JPH03121969A - Anti-skid control device - Google Patents

Abstract

PURPOSE:To attain fail-safe performance without impeding anti-skid control by prohibiting the driving of pressure control valve devices by a braking force control means when the current larger than the current for making braking liquid pressure the lowest is applied to the pressure control valve devices. CONSTITUTION:At the time of performing anti-skid control on the basis of the signals of wheel speed sensors 41-44, an electronic control device 10 drives pressure control valve devise 31-34 with currents corresponding to the wheel speed and supplies corresponding oil pressure to wheel cylinders 51-54. When the current larger than the current for making braking liquid pressure the lowest is applied, the driving of the pressure control valve devices 31-34 by the electronic control device 10 is prohibited, and braking liquid pressure corresponding to the stepping-in quantity of a brake pedal 3 from a liquid pressure control device 2 is supplied to the wheel cylinders 51-54. Fail-safe performance at the time of failure can be thus attained without impeding normal anti-skid controlling performance.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention provides a system for controlling braking force on wheels when braking a vehicle,
The present invention relates to an anti-skid control device that prevents wheels from locking.

(Prior Art) It is well known that when the wheels of a vehicle lock during sudden braking, driving may become unstable or steering performance may be impaired depending on road surface conditions. For this reason, in order to prevent the wheels from locking during sudden braking, anti-skid control devices are used that control the braking force by reducing, increasing, or maintaining the brake fluid pressure to the wheel cylinders. (1) (2) ) Also called an anti-lock control device.

In anti-skid control, in consideration of the fact that when the brake fluid pressure to the wheel cylinders (abbreviated as wheel cylinder fluid pressure) is increased, the wheel speed suddenly decreases just before the friction coefficient μ for the wheels reaches its maximum. The wheel cylinder hydraulic pressure is controlled according to the speed, and the braking force is controlled so that the slip ratio of the wheels becomes around 20%, that is, the maximum coefficient of friction is obtained.

Here, control of the wheel cylinder hydraulic pressure is performed by a braking force control means, which controls a valve device that can selectively communicate the wheel cylinder with a high pressure source (hydraulic pump) or a low pressure source (reservoir) depending on the deceleration. It is known to perform switching control using a circuit, or to control the current applied to a control valve that generates brake fluid pressure proportional to the applied current using a control circuit in accordance with the deceleration. However, in the above-mentioned anti-skid control device, due to a failure of the control circuit,
If a certain current value continues to flow through the valve device or control valve, the valve device or control valve will continue to remain open or closed, leading to insufficient braking force or premature locking of the wheels. .

Therefore, conventionally, when a certain current value continues to flow to the valve device or control valve, as described in Japanese Patent Publication No. 44-9693, the power supply to these valve devices, etc. is cut off, and the braking force is insufficient due to a failure of the control circuit. A technique for preventing the occurrence of early locking has been disclosed.

(Problem to be Solved by the Invention) However, according to the conventional device described above, the wheels actually lock for a long time and it is necessary to reduce the pressure (for example, when braking at high speed on ice, the drive wheel is However, even if the wheel speed continues to drop, energization (depressurization) is discontinued, which poses a problem that not only fails as a fail-safe in the event of a failure, but also impairs normal anti-skid control performance.

Therefore, the present invention aims to perform fail-safe operation only in the event of a failure, without interfering with the performance of normal anti-skid control, in an anti-skid control device that generates brake fluid pressure proportional to the applied current (3) (4) The technical challenge is to make it possible.

[Structure of the invention]

(Means for solving the problem) The means taken to solve the above-mentioned technical problem are: a wheel cylinder that applies braking force to the wheels of a vehicle;
A hydraulic pressure generating device that supplies brake fluid pressure to the wheel cylinder; and a pressure control valve that is interposed in a hydraulic pressure path that communicates and connects the hydraulic pressure generating device and the wheel cylinder, and that generates brake fluid pressure that is proportional to the energizing current. a wheel speed detection means for detecting the rotational speed of the wheel; and a controller for driving the pressure control valve device and controlling brake fluid pressure supplied to the wheel cylinder in accordance with at least an output signal of the wheel speed detection means. In the anti-skid control device equipped with a power control means, when a current larger than a current that lowers the brake fluid pressure to the lowest pressure is applied to the pressure control valve device, the braking force control means of the pressure control valve device This is because a driving prohibition means for prohibiting driving is provided.

