JP3380428B2 - Anti-lock brake control device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle in which wheels are driven by a power unit such as an engine via a torque transmission member that includes a wheel drive shaft and is subjected to a short braking while maintaining high braking stability. The present invention relates to an antilock brake control device capable of controlling a braking force of wheels so that a stopping distance can be obtained.

[0002]

2. Description of the Related Art Generally, in an anti-lock brake control device, a wheel locking tendency is detected based on a comparison between a wheel speed and an estimated vehicle speed, a deceleration of the wheel, etc., and a braking fluid pressure is adjusted accordingly. As a result, the skid of the wheel is maintained in the vicinity of the region where the friction between the wheel and the road surface reaches a peak, the braking distance is shortened, and the stability of the vehicle body and the steering stability are improved. For example, in this type of device, when the wheel behavior such as slip or wheel acceleration, which is the amount of sinking of the wheel speed with respect to the estimated vehicle speed, reaches a predetermined threshold value, it is determined that the wheel is in a lock tendency, and braking is performed. A judgment is made to reduce the hydraulic pressure, and the braking hydraulic pressure is adjusted to be reduced.

Since the braking fluid pressure is controlled based on the state of the wheel speed and its acceleration, when the braking force is suddenly applied, the wheel connected to the engine via the wheel drive shaft, that is, the driving wheel is rapidly decelerated. However, since the engine has a large inertia, it slows down more slowly than the wheels. For this reason, a large twist occurs in the wheel drive shaft that connects the engine and the drive wheels. Under the influence of the twist of the wheel drive shaft, the wheel repeatedly accelerates and decelerates regardless of the braking force and the road surface reaction force, causing vibration.

Therefore, in order to suppress the vibration of the wheels affected by the torsion, the braking hydraulic pressure is reduced regardless of the road surface condition, and the braking distance becomes long. Also, on a road surface with a low coefficient of friction, wheel vibration may be determined to be a bad road, and a braking pressure higher than the road surface reaction force may be maintained. Sex will deteriorate. Therefore, there are cases where it is not always possible to obtain an appropriate braking force according to the running condition and the road surface condition.

As a measure against this, Japanese Patent Application No. 6-96693 proposed by the same applicant previously detects a torsion torque generated between an engine and a wheel connected through a wheel drive shaft. Then, the corrected acceleration is calculated by adding the torsion torque to the wheel acceleration to correct the wheel acceleration. This corrected acceleration can be obtained as follows.

When the wheel drive shaft is twisted, the equation of motion of the wheel that takes it into account can be expressed as Iw · (dω / dt) = μ · W · r-Tb-Tt (1). Here, Iw is the moment of inertia of the wheel, ω is the rotational angular velocity of the wheel, Tt is the torsional torque, μ is the friction coefficient of the road surface, W is the load applied to the wheel, r is the wheel radius, and Tb is the brake torque.

The relationship between the wheel angular velocity ω and the wheel acceleration is given by the following equation: Gw = Kr · (dω / dt) (2) Here, Kr is a constant. That is, the corrected acceleration Gc is calculated from the equations (1) and (2) using the wheel acceleration Gw and the torsion torque Tt as Gc = Gw + (Kr / Iw) · Tt (3).

Further, the corrected acceleration Gc is calculated by the equation (1),
From (3), it can be expressed as Gc = (Kr / Iw) · (μ · W · r−Tb) (4), and the road surface friction coefficient μ and the reaction force μ · W from the road surface caused by the wheel load W The relationship between the tire torque μ · W · r calculated from the wheel radius r and the brake torque Tb generated by the braking hydraulic pressure can be calculated by the corrected acceleration Gc.

Therefore, it is necessary to know from the corrected acceleration Gc whether or not the tire torque is higher than the brake torque and the difference between the tire torque and the brake torque, that is, the relationship between the road surface reaction force and the braking force. You can When the braking force becomes equal to or less than the road surface reaction force due to the corrected acceleration, the reduction of the braking force is stopped, and if the wheel acceleration is sufficiently large, the braking force is increased.

Therefore, by using the corrected acceleration obtained by correcting the wheel acceleration by the torsion torque, the braking hydraulic pressure at the time of the behavior of the wheel due to the influence of the torsion torque is adjusted,
It is possible to control to an appropriate braking force against the reaction force from the road surface.

The torsion torque can be calculated by detecting the rotational speed of a power unit such as an engine or a drive shaft. Therefore, the torsion torque can be easily utilized.

[0012]

In the above-mentioned conventional anti-lock brake control device, the anti-lock control relates to the start timing condition of pressure reduction or pressure increase or the stop timing condition of pressure reduction or pressure increase, that is, Whether the braking force exceeds the road reaction force due to the corrected acceleration,
Alternatively, control has been performed by determining whether or not it has fallen below. Therefore, it can be used only at the timing of decompression stop of the brake fluid pressure or the timing of start of pressure increase,
The torsion torque could not be positively used for other antilock control.

Further, as an inexpensive means for detecting the torsion torque, the rotational speed of a power unit such as an engine is detected,
The torsion torque is obtained based on the amount of change in the rotation speed. This engine speed is usually obtained from the output of a crank angle sensor or the like that detects the crank angle of the engine.
The timing obtained when the engine rotates, that is, the rotation angle pulse output from the crank angle sensor is much smaller than the rotation angle pulse output from the wheel speed sensor that is the wheel speed detecting means. Therefore, it takes more time to obtain the engine speed, that is, the torsion torque information, as compared with the information about the wheel speed. Therefore,
There is a possibility that the decompression stop determination will be delayed due to the corrected acceleration, and the decompression stop timing will be delayed by that amount, causing the pressure to drop too much and the braking force to drop when the vehicle is traveling on a road surface having a high friction coefficient.

