JP2527062B2 - Anti-skidding control device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-skid control device for preventing wheel lock during braking, and particularly performs inappropriate operation even during vehicle braking due to vehicle vibration due to a bad road or the like. Not about the anti-skid controller.

[Conventional technology]

FIG. 6 is an explanatory diagram showing an example of operation of a conventional antenna skid control device disclosed in, for example, Japanese Patent Laid-Open No. 62-261566, which prevents early reduction of braking pressure on a bad road or the like. In FIG. 6, the wheel speed 101 is followed by a speed difference lower by a predetermined speed ΔV _0, and the wheel speed 101 is decelerated with a constant deceleration gradient θ from the time when the deceleration reaches a predetermined value. Pseudo wheel speed 102 is wheel speed 101
The pressure reduction of the braking pressure 103 is started from the time point when it becomes equal to. Further, a time T from the start of the brake operation or the high peak time of the wheel speed to the next high peak time of the wheel speed, and a time t from the low peak time of the wheel speed to the high peak time within this time T.
And the speed difference Δv between both time points is measured. Then, the times T and t are within the preset times T ₀ and t ₀ , respectively, and the speed difference Δv is the preset speed difference Δv _0.
If the above is the case, by changing the predetermined speed difference ΔV ₀ of the pseudo wheel speed 102 to the predetermined speed difference ΔV ₁ larger than the speed difference ΔV ₀ , the early reduction of the braking pressure P101 is started. To prevent the braking distance from becoming long. In FIG. 6, P101 is the braking pressure in the first cycle and P102 is 2
It is the braking pressure after the second cycle.

[Problems to be Solved by the Invention]

In the conventional antenna skid control device as described above,
For example, if the brake is applied while the transmission is geared while traveling on a low friction coefficient road, there is a possibility that vibration of wheel speed due to engine rotation may occur in the drive wheels. In the above case, if the road is determined to be a bad road due to the vibration of the wheel speed and the braking pressure is prohibited from being reduced by the correction of the bad road, there is a risk that the wheel may be locked. In addition, when vibration of the wheel speed occurs on a bad road, the braking distance increases due to over-decompression unless the bad road is detected early and correction is not performed.

The present invention has been made in view of such a point,
The object is to obtain an anti-skid control device that detects a bad road early and accurately and optimizes the amount of pressure increase / decrease.

[Means for solving the problem]

In order to solve such a problem, the present invention provides an acceleration detecting means and a deceleration detecting means for generating an acceleration control signal and a deceleration control signal at a wheel acceleration and a wheel deceleration higher than a predetermined acceleration reference value and deceleration reference value. Means and
First time measuring means for measuring a first time after the deceleration control signal is generated until the acceleration control signal is generated,
Second time measuring means for measuring a second time until the deceleration control signal is generated after the acceleration control signal disappears;
First and second rough road index converting means for converting each of the first time and the second time into a predetermined first and second rough road index, and a first and a second rough road index A rough road index adding means for adding and a boosting / decreasing amount correcting means for correcting the boosting / decreasing amount according to the added rough road index are provided.

[Action]

In the anti-skid control device according to the present invention, the rough road index converting means converts the first time and the second time into a rough road index, and the boosting / decreasing amount calculating means by the boosting / decreasing amount correcting means according to the rough road index. Then, the amount of pressure increase / decrease is corrected to make the braking pressure the optimum pressure on a bad road.

〔Example〕

An embodiment of an anti-skid control device according to the present invention will be described below with reference to the drawings.

FIG. 1 is a block system diagram showing an embodiment of an anti-skid control device according to the present invention. In the figure,
1 is a wheel speed detecting means, 2 is a slip ratio calculating means, 3 is a wheel acceleration calculating means, 4 is a wheel acceleration detecting means, 5 is a wheel deceleration detecting means, 6 is a first time measuring means, and 7 is a second.
Time measuring means, 8 is a first rough road index converting means, 9 is a second rough road index converting means, 10 is a rough road index adding means, 11 is a pressure increasing / decreasing amount correcting means, and 12 is a pressure increasing / decreasing amount calculating means. , 13 are braking pressure adjusting means.

