JPH10152037A - Antiskid controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide ABS brake of high reliability, by determining the body deceleration estimate value to be low when the pressure is low and the wheel deceleration is high, and to be high when the pressure is high and the wheel deceleration is low, corresponding to the detected generated brake pressure and the deceleration of the wheel. SOLUTION: A hydraulic control unit 2 gives the braking pressure to hydraulic passages of the wheel cylinders 51-54 of the wheels FR, FL, RR, RL by the driving of a brake pedal 3. The wheel speed sensors 41-44 of the wheels FR, FL, RR, RL respectively input the wheel speed signals of the wheels to an electronic controlling device 10. A pressure sensor 2s of a master cylinder 2a gives a pressure detecting signal to the electronic controlling device 10, and a brake switch 3s of the brake pedal 3 gives the with or without of pedalling, to the same 10. Then the deceleration of the maximum wheel speed is read out from a register, and is writen in a frictional coefficient register by each area data of the brake pressure and the deceleration, to control a pressure reducing speed, thereby the control can be finely performed corresponding to the various properties.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wheel for avoiding a complete stop (wheel lock) of wheel rotation during braking by a driver in order to ensure running stability and steering performance of a vehicle body. Anti-skid control (ABS control) in which the brake pressure is reduced, then increased so that the braking distance becomes as short as possible, and then reduced and increased as necessary.
About.

[0002]

2. Description of the Related Art The ABS control initially controls the wheel brake pressure of the rear two wheels of the front, rear, left and right four wheels, but recently, the ABS control is intended to improve the ABS control effect. Some control the brake pressure of each of the four wheel brakes. The slip rates of all four wheels are estimated and calculated based on the wheel speeds and the estimated vehicle body speeds (reference speeds) of the respective wheels, and the wheel brakes are depressurized so that the slip rates of the wheels become the target slip rates. In the ABS control for increasing the pressure, the slip ratio calculation error due to the difference between the inner and outer wheel speeds during the turning of the vehicle is small, so that the slip ratio control accuracy of each wheel is high and the ABS is high.
An S control effect is obtained. Such an ABS control device includes:
For example, it is described in JP-A-3-159854. In this ABS control device, the reduction rate in the calculation of a certain wheel portion estimated vehicle speed is determined in accordance with the reduction rate of another wheel portion estimated vehicle speed.

[0003]

However, in a four-wheel drive vehicle (4WD vehicle), the wheel rotational speed may drop at the same time due to wheel deceleration slip (lock inclination) due to wheel braking on a road surface with a low friction coefficient. . In the ABS control, when braking, for example, the highest speed among the rotational speeds (peripheral speeds) of the wheels is assumed to be close to the vehicle speed, and the vehicle speed is estimated and calculated based on the speed.
Since the wheel rotational speeds of all four wheels are values far apart from the actual vehicle speed, it is difficult to estimate the wheel speeds. Therefore, a vehicle is provided with an acceleration sensor (G sensor) to detect a vehicle body acceleration (including a deceleration), and integrates this to estimate a vehicle body speed. However, acceleration sensors are expensive.

The first object of the present invention is to realize highly reliable ABS control even when there is a simultaneous drop in the wheel speeds of a plurality of wheels due to wheel braking. It is a second object to realize it.

[0005]

[Means for Solving the Problems]

(1) A first aspect of the present invention is a brake pressure generating means (2) for applying a brake fluid pressure corresponding to a driver's operation force to wheel brakes (51 to 54), and wheel rotation. Wheel speed detecting means (41-44, 11) for detecting the speed (VWO), and vehicle speed calculating means (1) for calculating the vehicle speed (VSO) based on the estimated vehicle deceleration (αDN)
1) and brake pressure control means (11, 18a to 18i, 31 to 38) for reducing and increasing the wheel brake pressure based on the wheel rotational speed (VWO) and the vehicle speed (VSO). The anti-skid control device provided with the brake pressure generating means (2)
Pressure detecting means (2s) for detecting pressure generated by the vehicle; deceleration detecting means (11) for detecting wheel deceleration; and, corresponding to the pressure and wheel deceleration, low pressure and large wheel deceleration The vehicle body deceleration setting means (11) for determining the vehicle body deceleration estimated value (αDN) to a small value when the pressure is high and the wheel deceleration is small when the wheel deceleration is small (FIG. 1).
7). In addition, in the parentheses, for easy understanding, symbols attached to corresponding elements or corresponding items of the embodiment shown in the drawings are shown for reference.

