JP2823062B2 - Braking force control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a braking force control device capable of improving the steering stability of a vehicle during braking.

[0002]

2. Description of the Related Art As a conventional braking force control device, there is a device which controls a vehicle yaw characteristic by a differential pressure between left and right brakes as disclosed in Japanese Utility Model Laid-Open No. 155264/1984. Specifically, when braking is performed with the driver's steering angle being equal to or larger than a predetermined value, control is performed such that the pressure increase timing of the turning outer wheel is delayed to improve the turning performance during braking.

However, the above conventional braking force control device does not consider that the yaw rate generated by the front wheel steering and the difference between the left and right braking forces depends on the vehicle speed, and it is difficult to control the yaw rate to an appropriate value. However, there is an unsolved problem that it is difficult to improve the transient characteristics of the generated yaw rate. In order to solve the above-described problem, for example, a target yaw rate is set based on a vehicle speed and a steering angle, and a target left-right braking force difference required to match the target yaw rate with a yaw rate generated in an actual vehicle is determined in advance by the vehicle. Calculated by a calculation based on the vehicle model set by the specifications and the equation of motion, and the left and right braking force calculated from the target left and right braking force difference is applied to one wheel so that the actual left and right braking force matches. Increases the brake pressure corresponding to half of the target left and right braking force difference in addition to the brake pressure (master cylinder pressure) generated by the pedaling force, and corresponds to half of the target left and right braking force difference for the other wheel. A braking force control device that controls the brake pressure by subtracting it from the brake pressure (master cylinder pressure) generated by the pedaling force and reducing the pressure is considered. In this way, the fluctuation of the entire braking force is prevented, and the transient characteristic of the yaw rate generated depending on the vehicle speed is improved.

[0004]

However, in the above-mentioned braking force control device, if the pressure is increased on one wheel and reduced on the other wheel, for example, the braking force is reduced by lightly depressing the brake. If a sharp steering operation is performed in a gentle braking state where the braking force is small, a target left-right braking force difference larger than the actual braking force according to the pedaling force is given, and there is a possibility that the braking force on the pressure-increasing side may increase. .

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a braking force control device capable of realizing higher steering stability by preventing unnecessary braking force from being generated. Aim.

[0006]

In order to achieve the above object, a braking force control apparatus according to the present invention comprises a steering state detecting means for detecting a steering state of a vehicle, as shown in a basic configuration of FIG. Speed detection means for detecting the front-rear direction speed of the vehicle, target yaw rate setting means for inputting signals from the steering state detection means and the speed detection means to set a target yaw rate of the vehicle, and at least one of front wheels and rear wheels. The left and right braking means provided, the braking pressure detecting means for detecting the braking pressure of each of the braking means, and the necessary yaw rate set by the target yaw rate setting means are required to be realized by the vehicle to be controlled. Target braking force calculation means for calculating at least one of the left and right target braking forces of the front wheels and the rear wheels by calculation based on a vehicle model set in advance by vehicle specifications and equations of motion; A braking force control means for independently controlling the braking force of the braking means to match the target braking force calculated by the target braking force calculation means. The means limits the target braking force to the upper limit value when the calculated target braking force on the pressure increasing side is equal to or more than an upper limit value corresponding to the braking force generated by the pedaling force.

[0007]

In the braking force control apparatus of the present invention, the target yaw rate 設定 'r is calculated by the target yaw rate setting means based on the detected value of the steering state of the vehicle, for example, the detected steering angle and the speed of the vehicle in the longitudinal direction, for example, the vehicle speed. Then, the target braking force calculating means performs a calculation based on the vehicle model and the vehicle model set by the equation of motion so that the target yaw rate ψ'r matches the yaw rate actually generated in the vehicle. A target braking force which causes the braking force control means to generate a braking force difference is calculated. At this time, if the calculated target braking force on the pressure increasing side is equal to or greater than the upper limit value corresponding to the braking force generated by the pedaling force, the target braking force becomes the same upper limit value, thereby preventing unnecessary increase in the braking force. As a result, the steering stability of the vehicle is improved.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a hydraulic and electric system diagram showing one embodiment of the present invention. In the figure, 1FL, 1FR are wheel cylinders, 1RL, 1RR as braking means attached to the front wheels.
Is a wheel cylinder as braking means attached to the rear wheel, of which a wheel cylinder 1F on the front wheel side
The brake fluid pressure supplied to L, 1FR is controlled by the two actuators 2, 15, and the brake fluid pressure supplied to the rear wheel cylinders 1RL, 1RR is controlled by only one actuator 2.