The present invention is intended to solve the above-mentioned problems, and an object thereof is to reduce or increase the braking hydraulic pressure only by comparing the road surface reaction force with the braking force by the corrected acceleration using the torsion torque. Not only can the timing be controlled, but a series of hydraulic pressure controls such as reducing, increasing, and holding the braking hydraulic pressure can also be performed based on the state of both the wheel acceleration and the corrected acceleration, and the wheel acceleration and correction can be performed. It is an object of the present invention to provide an antilock brake control device that can compensate for a delay in engine speed detection by acceleration and perform control at appropriate timing.

[0015]

According to a first aspect of the present invention, an anti-lock brake control device reduces the braking hydraulic pressure when the wheels are decelerated and locks during braking, and the wheel speed is restored by the pressure reduction. In an anti-lock brake control device for avoiding a locked state of wheels to safely brake a vehicle by repeating an operation of increasing the braking fluid pressure again, a wheel speed detecting means for detecting a rotation speed of each wheel of the vehicle, Wheel acceleration calculation means for calculating the acceleration of the wheel from the wheel speed obtained from the wheel speed detection means,
A value obtained by correcting the torsional torque detecting means for detecting the torsional torque applied to the drive shaft of each wheel connected to the drive device, and the wheel acceleration obtained from the wheel acceleration calculating means with the torsion torque obtained by the torsion torque detecting means. The correction acceleration calculation means for calculating the correction acceleration, the control command means for dividing the region to be controlled by the state of the wheel acceleration and the state of the correction acceleration, and issuing the command for controlling the braking force, and the braking force based on the command. And a braking force adjusting means for controlling the wheel acceleration.
It is larger than the fixed value and the corrected acceleration is larger than the second predetermined value.
When it is large, a signal that increases the braking force is applied to the brake fluid pressure adjustment.
It is configured to output to the adjusting means.

[0016]

[0017]

The anti-lock brake control equipment according to claim 2 of the present invention, lock the wheel decelerates during braking shiso
When this happens, the braking fluid pressure is reduced, and the reduction in speed reduces the wheel speed.
When recovering, repeat the operation to increase the braking fluid pressure again
To prevent the wheels from being locked and to safely brake the vehicle.
Anti-lock brake control device
A wheel speed detecting means for detecting the rotation speed of the wheel;
Acceleration of the wheel from the wheel speed obtained from the wheel speed detection means
Connected to the drive device and the wheel acceleration calculation means for calculating the degree
It detects the torsional torque applied to the drive shaft of each wheel.
It is obtained from the twisting torque detecting means and the wheel acceleration calculating means.
The wheel acceleration to be obtained from the torsion torque detecting means.
The corrected acceleration, which is the value corrected by the twisting torque
Compensated acceleration calculation means for calculating, and the state of the wheel acceleration
The braking force is divided by dividing the controlled area according to the state of positive acceleration.
Control command means for issuing a command to control the
Braking force adjusting means for controlling the braking force, wherein the control command means is such that when the wheel acceleration is smaller than a first predetermined value and the corrected acceleration is larger than a second predetermined value,
A signal for holding the braking force is output to the braking hydraulic pressure adjusting means.

[0019]

According to the third aspect of the present invention, in the antilock brake control device , the wheels are decelerated and locked during braking.
When this happens, the braking fluid pressure is reduced, and the reduction in speed reduces the wheel speed.
When recovering, repeat the operation to increase the braking fluid pressure again
To prevent the wheels from being locked and to safely brake the vehicle.
Anti-lock brake control device
A wheel speed detecting means for detecting the rotation speed of the wheel;
Acceleration of the wheel from the wheel speed obtained from the wheel speed detection means
Connected to the drive device and the wheel acceleration calculation means for calculating the degree
It detects the torsional torque applied to the drive shaft of each wheel.
It is obtained from the twisting torque detecting means and the wheel acceleration calculating means.
The wheel acceleration to be obtained from the torsion torque detecting means.
The corrected acceleration, which is the value corrected by the twisting torque
Compensated acceleration calculation means for calculating, and the state of the wheel acceleration
The braking force is divided by dividing the controlled area according to the state of positive acceleration.
Control command means for issuing a command to control the
Braking force adjusting means for controlling the braking force, wherein the control command means is such that the wheel acceleration is within a first predetermined range,
When the corrected acceleration is within the predetermined range and the wheel acceleration is decreasing, a signal for gradually increasing the braking force is output to the braking hydraulic pressure adjusting means.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. First, the basic concept of the present invention will be described with reference to FIG. As shown in FIG. 1, the antilock brake control device of the present invention is a wheel speed detecting means 101 for detecting the rotation speed of each wheel of a vehicle.
And a wheel acceleration calculating means 10 for calculating the acceleration of the wheel from the wheel speed obtained from the wheel speed detecting means 101.
2, the torsion torque detecting means 103 for detecting the torsion torque applied to the drive shaft of each wheel connected to the drive device such as the engine, and the wheel acceleration obtained from the wheel acceleration calculating means 102 are obtained from the torsion torque detecting means 103. Correction acceleration calculation means 104 for calculating a correction acceleration that is a value corrected by the twisting torque and a control command means for dividing a region to be controlled according to the state of the wheel acceleration and the state of the correction acceleration and issuing a command for controlling the braking force. 105 and braking force adjusting means 106 for controlling the braking force based on the command.