According to this, when the brake pressure corresponding to the driver's operation force is low and the wheel deceleration is large, that is, when the friction coefficient μ of the road surface is estimated to be low, the vehicle deceleration setting means (11) ) Reduces the estimated vehicle deceleration (αDN) to a small value (0.4G)
Set forth in As a result, since the deceleration of the vehicle speed (VSO) calculated by the vehicle speed calculation means (11) is small and the wheel deceleration is large, the deviation of the wheel rotation speed from the vehicle speed (VSO) becomes large (the wheel slip ratio becomes small). And the brake pressure control means (11, 18a to 18i, 31 to 38) reduces the wheel brake pressure, thereby suppressing an excessive slip (deceleration slip) of the wheel.

To obtain the vehicle body deceleration, the pressure generated by the brake pressure generating means (2) and the wheel deceleration are used. The wheel deceleration can be calculated based on the wheel speed. It is not necessary to add a hardware element to the. The pressure generated by the brake pressure generating means (2) is detected by the pressure detecting means (2s).
Therefore, it is necessary to provide a pressure detecting means (2s). However, some vehicles already have pressure detecting means, in which case it is not necessary to add a new pressure detecting means for implementing the present invention.

(2) A second aspect of the present invention is a brake pressure generating means (2) for applying a brake fluid pressure according to the driver's operation force to the wheel brakes (51 to 54). Wheel speed detecting means (41-44, 11) for detecting wheel rotational speed (VWO), vehicle speed calculating means (11) for calculating vehicle speed (VSO) based on estimated vehicle deceleration (αDN), and Anti-skid control including brake pressure control means (11, 18a to 18i, 31 to 38) for reducing and increasing wheel brake pressure based on the wheel rotation speed (VWO) and the vehicle speed (VSO) In the apparatus, an operator (3) of the brake pressure generating means (2) for applying an operating force by a driver.
Operation amount detection means (3p) for detecting the operation amount of the vehicle; deceleration detection means (11) for detecting the deceleration of the wheel; and, corresponding to the operation amount and the wheel deceleration, the operation amount is small and the wheel deceleration is small. The vehicle body deceleration setting means (11) for determining the vehicle body deceleration estimated value is set to a small value when the operation amount is large, and to a large value when the operation amount is large and the wheel deceleration is small.
8).

According to this, when the operation amount of the driver is small and the wheel deceleration is large, that is, when it is estimated that the friction coefficient μ of the road surface is low, the vehicle deceleration setting means (11) sets the vehicle deceleration estimation The value (αDN) is set to a small value (0.4G). As a result, the deceleration of the vehicle speed (VSO) calculated by the vehicle speed calculating means (11) is small and the wheel deceleration is large, so that the vehicle speed (V
SO), the deviation of the wheel rotational speed with respect to (SO) increases (the wheel slip ratio increases), and the brake pressure control means (11, 18a to 18i, 31)
38) reduce the wheel brake pressure, thereby suppressing excessive slip (deceleration slip) of the wheel.

In order to obtain the vehicle body deceleration, the amount of operation of the driver with respect to the brake pressure generating means (2) and the wheel deceleration are used. The wheel deceleration can be calculated based on the wheel speed. There is no need to add hardware elements for this. The operation amount of the brake pressure generation means (2) is detected by the operation amount detection means.
Since the detection is performed in (3p), it is necessary to equip the operation amount detection means (3p). However, some vehicles already have an operation amount detecting means (stroke sensor). In that case, it is not necessary to add a new operation amount detecting means for implementing the present invention.

Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION

[0013]

【Example】

-First Embodiment- Fig. 1 shows a first embodiment of the present invention. Hydraulic pressure control device 2
Consists of a master cylinder 2a and a booster 2b, and when driven by the brake pedal 3, the wheels FR, FL,
Wheel cylinders 51 to 54 disposed on RR and RL
Applies a brake pressure to the hydraulic pressure path connected to. The pumps 21 and 22, the reservoirs 23 and 24, and the solenoid valves 31 to 38 are connected or inserted into the hydraulic path. In addition, wheel FR
Indicates wheels on the front right side as viewed from the driver's seat, and hereinafter wheels FL
Indicates a front left wheel, a wheel RR indicates a rear right wheel, and a wheel RL indicates a rear left wheel. As is apparent from FIG. 1, a so-called diagonal pipe is formed.