The drive inhibiting means prohibits the braking force control means from driving the pressure control valve device when a current larger than a current that lowers the brake fluid pressure to a minimum pressure is applied to the pressure control valve device for a predetermined period or more. It is desirable to do so.

(Operation and Effects of the Invention) According to the present invention, the braking force control means allows the pressure control valve device to be energized for a long time at the current value required for normal anti-skid control, and when the current value is originally impossible, Only the pressure control valve device can be prohibited from being driven by the braking force control means.

(Example) Hereinafter, as an example of the present invention, a vehicle equipped with the above-mentioned anti-skid control device will be specifically described.

FIG. 1 shows an anti-skid control device according to an embodiment of the present invention, which is composed of a mask cylinder 2a and a booster 2b, and includes a hydraulic pressure control device 2 driven by a brake pedal 3, and wheels PR, FLRR, and RL. Pumps 21, 22, reservoirs 23, 24, and pressure control valve devices 31(5) (6) to 34 are interposed in the hydraulic pressure path to which the wheel cylinders 51 to 54 are connected. Note that the wheel FR indicates the front right wheel when viewed from the driver's seat, hereinafter, the wheel FI- indicates the front left wheel, the wheel RR indicates the rear right wheel, and the wheel RL indicates the rear left wheel, as shown in Fig. 1. The so-called diagonal piping is configured.

A pressure control valve device 31.34 is interposed in each hydraulic pressure path connecting one output boat of the mask cylinder 2a and the wheel cylinder 51.54, and a pump 22 is interposed between the two. Similarly, pressure control valves 32, 33 are interposed in the hydraulic lines connecting the other output boat of the mask cylinder 2a and the wheel cylinders 52, 53, respectively, and a pump 2, 33 is provided between the two.
1 is interposed. Pumps 21 and 22 are electric motors 2
0, and brake fluid pressurized to a predetermined pressure is supplied to these hydraulic pressure paths. Thus, these hydraulic pressure passages are on the supply side of brake hydraulic pressure to the pressure control valve devices 31 to 34, and the hydraulic pressure control device 2 and the pumps 21 and 22 are connected to the hydraulic pressure generating device according to the present invention. It consists of

The discharge side hydraulic pressure path of the pressure control valve device 31.34 is connected to the reservoir 2.
3 to the pump 21 and a pressure control valve device 32
．． It is connected to the pump 22 via a reservoir 24 of 33. The reservoirs 23 and 24 are each equipped with a piston and a spring, and contain the brake fluid that is returned from the pressure control valve devices 31 to 34 via the discharge side hydraulic pressure path, and when the pumps 21 and 22 are operated, the brake fluid is supplied to these reservoirs. It is intended to supply

The pressure control valve devices 31 to 34 are each equipped with a proportional pressure control solenoid valve 300 and a check valve shown in FIG. Supply and Reservoir 23.
24 is controlled, and the discharge to the wheel cylinders 51 to 5 is controlled.
Brake fluid pressure is output to each of 4 in approximately linear proportion (1 in this embodiment, inverse proportion) to the current flowing to the solenoid coil of the electromagnetic valve 300.

FIG. 1a shows a solenoid valve 3 used in a pressure control valve device 31.
00, and the other pressure control valve devices 32 to 34 are similarly configured (7) (8). The solenoid valve 300 is made up of a case 301 that is a cylinder with a bottom and a yoke 331 that is a cylinder with a bottom, both open ends of which are joined together, and a plunger 30 is inserted into a cylinder hole formed inside both of them at the negative end.
A magnetic spool 303 having a magnetic material 2 is slidably housed therein. Two annular grooves 304 and 305 are formed perpendicularly to the axial direction on the inner surface of the cylinder hole of the case 301.
The annular groove 304 is connected to the hydraulic pressure control device 2 of FIG. 1 via a filter 337, and the annular groove 305 is connected to the reservoir 23
is connected to. Further, a pressure chamber 309 is formed at the bottom of the case 301, and a plunger 302 of a spool 303 is slidably fitted in a liquid-tight manner into a through hole formed in the axial direction of the bottom.

