JP2011140303A - Brake control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a brake control device capable of suppressing a large vehicle behavior. <P>SOLUTION: When a pitch behavior where a front part of a vehicle body rises becomes large, deformed pitch angular velocity α×dθ/dt becomes a prescribed value j01 or below, and a brake signal F for behavior control output by a brake signal calculation circuit 14 for behavior control is input as a target braking force signal K into an actuator 17, a brake means for a front wheel generates braking force according to the brake signal F for behavior control. Load movement in the forward direction is generated in the vehicle body to suppress the pitch behavior. Since the suppression of a pitch movement is not performed by the operation of a shock absorber, but is performed by braking the wheel, the suppression of a large pitch behavior can be performed responding to a large pitch behavior where the shock absorber is fully stroked, and the suppression of the pitch movement becomes a difficult state depending on the shock absorber. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a brake control device that is used in a vehicle to ensure riding comfort and handling stability.

  As an example of a device for ensuring the ride comfort and steering stability of a vehicle, there is a suspension control device shown in Patent Document 1. The suspension control device disclosed in Patent Document 1 includes a variable damping coefficient type shock absorber provided between a vehicle body and an axle of a vehicle, and a vibration detection unit that detects vertical vibrations of the vehicle body. The shock absorber is controlled based on the detection result.

JP-A-5-330325

By the way, in the said prior art, there exists a fixed restriction | limiting in the stroke of a shock absorber, and the behavioral suppression amount of the vehicle which can be controlled in connection with this is also restricted. For this reason, in the prior art, a vehicle can move a road having large irregularities such as a long wave road (a road surface having a large wave shape with a long wavelength when the road is cut in the longitudinal direction) at a high speed. When the vehicle travels, the shock absorber may make a full stroke. In this case, even if the pitching control is performed, the pitch behavior cannot be satisfactorily suppressed.
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a brake control device that can suppress the behavior of a large vehicle behavior by using a braking force applied to wheels.

According to the first aspect of the present invention, there is provided a brake control device that is actuated by an actuator to brake a vehicle wheel, a vehicle body behavior detection unit that detects a vertical behavior of the vehicle body of the vehicle, and the vehicle body behavior. Control means for controlling the brake means by driving the actuator according to the detection result of the detection means.
According to a second aspect of the present invention, in the brake control device according to the first aspect, the vehicle body behavior detecting means is a pitch behavior detecting means for detecting a pitch behavior of the vehicle body of the vehicle.
According to a third aspect of the present invention, in the brake control device according to the first or second aspect, the control means is a detection result of the vehicle body behavior detecting means when at least a driver of the vehicle is not performing a brake operation. The actuator is controlled according to the above.

According to the first to third aspects of the invention, since the wheel is braked by controlling the brake means according to the behavior of the vehicle body, the load movement of the vehicle body is generated according to the position of the wheel to which the braking force is applied. However, the behavior of the vehicle body can be suppressed accordingly.
According to invention of Claim 2, suppression of pitch behavior can be aimed at.

It is a figure showing typically the brake control device concerning a 1st embodiment of the present invention. FIG. 2 is a block diagram schematically showing the controller of FIG. 1. It is a flowchart which shows the control content of the controller of FIG. It is a block diagram showing typically a controller which a brake control device concerning a 2nd embodiment of the present invention uses.

Hereinafter, a brake control device 1 according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 3.
1 and 2, between the vehicle body 3 (sprung) constituting the automobile 2 (vehicle) and the four wheels 4 side [unsprung member (axle shock absorber mounting bracket, etc.)] (unsprung). A spring 5 and a shock absorber 6 (damping characteristic reversal type shock absorber 6) capable of adjusting a damping characteristic are interposed in parallel, and these support the vehicle body 3. A piston 7 is movably accommodated in the shock absorber 6, a piston rod 8 connected to the piston 7 is held by the vehicle body 3, and the shock absorber 6 is held on the wheel 4 side (a shock absorber 6 mounting bracket or the like). .
In FIG. 1, only two wheels 4 are illustrated: a left front wheel (left front wheel 4) and a left rear wheel (left rear wheel 4). Also, four shock absorbers 6 and four springs 5 are provided corresponding to the four wheels 4, respectively, but only two of them before and after the automobile are shown for convenience.