Solenoid valves 31, 32 and solenoid valves 33, 34 are interposed in a hydraulic passage connecting one output port of the master cylinder 2a and each of the wheel cylinders 51, 54, respectively. A pump 21 is interposed therebetween. Similarly, solenoid valves 35 and 36 and solenoid valves 37 and 3 are connected to hydraulic paths connecting the other output port of master cylinder 2a and wheel cylinders 52 and 53, respectively.
8 are interposed, and a pump 22 is interposed between them and the master cylinder 2a. The pumps 21 and 22 are driven by the electric motor 20, and a brake fluid having a predetermined pressure is supplied to these hydraulic paths. Thus, these hydraulic pressure paths are on the supply side of the brake hydraulic pressure to the normally open solenoid valves 31, 33, 35, 37. The discharge-side hydraulic pressure paths of the normally closed solenoid valves 32 and 34 are connected to the pump 21 via the reservoir 23, and the discharge-side hydraulic pressure paths of the normally closed solenoid valves 36 and 38 are connected to the pump 22 via the reservoir 24. It is connected. The reservoirs 23 and 24 are provided with pistons and springs, respectively, and store the brake fluid that is recirculated from the solenoid valves 32, 34, 36 and 38 via the discharge-side hydraulic pressure passage, and store the brake fluid when the pumps 21 and 22 operate. It supplies brake fluid. Solenoid valves 31 to 38 are 2 port 2
When the solenoid coil is not energized, each of the wheel cylinders 51 to 54 is located at the first position shown in FIG.
Communicates with 2. When the solenoid coil is energized, it becomes the second position, and the wheel cylinders 51 to 54 are cut off from the hydraulic pressure control device 2 and the pumps 21 and 22, and communicate with the reservoir 23 or 24. The check valve in FIG. 1 allows the flow from the wheel cylinders 51 to 54 and the reservoirs 23 and 24 to the hydraulic pressure control device 2 side, and shuts off the flow in the reverse direction.

By controlling the energization and non-energization of the solenoid coils of the solenoid valves 31 to 38, the brake fluid pressure in the wheel cylinders 51 to 54 (hereinafter referred to as wheel cylinder fluid pressure) is increased or decreased. be able to. That is, when the solenoid coils of the solenoid valves 31 to 38 are not energized, the hydraulic pressure control device 2 is connected to the wheel cylinders 51 to 54.
In addition, the brake fluid pressure is supplied from the pump 21 or 22 to increase the pressure. When the brake fluid pressure is applied, the brake fluid communicates with the reservoir 23 or 24 to reduce the pressure. It should be noted that half of the 3-port 2-position electromagnetic switching valves may be used instead of the electromagnetic valves 31 to 38.

The solenoid valves 31 to 38 are provided in the electronic control unit 1
0, energize each solenoid coil,
De-energization is controlled. The motor 20 is also connected to the electronic control unit 10 and is driven and controlled thereby. Wheel F
R, FL, RR, RL have wheel speed sensors 41 to 4, respectively.
4 are connected to the electronic control unit 10, and the rotation speed of each wheel, that is, a wheel speed signal is input to the electronic control unit 10. The wheel speed sensors 41 to 44 are well-known electromagnetic induction type sensors including a toothed rotor that rotates with the rotation of each wheel and a pickup provided to face the tooth portion of the rotor.
It outputs a pulse voltage having a frequency proportional to the rotation speed of each wheel. Note that a Hall IC, an optical sensor, or the like may be used instead.

The master cylinder 2a is provided with a pressure sensor 2s for detecting the pressure at its output port, which provides a detection signal indicating the pressure to the electronic control unit 10.
Further, there is a brake switch 3 s for detecting depression of the brake pedal 3, which gives a detection signal indicating whether the brake pedal 3 is depressed to the electronic control unit 10.

As shown in FIG. 2, the electronic control unit 10 comprises:
A microcomputer 1 having a CPU 14, a ROM 15, a RAM 16, and the like, connected to an input port 12 and an output port 13 via a common bus and performing input / output with the outside.
1 is provided. The detection signals of the wheel speed sensors 41 to 44, the pressure sensor 2s, and the brake switch 3s are as follows.
The signals are input from the input port 12 to the CPU 14 via the amplifier circuits 17a to 17f. Further, a motor drive signal is applied from the output port 13 to the drive circuit 18a, and the drive circuit 1
8a energizes the motor 20. That is, the motor 20 is driven to rotate. Each of the drive circuits 18b to 18i has a solenoid valve 3
1 to 38 control signals are output.

