the road surface μ gradient K immediately before the start of the pressure reduction.
1 'may be replaced by a road surface μ gradient K2 ′ immediately before the start of pressure increase, instead of the road surface μ gradient K2 at the start of the previous pressure increase. At this time, the correction circuit 63 executes the processing from step ST41 to step ST48 shown in FIG.
The specific processing contents are the same as the processing from step ST31 to step ST38 shown in FIG. Here, instead of K3, K4, K5, and K6, K7, K8,
Using K9 and K10, S1_3, S1_4, S2
_3, S2_4 instead of S1_5, S1_6, S2_5, S
2-6 is used.

As described above, the correction circuit 63 performs the processing from step ST31 to step ST38 shown in FIG. 7 or the processing from step ST41 to step ST4 shown in FIG.
By ending the processing up to 8, the step ST12 of the main routine shown in FIG. 5 is ended.

(Selection of Control Mode) When the correction of the parameter is completed, the correction circuit 63 performs a control mode selection process (step ST13). Here, the correction circuit 63
Specifically, the processing from step ST51 to step ST58 shown in FIG. 13 is executed.

The correction circuit 63 determines whether or not the actual slip ratio S of the wheel to be controlled is larger than the threshold value S2 (S> S2) (step ST51), and when the (S> S2) is affirmed, the actual slip ratio is further increased. Is S greater than threshold value S1 (S> S
1) is determined (step ST52), and when (S> S2) is denied, the process proceeds to step ST58. Correction circuit 63
Is satisfied if (S> S1) is affirmed in step ST52, is the wheel acceleration DVw greater than the threshold value G1 (DVw> G
1) is determined (step ST53), and step ST52 is determined.
If (S> S1) is denied, the process proceeds to step ST55.

The correcting circuit 63 sets (D
When (Vw> G1) is affirmed, it is determined whether the wheel acceleration DVw is larger than the threshold value G2 (DVw> G2) (step ST54), and when (DVw> G1) is denied in step ST53, the process proceeds to step ST56. Correction circuit 63
Proceeds to step ST58 when (DVw> G2) is affirmed in step ST54, and proceeds to step ST57 when (DVw> G2) is denied.

On the other hand, the correction circuit 63 determines in step ST52
Also, when (S> S1) is denied, it is determined whether (DVw> G1) (step ST55), and (DVw> G).
If 1) is affirmed, the process proceeds to step ST58, and if it is denied, the process proceeds to step ST56.

(Decrease Mode) When DVw> G1 is denied in step ST53 or ST55, the correction circuit 63 selects the depressurization mode, and the ABS control circuit 64
Is instructed to perform pressure reduction control (step ST56). At this time, the correction circuit 63 specifically executes the processing from step ST61 to step ST65 of the subroutine shown in FIG.

The correction circuit 63 determines whether the road surface μ gradient K1 at the time of the start of the previous pressure reduction or the road surface μ gradient K1 ′ immediately before the start of the pressure reduction is equal to or larger than a predetermined value K11 (K1 or K1 ′ ≧ K11) (step ST61). ). The correction circuit 63 calculates (K1
or K1 '≧ K11), the pressure reduction time T1
Is reduced by a predetermined value T1_3 (step ST62). When the value of K1 or K1 'is large,
The wheel depressurization time is set short because there is room in the grip of the wheel and the wheel slip can be recovered by a slight decompression.

The correction circuit 63 sets (K) in step ST61.
When 1 or K1 ′ ≧ K11) is denied, or when the process of step ST62 is completed, whether K1 or K1 ′ is equal to or less than a predetermined value K12 (K1 or K1 ′ ≦ K12).
Is determined (step ST63). Correction circuit 6
3, when (K1 or K1 '≦ K12) is affirmed,
The decompression time T1 is corrected so as to be increased by a predetermined value T1_4 (step ST64). When the value of K1 or K1 'is small, there is no room in the grip of the wheel,
By extending the decompression time, the wheel grip is surely restored.

