JP2777992B2 - Vehicle braking control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial application field) The present invention relates to a vehicle brake control device,
The present invention relates to a vehicle brake control device equipped with an anti-skid braking system for individually controlling a braking force on each wheel.

(Prior Art) Generally, an anti-skid braking system is known as a vehicle brake system. For example, according to Japanese Unexamined Utility Model Publication No. 62-122765, the braking force for each wheel is determined based on the result of comparison between the rotation speed of each wheel during braking and the pseudo vehicle speed determined from the rotation speed of each wheel. An anti-skid braking system is disclosed in which individual controls are performed to prevent each wheel from being locked or skid during braking, thereby enhancing braking performance.

(Problems to be Solved by the Invention) By the way, as described above, the anti-skid braking system locks the vehicle in the locked state based on the rotational speed difference detected by the wheel speed sensor provided for each wheel during braking. It is determined whether or not there is a wheel, and if there is a wheel in a locked state, the brake oil pressure (brake fluid pressure) for the wheel is reduced to thereby quickly cancel the locked state of the wheel. . That is, the anti-skid braking system, when detecting the locked state of the wheel, reduces the brake hydraulic pressure for the wheel, and when the locked state of the wheel starts to be released, increases the brake hydraulic pressure for the wheel again. By repeatedly performing, while suppressing the locking of the wheel, it is intended to effectively brake, but also in the individual wheel in the locked state, the road surface condition for each wheel,
Alternatively, there are wheels that are easy to lock due to various factors such as a difference in the grounding load of each wheel on the road surface, and wheels that are difficult to lock. For this reason, when the braking oil pressure is repeatedly reduced and increased on the wheels that are easy to lock and the wheels that are difficult to lock under a uniform condition, the braking is difficult on the wheels that are easy to lock. When the hydraulic pressure is increased, the lock state is established again, whereby the pressure reduction and pressure increase operations are repeated for a long period of time, making it difficult to realize quick braking control.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to improve a braking performance of an anti-skid braking system in a vehicle equipped with the anti-skid braking system, and particularly, when an active suspension device is provided, a pressure sensor used in the device. An object of the present invention is to achieve the above-mentioned object at low cost by using a computer.

(Means for Solving the Problems) In order to solve the above problems, the present invention is characterized in that it is configured as follows.

That is, during the braking operation, the vehicle brake control device according to the present invention reduces the brake fluid pressure on the wheel in which the locked state is detected based on the detection result of the wheel speed sensor provided for each wheel, An anti-skid braking system that controls to increase the pressure again, and a pressure sensor that detects the pressure in each of the hydraulic cylinders to supply hydraulic oil to hydraulic cylinders individually arranged between each wheel and the vehicle body. In a vehicle provided with an active suspension device that controls based on a detected value, a ground load detecting unit that detects a ground load of each wheel based on a detected value of the pressure sensor, and the vehicle is detected by the ground load detecting unit. The brake fluid pressure by the anti-skid braking system was reduced when the wheel where the ground load was smaller than the predetermined load was locked. The brake hydraulic pressure is set so that the control time from the start of pressure reduction to the end of pressure increase in the pressure increase control is longer than the control time when the wheel whose ground contact load is larger than the predetermined load is locked. And a correction control means for correcting the above control.

(Operation) According to the above configuration, when the contact load of the wheel detected by the contact load detecting means is smaller than the predetermined load, the braking control for the wheel whose contact load is smaller than the predetermined load is corrected by the correction control means. become. That is, a wheel having a ground contact load smaller than a predetermined load tends to lock easily during a braking operation. However, when such a wheel is locked during a braking operation, the brake fluid pressure by the anti-skid braking system is reduced. When the brake fluid pressure is increased because the control time from the start of pressure reduction to the end of pressure increase in the control for increasing pressure again after pressure reduction is longer than when the wheel where the ground load is larger than the predetermined load is locked. To
It is effectively suppressed that the wheel whose ground contact load is smaller than the predetermined load is in the re-lock state. And
In particular, according to the present invention, in a vehicle equipped with an active suspension device, the pressure load sensor used in the device is used to detect the ground load of each wheel, so that the ground load can be detected. The above operation can be obtained without providing a sensor again.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows an overall schematic configuration of a vehicle equipped with an anti-skid braking system.
The left and right front wheels 2L, 2R and the right and left rear wheels 3L, 3R have disk rotors 4a ... 4a, which rotate integrally with these wheels 2L, 2R, 3L, 3R, and braking hydraulic pressure (hereinafter referred to as brake hydraulic pressure). Are supplied when the above-mentioned disk rotors are supplied.
Brake devices 4... 4 including calipers 4 b.