In the electronic control unit 10, a series of processes for anti-skid control are performed by the computer 11, which will be described below with reference to FIGS.

FIG. 3 shows an outline of anti-skid control by the computer 11, and FIGS. The anti-skid control shown in FIG.
5) is repeatedly executed at a substantially constant cycle Ts. When the ignition switch is turned on, initial settings are made in step 1 as a preliminary process in FIG. 3, and counters, timers, and the like are cleared. Further, an interrupt process executed for each pulse of the pulse voltage generated by the wheel speed sensors 41 to 44 is permitted. For example, wheel speed sensor 41
Generates one pulse, the CPU 14 of the computer 11
Responds to this, executes an interrupt process, writes a clock pulse (clock pulse) count value in a pulse cycle register addressed to the front right wheel FR, and clears the clock pulse counter. The timer pulse counter always counts up the clock pulse while the interrupt processing is permitted. Therefore, the pulse cycle register addressed to the front right wheel FR stores the latest one of the pulse voltages generated by the wheel speed sensor 41 in the register. The cycle (reciprocal of the wheel speed) is always maintained. The CPU also controls the voltage pulses generated by the wheel speed sensors 42 to 44.
14 performs the same processing, so that after the interruption processing is permitted, the latest one-cycle data of the voltage pulse generated by the wheel speed sensors 41 to 44 is always maintained in each pulse cycle register. . In the "calculation of each wheel speed" (step 4) described later, the CPU 14 calculates the wheel speed by multiplying the reciprocal of the data of the pulse cycle register by a coefficient (cycle / speed conversion coefficient).

Here, a counter, a timer, and the like used in the present embodiment will be generally described. First, a mode register and a flag register are provided as internal registers, and at least the following control modes are set in the former. That is, in addition to the pressure reducing mode, the pressure increasing mode, or the holding mode in which the brake fluid pressure in the wheel cylinders 51 to 54 is reduced, increased, or held, respectively, the pulse pressure increasing mode,
The pulse pressure reduction mode and the rapid reduction mode are set. The pulse depressurization mode is a mode in which “depressurization” is performed for a predetermined time appropriately set as described later, “hold” is performed for the next predetermined time, and “depressurization” and “hold” are alternately and repeatedly performed. Similarly, the pressure mode is a mode in which “pressure increase” and “holding” are alternately and repeatedly performed.

In the rapid decrease mode, only "decompression" is performed, and a rapid decrease operation is performed as compared with the operation in the pulse decompression mode. The flag has at least a rapid decrease flag and a pulse pressure increase flag. When the rapid decrease flag is set ("1"), the mode is the rapid decrease mode, and when the pulse pressure increase flag is set, the mode is the pulse pressure increase mode. The counter includes at least a pulse pressure increasing counter, and the pulse pressure increasing counter counts the number of times the pulse pressure increasing is performed. The timer includes at least a pressure reducing timer, a pressure increasing timer, and a holding timer in addition to the system timer. Is output.

Referring again to FIG. 3, when the initial setting is completed in step 1, the process from step 2 to step 15 is performed, and then the process returns to step 2. In step 2, T
Start the timer for the s period. In step 3, the detection signal (detection pressure Pb) of the pressure sensor 2s is converted into digital data Pb.
And write it into the input register,
The s detection signal (ON: pedal depressed / OFF: no depressed) is written into the input register, and the above-described pulse cycle register (4 addressed to FR, addressed to FL, addressed to RR & addressed to RL) is written.
) Is read and written to the input register. In step 4, the wheel speeds (peripheral speeds) VWFL, VWFR, VWRR and VWRL of each of the wheels FL, FR, RL and RR are calculated and written in the wheel speed registers. Wheel deceleration D
VWFL, DVWFR, DVWRR and DVWRL (positive value is deceleration, negative value is acceleration) are calculated and written to the wheel deceleration register. Then, in step 6, the road surface friction coefficient μ is estimated.

