JP2008037359A - Brake controller and brake control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduced rocking back behavior caused by twisting of a tire not depending on operation technology of a driver. <P>SOLUTION: When stepping operation is performed relative to a brake pedal 26 by a driver, a braking control part 3 obtains a detection signal of the stepping operation of the brake pedal 26 through interface 6 and obtains data regarding a vehicle body speed detected by a vehicle body speed sensor 2. When the vehicle body speed becomes zero, a control signal for releasing or relaxing braking force generated by the braking device 20 once is produced and fed to a braking control hydraulic device 25. Further, when a predetermined period is passed, a control signal for operating the braking device 20 again is fed. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a brake control device and a brake control method for controlling a brake mechanism that applies a braking force to a wheel of a vehicle to stop the vehicle, and more particularly, a brake control device that relaxes a swing-back behavior to the vehicle immediately after the wheel stops. The present invention relates to a brake control method.

  When a driver operates a brake mechanism equipped on the vehicle to stop the traveling vehicle, the vehicle is accelerated in the deceleration direction and the load moves in the vehicle body traveling direction. As the load moves, a phenomenon (pitching behavior) occurs in which the front part of the vehicle body sinks and the rear part floats. When the vehicle travels at a low speed and eventually stops, a so-called swing-back behavior occurs in which the body moves from the pitched body front to the normal state immediately after stopping. . The driver and the occupant receive an inertial force in the vehicle traveling direction when braking the vehicle, and when the vehicle body is completely stopped, the driver and the occupant are subjected to a force in the reverse direction (the direction opposite to the traveling direction) due to the swing-back behavior at the time of stopping It will be shaken back and forth from during braking to after stopping. This swing-back behavior significantly impairs the ride comfort and comfort of the driver and passengers.

As a technology to relieve the swing-back behavior, for example, when detecting the acceleration at the time of stopping when the vehicle is likely to swing back, the brake fluid pressure applied to the wheel cylinders on the front wheel side and the rear wheel side is reduced to weaken the braking force. Thus, a technique for controlling braking so as to stop at a stop speed at which no swingback occurs is disclosed. Further, since load movement occurs at the front part during braking, a technique is disclosed in which braking control is performed so as to increase the distribution ratio of the braking force applied to the rear wheels immediately before the vehicle stops (see, for example, Patent Document 1).
JP 2001-18777 A

  A technique for controlling braking so as not to cause rocking back by reducing the brake applied to the wheel cylinders on the front and rear wheels and weakening the braking force is, for example, controlled by reducing the brake fluid pressure applied to the wheel cylinders. When controlling the power, there is a problem that if the amount of decompression is too large, the braking force becomes too weak, and the swing-back behavior is alleviated while sufficient braking force cannot be obtained. In the technique of Patent Document 1, since the braking force itself is reduced in order to relax the swingback behavior, it is difficult to reduce the swingback behavior while securing the minimum braking force necessary for stopping the vehicle. .

  In addition, since the swing back behavior occurs due to the release of the distortion energy generated in the suspension, tire, etc. due to the braking force when the vehicle stops, for example, when the driver gradually brakes sufficiently from the stop position, It becomes larger as it tries to stop at a shorter braking distance. Actually, when the vehicle is stopped, if the driver adjusts the brake depression and immediately reduces the braking force immediately before the vehicle stops to stop the vehicle smoothly, it can be reduced to some extent. However, there is a concern that the braking distance becomes long. As described above, the suppression of the swing back behavior also depends on the skill of the driver.

  As described above, the swing-back behavior is caused by tire twisting in addition to the pitching behavior due to the expansion and contraction of the suspension. Specifically, when braking is performed and the vehicle body is completely stopped (when the vehicle body speed becomes zero), the tire is twisted in the rotational direction with respect to the tire wheel. Therefore, once the vehicle body speed becomes zero, this twist is released and a reverse force is generated. This reaction of the twisting of the tire contributes to the shaking of the vehicle body along with the expansion and contraction of the suspension. The swing-back behavior of the vehicle body caused by the twisting of the tire cannot be solved by the technique described in Patent Document 1.