  The rear portion 3r of the vehicle body 3 is provided with a rear acceleration sensor 9r that detects vertical acceleration (vehicle body rear spring acceleration) of the rear portion 3r of the vehicle body 3. A front acceleration sensor 9 f that detects vertical acceleration (vehicle body front spring acceleration) of the front portion 3 f of the vehicle body 3 is provided at the front portion 3 f of the vehicle body 3. The distance between the front acceleration sensor 9f and the rear acceleration sensor 9r (the distance between the front and rear sensors) is set to a dimension L. A rear integration circuit 11r is connected to the rear acceleration sensor 9r, and a front integration circuit 11f is connected to the front acceleration sensor 9f. The rear integration circuit 11r integrates the vehicle body rear sprung acceleration from the rear acceleration sensor 9r to obtain a rear vertical speed vr. The front integration circuit 11f integrates the vehicle body front sprung acceleration from the front acceleration sensor 9f to obtain a front vertical speed vf.

Connected to the front integration circuit 11f and the rear integration circuit 11r are a pitch angular velocity calculation circuit 12 that constitutes a pitch angular velocity detection means together with the front and rear acceleration sensors 9f and 9r and the front and rear integration circuits 11f and 11r. . The pitch angular velocity calculation circuit 12 subtracts the front vertical velocity vf from the rear vertical velocity vr to obtain a velocity difference (vr−vf), and uses the distance L between the front and rear sensors to calculate the pitch angular velocity dθ / dt is obtained.
dθ / dt = tan ⁻¹ [(vr−vf) / L] (1)

An amplifier circuit 13 is connected to the pitch angular velocity calculation circuit 12. The amplification circuit 13 multiplies the pitch angular velocity dθ / dt by the gain α to obtain a pitch angular velocity (hereinafter referred to as a modified pitch angular velocity for convenience) α · dθ / dt for calculating the behavior control braking signal F. I have to.
A behavior control braking signal calculation circuit 14 is connected to the amplification circuit 13. The behavior control braking signal calculation circuit 14 receives the input of the deformation pitch angular velocity α · dθ / dt, and receives the input of the deformation pitch angular velocity α · dθ / dt, and indicates the correspondence relationship between the behavior control braking signal F and the deformation pitch angular velocity α · dθ / dt. The behavior control braking signal F is obtained by applying to the calculation table Ta0.

The behavior control braking signal calculation circuit 14 is provided with a brake control unit 15, an actuator 17, and a brake unit 19 that is actuated by the actuator 17 to generate a braking force to brake each wheel 4 in this order. Yes. The brake controller 15 receives the behavior control braking signal F and a signal to be described later, selects one signal from these signals, and inputs the selected signal to the actuator 17 as the target braking force signal K. The actuator 17 operates the brake means 19 based on the target braking force signal K received.
In addition to the behavior control braking signal F, the brake control unit 15 outputs a braking operation command signal Am for operating the brake means 19 obtained based on the driver's braking operation, and a vehicle behavior stabilizing device (not shown). Then, a behavior stabilization braking signal Bm for operating the brake means 19 is input.

  The behavior control braking signal F, the braking operation command signal Am, and the behavior stabilization braking signal Bm are selected by the brake control unit 15, and the selected signals are output to the actuator 17 as the target braking force signal K to be brake means. Used to generate 19 braking forces. Each signal F, Am, and Bm includes a request content indicating the braking force generated by the brake means 19. The selection of each signal F, Am, Bm by the brake control unit 15 is performed based on the request content (braking force generated by the brake means 19) included in each signal F, Am, Bm.

  In the behavior control braking signal calculation table Ta0, as described in the rectangular frame showing the behavior control braking signal calculation circuit 14 in FIG. 2, the deformation pitch angular velocity α · dθ / dt is taken along the horizontal axis, and the behavior control is performed. The brake signal F for operation is taken as a vertical axis, and is composed of a graph including a line segment (hereinafter referred to as a behavior control brake signal calculation line segment 20g) indicating a correspondence relationship between the two. The deformation pitch angular velocity α · dθ / dt, which is proportional to the pitch angular velocity dθ / dt, is a positive value when the front portion 3f of the vehicle body 3 is lowered (a negative value when the front portion 3f is raised). Is set. In the table Ta0 in FIG. 2, the deformation pitch angular velocity α · dθ / dt is positive in the portion on the right side of the vertical axis on the horizontal axis, and the deformation pitch angular velocity α · dθ / dt is negative in the portion on the left side of the vertical axis on the horizontal axis. It is created to show the value of.