FIG. 4 shows the contents of the "estimation of road friction coefficient μ" (step 6). Here, the CPU 14 first checks whether the brake pressure Pb read in step 3 is in a low area, a middle area, or a high area, and generates data indicating which area the brake pressure Pb belongs to (step S3). Step 21). next,
The deceleration of the maximum wheel speed is read from the wheel deceleration register, and it is checked whether the deceleration is in a small area, a medium area, or a large area, and data indicating which area the deceleration belongs to is determined. Generate it (step 22). And the blaze
Based on the brake pressure area data and the deceleration area data, the brake pressure is low and the deceleration is small, the brake pressure is during and the deceleration, or the brake pressure is high and the deceleration is large. In the case of, the road surface friction coefficient μ is estimated to be in the middle region; otherwise, the road surface friction coefficient μ is estimated to be in the low region when the brake pressure is low or medium & deceleration is large or medium; The coefficient μ is estimated to be a high area, and data indicating the estimated area is written in the friction coefficient register (steps 23 to 27).

Referring again to FIG. Next, the CPU 14
"Estimated vehicle speed calculation" (step 7)
(n) is calculated. Note that n of VSO (n) means the current calculated value, and n-1 appearing later means the calculated value of the previous time (before Ts).

FIG. 5 shows the contents of the "estimated vehicle speed calculation" (step 7). Here, first, corresponding to the estimated road surface friction coefficient μ (high region, middle region or low region), the vehicle body deceleration αDN is determined to be 1.1G if the region is a high region, and is set to 0.1G if the region is a medium region. 6G, and 0.
4G is determined (steps 31 to 35). Then, the vehicle body acceleration αUP is set to 0.5 G (step 36). Next, the highest wheel speed among the wheel speeds VWFL, VWFR, VWRR, VWRL is selected, and the current vehicle speed VWO (n-1) estimated from the previous calculated value VWO (n-1) and the deceleration αDN. −αDN · Ts, and the current vehicle speed VWO (n−1) + αUP · Ts estimated from the previous calculated value VWO (n−1) and the acceleration αUP is calculated, and the intermediate value (average) ) Is calculated and set as the current vehicle speed VWO (n) (step 37).

Next, the CPU 14 calculates an estimated vehicle speed of each wheel section (step 8). The contents are shown in FIG. Here, the current value VWFR (n) of the front right wheel speed, the previous value VWFR
From (n-1), the deceleration amount αDN · T during Ts at the deceleration αDN
The value of VWFR (n-1) −αDN · Ts obtained by subtracting s and the previous value VWFR (n−1) are added to the speed increase amount αUP during Ts at the acceleration αUP.
Calculates the intermediate value of the three values, VWFR (n-1) + αUP · Ts, to which Ts has been added, and calculates the estimated vehicle speed VSOFR as the front right wheel portion.
(n) (step 41). Similarly, the front left wheel portion estimated vehicle speed VSOFL (n), the present value VWRR (n) of the rear right wheel speed, and the rear left wheel portion estimated vehicle speed VSORL (n) are calculated (steps 42 to 44).

Referring again to FIG. 3, the CPU 14 next calculates "front left wheel FL control calculation" (step 9FL), "front right wheel FR control calculation" (9FR), "rear left wheel FL control calculation" (9RL) and "Rear right wheel FR control calculation" (9R
R). Since these contents are substantially the same except that the target wheels are different, representatively, "the left front wheel F
The contents of “L control calculation” (9FL) will be described with reference to FIG.

In FIG. 7, the estimated vehicle speed VSOFL (n)
[Hereinafter referred to as VSOFL] is the minimum speed of control start (4km / h)
Is determined (step 51), and if not, the wheel slip ratio Sp is set to 0 (step 52). If the estimated vehicle speed VSOFL exceeds the minimum speed, a wheel step rate Sp is calculated from the estimated vehicle speed VSOFL and the wheel speed VWFL (step 53).

Then, the estimated vehicle speed VSFL and the wheel speed VWFL
Is calculated (step 5).
4). Next, it is checked whether or not the motor 20 is off, that is, whether or not the control is being performed (step 55). For example, when the motor 20 is off as in the initial state, it is checked whether the conditions of steps 56 and 57 are satisfied.
That is, first, the estimated vehicle speed VSOFL is equal to the predetermined speed 10 km / h.
Is checked (56), and if it is 10 km / h or less, the process exits from "front left wheel FL control calculation" (9FL).

If the speed exceeds 10 km / h, it is checked whether or not the condition of step 57 is satisfied. If the condition is not satisfied, the process exits from "front left wheel FL control calculation" (9FL). Turns on the motor 20 if it is sufficient (energization: drive the pumps 21 and 22)
To “K3 · VSOFL-K4” in step 57
Represents an anti-skid control start determination reference speed for the wheel FL of the wheel speed VWFL, and K3 and K4 are constants.
In this embodiment, K3 is 0.95 and K4 is 2.0 km.
Although / h is set, various values can be set for these constants according to the characteristics of the vehicle and the like.