The correction circuit 63 sets (K) in step ST63.
When 1 or K1 ′ ≦ K12) is denied, or when the process of step ST64 is completed, the corrected decompression time T1 is supplied to the ABS control circuit 64. The ABS control circuit 64 outputs a signal of the corrected decompression time T1 to each solenoid SOL of the ABS hydraulic circuit 40 (step ST65). The correction circuit 63 completes the processing of step ST56 shown in FIG. 13 by performing the processing of steps ST61 to ST65.

(Pulse pressure reduction mode) When DVw> G2 is denied in step ST54 shown in FIG. 13, the correction circuit 63 selects the pulse pressure reduction mode and instructs the ABS control circuit 64 to perform pulse pressure reduction control. (Step ST
57). At this time, the correction circuit 63, specifically,
Steps ST71 to S of the subroutine shown in FIG.
The processing up to T75 is executed.

The correction circuit 63 determines whether the road surface μ gradient K1 at the start of the previous pressure reduction or the road surface μ gradient K1 ′ immediately before the start of pressure reduction is equal to or larger than a predetermined value K13 (K1 or K1 ′ ≧ K13) (step ST71). ). The correction circuit 63 calculates (K1
or K1 ′ ≧ K13), the pressure reduction duty ratio D1 is corrected so as to be reduced by a predetermined value D1_3 (step ST72). When the value of K1 or K1 'is large, there is room in the grip of the wheel, and the wheel slip is recovered by a slight pressure reduction. Therefore, the pressure reduction duty ratio D1 is reduced as shown in FIG. are doing.

The correction circuit 63 sets (K) in step ST71.
When 1 or K1 ′ ≧ K13) is denied, or when the process of step ST72 is completed, whether K1 or K1 ′ is equal to or smaller than a predetermined value K14 (K1 or K1 ′ ≦ K14).
Is determined (step ST73). Correction circuit 6
3, when (K1 or K1 '≦ K14) is affirmed,
The pressure reduction duty ratio D1 is corrected so as to be increased by a predetermined value D1_4 (step ST74). K1 or K1 '
When the value is small, there is no room in the grip of the wheel, and as shown in FIG. 17, the pressure reduction amount is increased by increasing the pressure reduction duty ratio D1, so that the wheel grip is surely recovered.

The correction circuit 63 sets (K) in step ST73.
When 1 or K1 ′ ≦ K14) is denied, or when the process of step ST74 is completed, the corrected decompression duty ratio D1 is supplied to the ABS control circuit 64. ABS
The control circuit 64 controls each solenoid S of the ABS hydraulic circuit 40.
A signal of the reduced pressure duty ratio D1 after correction is output to OL (step ST75). The correction circuit 63 completes the processing of step ST57 shown in FIG. 13 by performing the processing of steps ST71 to ST75.

(Pulse boost mode) The correction circuit 63 determines whether (S> S2) is denied in step ST51 shown in FIG. 13, or if (DVw> G2) is affirmed in step ST54, or step ST55. And (DVw> G
When affirmative in 1), the pulse pressure increasing mode is selected and A
A pulse pressure increase control is instructed to the BS control circuit 64 (step ST58). At this time, the correction circuit 63 is specifically configured as step ST81 of the subroutine shown in FIG.
From step ST87 to step ST87. Note that the following predetermined values K15, K16, and K17 are K
15>K16> K17.

The correction circuit 63 determines whether the road surface μ gradient K2 at the start of the previous pressure reduction or the road surface μ gradient K2 ′ immediately before the start of pressure reduction is equal to or larger than a predetermined value K15 (K2 or K2 ′ ≧ K15) (step ST81). ). The correction circuit 63 calculates (K2
or K2 ′ ≧ K15), the pressure increasing duty ratio D2 is corrected to be increased by a predetermined value D2_3 (step ST82). When the value of K2 or K2 'is large, for example, when at point A shown in FIG. 19, there is room in the grip of the wheel. Therefore, in order to utilize this grip, as shown in FIG.
By increasing 2, the pressure increase amount is increased so that the μ peak (point B) of the μ-S characteristic is quickly reached.