Three land portions are formed on the spool 303,
Annular recesses 306 and 307 are formed between them. The recess 306 is in the annular groove 3 in the initial position shown in FIG. 1a.
04, and the recess 307 is formed to face the annular groove 305. Further, a boat is formed on the inner surface of the cylinder hole of the case 301 facing the recess 306, and the recess 306 is constantly communicated with the wheel cylinder 51 via this port and a filter 338. Recess 306
The opening area of the flow path formed by the annular groove 304 and the annular groove 304 is
The spool 303 is at its maximum in the initial position shown in the figure, and the yoke 3
As it moves in the 31 direction, it is reduced in size and is interrupted at approximately the middle position. When the spool 303 slides further, the recess 306 and the annular groove 305 face each other to form a flow path. Although the opening area of the flow path formed by the recess 307 and the annular groove 305 decreases as the spool 303 moves toward the yoke 331, a state of communication is maintained at all times.

A communication hole 308 is formed in the axial direction of the spool 303 and opens outward from the land portions at both ends.
8 is communicatively connected to the recess 307. Therefore, the annular grooves 305 are located outside the land portions at both ends of the spool 303.
It communicates with the reservoir 23 via the spool 303.
Both ends are drain pressure. The pressure chamber 309 is communicated with the boat (9) (10) of the case 301 that opens into the recess 306 of the spool 303, and is connected to the hydraulic control device 2 through a flow path formed by the annular groove 304 and the recess 306. Brake fluid pressure is supplied from Therefore, while the flow path is being formed, pressure is applied to the spool 303 in the direction of the yoke 331, which acts on the end surface of the plunger 302.

A non-magnetic ring 332 is disposed in the inner cylindrical portion of the yoke 331 to form an air gap.

A solenoid coil 333 is wound around this inner cylindrical portion, and one end of the solenoid coil 333 is connected to the electronic control device IO. A spring 334 is housed in the cylinder hole of the yoke 331, and the spool 303 is biased toward the focusing chamber 309.

In the solenoid valve 300 configured as described above, when the solenoid coil 333 is de-energized, it is in the initial position shown in FIG. .

When the solenoid coil 333 is energized, the sprue 303
moves in the direction of the yoke 331 and forms the annular groove 304 and the recess 306.
As a result, the brake fluid pressure supplied to the wheel cylinder 51 is reduced to the spool 303
decreases depending on the distance traveled. Solenoid coil 333
Since the current applied to the yoke 331 is small and the electromagnetic force of the yoke 331 is also small, the distance by which the spool 303 slides in the direction of the yoke 331 against the biasing force of the spring 334 is small. At this time, since the spool 303 is separated from the yoke 331, the urging force of the spring 334 does not apply an electromagnetic force corresponding to the magnitude of the current flowing. For this reason,
In this embodiment, a pressure chamber 309 is provided, during which brake hydraulic pressure output from the hydraulic pressure control device 2 is applied to the plunger 302 to counteract the biasing force of the spring 334.

When the current applied to the solenoid coil 333 is gradually increased, the spool 303 moves further toward the yoke 331 due to the electromagnetic force, and the flow path formed by the annular groove 304 and the recess 3.degree. 6 is interrupted, resulting in a hold state.

Then, when the applied current is further increased, the recess 306 faces the annular groove 305, and the wheel cylinder 51 moves toward the reservoir 23.
This will lead to communication. As the applied current increases, the opening area of the flow path formed by the recess 306 and the annular groove 305 increases. As a result, the brake fluid pressure in the wheel cylinder 51 decreases, and when the spool 303 comes into contact with the stopper of the yoke 331, the opening area reaches its maximum and becomes close to the drain pressure. During this time, plunger 3
The hydraulic pressure applied to the spring 334 is the drain pressure supplied through the recess 306 and the annular groove 305.
The force that opposes the urging force of is becoming smaller.

Therefore, the cross-sectional area of the plunger 302, the annular groove 304.3
05 and the dimensions and positions of the recesses 306 and 307, the biasing force of the spring 334, and the electromagnetic force of the solenoid coil 333, etc., it is possible to obtain a substantially linear current-output hydraulic characteristic as shown in Fig. 1b. can get. Note that check valves 335 and 336 are disposed within the pressure control valve device 31 to allow brake fluid to flow back to the hydraulic pressure control device 2.