  Therefore, the present invention has been made in view of the above-described conventional situation, and can reduce the swing-back behavior caused by the twisting of the tire and reliably stop the vehicle without being influenced by the driver's steering technique. It is an object of the present invention to provide a vehicle brake control device and a brake control method.

  In order to achieve the above-mentioned object, the invention according to claim 1 is a brake control device for controlling a braking device for generating a braking force on a wheel provided in the vehicle body, and for detecting a vehicle body speed. And braking control means for controlling the operation and release of the braking device in accordance with the detection result of the vehicle body speed detecting means, and the vehicle speed detected by the vehicle body speed detecting means is zero. In some cases, the control is performed to release the braking force generated by the braking device.

  According to the first aspect of the present invention, when the vehicle body speed detected by the vehicle body speed detecting means becomes zero, the control is performed to release the braking force generated by the braking device, thereby causing the vibration caused by the tire torsion. The return behavior can be reduced.

  Further, in the invention according to claim 2, the braking control means executes the control for relaxing the braking force generated by the braking device when the vehicle body speed becomes zero, so that the braking force of the braking device is completely reduced. It is possible to reduce the swing-back behavior caused by the twisting of the tire without releasing it.

  In the invention according to claim 3, the braking control means releases the braking force generated by the braking device for a certain period of time, and then executes a control for operating the braking device again, thereby causing the swing-back behavior caused by the tire torsion. As well as preventing the tire from rotating unnecessarily, the stability of the stopped vehicle body can be improved.

  According to a fourth aspect of the present invention, the brake control device includes an inclination degree detecting means for detecting the inclination degree, and the braking control means sets the braking device according to the value of the inclination degree detected by the inclination degree detecting means. The control for changing the period until the operation is performed again is executed. Therefore, it is possible to reduce the swing-back behavior caused by the twisting of the tire at the time of braking on the slope, and to prevent the tire from rotating unnecessarily and the vehicle body starting to move below the slope.

  Further, in the invention according to claim 5, the braking control means executes control not to release the braking force generated by the braking device when the inclination detected by the inclination detecting means is larger than a predetermined threshold. As a result, it is possible to prevent the vehicle body from starting to move downward on the slope immediately after stopping on the slope. Especially when the slope is large, by executing control that does not release the braking force of the braking device, It is possible to prevent the vehicle body from moving.

  Furthermore, in the invention according to claim 6, the brake control device includes a depression pressure detecting means for detecting a brake depression pressure by the driver, and the braking control means has a predetermined depression pressure detected by the depression pressure detection means. If it is greater than the threshold value, control is performed that does not release the braking force generated by the braking device. As a result, when the stepping pressure by the driver is larger than a predetermined threshold, the braking force is prioritized over the driver's riding comfort by not executing the braking force release and reactivation control on the braking device.

  In order to achieve the above-mentioned object, an invention according to claim 7 of the present invention is a brake control method for controlling a braking device for generating a braking force on a wheel provided on a vehicle body, wherein the speed of the vehicle body is controlled. A vehicle body speed detecting step for detecting, and a braking control step for controlling the operation and release of the braking device in accordance with the detection result of the vehicle body speed, and in the braking control step, when the detected vehicle body speed becomes zero Control for releasing the braking force generated by the braking device is executed.

  In the invention according to claim 7, by performing control to release the braking force of the braking device when the detected vehicle body speed is zero, it is possible to reduce the swing-back behavior caused by the tire twisting.

  The inventions according to claims 8 to 12 are method inventions corresponding to the inventions of the apparatuses according to claims 2 to 6, respectively. In the invention according to claim 8, when the vehicle body speed becomes zero, the control for reducing the braking force generated by the braking device is executed, so that it is possible to twist the tire without completely releasing the braking force of the braking device. It is possible to reduce the swing-back behavior caused by.

  Further, in the invention according to claim 9, since the control for reactivating the braking device is executed after releasing the braking force generated by the braking device for a certain period of time, the swing-back behavior caused by the twisting of the tire is reduced. Further, the tire can be prevented from rotating unnecessarily, and the stability of the stopped vehicle body can be improved.