The correction circuit 63 sets (K) in step ST81.
When 2 or K2 ′ ≧ K15) is denied, or when the process of step ST82 ends, whether K2 or K2 ′ is equal to or smaller than a predetermined value K16 (K2 or K2 ′ ≦ K16).
Is determined (step ST83). Correction circuit 6
3, when (K2 or K2 '≦ K16) is affirmed,
The pressure increasing duty ratio D2 is corrected so as to be reduced by a predetermined value D2_4 (step ST84). K2 or K2 '
Is small, the wheel grip is approaching the limit (point B). Therefore, by reducing the pressure-increase duty ratio D2 to make the pressure-increase amount small, the state immediately before the μ peak of the μ-S characteristic is maintained, and the grip of the wheel is effectively used.

The correction circuit 63 sets (K) in step ST83.
When 2 or K2 ′ ≦ K16) is denied, or when the process of step ST84 ends, whether K2 or K2 ′ is equal to or less than a predetermined value K17 (K2 or K2 ′ ≦ K17).
Is determined (step ST85). Correction circuit 6
3, when (K2 or K2 '≦ K17) is affirmed,
The holding mode is set to hold the hydraulic pressure of the ABS hydraulic circuit 40 as it is (step ST86). In this case, since the μ peak has been reached, the state is maintained and the grip is used to the maximum.

The correction circuit 63 sets (K) in step ST85.
When 2 or K2 ′ ≦ K17) is denied, or when the process of step ST86 is completed, the corrected pressure-increase duty ratio D2 is supplied to the ABS control circuit 64. ABS
The control circuit 64 controls each solenoid S of the ABS hydraulic circuit 40.
A signal of the pressure-increase duty ratio D2 after correction is output to OL (step ST87). The correction circuit 63 completes the processing of step ST58 shown in FIG. 13 by performing the processing of steps ST81 to ST87.

When one of the processes from step ST56 to step ST58 shown in FIG. 13 is completed,
Is completed, and the process returns to step ST2 again.

As described above, the ABS control device 1
By estimating the road surface μ gradient at the time of S control and correcting the threshold value of the ABS control parameter, and always keeping the tire state on the μ peak of the μ-S characteristic, the grip of the tire can be utilized to the maximum. . At this time, the amount of brake fluid consumed during the ABS control can be further reduced, so that the pump amount can be reduced and a pumpless system can be realized.

Further, since the ABS control device 1 performs the ABS control by estimating the road surface gradient of the tire actually used, the responsiveness is higher than when the ABS control is performed according to the characteristics of a general tire. It can improve and stabilize the vehicle condition.

(Second Embodiment) Next, a second embodiment of the present invention will be described. Circuits, processes, and the like that are the same as those in the first embodiment are denoted by the same reference numerals, and detailed description is omitted.

In this embodiment, the ABS control device 1
As shown in FIG. 20, steps ST7 and ST8
During the period, the μ split / turn determination is performed (step ST
20). Here, specifically, step S shown in FIG.
A subroutine process from T91 to step ST95 is performed. This process may be performed during the ABS control or may be performed during the ABS control.

The correction circuit 63 of the ABS control device 1 calculates the road surface μ gradient KR of the right wheel estimated by the road surface gradient estimation circuit 62.
Is not less than a predetermined value K18 (KR ≧ K18), or
The road surface μ gradient KL of the left wheel is equal to or greater than a predetermined value K18 (KL ≧ K
18) is determined (step ST91). In the case of μ-split, a difference in the road μ gradient value between the left and right wheels occurs due to a decrease in the road μ gradient on the low μ side. Therefore, in order to determine whether the vehicle is in the turning state or the μ-split state in step ST91, the predetermined value K18 is preferably a value slightly larger than the μ-gradient of the road surface when traveling straight. And
When (KR ≧ K18 or KL ≧ K18) is affirmed, the process proceeds to step ST92, and when it is denied, the process proceeds to step ST94.