Next, the wheel lock degree Lk indicating the wheel lock state is calculated based on the following equation (1) (step 5).
9). Lk = (C · Sp + D · ΔVWFL) / (C + D) (1) where C and D are constants, and the slip ratio S
p and the wheel speed deviation ΔVWFL are weighted. In general, when the weight on the slip ratio Sp is increased, excessive pressure reduction is likely to occur in the low speed range, and when the weight on the wheel speed deviation ΔVWFL side is increased, excessive pressure reduction is likely in the high speed region.

At step 60, the data map (Lk and Dk)
Pulse pressure increasing mode, pressure decreasing mode with Vw as a parameter
Data table in which the data of the increase, decompression time and holding time in which the Lk and DVw are the parameters in the pulse increase and decompression sections are written. Area), the pressure reduction time and the holding time of the wheel cylinder fluid pressure are determined based on the time distribution in any of the pulse pressure reduction mode or the pulse pressure increase mode selected according to the wheel lock degree Lk and the wheel acceleration DVWFL. And the distribution of pressure increase time and holding time. Also, when the area corresponds to the rapid decrease mode area on the map, the rapid decrease flag is set ("1").

The pulse pressure reduction mode is a control mode in which the pressure reduction operation and the holding operation with respect to the wheel cylinder hydraulic pressure are alternately repeated, and the drive of the solenoid valves 31 to 38 is controlled according to the pressure reduction time and the holding time. The cylinder hydraulic pressure is reduced. Therefore, the pressure reduction speed is controlled according to the ratio between the pressure reduction time and the holding time. Similarly, in the pulse pressure increasing mode, the solenoid valves 31 to 3 are set according to the pressure increasing time and the holding time.
8 is drive-controlled. The pressure reduction time, the pressure increase time, and the holding time are measured by a pressure reduction timer, a pressure increase timer, and a holding timer.

The time distribution between the pressure reduction time and the holding time in the pulse pressure reduction mode will be described. Wheel acceleration DV
Since WFL indicates excess or insufficient wheel cylinder hydraulic pressure, the distribution of the pressure reduction time and the holding time is set so that when the wheel acceleration DVWFL decreases, that is, when the deceleration increases, the reduction amount of the wheel cylinder hydraulic pressure increases. Have been. That is, the pressure reduction time is set to be long and the holding time is set to be short. In addition, when the wheel lock degree Lk is large, it is determined that the vehicle is traveling on a road surface having a lower friction coefficient, and the pressure reduction speed when the wheel cylinder hydraulic pressure is reduced from a relatively low pressure is reduced. The distribution of the pressure reduction time and the holding time is set so that the pressure reduction amount is increased.

On the other hand, in the pulse pressure increasing mode, even if the wheel lock degree Lk is large, the wheel acceleration DVWF
When L is large, the time distribution between the pressure increasing time and the holding time is set so that the pressure increase amount of the wheel cylinder hydraulic pressure is increased, and the extension of the braking distance due to insufficient wheel cylinder hydraulic pressure is suppressed. Then, when the wheels show a tendency to lock after the wheel lock degree Lk becomes small, the wheel cylinder hydraulic pressure is set to be gently increased, and a sharp decrease in the wheel speed VWFL is prevented. I have.

As described above, by appropriately setting the time distribution between the pressure reducing time and the holding time in the pulse pressure reducing mode and the time distribution between the pressure increasing time and the holding time in the pulse pressure increasing mode, the response of the solenoid valves 31 to 38 can be improved. Fine control according to various characteristics at the time of vehicle braking, such as performance, pressure reduction speed, or pressure increase speed, can be performed.

Referring back to FIG. 9FL each wheel control calculation
9RR, the CPU 14 checks whether or not the brake switch 2s is ON (the brake pedal is depressed) (10). If the brake switch 2s is ON, the wheel control calculation 9FL is performed.
On / off instructions are output to the motor driver and the solenoid drivers 18a to 18i in accordance with the calculation results of RR to 9RR (step 11).

When the brake switch 2s is off, the motor driver and the solenoid drivers 18a to 18i
Output an OFF instruction to clear the holding timer, the pressure reduction timer, and the pressure increase timer.
The pulse pressure increase flag and the rapid pressure decrease flag are cleared (step 12).