  The invention according to claim 10 further includes an inclination detection step for detecting the inclination, and changes a period until the braking device is operated again according to the value of the inclination detected in the inclination detection step. Since the control is executed, it is possible to reduce the swing-back behavior caused by the twisting of the tire at the time of braking on the slope, and to prevent the tire from rotating unnecessarily and the vehicle body starting to move below the slope.

  According to the eleventh aspect of the present invention, when the degree of inclination is greater than a predetermined threshold value, control is performed so as not to release the braking force generated by the braking device. It is possible to prevent the vehicle from starting to move. In particular, when the degree of inclination is large, it is possible to prevent the vehicle body from moving below the slope by executing control that does not release the braking force of the braking device.

  Furthermore, according to the twelfth aspect of the present invention, there is provided a stepping pressure detecting step for detecting a brake stepping pressure by the driver, and when the detected stepping pressure is larger than a predetermined threshold value, the braking force generated by the braking device is provided. Execute control that does not release power. As a result, when the driver's stepping pressure is greater than a predetermined threshold, the braking force is not released from the braking device and the reactivation control is not executed, so that the rapid braking is prioritized over the ride comfort of the driver and the occupant. .

  According to the present invention, it is possible to reduce the swing-back behavior caused by the twisting of the tire at the time of brake braking, without depending on the driver's steering technique and without increasing the braking distance.

  Hereinafter, an embodiment of a brake control device according to the present invention will be described with reference to FIG. As shown in FIG. 1, the brake control device 1 generates a vehicle speed sensor 2 as a vehicle speed detection means for detecting the speed of the vehicle body, and a signal for controlling a braking device 20 (to be described later) according to the detection result of each sensor. A braking control unit 3 as a braking control means, a ROM 4 in which a program for executing the braking control according to the present invention is stored, and a RAM 5 as a work area of the braking control unit 3. It is connected to the. Signals such as control signals and operation setting information generated in the braking control unit 3 are supplied to the braking device 20 via the interface 6.

  As shown in FIG. 1, the braking device 20 includes a brake unit having a brake caliper 21 having a brake cylinder 22 and a brake pad 23, and a rotor 24 sandwiched between the brake pads 23 for each wheel. A braking device for generating a braking force between a wheel and a road surface via an axle connected to the rotor 24 by reducing a rotational force of the rotor 24 by a frictional force generated between the rotor 23 and the rotor 24. It is. The configurations of these brake units are denoted by symbols a to d, indicating that they are separate units provided for the left front wheel, the right front wheel, the left rear wheel, and the right rear wheel.

  The brake cylinders 22a to 22d are connected to a brake control hydraulic device (hydraulic unit) 25 by brake lines 28a to 28d filled with brake fluid.

  A brake pedal 26 is connected to the brake control hydraulic device 25 via a master cylinder 27 connected by a brake line 28e. The level of the depression pressure generated by the depression operation of the brake pedal 26 by the driver is transmitted to the braking control hydraulic device 25 by the hydraulic pressure of the brake fluid filled in the master cylinder 27 and the brake line 28e, and further the braking control hydraulic pressure. The pressure is transmitted from the device 25 to each unit at an appropriate distribution ratio, so that the pressing pressure of the brake pad 23 against the rotor 24 is adjusted.

  In this embodiment, the disc brake is applied to all four wheels, but a drum brake may be used. Further, both may be used in combination, such as a disc brake for the front wheel and a drum brake for the rear wheel.

  Then, each structure of the brake control apparatus 1 is demonstrated concretely. The brake control device 1 is executed by the vehicle speed sensor 2 that detects the vehicle speed, the brake control unit 3 that controls the operation and release of the brake device 20 according to the detection result of the vehicle speed sensor 2, and the brake control unit 3. And a RAM 5 as a work area of the braking control unit 3. The brake control hydraulic device 25 of the braking device 20 includes an interface 6 for transmitting and receiving various signals. Signals such as control signals and operation setting information generated in the brake control unit 3 are transmitted via the interface 6 to the braking device. 20 is supplied.

  As the vehicle body speed sensor 2, for example, a sensor using a Doppler effect or a sensor using a spatial filter can be used. In the Doppler method, laser light, microwaves, ultrasonic waves, or the like are emitted to a measurement target, and the velocity is measured from the frequency change of the reflected wave. The spatial filter type detects a movement of optical unevenness of a measurement target from an optical image formed on a light receiving element formed in a lattice shape to obtain a speed signal.