The correction circuit 63 determines whether the absolute value of the difference between KR and KL is equal to or greater than a predetermined value K20 (| KR−KL | ≧ K2
0) is determined (step ST92). If the result is affirmative, the turning control is performed (step ST93). If the result is negative, the subroutine is exited. Here, for example, when turning left, the load moves, and as shown in FIG. 22, the road surface μ gradient KR of the turning outer wheel (right wheel) increases, and the road surface μ gradient KL of the turning inner wheel (left wheel) decreases. As shown in FIG. 23, the road surface μ gradient of the turning outer wheel becomes larger and the road surface gradient of the turning inner wheel becomes smaller than the road surface μ gradient during straight running.

Therefore, when turning, that is, when a slip angle is given to the wheel, the wheel slip that generates the μ peak becomes large, so that the pressure reduction start slip threshold S1 and the pressure increase start slip threshold S2 are increased. By setting, the slip is increased during the ABS control, and correction is made so that deceleration can be obtained.

On the other hand, the correction circuit 63 determines in step ST91
If (KR ≧ K18 or KL ≧ K18) is denied, it is determined whether the absolute value of the difference between KR and KL is equal to or greater than a predetermined value K19 (| KR−KL | ≧ K19) (step S).
T94). When (| KR-KL | ≧ K19) is affirmed, μ split control is performed (step ST95), and when it is denied, the subroutine is exited.

In the μ split control, the pressure reduction start slip threshold S1 is set so that the wheel slip on the low μ side is not increased and the steering stability of the vehicle is not reduced.
And the pressure increase start slip threshold S2 is reduced.
Further, in order to execute the so-called yaw control so that the vehicle stability does not decrease due to the yaw moment caused by the left-right difference in the braking force, the time gradient of the pressure increase on the high μ road side is corrected as shown in FIG.

The difference in the road μ gradient between the right wheel and the left wheel indicates the difference in the braking force that can be generated on the road surface. Therefore,
The pressure increasing time gradient on the high μ road side is determined based on the difference of the road μ gradient. That is, when the difference between the road μ gradients of the left and right wheels is large, the pressure increase time gradient is reduced, and when the difference is small, the pressure increase time gradient is set large.

As described above, A according to the second embodiment
When the BS control device 1 detects a μ split or a turning state, the BS control device 1 reduces the difference between the road surface μ gradients of the left and right wheels,
Depressurization start slip threshold S1 and pressure increase start slip threshold S2
And the like can be corrected to improve the stabilization of the vehicle running state.

[0134]

The ABS control device according to the present invention provides a
The control parameters generated by the control parameter generating means are corrected based on the road μ gradient estimated by the gradient estimating means, and the control parameters are appropriately set by performing ABS control based on the corrected control parameters. As a result, control responsiveness and vehicle stability during ABS control can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a specific configuration of an ABS control device according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram showing a configuration of an ABS hydraulic circuit provided in the ABS control device.

FIG. 3 is a block diagram showing a functional configuration of the ABS control device.

FIG. 4 is a block diagram illustrating a configuration of a road surface gradient estimating circuit.

FIG. 5 is a flowchart of a main routine for explaining the operation of the ABS control device.

FIG. 6 is a flowchart illustrating the operation of initializing ABS control parameters.

FIG. 7 is a flowchart illustrating an operation content of parameter correction for control mode selection.

FIG. 8 is a diagram showing characteristics of a road surface μ with respect to a wheel slip speed.

FIG. 9 is a diagram showing characteristics of a road surface μ with respect to a wheel slip speed.

FIG. 10 is a diagram showing characteristics of a road surface μ with respect to a wheel slip speed.

FIG. 11 is a diagram showing characteristics of a road surface μ with respect to a wheel slip speed.