Then, the wheel speed detecting means 101 detects the rotational speed of each wheel, inputs the output to the output wheel acceleration calculating means 102, and calculates the wheel acceleration there. Further, the torsion torque detecting means 103 detects the torsion torque applied to the drive shaft of each wheel. The outputs of the output wheel acceleration calculation means 102 and the torsion torque detection means 103 are input to the correction acceleration calculation means 104 to obtain the correction acceleration by correcting the wheel acceleration with the torsion torque. The control command means 105 divides the area according to the state of the wheel acceleration and the state of the corrected acceleration, and generates a signal for controlling the braking force based on the area. Based on this control signal,
The braking force adjusting means 106 controls the braking force.

Embodiment 1. 2 to 4 show an anti-lock brake control device mounted on a vehicle according to an embodiment of the present invention. FIG. 2 is a schematic configuration diagram showing the overall configuration of the antilock brake control device of the present invention. FIG. 3 is a detailed configuration diagram showing a detailed configuration of the actuator. FIG. 4 is a block diagram showing the configuration of the controller.

In FIG. 2, a wheel speed sensor 2a-2d of electromagnetic pickup type or photoelectric conversion type for detecting the speed of each wheel is provided in the vicinity of each wheel 1a-1d of the vehicle.
Are arranged, and these wheel speed sensors 2a-2d
Generates a signal according to the rotation of the corresponding wheel 1a-1d. Incidentally, these wheel speed sensors 2a-2
d constitutes the wheel speed detecting means 101.

Axle shafts 4a and 4b connected to the engine 6 via a differential 5 and a drive shaft 33 are attached to the drive wheels 1a and 1b of the wheels 1a-1d. Torque sensors 3a, 3 are provided on axle shafts 4a, 4b that connect the differential device 5 to the drive wheels 1a, 1b.
b is attached. When the vehicle to be controlled is a front-wheel drive vehicle, the drive wheels 1a and 1b are front wheels,
In the case of rear wheel drive, the drive wheels 1a and 1b are rear wheels. The torque sensors 3a and 3b are attached to the drive wheel side.

Specifically, each torque sensor 3a, 3b is constructed as follows. That is, a strain gauge configured as a bridge circuit is attached to the corresponding axle shafts 4a and 4b so as to distort by an amount according to the torsion torque of the axle shafts 4a and 4b, and this change is detected and amplified by the voltage across the bridge. , A signal is transmitted from the torque sensors 3a, 3b on the rotating axle shafts 4a, 4b to the controller 11 described later via slip rings or by replacing with electromagnetic waves. The torque sensors 3a and 3b are the torsion torque detecting means 10 described above.
Make up 3.

A brake device 7a-is attached to each wheel 1a-1d.
7d is attached to these brake devices 7a
-7d constitutes the braking member.

A master cylinder 9 is connected to the brake pedal 8 via a transmission member such as a rod. When the brake pedal 8 is depressed, a braking pressure corresponding to the depression force of the brake pedal 8 is applied to the master cylinder 9. Is generated. The braking pressure from the master cylinder 9 is adjusted by the actuator means 10 according to the output from the controller 11 described later and is sent to the brake device 7. The actuator means 10 is composed of four actuator means 10a-10d respectively corresponding to the four wheels 1a-1d. The actuator means 10 constitutes the braking pressure adjusting means 105.

The controller 11 is a wheel speed sensor 2a.
-2d and the signals from the torque sensors 3a and 3b are received,
The calculation and control processing for anti-skid control is performed, and an output signal for driving the actuator means 10 is generated.

Next, the actuator means 10 is constructed as shown in FIG. The actuator means 10 is
As described above, the actuators 10a-10d corresponding to the brake devices 7a-7d are provided, but since each actuator is configured in the same manner, the actuator 10a will be described here, but the following description will be made on the other actuators 10b-. The same applies to 10d.

In the actuator 10a, a holding solenoid valve 12 is provided in a path from the master cylinder 9 to the brake device 7a, and a master tank is provided from the brake device 7a via a reservoir tank 14 and a hydraulic pressure recovery pump 15. A depressurizing solenoid valve 13 is provided in the hydraulic pressure recovery path to the cylinder 9, and these holding solenoid valve 12 and depressurizing solenoid valve 13 are switched by being energized or cut off by a controller 11. It is a thing. Reference numeral 16 represents a motor relay that switches the connection between the motor of the pump 15 and the power supply source according to the output of the controller 11.

In such a structure, when the brake pedal 8 is depressed, pressure is supplied to the master cylinder 9, and the master cylinder 9 drives the actuator 10a-
The braking fluid flows into the braking devices 7a-7d through the holding solenoid 13 of 10d, and the braking pressure increases.

When the pressure reducing signal is output from the controller 11, the holding solenoid valve 12 and the pressure reducing solenoid valve 13 are energized and their electromagnetic solenoids are driven. As a result, the path between the master cylinder 9 and the brake devices 7a-7d is blocked, and instead the path between the brake devices 7a-7d and the reservoir tank 14 is connected. Therefore, the braking device 7a-7
The braking fluid pressure in d flows out to the reservoir tank 14, and the braking pressure decreases. At the same time, the motor relay 16 is driven to operate the pump 15 to increase the pressure of the brake fluid flowing into the reservoir tank 14 into the master cylinder 9
To prepare for the next control.