As shown in FIG. 1, the pressure control valve devices 31 to 34 are connected to the electronic control device 10, and the current applied to the solenoid coil 333 of the electromagnetic valve 300 is controlled. The electric motor 20 is also connected to the electronic control device 10 and is driven and controlled thereby. Further, wheel speed sensors 417'l to 44 are arranged on the wheels PR, FL, RR, and RL, respectively, and these are connected to the electronic control bag [10, so that the rotational speed of each wheel, ! The wheel speed signal is input to the electronic control unit ``0''. The wheel speed sensors 41 to 44 in this embodiment are composed of a pickup section in which a coil is wound around a permanent magnet once, and a rotor section in which teeth are formed on the outer peripheral end, and output an alternating current voltage, and the configuration thereof is well known. Therefore, the explanation will be omitted.

As shown in FIG. 2, the electronic control device 10 includes a microcomputer 11.
1 has a CPU, ROM, RAM, etc. (not shown), and is connected via a common bus to input ports 1-IPI to IP8 and output ports OPI to O(13) (14) P6 to perform input/output with the outside. . 1- The detection signals of the wheel speed sensors 41 to 44 are transmitted to the waveform shaping circuit 1.
microphone C1::Imp:7. -Input on evening 11th. In addition, the output capacitors 1-Or) 1 to 0I) 4 are connected to drive circuits 13a to 13d and current detection resistors 14a to 14d, respectively.
A pulse width modulation (PWM) signal is output to each solenoid coil of the pressure control valves 31 and 34 through the
A control signal is output from the output boat OP5 to the conductive motor 20 via the drive circuit 13e.

The current detection resistors 14a to 14d detect the current flowing through each solenoid of the pressure control valve devices 31 to 34, and their resistance values are extremely small. and,
The detection signals of these current detection resistors 14, 1 to 14d are sent to the microcomputer 11 via voltage amplifiers 15a to 15d and A/L converters 16a to 16d, respectively.
The input capo-L 11) is configured to be input to IP8.

Thus, the PWM signal is output from the microcomputer 11, and the drive circuits 13a to 13d energize each solenoid coil of the pressure control valve devices 31 to 34, and a detection signal indicating the value of each energized current is sent to the microcomputer 11. is input. The values of these currents are the first
1) As shown in the figure, since it is approximately linearly and inversely proportional to the brake fluid pressure output from the pressure control valve devices 31 to 34, the pressure is approximately linearly inversely proportional to the brake fluid pressure outputted from the pressure control valve devices 31 to 34, so that the pressure is approximately linearly inversely proportional to the brake fluid pressure outputted from the pressure control valve devices 31 to 34, so that the pressure is approximately linearly inversely proportional to the brake fluid pressure outputted from the pressure control valve devices 31 to 34. The input detection signal corresponds to the brake fluid pressure supplied from the pressure control valves 31 to 34 to each of the wheel cylinders 51 to 54.

Further, in this embodiment, the pressure gradient control valve devices 31 to 3
4, when the spool 303 comes into contact with the stopper of the yoke 331 and reaches its maximum opening area, the hydraulic pressure in each wheel cylinder becomes close to the drain pressure (when the brake hydraulic pressure is at the lowest pressure (
The maximum output current value of the energizing current to each solenoid coil is determined when 'i 0 kg/cm2). Then, through each voltage amplifier 15a to i5d,
The currents flowing through the solenoid coils of the pressure control valve devices 31 to 34, which are input to the A/D converters 16a to 16d and detected by the current detection resistors 14a to 14d, are compared by the comparators 17a to 17d, respectively. Each output signal is AN along with the output signal from output port 1-OP6
The signal is input to the D gate 18a. AN
The output signal of the D gate 18a is energized through the output amplifier 18b to the relay coil of the fail-safe relay 19 to turn the fail-safe relay 19 on. In addition, the fail-safe relay 19 is
It is interposed in the output circuit of each solenoid coil of each pressure control valve device 31 to 34, and allows energization of each solenoid coil in an ON state, and cuts off energization of each solenoid coil in an OFF state. There is.

In the electronic control device 10, a series of processes for anti-skid control are performed, which will be explained below based on FIGS. 3 to 12.