FIG. 12 is a flowchart illustrating another operation content of parameter correction for selecting a control mode.

FIG. 13 is a flowchart illustrating an operation content of a control mode selection process.

FIG. 14 is a flowchart illustrating an operation in a pressure reduction control mode.

FIG. 15 is a flowchart illustrating an operation in a pulse pressure reduction control mode.

FIG. 16 is a diagram for explaining reducing the pressure reduction duty ratio D1.

FIG. 17 is a diagram illustrating increasing the pressure reduction duty ratio D1.

FIG. 18 is a flowchart illustrating an operation content of a pulse pressure increase control mode.

FIG. 19 is a diagram illustrating the relationship between the characteristics of road surface μ with respect to wheel slip speed and the pressure increasing duty ratio D2.

FIG. 20 is a flowchart of another main routine for explaining the operation of the ABS control device.

FIG. 21 is a flowchart illustrating an operation content when performing μ split / turn determination.

FIG. 22 is a diagram illustrating characteristics of a road surface μ with respect to a wheel slip speed in a case of a high μ and a low μ.

FIG. 23 is a diagram illustrating characteristics of a road surface μ with respect to a wheel slip speed in a case of a high μ and a low μ.

FIG. 24 is a diagram for explaining correction of a pressure-increase time gradient when the brake fluid pressure is increased.

FIG. 25 is a diagram showing characteristics of a road surface μ with respect to a wheel slip speed.

[Explanation of symbols]

 Reference Signs List 10 wheel speed sensor 40 ABS hydraulic circuit 61 ABS control parameter generation circuit 62 road surface gradient estimation circuit 63 correction circuit 64 ABS control circuit

Continuation of the front page (71) Applicant 000004260 DENSO Corporation 1-1, Showa-cho, Kariya-shi, Aichi (72) Inventor Yoshiyuki Yasui 2-1-1, Asahi-cho, Kariya-shi, Aichi Aisin Seiki Co., Ltd. (72) Inventor Tsutsuharu Matsunaga 41-cho, Chuchu-shi Yokomichi, Nagakute-cho, Aichi-gun, Aichi Prefecture Inside Toyota Central Research Institute, Inc. (72) Inventor Kenji Asano 2-1-1 Asahimachi, Kariya-shi, Aichi Aisin Seiki Co., Ltd. 72) Inventor Hiroaki Yoshida 1 Toyota Town, Toyota City, Aichi Prefecture Inside Toyota Motor Corporation (72) Inventor Mamoru Sawada 1-1-1 Showacho, Kariya City, Aichi Prefecture F-term in DENSO Corporation (Reference) 3D046 BB23 BB28 CC02 HH02 HH36 HH46 JJ02 JJ14 JJ19 JJ21 KK06 LL02 LL47 LL50

Claims (16)