Then, it is checked whether the timer Ts has timed out (step 13), and an abnormality check is performed until the time is over.
Return to step 2. When an abnormality is detected, the brake pressure control is released and an alarm is generated (steps 14 to 1).
6).

Second Embodiment FIG. 8 shows a second embodiment. In the second embodiment, a potentiometer 3p is used as a depression stroke sensor of the brake pedal 3 instead of the pressure sensor 2s.
The potentiometer 3p is connected to a rotation shaft fixed to the brake pedal 3, and generates an angle signal indicating a rotation angle when the brake pedal 3 is depressed. Other hardware configurations of the second embodiment are the same as those of the first embodiment shown in FIGS. CPU 14 of the second embodiment
Is the same as that of the first embodiment shown in FIGS. However, "reading of brake pressure" in step 3 of FIG. 3 means "reading of angle signal of potentiometer 3p".
Step 21 in FIG. 4 includes "three-valued detection angle of potentiometer 3p to low, medium, and high", and steps 23 and 2
The brake pressure of 5 is read as "detection angle". Other parts are the same as in the first embodiment.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a first exemplary embodiment of the present invention.

FIG. 2 is a block diagram showing a schematic configuration of an electronic control device 10 shown in FIG.

FIG. 3 is a flowchart showing an outline of anti-skid control of a microcomputer 11 shown in FIG. 2;

FIG. 4 is a flowchart showing the content of “calculation of road surface friction coefficient μ” (step 6) shown in FIG. 3;

FIG. 5 is a flowchart showing the content of “calculation of estimated vehicle speed” (step 7) shown in FIG. 3;

FIG. 6 is a flowchart showing the contents of “calculation of estimated vehicle speed of each wheel section” (step 8) shown in FIG. 3;

FIG. 7 is a flowchart showing a part of the content of “front left wheel FL control calculation” (step 9FL) shown in FIG. 3;

FIG. 8 is a block diagram illustrating a configuration of a second exemplary embodiment of the present invention.

[Description of Signs] 2: Hydraulic pressure controller 2a: Master cylinder 2b: Booster 2s: Pressure sensor 3: Brake pedal 3s Brake switch 3p: Potentiometer 10: Electronic controller 11: Microcomputer 12: input port 13: output port 14: CPU 15: ROM 16: RAM 17a to 17f: amplifier circuit 18a to 18i: driver 20: electric motor 21, 22: pump 23, 24: reservoir 31 to 38: solenoid valve 41 to 44: wheel speed sensor 51 to 54: wheel cylinder FR: front right wheel FL: front left wheel RR: rear right wheel RL: rear left wheel

Claims (2)

[Claims] A brake pressure generating means for applying a brake fluid pressure corresponding to a driver's operation force to a wheel brake; a wheel speed detecting means for detecting a wheel rotation speed; An anti-skid comprising: a vehicle speed calculating means for calculating a vehicle speed from an estimated vehicle deceleration value; and a brake pressure control means for reducing and increasing the wheel brake pressure based on the wheel rotational speed and the vehicle speed. In the control device, a pressure detecting means for detecting a pressure generated by the brake pressure generating means; a deceleration detecting means for detecting a wheel deceleration; and a pressure low corresponding to the pressure and the wheel deceleration. A vehicle deceleration setting means for setting the vehicle deceleration estimated value to a small value when the wheel deceleration is large and to a large value when the pressure is high and the wheel deceleration is small. 2. A brake pressure generating means for applying a brake fluid pressure corresponding to a driver's operating force to a wheel brake, a wheel speed detecting means for detecting a wheel rotation speed, An anti-skid comprising: a vehicle speed calculating means for calculating a vehicle speed from an estimated vehicle deceleration value; and a brake pressure control means for reducing and increasing the wheel brake pressure based on the wheel rotational speed and the vehicle speed. In the control device, an operation amount detection means for detecting an operation amount of an operation element for applying an operation force by a driver of the brake pressure generation means; a deceleration detection means for detecting wheel deceleration; Corresponding to the operation amount and the wheel deceleration, the vehicle deceleration that determines the estimated vehicle body deceleration value becomes a small value when the operation amount is small and the wheel deceleration is large, and a large value when the operation amount is large and the wheel deceleration is small. Setting means; Anti-skid control apparatus characterized by obtaining.