FIG. 3 shows Freezer 1 which shows an outline of the control of an embodiment of the anti-skid control device of the present invention, which is repeatedly executed at predetermined time intervals. When the power is turned on and the routine is started in step 100, the routine is first initialized in step 110, and the estimated vehicle speed ``8'' and the wheel speed of each wheel (hereinafter referred to as wheel speed ``8'' representing each wheel) are initialized in step 110. ) is set to 0, and the process proceeds to step 120, where the wheel speeds Vl, l detected by the wheel speed sensors 41 to 44 are read.

Next, in step 130, the wheel speed ■ is determined. The wheel acceleration of each wheel (hereinafter referred to as wheel acceleration DVW representing each wheel) is calculated from 1. Estimated vehicle speed ■
, and wheel speed■. The slip rate S of each wheel is calculated from . Then, when 5m5ec has elapsed, it is determined whether map control is in progress (steps 140, 150). That is, it is determined whether anti-skid control for each wheel, which will be described later, is being executed. Since anti-skid control is not performed in the first process, the process proceeds to step 160, where it is determined whether or not the initial logic is in operation. The initial logic (17) (18) is executed in steps 201 to 204 at the first stage of anti-skid control, and details will be described later.

The starting conditions for the initial logic are determined in step 200, and according to the map shown in FIG.
When the slip rate S is below a predetermined value and the slip ratio S is above a predetermined value, the anti-skid control is started, that is, the initial logic is executed, and the process proceeds to steps 201 to 204. If the area does not fall within the above range, the process directly proceeds to step 500. In addition, in the above region, when a braking force is applied to a wheel, the wheel speed rapidly decreases when the wheel becomes locked and starts to slip. Undeath control is set to start when .

When the target hydraulic pressure is set in steps 201 to 204, control is performed in steps 401 to 404 to output brake hydraulic pressure corresponding to this target hydraulic pressure to the wheel cylinders 51 to 54. That is, the pressure control valve device 31 is adjusted so that the brake fluid pressure supplied to the wheel cylinders 51 to 54 in FIG. 1 has the same fluid pressure value as the target fluid pressure.
The drive currents for the solenoid coils 34 through 34 are controlled. The pressure control valve devices 31 to 34, as described above,
Each of them is composed of the proportional pressure control solenoid valve 300 shown in FIG. 1a, and is controlled to be approximately linearly and inversely proportional to the current supplied through the drive circuits 13a to 13d shown in FIG. 2, respectively. Therefore, the PWM supplied from the microcomputer 11 to these drive circuits 13a to 13d
By setting the output to a value corresponding to each target hydraulic pressure,
The brake fluid pressures supplied from the pressure control valve devices 3-34 to the wheel cylinders 51-54, respectively, can be controlled to respective target fluid pressure values.

Steps 201 to 204 and Steps 401 to 40
When the initial logic execution is completed through step 4, steps 301 to 304 and steps 401 to 40 will be executed from next time onwards.
4 for each wheel PR, Fi.

, RR, RL wheel cylinders 51 to 54 are controlled by a map, and l Qms
Estimated vehicle speed ■, etc. are calculated and read in the e c cycle (steps 500, 600, and 120).

Next, each wheel F in the above steps 201 to 204
The initial 1'' sick subroutine of R, FL, RR, R1 will be explained based on FIG.

When transitioning to the initial logic, a timer is set, and a snap 211 determines whether 20 rnsec has elapsed, and the target hydraulic pressure is set to a predetermined value, for example, 20 kg/cm 2 for 20 m5 sec after the start of the initial logic. Then, in steps 401 to 404 in FIG. 3, the pressure control valve devices 31 to 34 are adjusted so that the brake fluid pressure supplied to the wheel cylinders 51 to 54 in FIG. is driven and controlled.

The operation during this time is the wheel speed during braking and the wheel acceleration DV.
Explaining based on FIG. 8 showing changes in W and wheel cylinder hydraulic pressure, the brake pedal 3 is operated at point (a), the brake hydraulic pressure in the wheel cylinders 51 to 54 increases, and a braking force is applied to the wheels. is given. At point (b), the wheel acceleration D■W becomes less than the predetermined value, and the process shifts to anti-skid control. At the first stage, the pressure is reduced at once for 20 m5ec to the target hydraulic pressure of 20 kg/am2. If reduced, the time required for this decompression operation is approximately 2
Since it is 0rnsec, step 2 above is performed accordingly.
]1 time is set. Therefore, step 211
The above-mentioned time in is set according to the target hydraulic pressure and the pressure reduction operation time of the pressure control valve devices 31 to 34.