[Claims] 1. A road surface detecting means for detecting a wheel speed of a wheel, and a road surface estimating a road surface μ gradient which is a gradient of a road surface μ with respect to a wheel slip speed based on the wheel speed detected by the wheel speed detecting device. μ gradient estimating means, control parameter generating means for generating control parameters for ABS control, and control parameters generated by the control parameter generating means based on the road μ gradient estimated by the road μ gradient estimating means. An ABS control apparatus comprising: a control parameter correction unit for correcting; and an ABS control unit for performing ABS control based on the control parameter corrected by the control parameter correction unit. 2. The control parameter correction means according to claim 1, wherein
If the road μ gradient estimated by the road μ gradient estimating means is larger than the first predetermined value when the brake hydraulic pressure is increased, the control parameter is corrected so as to increase the amount of increase in the ABS brake hydraulic pressure. The ABS control device according to claim 1, wherein 3. The control parameter correction means includes:
If the road μ gradient estimated by the road μ gradient estimating means is smaller than the second predetermined value when the brake hydraulic pressure is increased, the control parameter is corrected so as to reduce the amount of increase in the ABS brake hydraulic pressure. The ABS control device according to claim 1 or 2, wherein 4. The control parameter correcting means further comprises: a control parameter for maintaining an ABS braking hydraulic pressure when the road μ gradient estimated by the road μ gradient estimating means is smaller than a third predetermined value. A according to claim 3 for correcting.
BS control device. 5. The control parameter correction unit according to claim 1, wherein:
If the road μ gradient at the start of depressurization estimated by the road μ gradient estimating means is larger than a predetermined value during the depressurization of the brake hydraulic pressure, the pressure reduction time of the ABS brake hydraulic pressure is reduced or the pressure reduction time is shortened. The ABS control device according to claim 1, wherein the control parameter is corrected so as to perform the control. 6. The control parameter correction means includes:
If the road μ gradient at the start of depressurization estimated by the road μ gradient estimating means is smaller than a predetermined value during the depressurization of the brake hydraulic pressure, the amount of depressurization of the ABS brake hydraulic is increased or the decompression time is lengthened. The ABS control device according to claim 1, wherein the control parameter is corrected so as to perform the control. 7. The control parameter correcting unit corrects a slip threshold indicating the start of depressurization of the ABS brake hydraulic pressure based on the road surface μ gradient at the start of pressure reduction estimated by the road surface μ gradient estimating unit. ABS control device. 8. The control parameter correcting means increases the slip threshold value indicating the start of depressurization of the ABS brake hydraulic pressure when the road μ gradient at the start of pressure reduction estimated by the road μ gradient estimating means is larger than a predetermined value. Claim 7
The ABS control device as described in the above. 9. The control parameter correction means, when the road μ gradient at the start of pressure reduction estimated by the road μ gradient estimation means is smaller than a predetermined value, reduces the slip threshold indicating the start of pressure reduction of the ABS brake hydraulic pressure. Claim 7
The ABS control device as described in the above. 10. The control parameter correction unit according to claim 1, wherein
10. The slip threshold value indicating the start of pressure reduction of the S brake hydraulic pressure is corrected, and the slip threshold value indicating the start of pressure increase of the ABS brake hydraulic pressure is corrected according to the correction amount. ABS control device. 11. The control parameter correcting means corrects a slip threshold value indicating the start of increasing the ABS brake hydraulic pressure based on the road μ gradient at the start of pressure increase estimated by the road μ gradient estimating means. 2. The ABS control device according to 1. 12. The control parameter correction means sets a slip threshold value indicating the start of pressure increase of the ABS brake hydraulic pressure when the road surface μ gradient at the start of pressure increase estimated by the road surface μ gradient estimation means is larger than a predetermined value. The ABS control device according to claim 11, wherein the correction is performed to increase the value. 13. The control parameter correcting means sets a slip threshold value indicating the start of pressure increase of the ABS braking hydraulic pressure when the road surface μ gradient at the start of pressure increase estimated by the road surface μ gradient estimating means is smaller than a predetermined value. The ABS control device according to claim 11, wherein the correction is performed so as to reduce the value. 14. The control parameter correcting means, wherein AB
14. The slip threshold value indicating the start of pressure increase of the S brake fluid pressure is corrected, and the slip threshold value indicating the start of pressure decrease of the ABS brake fluid pressure is corrected according to the correction amount.
The ABS control device according to any one of claims 1 to 4. 15. The control parameter correction unit corrects the control parameter generated by the control parameter generation unit based on the road μ gradient before the start of the ABS control estimated by the road μ gradient estimation unit. AB described in 1
S control device. 16. The control parameter correcting means increases and / or increases the pressure reduction amount of the ABS brake hydraulic pressure when the road surface μ gradient estimated by the road surface gradient estimating means before the ABS control is started is smaller than a predetermined value. The pressure increase amount is reduced and the AB
When the road surface μ gradient before the start of the S control is larger than a predetermined value,
16. The ABS control device according to claim 15, wherein the pressure reduction amount of the ABS brake hydraulic pressure is reduced and / or the pressure increase amount is increased.