  The behavior control braking signal calculation line 20g has a predetermined value j01 (negative value) even when the deformation pitch angular velocity α · dθ / dt is a positive value (right side of the vertical axis in FIG. 2) and a negative value. If it is larger, the value of the behavior control braking signal F is set to “0” (becomes a dead zone). When the deformation pitch angular velocity α · dθ / dt is equal to or smaller than the predetermined value j01, the behavior control braking signal F increases as the behavior control braking signal calculation line segment 20g becomes equal to or smaller than the predetermined value j01. When α · dθ / dt is smaller than a fixed value j00 [j00 <j01] smaller than the predetermined value j01, the value of the behavior control braking signal F is set to a constant value. The value of the behavior control braking signal F corresponds to the magnitude of the braking force generated by the brake means 19.

  As described above, the behavior control braking signal calculation table Ta0 is a dead zone when the deformation pitch angular velocity α · dθ / dt is greater than the predetermined value j01. Further, the behavior control braking signal F output to the actuator 17 as the target braking force signal K contributes to the braking force generation of the brake means 19 when the value is equal to or less than the predetermined value j01 excluding the dead zone.

  When the braking operation command signal Am is input to the actuator 17, the actuator 17 activates the brake unit 19 and causes the braking unit 19 to generate a braking force having a magnitude corresponding to the request content included in the braking operation command signal Am. When the behavior stabilization braking signal Bm is input to the actuator 17, the actuator 17 activates the brake unit 19 and applies a braking force having a magnitude corresponding to the required content included in the behavior stabilization braking signal Bm. To generate.

The brake control unit 15 outputs, to the actuator 17 as a target braking force signal K, a signal requiring the largest braking force among the braking operation command signal Am, the behavior stabilizing braking signal Bm, and the behavior controlling braking signal F. To do. For example, if the brake control unit 15 receives the behavior control braking signal F but does not receive the braking operation command signal Am and the behavior stabilization braking signal Bm, the brake control unit 15 performs the behavior control braking signal. F is output to the actuator 17 as the target braking force signal K so as to be used for the operation of the brake means 19. In addition, when the brake control unit 15 receives at least two of the braking operation command signal Am, the behavior stabilization braking signal Bm, and the behavior control braking signal F, the braking force requested is the maximum. The signal is output to the actuator 17 as the target braking force signal K.
The front integration circuit 11f, the rear integration circuit 11r, the pitch angular velocity calculation circuit 12, the amplification circuit 13, the behavior control braking signal calculation circuit 14, and the brake control unit 15 constitute a controller 20 (control means).

The operation of the brake control device 1 configured as described above will be described based on the flowchart of FIG.
As shown in FIG. 3, when the controller 20 receives power supply by starting the engine (not shown) of the automobile 2 (step S1), the controller 20 first performs initialization (step S2) and determines whether or not the control cycle has been reached. Is determined (step S3). In step S3, it is repeatedly determined whether or not the control cycle has been reached until it is determined that the control cycle has been reached.

  If it is determined in step S3 that the control cycle has been reached, among the braking operation command signal Am, the behavior stabilization braking signal Bm, and the behavior control braking signal F, the signal for which the braking force required by each signal is maximum is the target control. The power signal K is input to the actuator 17 and the actuator 17 is driven (step S4). In this step S4, for the braking operation command signal Am, the behavior stabilization braking signal Bm, and the behavior control braking signal F, signals obtained in the previous control cycle (steps S6 and S7 described later) are used.

  Subsequently, a signal corresponding to another port such as an LED is output (step S5). Subsequently, in step S6, detection signals are read from the front and rear acceleration sensors 9f, 9r, etc. (step S6). In step S6, a signal including the braking operation command signal Am and the behavior stabilization braking signal Bm is input and used in step S4 of the next control cycle.

