JP2670784B2 - Anti-lock brake control device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an anti-lock brake control device for a vehicle that detects a wheel speed and alternately increases or decreases brake fluid pressure based on the detected wheel speed. (Prior Art) In a conventional vehicle anti-lock brake control device, the wheel rotation speed detected by a wheel rotation speed sensor is used for the purpose of ensuring the steerability and running stability of the vehicle during braking and shortening the control distance. The microcomputer controls the brake fluid pressure by increasing or decreasing the brake fluid pressure by opening and closing a build valve and a decay valve, which are electromagnetic valves, by determining a brake fluid pressure control mode based on the electric signal. However, in such a conventional anti-lock brake control device, the behavior of the wheels causes the brake fluid pressure to be reduced when the wheels are locked, and to be increased when the wheels are recovered. Moreover, when the gear is engaged, as shown in FIG. 4, when the brake fluid pressure is reduced, the wheel speed is restored by the driving force, and when the brake fluid pressure is increased, the wheel speed decreases. There was a problem that the phenomenon of not doing occurs. (Object of the Invention) Therefore, an object of the present invention is to provide an anti-block brake control device that can effectively solve the above problems. (Structure of the Invention) An anti-block brake control device according to the present invention comprises means for calculating a vehicle wheel speed and means for calculating a pseudo vehicle body speed based on each wheel speed, and the pseudo vehicle body speed is a predetermined value. A first detecting means for detecting that the vehicle speed has fallen below a predetermined value, and that a periodic increase or decrease in the wheel speed caused by repetition of pressurization and depressurization of the brake fluid pressure has continued for a predetermined number of times or for a predetermined time with a cycle equal to or less than a predetermined cycle. And a second detecting means for detecting. When both the first and second detection means detect the pressure, the brake fluid pressure is prohibited from being reduced and only the pressurization is performed. (Effect of the Invention) According to the present invention, when the increase / decrease of the wheel speed is repeated with a high frequency in the state where the vehicle speed becomes low,
Since only the brake fluid pressure is applied, if the recovery of the wheel speed due to the pressure reduction and the decrease in the wheel speed due to the pressure application are repeated on a low μ road, low speed, and when the gear is engaged,
The vehicle can be stopped immediately. (Embodiment) Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration centering on a control circuit of an apparatus according to an embodiment of the present invention. In the figure, 1a,
1b, 1c, 1d is a wheel rotation speed sensor for detecting the rotation speed of each wheel, 2a, 2b, 2c, 2d, respectively receiving the signals from the sensors 1a ~ 1d, the wheel speed Vw of each wheel.
This is a wheel speed calculation circuit that calculates a, Vwb, Vwc, and Vwd. The output sides of these wheel speed calculation circuits 2a to 2d are provided to control circuits 3a, 3b, 3c, 3d that determine the control mode of the brake fluid pressure for the wheels according to the state of each wheel speed Vwa to Vwd.
Although they are connected to each other, the control circuits 3b to 3d are not shown here to avoid duplication. Next, the configuration of the control circuit 3a will be described. First,
The output side of the wheel speed calculation circuits 2a to 2d is connected to a pseudo vehicle body speed Vv calculation circuit 4, and in this calculation circuit 4, the wheel speeds Vwa to Vwd of the four wheels are selected high and further selected. The pseudo vehicle body speed Vv is calculated by limiting the acceleration / deceleration range of the increased speed to within ± 1G. The output of the pseudo vehicle body speed Vv calculation circuit 4 and the output of the wheel speed calculation circuit 2a are both reduced pressure determination circuit 5
And applied to the pressurization determination circuit 6. On the other hand, the output of the pseudo vehicle body speed Vv arithmetic circuit is given to the comparison circuit 7. This comparison circuit 7 compares the pseudo vehicle body speed Vv with a predetermined speed, for example, 10 km / h, and outputs when Vv ≦ 10 km / h. To occur. The output of the wheel speed calculation circuit 2a is supplied to a high peak determination circuit 8, which generates an output when determining the high peak of the wheel speed Vwa. The outputs of the comparison circuit 7 and the high peak determination circuit 8 are given to the AND circuit 9, and the output of the AND circuit 9 is the high peak period detection circuit.