After that, when the holding signal is output from the controller 11, only the holding solenoid valve 12 is energized, all paths are cut off, and the braking pressure is held.

Further, when the pressure increasing signal is output from the controller 11, the power supply to the holding solenoid valve 12 and the pressure reducing solenoid valve 13 is cut off, and the path between the master cylinder 9 and the braking devices 7a-7d is cut off. High-pressure braking fluid reconnected and returned to the master cylinder 9,
The braking fluid discharged from the pump 15 again flows into the braking devices 7a-7d, and the braking pressure increases.

As described above, in order to prevent the wheels from being locked, according to the command output from the controller 11,
The braking pressure is adjusted by repeating depressurization, holding, and pressure increase.

The controller 11 has a circuit configuration as shown in FIG. In FIG. 4, the controller 11
Is a waveform shaping circuit 20a-20d that shapes the output signal of the vehicle speed sensor 2a-2d into a pulse signal suitable for processing by the microcomputer 23 and outputs the pulse signal, and the torque sensor 3
Amplifiers 21a and 21b for converting the signals from a and 3b into digital signals (pulse signals) suitable for the processing of the microcomputer 23, and a power supply for supplying a constant voltage to the microcomputer 23 and the like when the ignition switch 27 is turned on. Circuit 22, CPU 23a, RAM 23b, R
A microcomputer 23 including an OM 23c, an I / O interface 23d, etc., and a microcomputer 2
The actuator 1 outputs an output signal corresponding to the control signal from the actuator 3.
0a-10d to supply actuators 10a-10d
Actuator drive circuits 24a-24d for driving each electromagnetic solenoid, and a drive circuit 25 for energizing the coil 16b of the motor relay 16 having the normally open contact 16a to turn on the normally open contact 16a. .

The operation of the microcomputer 23 in the controller 11 having the above-mentioned configuration is shown in FIGS.
It will be described based on the flowchart shown in FIG. First, in FIG. 5 showing the flow of the whole processing, step S1 is RA
Initialize the M23b, the I / O interface 23d, and the like.

Next, in step S2, the wheel speed Vw is calculated. As an example of a method of calculating the wheel speed Vw, an output signal from the wheel speed sensors 2a-2d is input to the waveform shaping amplifier circuit 20a-20d as the wheels 1a-1d rotate, and a frequency corresponding to the wheel rotation speed is output. The pulse signal is input to the microcomputer 23 from the waveform shaping amplifier circuits 20a-20d, and the microcomputer 23 performs wheel speed calculation processing (step S2) based on this input.
The number of pulses Pn for starting the measurement after this processing is counted, and the time Tn after the start of the measurement is measured.

Here, there is a period measuring method for obtaining the wheel speed Vw from the following equation, Vw = Kv · (Pn / Tn) (5). Here, Kv is a constant and is determined by the wheel diameter, the characteristics of the wheel speed sensor 2, and the like.

Next, in step S3, the wheel acceleration Gw is calculated. Wheel speed Vw obtained in step S2, 1
Based on the wheel speed Vwl obtained in step S2 before the control cycle and the control cycle TL for performing this processing, the wheel acceleration G
w can be obtained from the equation GW = Kg · (Vw−Vw1) / TL (9). Here, Kg is a constant. Therefore, the wheel acceleration Gw indicates that the wheel accelerates when Gw> 0, and decelerates when Gw <0.

In step S4, each wheel 1a-1d
The vehicle body speed Vb is estimated from the wheel speed Vw. As an estimation method, a value obtained by decelerating the vehicle body speed Vbl one control cycle before with a gradient of -1 g and the wheel speed V of the four wheels 1a-1d
The fastest one of w is the vehicle body speed Vb.

In step S5, the torsion torque Tt is calculated. From the torque sensor 3a, 3b to the axle shaft 4
The voltage value corresponding to the torsion torque amount of a and 4b is the amplification circuit 2
It is input to the microcomputer 23 via 1a and 21b, and the analog signal is input in the microcomputer 23.
The torsional torque Tt is obtained by digital conversion.

In step S6, the corrected acceleration Gc is calculated from the wheel acceleration Gw and the torsion torque Tt using the equation (3).
Is calculated.

In step S7, the braking pressure is controlled to be increased or decreased, as will be described later, and this step is a process for determining the pressure reducing, holding and pressure increasing commands.

In step S8, a signal is output from the controller 11 to the actuators 10a-10d based on the command determined in the pressure increasing / decreasing control process of step S7. Since the actuators 10a to 10d have only three modes of pressure reduction, holding and pressure increase, for example, when it is desired to gently increase the braking pressure, that is, to suppress the gain of the pressure increase, the actuators 10a to 10d may be pressed during the pressure increase signal. The holding signal is periodically output to perform the process of gradually increasing the pressure, and the same process as the pressure increasing is performed even if the pressure is reduced.

The above processing is performed, and when the predetermined control cycle time is reached, the process returns to step S2. This is repeated until the ignition switch 27 is turned off.

Next, regarding the pressure increase / decrease control processing of step S7 for determining the pressure decrease, the holding, or the pressure increase of the braking pressure,
The flowchart shown in FIG. 6 and the wheel acceleration G shown in FIG.
Description will be made based on a Gc-Gw map that is divided into regions by w and the corrected acceleration Gc. The Gc-Gw map of FIG. 7 represents the state of the wheel acceleration and the state of the corrected acceleration on the map, and the state of the wheel based on the values of the wheel acceleration Gw and the corrected acceleration Gc and the braking fluid to be determined. It shows a pressure increase / decrease command.