In FIG. 1, the slip rate calculating means 2 calculates the slip rate from the wheel speed detected by the wheel speed detecting means 1, and the wheel acceleration calculating means calculates the wheel acceleration. Further, the wheel acceleration detecting means 4 and the wheel deceleration detecting means 5 generate the acceleration control signal α1 and the deceleration control signal α2 when the wheel acceleration and the wheel deceleration are equal to or higher than a predetermined acceleration reference value and deceleration reference value, respectively. ing.
The time measuring means 6 measures the time T ₁ from the occurrence of α2 to the occurrence of α1 and the time measuring means 7 measures the time T ₂ from the disappearance of α1 to the occurrence of α2. The rough road index conversion means 8 and the rough road index conversion means 9 operate at time T ₁ and
T ₂ is converted to predetermined rough road indexes g 1 and g ₂ , respectively, and the converted rough road indexes g 1 and g 2 are added to rough road index adding means.
According to the rough road index G added by 10, the pressure increase / decrease amount correction means 11 outputs a signal gg indicating G to the pressure increase / decrease amount calculation means 12 so that the braking pressure becomes optimum. The pressure increase / decrease amount calculation unit 12 calculates the pressure increase / decrease amount based on the slip ratio, the wheel acceleration, and the output signal gg of the pressure increase / decrease amount correction unit 11, and outputs the pressure increase signal / pressure decrease signal to the braking pressure adjustment unit 13. . The braking pressure adjusting means 13 is driven by the pressure increasing signal and the pressure reducing signal to increase and decrease the braking pressure.

Next, a more specific example of the present invention will be described with reference to FIG. FIG. 2 (a) is a configuration diagram thereof, and only one wheel is shown for simplification. In FIG. 2 (a), 14 is a wheel brake, 15 is a wheel speed sensor arranged on the wheel, 16 is a control circuit, 17 is a power switch, 18 is an automobile battery, 19 is a brake pedal, and 20 is a master cylinder. , 21 is an actuator for adjusting the braking pressure, 22 is a conduit, 23
Is a reservoir, 24 is a pump motor, and 25 is a pressure accumulator. 16a is an input circuit, 16b is a CPU, 16c is a memory, 16d is an output circuit, 21a, 21b and 21g are rooms, 21c is a cut valve, 21d.
Is a piston, 21e is a pressure reducing solenoid, and 21f is a holding solenoid.

In FIG. 2 (a), the control circuit (16) receives power supply from the vehicle battery 18 through the power switch 17, and receives the signal from the wheel speed sensor 15 at the input circuit 16a.
A CPU 16b using a microcomputer is operated by a memory 16c storing an instruction program, and outputs a calculation result through an output circuit 16d. Normally, when the driver steps on the brake pedal 19, the braking force passes through the master cylinder 20 and the braking pressure adjusting actuator 21,
Reach wheel brake 14.

On the other hand, the operation when in the anti-skid control state will be described together with the enlarged view of the actuator in FIG. 2 (b). Normally, the chambers 21a and 21b are kept at the same pressure, and the cut valve 21c is opened by being pushed by the piston 21d. When the pressure reduction signal is output from the control circuit 16, the pressure reduction solenoid
Both 21e and the holding solenoid 21f are driven to release the pressure in the chamber 21a through the conduit 22 to the reservoir 23. Therefore, the piston 21d moves upward in the figure, and the cut valve 2
1c is closed, the master pressure and the wheel pressure are cut off, the volume of the room 21g is expanded, the wheel pressure is reduced, and the braking force is reduced. Next, when the control circuit 16 outputs a holding signal, the pressure reducing solenoid 21e is deactivated and only the holding solenoid 21f is driven. As a result, the piston 21d stops and the braking force is retained. Next, when the control circuit 16 outputs the pressure increase signal, the pressure reducing solenoid 21e and the holding solenoid 2 are
Since both 1f are inoperative, the pump motor 24 and the pressure accumulator 25 that maintain high pressure are used as power sources, pressure enters the chamber 21a, the piston 21d moves downward in the figure, and the volume of the chamber 21g is reduced. By reducing it, the braking pressure increases.

As described above, according to the command from the control circuit 16, decompression /
It has a function of adjusting the braking force to prevent the wheels from being locked by repeating the holding and increasing the pressure.