  Next, the pitch angular velocity dθ / dt and the deformation pitch angular velocity α · dθ / dt are obtained based on the vehicle body front spring acceleration and the vehicle rear spring acceleration, and the deformation pitch angular velocity α · dθ / dt is determined as a braking signal for behavior control. The behavior control braking signal F is obtained by applying the calculation table Ta0 (step S7). This behavior control braking signal F is used in step S4 of the next control cycle.

  When the automobile 2 travels, the front part 3f of the vehicle body 3 rises (in the table Ta, the deformation pitch angular velocity α · dθ / dt is negative), that is, the vehicle body 3 behaves in a clockwise direction in FIG. In step S7, a braking signal F for behavior control corresponding to the pitch behavior is obtained. If the braking force required by the behavior control braking signal F obtained in step S7 is greater than the braking force requested by the braking operation command signal Am and behavior stabilization braking signal Bm obtained in step S6, the relevant step The behavior control braking signal F obtained in S7 is input as the target braking force signal K to the front wheel actuator 17 in step S4 of the next control cycle, and the front wheel brake means 19 is changed to the behavior control braking signal F. A corresponding braking force is generated. Thereby, forward load movement occurs in the vehicle body 3, and the pitch behavior of the vehicle body 3 in the clockwise direction in FIG.

In the present embodiment, when the pitch behavior at which the front portion 3f of the vehicle body 3 rises becomes greater than a predetermined level (below a predetermined value J01 of the deformation pitch angular velocity α · dθ / dt), control is performed to reduce the pitch motion. Since the pitch motion is reduced by applying a braking force to the wheels 4, the vehicle speed can be reduced in the process of reducing the pitch motion, and the vehicle 2 can be kept running stably.
Furthermore, since the pitch motion is not controlled by the operation of the shock absorber 6 but by braking the wheels 4, the shock absorber 6 is fully stroked. Depending on the shock absorber 6, it is difficult to suppress the pitch motion. It is possible to cope with a large pitch behavior that becomes a situation, and to suppress the large pitch behavior.

  In the above embodiment, the behavior control braking signal F is input to the front wheel actuator 17 as the target braking force signal K and the front wheel brake means 19 generates a braking force. Then, the behavior control braking signal F is input to the front and rear wheel actuators 17 as the target braking force signal K, and the front wheel and rear wheel brake means 19 generates braking force to suppress the pitch behavior. You may do it. However, as compared with the example in which the braking force is generated in the brake means 19 for the front wheels and the rear wheels in this way, the above embodiment is adopted (the behavior control braking signal F is input to the front wheel actuator 17 and the front wheel By generating a braking force on the brake means 19), a larger pitch behavior can be suppressed and a reduction in vehicle speed can be suppressed.

Next, a brake control device 1A according to a second embodiment of the present invention will be described with reference to FIG.
The brake control device 1A according to the second embodiment mainly differs from the brake control device 1 according to the first embodiment in the following items (1) to (5).
(1) Instead of providing one behavior control braking signal calculation circuit 14 in the brake control device 1, front wheel and rear wheel behavior control braking signal calculation circuits 14 f and 14 r are provided, and each detection result includes The brake means 19 for the front wheels and the rear wheels are actuated accordingly.
(2) A brake control unit 15 (hereinafter referred to as a second brake control unit 15A for convenience) provided in place of the brake control unit 15 is provided.
(3) A controller 20A is provided in place of the controller 20 of the first embodiment.
(4) Instead of the behavior control braking signal calculation table Ta0 used by the behavior control braking signal calculation circuit 14, the front wheel behavior control braking signal calculation circuit 14f uses the front wheel behavior control braking signal calculation table Taf. .
(5) In the table Taf, instead of the behavior control braking signal calculation line segment 20g of the table Ta0, the front wheel behavior control braking signal calculation line segment 20f having the same shape is used, and the behavior control braking signal F is used as the behavior control braking signal F. Instead, the front wheel behavior control braking signal Ff is provided, and the behavior control braking signal calculation circuit 14 outputs the behavior control braking signal Ff instead of outputting the behavior control braking signal Ff. What you did.