When 20 m5ec has elapsed after the transition to the initial logic, the process proceeds to step 213, where it is determined whether or not the pressure is increasing at a constant value of -1- shown in FIG. It is determined whether the wheel acceleration DVW has a peak, that is, whether it has reached its maximum value. Since the peak has not been reached at this stage, the value of the wheel acceleration DVW is compared with a predetermined value 5G in step 215. If the wheel speed DVW is below 5G, the target hydraulic pressure value Psg is set in step 216 using the following formula. Therefore, (2j) (22), target hydraulic pressure P S g −1/2 (1) s +
Pg). Here, Ps and Pg are determined based on the diagrams shown in FIGS. 9 and 10, respectively, and these diagrams are set according to the characteristics of the vehicle. Ps is PW
Pressure control valve devices 31 to 3 driven by the M output signal
The output hydraulic pressure of No. 4 is set to vary as shown in FIG. 9 according to the slip ratio S of each wheel. Pg is the same <PWM
Pressure control valve devices 31 to 3 driven by output signals
The output hydraulic pressure of No. 4 is set to vary as shown in FIG. 1O in accordance with the wheel acceleration D V W of each wheel. Furthermore, the 9th
In the figures and Fig. 10, Fr is the front wheel, that is, the wheel FL.
It shows the characteristics used for FR, and Rr is the rear wheel, that is, the wheel R.
The characteristics used for R and RL are shown, and the vertical axis shows the PWM output corresponding to the output hydraulic pressure of the pressure control valve devices 31 to 34. Therefore, the target hydraulic pressure Psg is also calculated as a PWM output.

For example, in the example of FIG. 8, the target hydraulic pressure Psg in step 216 is 20 kg at point (c).
/cm2, the minimum value of the wheel acceleration DVW, that is, the maximum value of the deceleration, has passed, the wheels are no longer locked, and the wheel acceleration DVW is recovering. The faster this recovery occurs, the more the vehicle is traveling on a road surface with a high coefficient of friction, so it is necessary to increase the wheel cylinder hydraulic pressure. At this time, the slip rate S has also recovered, and for example, from FIG.
Assuming that the PWM output (hereinafter simply indicates the hydraulic pressure value) is equivalent to s -30 kg/cm2 and the wheel acceleration DVW is near OG and becomes P g = 50 kg/cm2 from Fig. 10, the target hydraulic pressure Psg is 40 kg. /cm2, which means that the pressure will be increased from the initial target hydraulic pressure of 20 kg/cm2.

On the other hand, when the vehicle is running on a road surface with a low coefficient of friction, for example, the wheel acceleration DVW continues to decrease even if the pressure is reduced to 20 kg/cm2. Therefore, when the slip ratio S is, for example, 40%, Ps is a low value of, for example, 4 to 5 kg/cm Z. In addition, the wheel acceleration D■W also tends to lock and is low, so the pgO value is also 30 kg/c, for example.
It will be about m2. Therefore, the target hydraulic pressure is approximately 17 kg/cm
2, which is an even lower value than the initial target hydraulic pressure of 20 kg/cm''.

In this way, at least at this point, it is possible to determine whether the friction coefficient of the road surface is high or low.

Next, if it is determined in step 215 that the wheel acceleration DVW is 5G or more, the process proceeds to steps 217 and 218, and if the wheel acceleration DVW is not OG, the wheel speed ■ is compared with the estimated vehicle speed ■, and the wheel speed is still ■8 is estimated vehicle speed■
If it is less than 5, the next target hydraulic pressure Psg is set in step 219. In other words, the target hydraulic pressure Psg is a little amount (α) with respect to the target hydraulic pressure Psg obtained in step 216.
The increased value is used to set the pressure to gradually increase. As a result, pressure increase control from point (2) to point (e) in FIG. 8 is performed.

Steps 200 to 204 and 401 to 40 in FIG.
4, the control of the initial logic is completed, and when the wheel speed V and the estimated vehicle speed ■ become equal to point (e) in FIG. 8, the process proceeds from step 218 to step 220 in FIG. 4, and the initial logic ends. map control is started.

Further, in step 217, the wheel acceleration DVW is determined to be OG.
If so, the process also proceeds to step 220 and is processed in the same way.