  The braking control unit 3 includes a CPU having functions such as acquisition of sensor data from the vehicle body speed sensor 2 and the like, and execution of a program stored in the ROM 4 and the like, and braking according to the detection result of the vehicle body speed sensor 2. The operation and release of the device 20 are controlled. Specifically, the braking control unit 3 generates a control signal for once releasing the braking force of the braking device 20 when the vehicle body speed detected by the vehicle body speed sensor 2 becomes zero, and performs braking control via the interface 6. The hydraulic device 25 is supplied. Further, the braking control unit 3 does not completely release the braking force of the braking device 20 under the above-described conditions, but relaxes the braking force generated by the braking device 20 when the vehicle body speed becomes zero. The frictional force between the brake pad 23 and the rotor 24 can be maintained. Then, after the braking force generated by the braking device 20 is released or relaxed, the braking control unit 3 performs control that operates again after a predetermined period of time has elapsed.

  The ROM 4 stores a period of time for waiting for the rubber vibration generated by the torsional return of the tire to be attenuated to such an extent that it does not affect the longitudinal movement of the vehicle body, that is, a predetermined period until re-operation.

  The brake control device 1 having the above-described configuration detects the vehicle body speed when the driver depresses the brake pedal 26, and once releases the braking force when the vehicle body speed becomes zero. Alternatively, a control signal to be relaxed is generated and supplied to the brake control hydraulic device 25. In the brake control hydraulic device 25, the pressing pressure of the brake pad 23 against the rotor 24 is adjusted based on the supplied control signal. Then, after a predetermined period, control is performed to recover the braking force again.

  Next, specific processing for causing the brake control device 1 to cause the braking device 20 to perform release and reactivation will be described with reference to FIG.

  When the driver depresses the brake pedal 26, the brake control unit 3 of the brake control device 1 acquires a detection signal of the depressing operation of the brake pedal 26 via the interface 6 as step S <b> 1.

  In step S2, data relating to the vehicle speed detected by the vehicle speed sensor is acquired.

  Next, in step S3, it is determined whether or not the vehicle body speed is zero. When the vehicle body speed is zero (step S3: yes), in step S4, a control signal for temporarily releasing the braking force generated by the braking device 20 is issued. It is generated and supplied to the braking device 30 to start timing. If it is determined in step S5 that the predetermined period stored in the ROM 4 has elapsed, a control signal for operating the braking device 20 again is supplied in step S6.

  In the above-described processing, the predetermined period waiting in step S5 is stored in the ROM 4, and is set to, for example, 1.0 second. When the vehicle body speed becomes zero, the twist in the rotational direction is caused by the bending of the tire due to rubber elasticity. The predetermined period is a period of waiting for the rubber vibration generated by the twist return to be attenuated to such an extent that it does not affect the longitudinal movement of the vehicle body. The predetermined period can be changed as appropriate according to the design of the vehicle body, tire characteristics, tire size, and the like.

  As described above, according to the brake control device 1 shown as the embodiment of the present invention, the swing-back behavior at the time of stop can be reduced without being influenced by the driver's technique. In particular, since the brake control device 1 releases the braking device 20 and allows the tire (rotor 24) to freely rotate for a short period of time, the brake control device 1 is caused by the twisting of the tire that works between the tire ground contact surface and the control device 20 immediately after stopping. It can absorb the swing-back behavior.

  In addition, the brake control device 1 shown as the present embodiment performs control to reduce the braking force itself in order to alleviate the swing back behavior due to pitching, control to vary the distribution ratio of the braking force at the time of braking, etc. It can also be used in combination with the prior art.

  Next, another embodiment of the brake control device will be described with reference to FIGS.