In this vehicle 1, the output of a power plant 7 including an engine 5, a transmission 6, and the like is output from a propeller shaft 8
The output of the power plant 7 divided by the rear differential 9 is input to the right and left rear axles 10,
By being transmitted to the left and right rear wheels 3L, 3R via 11
The rear wheels 3L and 3R are respectively driven to rotate, and accordingly, the left and right front wheels 2L and 2R are respectively rotated.

Further, the vehicle 1 is equipped with an anti-skid braking system 12 for individually and variably adjusting the brake fluid pressure supplied to each of the brake devices 4 during a braking operation (when a brake pedal is depressed). The anti-skid braking system 12 includes front, rear, left and right wheels 2L, 2
Signals from wheel speed sensors 13, 14, 15, and 16 provided for each of R, 3L, and 3R to detect respective wheel speeds, and G sensors for detecting acceleration / deceleration as a basis for calculating the vehicle speed of the vehicle 1 An ABS control controller 19 to which a signal from the controller 17 and a signal from pressure sensors 18... 18 for detecting the pressures in the hydraulic chambers of the respective hydraulic cylinders constituting the active suspension, which will be described in detail later, are inputted. The hydraulic control valves 20, 21, 22, 23 for adjusting the brake fluid pressure supplied to each of the brake devices 4 based on the control signal output from the And a hydraulic unit (not shown) for supplying the brake fluid. At the time of the braking operation, signals from the wheel speed sensors 13 to 16 and the G sensor 17 are input to the ABS control controller 19, and based on the signals, the controller 19 sends control signals to the hydraulic control valves 20 to 23. Is output, the above wheels 2L, 2R, 3
The brake fluid pressure supplied to each brake device 4 is variably adjusted according to the rotation state of L and 3R, thereby preventing the lock of each of the wheels 2L, 2R, 3L and 3R, and maximizing the braking force. 2L, 2
R, 3L and 3R are braked.

On the other hand, the vehicle 1 is equipped with an active suspension device 24. The schematic configuration of the active suspension device 24 will be described with reference to FIG.
Hydraulic cylinders 25... 25 as oil dampers are arranged between 1a and the wheels 2L, 2R, 3L, 3R, respectively. These hydraulic cylinders 25 are inserted into cylinder bodies 25a. The hydraulic chamber 25c is defined by the piston 25b. And the upper end of the piston rod 25d connected to the piston 25b is connected to the vehicle body 1a side,
Each cylinder body 25a has a corresponding wheel 2
Linked to L, 2R, 3L, 3R.

Further, gas springs 27... 27 are connected to the hydraulic chambers 25c of the respective hydraulic cylinders 25 through communication passages 26 and 26, respectively. These gas springs 27 are provided with diaphragms 28 provided therein. , A gas chamber 27a and a hydraulic chamber 27b are defined, and the hydraulic chamber 27b is communicated with a hydraulic chamber 25c of the hydraulic cylinder 25.

The hydraulic pump 29 driven by the output of the engine 5 (see FIG. 1) is connected to flow control valves 31... 31 for each hydraulic cylinder 25 via a supply passage 30. Each of the above hydraulic cylinders from control valve 31
The hydraulic oil is supplied to and discharged from the hydraulic chamber 25c of the hydraulic chamber 25.