First, in step S11, a determination process of the depressurization condition corresponding to the area A in the Gc-Gw map is performed. Here, when the wheel acceleration Gw is less than the first predetermined value α and the corrected acceleration Gc is less than the second predetermined value β, the process proceeds to step S18 and the pressure reduction command is output. On the other hand, if the above condition is not satisfied in step S11, the process proceeds to step S12.

For example, when the torsional torque acts on the wheel as a braking force, the wheel acceleration is greatly reduced. However, the corrected acceleration is obtained by correcting the wheel acceleration with the torsion torque, and it can be determined from the corrected acceleration that the vehicle is decelerated with the torsion torque. Therefore, since the corrected acceleration does not satisfy the deceleration condition, it is possible to prevent the pressure reduction control. Further, since only the corrected acceleration is not the pressure reducing condition, and the pressure reducing condition is set by the AND condition with the wheel acceleration, there is a possibility that the torsion torque detection may be delayed and the determination by the corrected acceleration may be delayed. The delay can be compensated by adding the condition of the wheel acceleration to.

In step S12, the pressure increasing condition corresponding to the B region is determined by the Gc-Gw map. That is,
When the wheel acceleration Gw is greater than or equal to the first predetermined value α and the corrected acceleration Gc is greater than or equal to the second predetermined value β, the process proceeds to step S19 and the pressure increase command is output. If the condition of step S12 is not satisfied, the process proceeds to step S13.

When the torsion torque does not work in the process of increasing the pressure again after the completion of the sufficient pressure reduction, the wheel speed rapidly returns to the vehicle body speed and the wheel acceleration increases, but the torsion torque becomes the braking force. When working, the increase in wheel acceleration slows down. Judge this by the correction acceleration,
The braking hydraulic pressure can be increased. Therefore, even if the increase in the wheel acceleration is reduced by the torsion torque, sufficient pressure increase can be performed.

In step S13, the holding condition corresponding to the C region in the Gc-Gw map is determined. That is,
When the wheel acceleration Gw is less than the first predetermined value α and the corrected acceleration Gc is greater than or equal to the second predetermined value β, the process proceeds to step S20 and the holding command is output.

Since the corrected acceleration is sufficiently large, it is desired to increase the pressure. However, since the wheel acceleration is rapidly decelerated, the slip becomes large. Therefore, increasing the brake fluid pressure leads to an increase in slip, although temporarily. For this reason, the vehicle body may impair running stability. Therefore, when such a state occurs, the brake fluid pressure is maintained by prohibiting pressure increase and pressure reduction.

If the condition of step S13 is not satisfied, the process proceeds to step S14. In step S14, Gc
-Perform the determination process of the holding condition corresponding to the D area on the Gw map. That is, when the wheel acceleration Gw is greater than or equal to the first predetermined value α and the corrected acceleration Gc is less than the third predetermined value γ, the process proceeds to step S20 and the hold command is output.

When the braking fluid pressure is sufficient with respect to the road surface reaction force when the torsional torque does not work, the wheels are sufficiently decelerated so that the braking fluid pressure starts to be reduced, but the torsional torque is driven. When acting as a force, the wheels do not exhibit a sudden deceleration due to the torsional torque even if sufficient braking fluid pressure is obtained. In such a case, when the torsional torque acting as the driving force becomes small, the wheels start decelerating rapidly. At this time, it is possible to obtain a higher braking force by maintaining the proper braking force by avoiding the unnecessary increase of the braking hydraulic pressure and maintaining it, rather than increasing the pressure to accelerate deceleration. Therefore, when the wheel acceleration does not suddenly decrease and the correction acceleration rapidly decreases, the wheel acceleration is held.

If the condition of step S14 is not satisfied, the process proceeds to step S15. In step S15,
The holding condition corresponding to the E region is determined by the Gc-Gw map. When the wheel acceleration Gw is equal to or larger than the fourth predetermined value ζ (because the position is outside the conditions of steps S11 to S14, the region where the holding condition of the wheel speed and the correction acceleration is satisfied is limited; Gw ≧ ζ & γ ≦ Gc <Β), the process proceeds to step S20 and a holding command is output.

When the wheel acceleration Gw is within the corrected acceleration range (equal to or more than the predetermined value ζ), the influence of the torsion torque is small, and the wheel is easily linked to the movement of the braking hydraulic pressure. At this time, the influence of the torsion torque is not promoted by increasing the braking hydraulic pressure, and the increase of the torsion torque is prevented.

If the holding condition is not satisfied in step S15 (α ≦ Gw <ζ & γ ≦ Gc <β), step S16.
Go to. In step S16, the process for determining the gradually increased pressure / holding condition corresponding to the F region in the Gc-Gw map is performed. When the difference between the estimated vehicle body speed estimated in step S4 and the wheel speed (that is, the magnitude of slip) is equal to or larger than the fifth predetermined value b, the process proceeds to step S20, and when not, the step S20.
Proceed to 17.

In step S17, it is determined whether the wheel acceleration Gw is increasing. If it is increasing, the process proceeds to step S21 to output a slow pressure increasing command. On the contrary, if the condition is not satisfied, the process proceeds to step S20 to output the hold. Here, as a method of detecting that the wheel acceleration is increasing, the difference between the wheel acceleration calculated this time and the wheel acceleration calculated last time is obtained, and when the difference is larger than zero, the wheel acceleration is increased. It is determined that there is.