When the map control flag is set, step 301 in FIG.
In steps 304 to 304, the map control target hydraulic pressure for each wheel is calculated. The microcomputer 11 in FIG.
A map as shown in FIG. 3 is constructed using wheel acceleration DVW and slip rate S as parameters, and the pressure control valve devices 31 to 34 are controlled based on this map.

First, the wheel speed■, as in the initial stage immediately after shifting to map control. When V is approximately equal to the estimated vehicle speed V, control is performed to maintain that state. That is, the eighth
Assuming that the wheels are locked at point (f) in the diagram and the wheel cylinder hydraulic pressure at this point is Pl, if a predetermined percentage of this Pl, for example 80% or more, the braking torque is large but the wheel pressure is The hydraulic pressure is such that it will not cause locking.

In order to maintain this hydraulic control for as long as possible, the wheel cylinder hydraulic pressure is gradually increased, and when it falls below 80 (25) (26)%, the pressure is increased slowly so that it reaches this level quickly. controlled.

As shown in FIG. 5, which shows the processing contents of the subroutine of steps 301 to 304, the target pressure increase mode is set. When it is determined in step 31 (2) to start the map control, it is determined in steps 312 to 314 whether or not the target pressure increase mode can be executed. That is, it is determined whether the conditions of the "target pressure increase region" in FIG. 12 are satisfied.

When the process proceeds to step 315 and the target hydraulic pressure is set, the process proceeds to step 325 and step 326 in which the wheel cylinder hydraulic pressure is set to 80
It is determined whether or not it is smaller than %. 80% of hydraulic pressure P1
If the pressure control valve device 3 is smaller than the
A rapid pressure increase signal is output for 1 to 34, and if it is 80% or more, a slow pressure increase signal is output in step 328 to maintain this state.

Steps 316 and 317 in FIG.
In the process when the wheel cylinder hydraulic pressure is subjected to halt control, that is, pressure holding control, it is determined whether or not it is in the "hold region" in FIG. 12. Similarly, it is determined in steps 319 and 320 whether the state is in the "elephant, pressure increase region" in FIG.
A sudden pressure reduction signal is output at step 321. Step 322 for areas other than the area marked 1 in FIG.
A continuous pressure reduction signal is output. After this, if it was in the pressure increase or hold region during the previous treatment, step 3
24, the hydraulic pressure is stored as lock pressure Pl. Then, as shown in FIG. 3, the estimated vehicle speed Vs, etc. are calculated every 10 m5ec (steps 500 and 600), and l
The map control described above is repeated.

The estimated vehicle speed (2) is calculated according to the flowchart shown in FIG. First, in step 601, the wheel speeds of the four wheels VwFR+-+, VwF1. T.

), V W RR (nl+ V W RL (II)
The maximum value VWmax (nl) is calculated. Note that n represents the calculation time. Next, in step 602, the wheel cylinder hydraulic pressures PIFR, PIFL, PI when each wheel is locked are calculated.
R.R.

The average PIM of p i RL is determined, step 60
In step 3, acceleration (deceleration) αD N corresponding to PIM is set according to a predetermined diagram (not shown). Step 604
If it is determined that VWm++x(n) is larger than VS(n-11-αDN, then VS(11+=VS(11-11-α
It is considered as DN, and if it is not, ■. maX(nl is V5
(steps 605, 606).

Thereafter, in step 607, the various reference speeds VSN+VSI+VSNh=VSIi in FIG.
=0.8.

v, -10 (h/h).

In addition, the initial logic processing may be performed as appropriate even during map control, if the wheel speed (1) drops abnormally, or if the wheels do not lock despite a long period of gradual pressure increase. It may be configured to perform as shown in FIGS. 3 and 4.

Therefore, in this embodiment, as shown in FIG. 2, the maximum output current value of the pressure control valve devices 31 to 34 (the value that brings the brake fluid pressure to the lowest pressure (#Okg/cm")) is determined, and the pressure The currents flowing through the solenoid coils of the control valve devices 31 to 34 are compared by the comparators 17a to 17d, and their respective output signals are input to the AND gate 1-18a together with the output signal from the output port OP6. If the output signal of the AND game 18a is turned on, the relay coil of the fail-safe relay 19 is energized via the output amplifier 18b, and the fail-safe relay 19 is turned on.
It is designed to be in the N state.