Further, a signal from the main pressure sensor 32 for detecting the discharge pressure of the hydraulic pump 29, a signal from the pressure sensors 18... 18 for detecting the pressure in the hydraulic chamber 25c in each hydraulic cylinder 25, the vehicle body 1a and each wheel Signals from vehicle height sensors 33... 33 which are arranged between 2L, 2R, 3L and 3R to detect changes in vehicle height, and signals from a G sensor 34 which detects vertical acceleration of the vehicle 1 And an ACS control controller 36 to which a signal from a vehicle speed sensor 35 for detecting a vehicle speed is input, and from the controller 36, based on each of the above input signals, to each of the flow rate control valves 31. In response, a control signal is output, whereby the suspension characteristics are variably controlled.

Further, by controlling the supply and discharge of hydraulic oil to and from the hydraulic chamber 25c of each hydraulic cylinder 25 based on a control signal from the ACS control controller 36, control is performed so that the vehicle height becomes the target vehicle height, Control to reduce the vertical vibration of the vehicle 1 and control to equalize the supporting load between the left and right wheels on the front wheels 2L and 2R and the rear wheels 3L and 3R, to be sure, the ground load between the left and right wheels Is performed. Therefore, the values of the pressure sensors 18... 18 for detecting the pressure in the hydraulic chamber 25 c of each of the hydraulic cylinders 25 indicate the respective wheels 2 L, 2
The grounding load of R, 3L, and 3R can be detected.

Then, in the present embodiment, as shown in FIG.
The above-mentioned ABS control controller 19 is provided with the wheels 2L, 2R, 3L, 3
Signals from pressure sensors 18 ... 18 for detecting the pressure in the hydraulic chamber 25c in each of the hydraulic cylinders 25 constituting the active suspension device 24 are input together with the signals from the wheel speed sensors 13 to 16 provided for each R, Based on this, from the ABS control controller 19, each wheel 2L, 2L
Control signals are output to hydraulic control valves 20 to 23 for variably adjusting the brake fluid pressure supplied to the caliper 4b in the R, 3L, and 3R brake devices 4. Therefore, the signal from the pressure sensors 18...
9 and based on this, each wheel 2L, 2R, 3L, 3R
Is detected, and if there is a wheel whose ground load is smaller than a predetermined reference value set in advance, the brake fluid pressure for that wheel is variably controlled according to a predetermined characteristic.

Next, the operation of this embodiment will be described with reference to the ABS control controller 1.
If explained based on the flowchart of FIG. 4 showing the control operation by 9, the controller 19 during the ABS control, first, in step S _1, the hydraulic chamber in the hydraulic cylinder 25 constituting the active suspension device 24
The ground load P of each wheel 2L, 2R, 3L, 3R is detected based on a signal from each pressure sensor 18, which detects the pressure in 25c. Then, in step S _2, the wheels 2L, 2R,
3L, vertical load P of 3R is set to determine whether a predetermined criterion is smaller than the vertical load P ₀ in advance, if there is liable wheel locks smaller than the reference ground load P ₀ vertical load P is, step S ₃
In the case where the easily lockable wheel is in the locked state, the control time T from the time when the brake fluid pressure of the wheel is once reduced to the time when it is increased again is set to Δt from the predetermined time t.
Just set it longer. Then, in step S _4,
Upon detecting the actual locking state of easy to lock small vertical load P wheels, based on T (t + Δt) set control time by the step S _3, the braking control for the wheels. That is, as compared with the control time t of the brake fluid pressure contact load P shown by the solid line (b) in FIG. 5 is the reference ground contact load P ₀ or more wheels, vertical load P is the reference ground contact load P shown by a dotted line (b) The control time T of the brake fluid pressure for a wheel which is smaller than ₀ and is easily locked becomes longer by Δt, so that when the brake fluid pressure is once reduced and then the brake fluid pressure is increased again, the re-locking state is effectively achieved. As a result, the braking performance of the wheel, which has a small ground load P and is easily locked, is further improved. In addition,
For wheels where the ground load P is small and easy to lock,
As shown by a chain line (c) in the figure, the locked state of the wheel may be effectively canceled by increasing the pressure reduction amount of the brake fluid pressure.