The above is performed for each wheel for each processing of each step. In the anti-skid control of the wheels belonging to the drive wheels 1a and 1b, the wheel acceleration is corrected by using the above-described torsion torque, and the brake devices 7a and 7b on the drive wheel side are used.
Controls pressure increase / holding / depressurization. However, driven wheel 1
In c and 1d, unlike the drive wheels 1a and 1b, a large torsion torque is not generated on the wheel shaft. Therefore, it is considered that the torsion torque Tt does not work, Tt = 0 is set, and the same processing may be performed. When the clutch is disengaged, that is, when the engine 6 and the drive wheels 1a and 1b are disengaged, the inertia of the engine 6 does not act on the drive wheels 1a and 1b, the torsion torque becomes small, and the driven wheel 1c, Similar to 1d, control of Tt = 0 is performed.

Next, the operation when the above processing is performed will be described with reference to FIGS. 8 and 9. FIG. 8 is a time chart showing a series of controls, and FIG. 9 shows an estimated vehicle body speed Vb, a wheel speed Vw, and a wheel acceleration G in a region where the wheel acceleration Gw and the correction acceleration Gc at that time are Gc-Gw.
It is the result of tracing changes with time of w, the correction acceleration Gc, and the braking fluid pressure P. If a large braking pressure P appears when the brake pedal is depressed, the braking force greatly exceeds the road surface reaction force, the wheel speed Vw is rapidly reduced, and a large deceleration occurs. At time t1, the corrected acceleration Gc becomes equal to or smaller than the second predetermined value β and the wheel deceleration Gw becomes equal to or smaller than the first predetermined value α, so that the state of Gc-Gw becomes the area A and the pressure reduction command is output. Then, the braking fluid pressure is reduced.

At time t2, after the wheel speed drops sharply, the braking force decreases due to the pressure reduction, and the wheel speed tries to recover (accelerate). Therefore, the state changes from the area A to the area D. Therefore, the command is changed to hold and the braking fluid pressure is held. After that, the state changes from the F region to the E region while being affected by the torsion torque. At this time, in the F region, since the slip is deep, the gentle pressure increase command is not issued and the holding command is continuously output.

At time t3, the corrected acceleration Gc ≧ β (region B), the pressure increase command is output, and the braking hydraulic pressure is increased to increase the braking force.

At time t4, the corrected acceleration Gc <β
(B area → F area), the difference between the estimated vehicle body speed and the wheel speed becomes less than or equal to the fifth predetermined value b, and the wheel acceleration decreases. And the pressure increase are repeated periodically.

At time t5, the torsional torque Tt acts as a driving force, and the wheel acceleration increases slightly. At this time, the corrected acceleration Gc decreases beyond the third predetermined value γ. At this time, according to the equation (4), the braking force is near the road surface reaction force, and even if the pressure increase is continued as it is, the pressure is reduced at the next timing, and the braking force is reduced. In order to prevent this and obtain a high braking force, it is better to maintain the braking fluid pressure in the state of Gc <γ. Therefore, in the area D, the holding command is output to maintain the braking force.

At time t6, the corrected acceleration Gc becomes γ or more again (F region), so that the gentle pressure increase command is output.

At time t7, the wheel acceleration Gw becomes the first value.
Therefore, the pressure reduction command is output. By repeating the above process and increasing / decreasing the braking fluid pressure periodically, an appropriate braking force against the road surface reaction force can be obtained.

Embodiment 2. In the first embodiment, the torsion torque is obtained from the torque sensors 3a and 3b having strain gauges attached to the axle shafts 4a and 4b connected to the drive wheels 1a and 1b. In the case where it is connected to the engine 6 via the differential device 5, even if the torque sensor 32 for detecting the torsion torque is attached to the drive shaft 33 such as the propeller shaft shown in the overall configuration of FIG. The same effect as that of the first embodiment can be obtained.

The same torque is applied to the wheels connected to the left and right via the differential device, and therefore the torsional torques applied to the left and right wheels are the same. That is, by detecting the torque applied to the drive shaft 33 that connects the engine 6 and the differential device 5, the left and right wheels receive a torsion torque that is half the detected value.

Third Embodiment In the first or second embodiment,
The torsion torque was obtained from the axle shafts 4a and 4b connected to the drive wheels 1a and 1b, or the torque sensor 3a, 3b or 32 having a strain gauge attached to the drive shaft 33. Similar torque can be detected by obtaining the rotation speed. In the configuration shown in FIG. 2, the engine speed is obtained from the engine rotation sensor 31 such as a crank angle sensor. Since the drive wheels 1a, 1b and the engine 6 are connected via the differential device 5, the torsional torques applied to the left and right are the same, and the rotation angles of the left and right drive wheels 1a, 1b and the rotation angle of the engine 6 are the same. It is possible to calculate the torsion angle by obtaining the phase relationship of the above and obtain the phase difference, and to obtain the torsion torque proportional to this.

Here, the rotation angle of the engine 6 is obtained from the engine rotation sensor 31, and the left and right drive wheels 1a and 1b are also used.
The rotation angle of is determined by the wheel speed sensors 2a and 2b.
When the torsion torque is small and the torque load on the engine 6 is small, for example, before the control of the braking pressure is started,
It is assumed that there is no phase difference between the drive wheels 1a and 1b and the engine 6, and the respective angles are reset. From the start of control, the pulses of the drive wheels 1a, 1b and the engine 6 are counted, and when the count values are the rotation angles θr, θl of the left and right drive wheels 1a, 1b and the rotation angle θe of the engine 6,
The torsion angle θt is given by the following equation θt = Ki · θe− (θr + θl) / 2 (7), and the torsion torque Tt is obtained from the torsional rigidity Kp as Tt = Kp · θt (8).