Next, the operation of the microcomputer 16b in the control circuit 16 will be described based on the flowchart of FIG. First, in step 31, each RAM, output value, etc. are initialized, and in step 32, the wheel speed V _n is calculated.
As a calculation method, a pulse signal having a frequency proportional to the rotation speed of the wheel of the wheel speed sensor 15 is input to the input circuit of FIG. 2 (a).
Input through 16a, input pulse number P within a fixed period
_n and the time t when the first pulse is input after starting the measurement
And _P1, by the final pulse input time t _Pn, and the like _{V n = k (P n -1} ) / period measurement method for obtaining the formula of (t _Pn -t _P1). Here, k is a constant. Next, in step 33, the vehicle body speed V _Pn is calculated. As the calculation method, the higher value of the wheel speed V _n and the value obtained by reducing the vehicle body speed V _Pn-1 one control cycle before by a predetermined gradient is selected. Next, in step 34, the slip ratio Sn is calculated. As a calculation method is obtained from the equation of _{Sn = (V Pn -V n)} / V Pn. Next, at step 35, the wheel acceleration αn
Is calculated. A calculation method, by the wheel speed V _n-1 of the control period T _L and one control cycle before the microcomputer and current wheel speed _{V n, αn = L (V} n -V n-1) / T L of It can be obtained by a formula. Where L is a constant and α
Acceleration occurs when n> 0 and deceleration occurs when αn <0. Then step
At 36, the acceleration control signal α1 and the deceleration control signal α2 are generated when the wheel acceleration αn and the deceleration (−αn) are equal to or higher than the predetermined acceleration reference value and deceleration reference value. Next, in step 37, the time T ₁ from the occurrence of α2 to the occurrence of α1 and the time T ₂ from the disappearance of α1 to the occurrence of α2 are measured. Next, at step 38, from the T ₁ and T _2, a maximum value at a time corresponding to the fluctuation frequency 7~15Hz of the wheel speed in the rough road becomes smaller as the time becomes longer, T ₁ and T ₂ each Find the predetermined first and second rough road indices g1 and g2, and
At 39, the rough road indexes g1 and g2 are added. Next, at step 40, a predetermined increase / decrease amount correction time T _n that takes a larger value as the rough road index is larger is calculated from the added rough road index G. Further, the pressure increase / decrease amount correction time T _n is decreased each time the pressure reducing condition is satisfied in steps 41 and 42.

Next, in steps 41 and 42, the wheel acceleration αn and the slip ratio Sn are compared with the predetermined wheel deceleration reference value α0 and the slip ratio reference value S0. When αn ≧ α0 and Sn ≦ S0, the pressure increase is performed in step 43. When the condition is satisfied, the pressure increasing signal is output in step 44, and when the pressure increasing condition is not satisfied in step 43, the hold signal is output in step 45. Also step
In 41 and 42, when the wheel acceleration αn or the slip ratio Sn is larger than the wheel deceleration reference value α0 or the slip ratio reference value S0 (when αn <α0 or Sn> S0), the pressure increase / decrease amount correction time T _n is determined in step 46. When it is compared with zero, the pressure reduction signal is output in step 47 when it is zero, and the pressure increase signal or the hold signal is output in steps 43, 44 and 45 when it is greater than zero. That is, if T ₁ and T ₂ are short, then T ₁ and
Since the bad road index corresponding to T ₂ has a large value, it is determined that the road is a bad road, and if the pressure reduction is prohibited for a predetermined increase / decrease amount correction time T _n that is determined according to the size of the bad road index, the excess pressure is exceeded. Prevents decompression and sets the braking pressure to the optimum pressure for the road surface.

Next, regarding the case where the above operation is performed in the vehicle,
Description will be made with reference to FIGS. If the wheel speed changes on a rough road as indicated by the characteristic line 101 in FIG. 4A, the vehicle body speed is calculated as indicated by the characteristic line 104, and the vehicle body speed including the slip ratio S0% is indicated by the characteristic line 105. And the wheel acceleration shown in FIG. 4B is calculated as indicated by the characteristic line 106. Due to the wheel acceleration characteristic line 106, the acceleration control signal α1 and the deceleration control signal α2 shown in FIGS. 4 (c) and (d) change like waveforms 107 and 108, and the decompression signal shown in FIG. 4 (e) has a waveform. As shown by 109, the braking pressure shown in FIG. 4 (f) changes as shown by a waveform 103.
When the wheel acceleration in FIG. 4 (b) becomes less than or equal to the wheel deceleration reference value α0, that is, between times t ₁ and t ₂ , between t ₃ and t ₅ , t ₆
If the pressure is reduced between t ₈ and t ₈ , the braking pressure changes as shown by the broken line 110. However, in this embodiment, the acceleration control signal α1
And based on the deceleration control signal α2 the measured T _1n, by T _2n short, prohibited between decompression T _1n and T according to bad road index determined from _2n time T _n (t ₃ ~t ₄ times) And then T
By prohibiting the pressure reduction during the time T _{n + 1} (time from t _{6 to} t ₇ ) by _{1n + 1} and T _{2n + 1,} excessive pressure reduction on a bad road is prevented and the braking pressure is changed as shown in FIG. 4 (f). The pressure is controlled to be higher (the pressure indicated by the waveform 103) than in the case of the broken line 110 of.