Further, in step S _2, the wheels 2L, 2R, 3L,
3R contact load P is a predetermined reference contact load
When it is determined that the P ₀ or more, at step S _5, the wheels 2L, 2R, 3L, 3R a control time T of the brake fluid pressure for those wheels in case of locking, is set to a predetermined time t. Then, in step S _6, each wheel 2L,
2R, 3L, when detecting an actual lock state of the 3R, based on the set control time T (t) by the step S _5, the braking control for those wheels.

Incidentally, longer in step S _2, when it is detected that there is wheel tends to lock smaller than the vertical load P is the reference ground contact load P _0, as described above, the control time T of the brake fluid pressure for the wheel In addition to the setting, for example, when a brake is applied to a wheel that is easily locked, the brake fluid pressure on the wheel is reduced before the actual lock is detected, thereby preventing the locked state from occurring. It is possible to perform such predictive control,
The response of the braking control by the anti-skid braking system can be improved.

(Effects of the Invention) As described above, according to the present invention, during the braking operation, the brake fluid pressure for the wheel in which the locked state is detected is reduced based on the detection result of the wheel speed sensor provided for each wheel. Later, in a vehicle equipped with an anti-skid braking system that controls to increase the pressure again, for a wheel having a ground contact load smaller than a predetermined load, when the vehicle is locked during a braking operation, the anti-skid braking system is used. After the brake fluid pressure was reduced, the control time from the start of the pressure reduction to the end of the pressure increase in the control for increasing the pressure again was made longer than that of a wheel having a ground contact load larger than a predetermined load, so the brake fluid pressure was increased. This effectively prevents the wheels from re-locking, improving the braking performance of the anti-skid braking system. Will do.

In particular, according to the present invention, in a vehicle provided with an active suspension device, the contact load of each wheel is detected using a pressure sensor used in the device. It is not necessary to newly provide a sensor for this, and the above-mentioned effect can be obtained at low cost.

[Brief description of the drawings]

BRIEF DESCRIPTION OF THE DRAWINGS The drawings show an embodiment of the present invention, FIG. 1 is an overall schematic configuration diagram of a vehicle equipped with an anti-skid braking system, FIG. 2 is a schematic configuration diagram of an active suspension device equipped on the vehicle, FIG. 3 is a system diagram showing a schematic configuration of a vehicle braking control device according to the present embodiment.
FIG. 5 is a flowchart showing the control operation by the ABS control controller, and FIG. 5 is a graph showing a change state of the brake fluid pressure of the wheels during the ABS control. 2L, 2R: Front wheel, 3L, 3R: Rear wheel, 12: Anti-skid braking system, 18: 18 Ground contact load detecting means (pressure sensor), 19: Correction control means (ABS control controller) .

────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Kensuke Hayabuchi 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima Prefecture Inside Mazda Corporation (58) Field surveyed (Int. Cl. ⁶ , DB name) B60T 8/58

Claims (1)

(57) [Claims] An anti-skid which controls a brake fluid pressure for a wheel in which a locked state is detected based on a detection result of a wheel speed sensor provided for each wheel during a braking operation, and then increases the brake fluid pressure again. A braking system and an active suspension that controls supply of hydraulic oil to hydraulic cylinders individually disposed between each wheel and the vehicle body based on a detection value of a pressure sensor that detects a pressure in each of the hydraulic cylinders. A brake control device for a vehicle, comprising: a ground load detection unit configured to detect a ground load of each wheel based on a detection value of the pressure sensor; and a ground load detected by the ground load detection unit. When the wheels smaller than the predetermined load are locked, the brake fluid pressure by the above-described anti-skid braking system is reduced and then increased again. The control of the brake fluid pressure is performed so that the control time from the start of the pressure reduction to the end of the pressure increase in the control is longer than the control time when the wheel in which the ground contact load is larger than the predetermined load is locked. A braking control device for a vehicle, comprising: a correction control unit that performs correction.