  The brake control device 11 shown as the second embodiment can perform more complicated release / reactivation processing than the brake control device 1 shown as the first embodiment. Specifically, as shown in FIG. 2, the brake control device 11 includes a vehicle body speed sensor 12 that detects the vehicle body speed, and a brake that controls the operation and release of the brake device 20 according to the detection result of the vehicle body speed sensor 12. The control unit 14 includes a ROM 15 that stores a program for executing the braking control of the present embodiment, a threshold value of an inclination angle and a depression pressure, and a RAM 16 as a work area of the braking control unit 14. The brake control hydraulic device 25 of the brake device 20 is provided with an interface 17 for transmitting and receiving various signals. Signals such as control signals and operation setting information generated in the brake control unit 14 are transmitted via the interface 17 to the brake device. 20 is supplied.

  Further, the brake control device 11 includes an inclination angle sensor 13 as an inclination detection means for detecting the inclination of the road surface on which the vehicle body is traveling, and a braking device according to the value of the inclination detected by the inclination angle sensor 13. Control for changing a period until the 20 is operated again is executed. Further, the brake control device 11 obtains stepping pressure data from a pressure sensor 29 that is installed in the braking device 20 and serves as stepping pressure detecting means for detecting the brake stepping pressure by the driver, and is detected by the vehicle speed sensor 12. The control is performed by changing the braking force generated by the braking device 20 by adding the stepping pressure to the determined speed.

  The braking device 20 includes a pressure sensor 29 for detecting the driver's stepping pressure on the master cylinder 27, and the detected stepping pressure is supplied to the brake control device 11.

  The brake control device 11 having the above-described configuration is when the driver depresses the brake pedal 26 and detects the depressing pressure and the vehicle body speed and is operated by the normal depressing pressure. When the vehicle speed is zero, it generates a control signal that releases or relaxes the braking force.However, when the depression pressure is extremely high in a short period of time, it is determined that sudden braking is applied and the vehicle speed becomes zero. When it becomes, control that does not release the braking force is performed.

  Hereinafter, specific processing for the brake control device 11 to cause the braking device 20 to perform release and reactivation will be described with reference to FIG.

  When the driver depresses the brake pedal 26, the brake control unit 14 of the brake control device 11 acquires a detection signal of the depressing operation of the brake pedal 26 via the interface 17 as step S <b> 11.

  In step S12, the master cylinder pressure is acquired from the pressure sensor 29. In step S13, it is determined whether or not the master cylinder pressure is greater than or equal to a threshold value. If the master cylinder pressure is less than or equal to a predetermined threshold value, data on the tilt angle detected by the tilt angle sensor is acquired in step S14, and if the tilt angle is less than or equal to the threshold value (step S15; no), in step S16. A period during which the braking device 20 is released is set according to the data regarding the inclination angle.

  On the other hand, when the master cylinder pressure is equal to or greater than the predetermined threshold value and the inclination angle is equal to or greater than the predetermined threshold value, the process proceeds to step S22, and a control signal that does not release the braking device 20 is generated.

  Next, in step S17, data relating to the vehicle speed detected by the vehicle speed sensor is acquired. Next, in step S18, it is determined whether or not the vehicle body speed is zero. When the vehicle body speed is zero (step S18: yes), in step S19, the braking force generated by the braking device 20 is once released or relaxed. Generate and supply control signals and start timing. When it is determined in step S20 that the predetermined period has elapsed, a control signal for operating the braking device 20 again is supplied as step S21.

  In the present embodiment, the threshold value of the inclination angle in step S15 described above is, for example, 7 °. Depending on the degree of inclination, the vehicle body may move during a certain period of time until the braking device 20 is actuated again after releasing the braking force in order to reduce the swing-back behavior. By executing the control that does not release the braking force of the braking device, it is possible to improve the stability immediately after stopping and to perform a braking process that does not impair the driver's comfort as a result.

  The release period set for the tilt angle in step S16 is, for example, a function or correspondence table having a correspondence relationship so that the release period is shortened as the tilt angle is increased and stored in the ROM 15 in advance. Compared with the inclination angle acquired in step S14, a corresponding release period may be set.

  As described above, the brake control device 11 performs the control to change the period until the braking device 20 is operated again according to the value of the degree of inclination detected by the inclination angle sensor 13, so that the When stopping, it is possible to perform a braking process that increases the stability immediately after stopping and does not impair the comfort of the driver. In addition, the driver determines the urgency of the brake operation based on the brake depression pressure by the driver, gives priority to sudden braking over ride comfort, and controls the braking device so that it does not release and restart the braking device. Increases sex.