Supplied to 10. The high peak cycle detecting circuit 10 outputs a signal when detecting that the cycle between the previous high peak and the current high peak is a predetermined value, for example, 166 ms or less. The output of the high peak cycle detection circuit 10 is given to the counter 11, and the counter 11 counts the detection signal, and outputs the output when continuously counting three times or more. The high peak period detection circuit 10 is 16
When a high peak with a period longer than 6 ms is detected, a reset signal is generated and the counter 11 is reset. Reference numeral 12 denotes an AND circuit having one input terminal as a negative terminal. The positive input terminal of the AND circuit 12 receives the output of the pressure-reduction determining circuit 5, and the negative input terminal receives the output of the counter 11. It is designed to be used. Also,
Reference numeral 13 is an OR circuit, and the output of the pressurization determination circuit 6 is given to one input terminal and the output of the counter 11 is given to the other input terminal. And the AND circuit
The output of 12 is given to the decay valve DV drive circuit 14 to open / close the deckle valve DV, and the output of the OR circuit 13 is supplied to the build valve BV drive circuit 14 to open / close the build valve BV. Next, the operation of the characteristic portion of the control circuit 3a will be described based on the flowchart shown in FIG. First, it is determined whether or not the pseudo vehicle speed Vv is equal to or less than 10 km / h in step S1, and if “YES”, the flow proceeds to step S2 to determine whether or not the controlled wheel speed Vwa is at a high peak. If this determination is "YES", the flow proceeds to step S3, and it is determined whether or not the period between the previous high peak and the current high peak is 166 ms or less. The count n of the counter is set to zero in S4. on the other hand,
If this determination is "YES", 1 is added to the count n of the counter in step S5, and the process proceeds to step S6. Step S6
Then, it is determined whether or not n ≧ 3, and if “YES”, the brake fluid pressure is set to the pressurization mode (step S7) and the pressure reduction is prohibited (step S8). FIG. 3 is a diagram showing the states of the controlled wheel speed Vw and the brake fluid pressure Pw in this embodiment. In the figure, if the simulated vehicle speed Vv is 10 km / h or less
When the cycle between the high peak of Vw and the high peak is 166 ms or less, that is, the frequency of periodic increase and decrease of the wheel speed Vw is 6 Hz or less, if the repetition is repeated three times, the normal antilock control is stopped from that point and the pressurization mode is set. It prohibits decompression and stops the vehicle. As described above, according to the present embodiment, each wheel speed
The pseudo vehicle body speed Vv is calculated based on Vw, and when the pseudo vehicle body speed Vv is equal to or lower than a predetermined speed (10 km / h), the cycle between the high peak and the high peak in the repeated deceleration of the controlled wheel speed Vw is When the speed is below a predetermined speed (166 ms) and high peaks below such a predetermined cycle continue for a predetermined number of times (3 times), the brake fluid pressure for the wheel
Since the pressure of Pw is prohibited and the pressure is increased, low μ road,
When the wheel speed is reduced by reducing the brake fluid pressure and the wheel speed is decreased by increasing the pressure at low speeds and when gears are engaged, the effect is that the repetition is interrupted and the vehicle can be stopped quickly. can get. In the present embodiment, a system is adopted in which the brake system is a four-system system and each wheel speed is a controlled wheel speed (system speed). However, the present invention is not limited to this. It can also be applied to such a system. Further, in the present embodiment, after detecting a high-peak repeating cycle in which the cycle between the high peak of the wheel speed Vw and the high peak is 166 ms or less, the detection signal is counted, and when it is counted three times in succession, pressurization is performed. Although a signal is generated, the present invention is not limited to this, and measures the time during which the detection signal of the high peak cycle of 166 ms or less as described above continues, and when the measured time exceeds a predetermined value. A pressure signal may be generated.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram mainly showing a control circuit of an apparatus according to an embodiment of the present invention, FIG. 2 is a flowchart showing an operation of the apparatus according to the embodiment, FIG. FIG. 4 is a diagram showing a state of wheel speed and brake hydraulic pressure in the present embodiment, and FIG. 4 is a diagram showing a state of wheel speed and brake hydraulic pressure in a conventional device. 1a to 1d ... Wheel rotation speed sensors 2a to 2d ... Wheel speed calculation circuits 3a to 3d ... Control circuit 4 ... Pseudo vehicle body speed Vv calculation circuit 5 ... Decompression determination circuit 6 ... Pressurization determination circuit 7 ... … Comparison circuit 8 …… High peak judgment circuit 9 …… AND circuit 10 …… High peak cycle detection circuit 11 …… Counter, 12 …… AND circuit 13 …… OR circuit 14 …… Decay valve DV drive circuit 15 …… Build valve BV Drive circuit

Claims (1)

(57) [Claims] Means for calculating the wheel speed of the vehicle, means for calculating the pseudo vehicle body speed based on each wheel speed, first detecting means for detecting that the pseudo vehicle body speed has fallen below a predetermined value, and brake fluid pressure Second detecting means for detecting that the periodic increase or decrease of the wheel speed caused by the repetition of the pressurization and depressurization has continued for a predetermined number of times or for a predetermined time with a cycle equal to or less than a predetermined cycle; and the first and second detection means The anti-lock brake control device further comprises means for prohibiting the pressure reduction of the brake fluid pressure and performing only the pressure increase when the above detection is performed.