In this embodiment having such a configuration, when a current exceeding the maximum output current value flows due to a failure in the microcomputer 11 or the drive circuits 13a to 13d, the comparators 17a to 17d detect this and The outputs from 17d to 17d become low level. As a result, the output of the AND gate 18a becomes low level, the output amplifier 18b outputs a low level, and as a result, the fail-safe relay 19 is turned off. Therefore, energization to each coil of the pressure control valve devices 31 to 34 is cut off, and the maximum value of the output hydraulic pressure shown in FIG. It is said that

This prevents the current from continuing to flow beyond the maximum output current value, and prevents the braking force from being insufficient due to the current continuing to flow.

In the above-mentioned embodiment, when a current exceeding the maximum output current value flows, the energization to each coil of the pressure control valve devices 3115 to 34 is cut off. It is also possible to shut it off when it continues for a certain period of time. Furthermore, in the embodiment described above, the energizing current is cut off when a current equal to or greater than the maximum output current flows through each coil, but it may also be detected by the magnitude of the PWM duty. .

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram of an embodiment of the anti-skid control device of the present invention, and FIG. 1a is a sectional view of the same pressure control valve device.
FIG. 1b is a characteristic diagram of the pressure control valve device shown in FIG. 1a, FIG. 2 is a block diagram showing the configuration of the electronic control device shown in FIG. 1, and FIG.
The figure is a flowchart 1 showing an overview of the processing for anti-skid control in the electronic control unit of Fig. 1, Fig. 4 is a flowchart showing the subroutine processing of the initial logic of Fig. 3, and Fig. Figure 6 shows the process of the map control target hydraulic pressure calculation subroutine. 7 is a graph for determining the start of the initial logic in FIG. 3, and FIG. 8 is a graph showing the wheel speed according to the initial logic processing in FIG. 4 and the target pressure increase mode processing in FIG. 5. . A time chart showing changes in wheel acceleration DVW and wheel cylinder hydraulic pressure, and Fig. 9 shows the output Ps and slip rate S for setting the target hydraulic pressure in the initial logic of Fig. 4.
Figure 10 is a graph showing the relationship between the output Pg and wheel acceleration DVW, and Figure 1 is a graph showing the relationship between the output Pg and wheel acceleration DVW. A graph showing the relationship between the current flowing through the device and the boosting speed, Figure 12 is the 5th graph.
Wheel acceleration DVW and wheel speed V for map control in the figure
It is a graph showing the relationship with w. 2... Hydraulic pressure control device (hydraulic pressure generating device), 2a... Mask cylinder, 3... Brake pedal, 10... Electronic control device, 11... Microcomputer, 12...
...Waveform shaping circuit, 13a to 13d...Drive circuit, 1
4a-14d...Current detection resistor, 17a-17d...
・Comparator, L8a...AND gate, 18b・
...Output amplifier, 19...Failsafe relay,
20... Electric motor, 21.22... Pump (hydraulic pressure generator), 23.24... Reservoir, 31-34.
...Pressure control valve device, 41-44...Wheel speed sensor, 51-54...Wheel cylinder, 300...Proportional pressure control solenoid valve, FR, EL, RR, RL...Wheel.

Claims (2)

[Claims] (1) A wheel cylinder that applies braking force to the wheels of a vehicle, a hydraulic pressure generator that supplies brake fluid pressure to the wheel cylinder, and a hydraulic pressure that supplies the hydraulic pressure generator and the wheel cylinder. a pressure control valve device that is installed in a road and generates a brake fluid pressure proportional to the applied current; a wheel speed detection device that detects the rotational speed of the wheel; and a pressure control valve device that detects the rotational speed of the wheel; In an anti-skid control device comprising a braking force control means for driving a control valve device and controlling brake fluid pressure supplied to the wheel cylinder, the pressure control valve device is provided with a current larger than the current that lowers the brake fluid pressure to a minimum pressure. An anti-skid control device comprising a drive inhibiting means for inhibiting the braking force control means from driving the pressure control valve device when a current is applied. (2) The drive inhibiting means controls the braking force control means of the pressure control valve device when a current larger than a current that lowers the brake fluid pressure to the lowest pressure is applied to the pressure control valve device for a predetermined period or more. The anti-skid control device according to claim 1, wherein the anti-skid control device prohibits driving.