The torsion torque Tt applied to the left and right drive wheels is also applied to the engine 6. When the accelerator pedal 8 is released during the operation of the antilock brake device (ABS), the output torque generated from the engine 6 becomes small. Therefore, the engine 6 is considered as an object having a large inertia, and the amount of change in the rotational speed (rotational speed) ωe of the engine 6 is captured and the motion of the engine itself shown in the following equation is applied to the drive wheels 1a and 1b. Torsional torque can be calculated. Tt = K · (dωe / dt) (9)

As described above, the torsional torque can be calculated by obtaining the rotational speed ωe of the engine 6 to obtain the phase angle when the torsional torque is generated and converting the torque. Alternatively, drive wheels 1a, 1b
The torque applied to the engine 6 is also applied to the engine 6, thereby causing the engine 6 to move, and the torsional torque can be calculated by obtaining the motion. The same result can be obtained by using the torsion torque obtained by the above method in the first embodiment.

Fourth Embodiment Although the rotation speed ωe of the engine 6 is detected in the third embodiment, the drive shaft 3 shown in FIG.
3 may be detected, and particularly in a vehicle having an automatic transmission, the drive wheels 1a and 1b are connected to the engine 6 via the torque converter, and therefore are not directly connected to the engine 6 and are driven. The torque generated from the wheels 1a and 1b is rarely transmitted to the engine 6. Therefore, the rotation speed of the drive shaft 33 is detected by the shaft rotation sensor 34,
The same result can be obtained by using the same method as that of the third embodiment.

Embodiment 5. 2 in the first and second embodiments
Although the wheel drive vehicle has been described, the braking pressure can be controlled in a four wheel drive vehicle by using a similar control method. When the torsion torque is measured using the strain gauge, the strain gauge is attached to each of the axle shafts of the four wheels, and the same process as the process described in each of the above-described embodiments is performed on each wheel. The same effect can be obtained.

Further, in the case of detecting the torsion of the drive shaft shown in the third embodiment, when the differential device is interposed between the engine 6 and the four wheels, the differential device causes the output side, That is, since the same torque acts on the two shafts on the wheel side, the torque appearing at the output can be obtained by providing a torque sensor on the input side shaft, that is, the engine side shaft. That is, in order to drive the four wheels,
When all the power of the engine 6 is divided into front and rear wheels or left and right wheels by a differential device, a torque sensor is provided between the engine 6 and the differential device that divides the power into the front and rear drive shafts. It is possible to obtain the torsional torque applied to.

When calculating the torsional torque by detecting the engine speed as shown in the fourth embodiment, the equation (8) is used when the power is transmitted by the differential gears for all four wheels. Alternatively, when the differential limiting device is operated in the part that divides the power into the front and the rear, the same effect as in the case of the first embodiment can be obtained by obtaining the equation (7) for each of the front and rear wheels. it can.

The same applies to the drive shaft 33 as in the case of detecting the engine speed.

[0080]

As described above, according to the present invention, the following excellent operational effects are exhibited.

[0081]

[0082]

According to the anti-lock brake control device of the first aspect of the present invention, the torque is detected and the torsion thereof is detected.
Use torque added to wheel acceleration for control
Therefore, the control that takes into account the torsion applied to the wheels is taken into consideration.
It becomes possible, when in-gear (driving with driving device such as engine
(When engaging a clutch or other device that controls power transmission between wheels)
If the drive shaft is twisted or vibrates,
It is possible to control various braking pressures. Also drive
Alternatively, use a means to detect the rotational speed of the drive shaft to
By calculating and calculating the torque,
Compared to measuring the torsion torque of the drive shaft with
This device can be configured as follows. In addition, wheel acceleration
The braking force is controlled by the two states of
Therefore, the detection delay of the torsion torque is corrected to the wheel acceleration
Can be corrected depending on the degree of
Can be adjusted and the braking force can be adjusted appropriately.
be able to. Further , since the braking force is increased when the corrected acceleration is equal to or greater than the second predetermined value, the torsion force acts on the wheel as a braking force to increase the braking force even when the acceleration of the wheel is suppressed. On the contrary, the torsion torque acts as a driving force, and when the wheel is accelerated, it is possible to prohibit the braking force from increasing. Therefore, when the wheel acceleration becomes equal to or less than the first predetermined value, the increase in the braking force is stopped, so that the delay in the detection of the torsion torque can be alleviated and an appropriate braking force can be obtained.

According to the antilock brake control device of the second aspect of the present invention, when the wheel acceleration is smaller than the first predetermined value and the correction acceleration is equal to or larger than the second predetermined value, the wheel is decelerated greatly. However, the corrected acceleration is sufficiently large, and the torsion torque acts as a braking force.
Therefore, because the wheel is decelerating due to the torsional torque,
It is not necessary to reduce the braking force because the twisting torque will eventually decrease, and by holding the braking force, the braking efficiency can be improved while avoiding the wheel lock without excessively reducing the braking force.

[0085]

According to the antilock brake control device of the third aspect of the present invention, when the corrected acceleration is within the predetermined range, there is no influence of the torsion torque,
That is, since it is a region that can be dealt with only by controlling the wheel acceleration, it can be dealt with under the control conditions of the conventional antilock brake control device.