Next, assuming that the wheel speed changes as indicated by the characteristic line 101 shown in FIG. 5 (a) during braking with a low friction coefficient and the transmission in gear, the wheel shown in FIG. 5 (b) is obtained. The acceleration is calculated as the characteristic line 106. Due to the wheel acceleration shown by the characteristic line 106, the acceleration control signal α1 and the deceleration control signal α2 shown in FIGS. 5 (c) and (d) change like waveforms 107 and 108, and the pressure reduction signal shown in FIG. 5 (e). Is output as a waveform 109, and the braking pressure shown in FIG. 5 (f) changes as a waveform 103.
In this embodiment, the acceleration control signal α1 and the deceleration control signal α
Since T ₁ and T ₂ measured based on ₂ are long, the rough road index obtained from T ₁ and T ₂ has a small value, so depressurization is not prohibited, and as usual between time t _{9 and} t ₁₀ , The pressure is reduced between t ₁₁ and t ₁₂ and between t ₁₃ and t ₁₄ to control the braking pressure to the optimum pressure for the low friction coefficient road.

〔The invention's effect〕

As described above, according to the present invention, the rough road index is obtained from the first and second times, and the pressure increase / decrease amount is corrected according to the rough road index. Since a bad road can be detected early and accurately in a cycle (first time or second time), excessive reduction of the braking pressure due to the bad road can be prevented, and the braking pressure can be adjusted to the optimum pressure for the road surface. There is an effect that can be.

[Brief description of drawings]

FIG. 1 is a block system diagram showing an embodiment of an anti-skid control device according to the present invention, FIG. 2 (a) is a configuration diagram more specifically showing the device of FIG. 1, and FIG. 2 (b) is a block diagram. 2 is an enlarged configuration diagram showing the braking pressure adjusting actuator in an enlarged manner, FIG. 3 is a flowchart showing the operation of the microcomputer incorporated in the control circuit of FIG. 2 (a),
4 and 5 are operation explanatory views of an embodiment of the antiskid control device according to the present invention, and FIG. 6 is an operation explanatory view of a conventional antiskid control device. 1 ... Wheel speed detecting means, 2 ... slip ratio calculating means,
3 ... Wheel acceleration calculating means, 4 ... Wheel acceleration detecting means, 5 ... Wheel deceleration detecting means, 6 ... First time measuring means, 7 ... Second time measuring means, 8 ... First Rough road index conversion means, 9 ... second rough road index conversion means, 10 ... bad road index addition means, 11 ... increase / decrease amount correction means, 12 ... increase / decrease amount calculation means, 13 ... braking Pressure adjusting means.

Claims (1)

(57) [Claims] 1. Wheel speed detecting means for detecting a wheel speed,
Slip ratio calculating means for calculating a slip ratio from the wheel speed, wheel acceleration calculating means for differentiating the wheel speed to calculate a wheel acceleration, and increasing / decreasing a braking pressure increasing / decreasing amount based on the slip ratio and the wheel acceleration In an anti-skid control device provided with a pressure amount calculating means and a braking pressure adjusting means for increasing / decreasing a braking pressure by the pressure increasing / decreasing amount, a wheel acceleration and a wheel deceleration which are equal to or higher than a predetermined acceleration reference value and deceleration reference value Acceleration detection means and deceleration detection means for generating a control signal and a deceleration control signal, and a first time measurement for measuring a first time after the deceleration control signal is generated until the acceleration control signal is generated. Means and second time measuring means for measuring a second time until the deceleration control signal is generated after the acceleration control signal disappears. , First and second bad road index converting means for converting the first time and the second time into predetermined first and second bad road indexes, respectively, and the first and second bad road indexes. An anti-skid control device comprising: a rough road index addition means for adding a road index, and a pressure increase / decrease amount correction means for correcting the pressure increase / decrease amount according to the added rough road index.