  As described above, the present invention can absorb the rubber vibration caused by the twist return generated in the tire immediately after stopping the vehicle body. Even if the torsional deformation remaining on the tire is not reduced by making fine adjustments to release, the vehicle body does not swing back due to the twisting of the tire, so the passenger comfort is ensured while ensuring good stability when stopping The vehicle body can be stopped without impairing the performance. In addition, the fact that the driver does not swing back after stopping the vehicle even if the driver continues to step on the brake pedal encourages the driver to perform a braking operation with a stable pedal pressure, and the brake characteristics (brake performance) are sufficient. Can be demonstrated.

  It should be noted that the technical scope of the present invention is determined only by the invention specifying matters according to the scope of claims reasonable from the above description, and is not limited to the above-described embodiment. The present invention can be variously modified without departing from the gist of the invention.

It is a schematic block diagram explaining the brake control apparatus shown as embodiment of this invention. It is a schematic block diagram explaining the brake control apparatus shown as another embodiment of this invention. It is a flowchart explaining the release and reactivation process in the brake control apparatus shown in FIG. It is a flowchart explaining the release and reactivation process in the brake control apparatus shown in FIG.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Brake control device, 2 ... Body speed sensor, 3 ... Brake control part, 4 ... ROM, 5 ... RAM, 6 ... Interface, 20 ... Brake control device, 25 ... Brake control hydraulic device, 26 ... Brake pedal

Claims (12)

A brake control device for controlling a braking device that generates a braking force on a wheel provided in a vehicle body,
Vehicle body speed detecting means for detecting the speed of the vehicle body;
Braking control means for controlling the operation and release of the braking device according to the detection result of the vehicle body speed detection means,
The brake control device, wherein the brake control device executes control to release the braking force generated by the brake device when the vehicle body speed detected by the vehicle body speed detection device becomes zero.   2. The brake control device according to claim 1, wherein when the vehicle body speed becomes zero, the braking control unit executes control for relaxing a braking force generated by the braking device. 3.   3. The control device according to claim 1, wherein the braking control unit executes control for operating the braking device again after releasing the braking force generated by the braking device for a certain period. Brake control device. Inclination degree detecting means for detecting the inclination degree,
The said braking control means performs control which changes the period until the said braking device is act | operated again according to the value of the inclination detected by the said inclination detection means. Brake control device.   5. The control according to claim 4, wherein the braking control unit executes control not to release the braking force generated by the braking device when the inclination detected by the inclination detection unit is larger than a predetermined threshold. The brake control device described. Provided with the depression pressure detecting means for detecting the brake depression pressure by the driver,
2. The control unit according to claim 1, wherein when the depression pressure detected by the depression pressure detection unit is larger than a predetermined threshold value, the braking control unit executes control that does not release the braking force generated by the braking device. The brake control device according to claim 5. A brake control method for controlling a braking device that generates braking force on a wheel provided in a vehicle body,
A vehicle body speed detecting step for detecting the speed of the vehicle body;
A braking control step for controlling the operation and release of the braking device according to the detection result of the vehicle body speed;
The brake control method, wherein the brake control step executes a control for releasing a braking force generated by the brake device when the detected vehicle speed becomes zero.   8. The brake control method according to claim 7, wherein the braking control step executes a control for relaxing a braking force generated by the braking device when the vehicle body speed becomes zero. 9.   9. The control according to claim 7, wherein the braking control step executes a control for operating the braking device again after releasing the braking force generated by the braking device for a certain period. Brake control method. An inclination detection step for detecting the inclination;
The said braking control step performs control which changes the period until the said braking device is act | operated again according to the value of the inclination detected by the said inclination detection step. Brake control method.   The brake control step performs control that does not release the braking force generated by the braking device when the inclination detected in the inclination detection step is greater than a predetermined threshold. The brake control method described. A stepping pressure detection step for detecting the brake stepping pressure by the driver,
8. The brake control step, when the stepping pressure detected in the stepping pressure detecting step is larger than a predetermined threshold value, executes a control that does not release the braking force generated by the braking device. The brake control method according to claim 11.

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