[Brief description of drawings]

FIG. 1 is a block diagram showing the basic concept of the present invention.

FIG. 2 is an overall configuration diagram showing an embodiment of the present invention.

FIG. 3 is a hydraulic circuit diagram showing braking fluid pressure adjusting means for one wheel according to an embodiment of the present invention.

FIG. 4 is a circuit configuration diagram of a controller according to an embodiment of the present invention.

FIG. 5 is a flowchart showing a flow of processing according to the embodiment of the present invention.

FIG. 6 is a flowchart showing a control flow of a braking hydraulic pressure according to the embodiment of the present invention.

FIG. 7 is a diagram showing Gc-Gw region division according to the embodiment of the present invention.

FIG. 8 is a diagram showing operation waveforms according to the embodiment of the present invention.

FIG. 9 is a diagram showing a trace of the operation of FIG. 8 in the Gc-Gw region division according to the embodiment of the present invention.

[Explanation of symbols]

1a-1d wheels, 2a-2d wheel speed sensors, 3
a, 3b torque sensor, 7a-7d brake device,
10 actuator means, 11 controller, 31
Engine rotation sensor, 32 Drive shaft rotation sensor, 10
1 wheel speed detecting means, 102 wheel acceleration detecting means,
103 torsion torque detecting means, 104 corrected acceleration calculating means, 105 control commanding means, 106 braking hydraulic pressure adjusting means.

Continuation of the front page (56) Reference JP-A-8-150913 (JP, A) JP-A-6-144193 (JP, A) JP-A-8-40244 (JP, A) JP-A-63-258254 (JP , A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B60T ^7/ 12-8/96

Claims (3)

(57) [Claims] 1. When braking, the wheels decelerate so that they are likely to lock.
When this happens, the braking fluid pressure is reduced, and the wheel speed is restored by this reduction.
Then, by repeating the operation of increasing the braking fluid pressure again,
Safely brake the vehicle by avoiding the locked state of the wheels
In the anti-lock brake control device, Wheel speed detecting means for detecting the rotational speed of each wheel of the vehicle
When, From the wheel speed obtained from the wheel speed detecting means, the wheel
Wheel acceleration calculation means for calculating the acceleration of Torsion on the drive shaft of each wheel connected to the drive
Torsion torque detection means for detecting the torque, The wheel acceleration obtained from the wheel acceleration calculation means is
Torsion torque required by the torsion torque detection means
Corrected acceleration calculation to calculate the corrected acceleration that is the corrected value
Means and Depending on the state of the wheel acceleration and the state of the corrected acceleration
Divide the control area and issue a command to control the braking force.
Control command means, Braking hydraulic pressure adjusting means for controlling braking force based on the command
When, Equipped with, In the control command means, the wheel acceleration is equal to or more than a first predetermined value.
And the corrected acceleration is equal to or greater than the second predetermined value, the braking force
Output a signal to increase the braking fluid pressure adjusting means. A
Punch lock brake control device. 2.When braking, the wheels decelerate and seem to lock up
When this happens, the braking fluid pressure is reduced, and the wheel speed is restored by this reduction.
Then, by repeating the operation of increasing the braking fluid pressure again,
Safely brake the vehicle by avoiding the locked state of the wheels
In the anti-lock brake control device, Wheel speed detecting means for detecting the rotational speed of each wheel of the vehicle
When, From the wheel speed obtained from the wheel speed detecting means, the wheel
Wheel acceleration calculation means for calculating the acceleration of Torsion on the drive shaft of each wheel connected to the drive
Torsion torque detection means for detecting the torque, The wheel acceleration obtained from the wheel acceleration calculation means is
Torsion torque required by the torsion torque detection means
Corrected acceleration calculation to calculate the corrected acceleration that is the corrected value
Means and Depending on the state of the wheel acceleration and the state of the corrected acceleration
Divide the control area and issue a command to control the braking force.
Control command means, Braking hydraulic pressure adjusting means for controlling braking force based on the command
When, Equipped with The control command means is such that the wheel acceleration is greater than a first predetermined value.
When the acceleration is small and the correction acceleration is equal to or greater than the second predetermined value,
Outputs a signal for maintaining power to the braking fluid pressure adjusting means.
RuaPunch lock brake control device. 3.When braking, the wheels decelerate and seem to lock up
When this happens, the braking fluid pressure is reduced, and the wheel speed is restored by this reduction.
Then, by repeating the operation of increasing the braking fluid pressure again,
Safely brake the vehicle by avoiding the locked state of the wheels
In the anti-lock brake control device, Wheel speed detecting means for detecting the rotational speed of each wheel of the vehicle
When, From the wheel speed obtained from the wheel speed detecting means, the wheel
Wheel acceleration calculation means for calculating the acceleration of Torsion on the drive shaft of each wheel connected to the drive
Torsion torque detection means for detecting the torque, The wheel acceleration obtained from the wheel acceleration calculation means is
Torsion torque required by the torsion torque detection means
Corrected acceleration calculation to calculate the corrected acceleration that is the corrected value
Means and Depending on the state of the wheel acceleration and the state of the corrected acceleration
Divide the control area and issue a command to control the braking force.
Control command means, Braking hydraulic pressure adjusting means for controlling braking force based on the command
When, Equipped with The control command means is such that the wheel acceleration falls within the first predetermined range.
Yes, and when the corrected acceleration is within the specified range
When the wheel acceleration is decreasing, the braking force is slowly increased.
Output to the braking hydraulic pressure adjusting means.RuaNichiro
Quake brake control device.