  The front wheel behavior control braking signal calculation line segment 20f has the same shape as the behavior control braking signal calculation line segment 20g as described above, but the value corresponding to the predetermined value j01 will be described for convenience. 1 Predetermined value j01 (signs are the same).

The rear wheel behavior control braking signal calculation circuit 14r obtains the rear wheel behavior control braking signal Fr using the rear wheel behavior control braking signal calculation table Tar, and outputs this to the brake control unit 15. The rear wheel behavior control braking signal calculation table Tar has a rear wheel behavior control braking signal 20r having a shape different from that of the front wheel behavior control braking signal calculation line 20f of the table Taf.
The braking signal 20r for rear wheel behavior control for the table Tar is a predetermined value (hereinafter referred to as a first value) when the deformation pitch angular velocity α · dθ / dt is a negative value (left side of the vertical axis in FIG. 4) and a positive value. 2 is smaller than the predetermined value j02), the rear wheel behavior control braking signal Fr is set to “0” (dead zone). Further, when the deformation pitch angular velocity α · dθ / dt is equal to or greater than the second predetermined value j02, the rear wheel behavior control braking signal Fr increases as the value increases. Has been.

The second brake control unit 15A has the most demanding braking force among the brake operation command signal Am, the behavior stabilization braking signal Bm, and the rear wheel behavior control braking signal Fr. A large signal is selected, and the selected signal is output as the target braking force signal K. Further, the actuator 17 for the front wheels is selected and selected from the braking operation command signal Am, the behavior stabilization braking signal Bm, and the front wheel behavior control braking signal Ff that requires the largest braking force. The signal is output as the target braking force signal K.
In the second embodiment, the controller 20A (control means) includes a front integration circuit 11f, a rear integration circuit 11r, a pitch angular velocity calculation circuit 12, an amplification circuit 13, a front wheel and rear wheel behavior control braking signal calculation circuit. 14f and 14r, and the 2nd brake control part 15A.

In the second embodiment described above, the front wheel brake means 19 generates a braking force when the deformation pitch angular velocity α · dθ / dt is equal to or smaller than the first predetermined value j01, and the rearward when the deformation pitch angular velocity α · dθ / dt is equal to or larger than the second predetermined value j02. The wheel brake means 19 generates a braking force. That is, when the front part of the vehicle body 3 rises above a predetermined level (the vehicle body 3 performs the pitch behavior in the clockwise direction in FIG. 1), the front wheel (the front wheel 4) is braked and the rear part of the vehicle body 3 exceeds a certain level. Ascending (the vehicle body 3 performs a counterclockwise pitch behavior in FIG. 1), the rear wheels (rear wheels 4) are braked.
As described above, the pitch motion is not controlled by the operation of the shock absorber 6 (see FIG. 1) but by braking the wheel 4 (see FIG. 1), so that the shock absorber 6 has a full stroke, Depending on the shock absorber 6, it is possible to cope with a large pitch behavior in which it is difficult to suppress the pitch motion, and the large pitch behavior can be suppressed.

  In the first and second embodiments, an anti-brake system control logic may be added. In this case, the braking force is controlled within a range in which the wheels 4 do not lock, and better running stability can be ensured.

  DESCRIPTION OF SYMBOLS 1, 1A ... Brake control apparatus, 9f, 9r ... Front part, rear acceleration sensor (vehicle body behavior detection means), 11f, 11r ... Front part, rear part integration circuit (vehicle body behavior detection means), 12 ... Pitch angular velocity calculation circuit, 17 ... Actuator, 19 ... Brake means, 20, 20A ... Controller (control means).

Claims (3)

Brake means actuated by an actuator to brake the wheels of the vehicle;
Vehicle body behavior detection means for detecting the vertical behavior of the vehicle body;
A brake control device comprising: a control unit that controls the brake unit by driving the actuator in accordance with a detection result of the vehicle body behavior detection unit.   2. The brake control device according to claim 1, wherein the vehicle body behavior detection means is pitch behavior detection means for detecting a pitch behavior of the vehicle body of the vehicle.   3. The control unit according to claim 1, wherein the control unit controls the actuator according to a detection result of the vehicle body behavior detection unit when at least a driver of the vehicle is not performing a brake operation. 4. Brake control device.

Images