As shown in FIG. 3, one of the actuators 2 has a configuration similar to that of a conventional anti-skid control actuator, and separately controls the front wheel-side wheel cylinders 1FL and 1FR via the other actuator 15. Two three-port three-position electromagnetic directional control valves 3FL and 3FR to be controlled, and wheel cylinders 1RL and 1R on the rear wheel side
3 port 3 position electromagnetic directional control valve 3R that simultaneously controls R
And These electromagnetic directional control valves 3FL to 3R
Is for controlling the brake fluid pressure of the wheel cylinders 1FL to 1R to be equal to or less than the brake fluid pressure of the master cylinder 5.

The electromagnetic directional control valves 3FL and 3FR
The P port is connected to one of the two systems of the master cylinder 5 connected to the brake pedal 4, the A ports of the electromagnetic directional valves 3FL and 3FR are individually connected to the other actuator 15, and the B port is connected to the other actuator 15. Hydraulic pump 7F rotationally driven by an electric motor (not shown)
Is connected to one of the systems of the master cylinder 5.

The P port of the electromagnetic directional control valve 3R is connected to the other system of the two-system master cylinder 5,
The A port of the electromagnetic directional control valve 3R is connected to the wheel cylinders 1RL and 1RR, and the B port is connected to the other system of the master cylinder 5 via a hydraulic pump 7R that is driven to rotate by an electric motor (not shown). ing.

Further, the electromagnetic directional control valves 3FL and 3FR
The accumulator 8F is connected to the pipeline between the P port and the hydraulic pump 7F, the reservoir tank 9F is connected to the pipeline between the B port and the hydraulic pump 7F, and the P port of the electromagnetic directional control valve 3R is similarly connected. The accumulator 8R is connected to a pipeline between the hydraulic pump 7R and the reservoir, and a reservoir tank 9R is connected to a pipeline between the B port and the hydraulic pump 7R.

Here, the front-wheel-side electromagnetic directional control valves 3FL, 3FL
As shown in FIG. 3, each of the FRs directly increases the brake fluid pressure to the brake fluid pressure of the master cylinder 5 by directly connecting the master cylinder 5 and the other actuator 15 at the first switching position of the normal position. State, the other actuator 15 is disconnected from the master cylinder 5 and the hydraulic pump 7F at the second switching position to maintain the brake fluid pressure, and the third actuator 15 is connected to the other actuator 15 at the third switching position. By connecting the master cylinder 5 to the master cylinder 5 via a hydraulic pump 7F, a decompression state in which the brake fluid is returned to the master cylinder 5 side is established, and these switching positions are supplied from a braking pressure control device 16 described later.
The switching is controlled by the current value of the step.

The rear-wheel electromagnetic directional switching valve 3R directly connects the master cylinder 5 and the wheel cylinders 1RL, 1RR at the first switching position of the normal position to control the brake fluid pressure of the wheel cylinders 1RL, 1RR. The pressure is increased to the brake fluid pressure of the cylinder 5 and the second
At the switching position, the connection between the wheel cylinders 1RL, 1RR and the master cylinder 5 and the hydraulic pump 7R is interrupted to maintain the brake fluid pressure of the wheel cylinders 1RL, 1RR, and the wheel cylinder 1RL at the third switching position. , 1RR and the master cylinder 5 are connected via a hydraulic pump 7R, so that the brake fluid in the wheel cylinders 1RL, 1RR can be
Side, and these switching positions are switched and controlled by three stages of current values supplied from a braking pressure control device 16 described later.

As shown in FIG. 4, the other actuator 15 has a configuration similar to that of a conventional traction control actuator, and applies brake fluid pressure from the one actuator 2 to the wheel cylinder 1 on the front wheel side.
Switching valves 21FL and 21F for inputting to the FL and 1FR and for shutting off the output from the actuator 15
R, a three-port three-position electromagnetic directional control valve 22FL for individually controlling the brake fluid pressure of the front wheel side wheel cylinders 1FL and 1FR to be equal to or higher than the brake fluid pressure of the master cylinder 5.
And 22FR.

The electromagnetic directional control valves 22FL and 22FL
The A port of FR is connected to a pipeline connecting the switching valves 21FL, 21FR and the wheel cylinders 1FL, 1FR, and between them, plunger-type pistons 23FL, 23FR for switching the switching valves 21FL, 21FR, and throttle valves 24FL, 24. And is interposed. The B ports of the electromagnetic directional switching valves 22FL and 22FR are connected to a hydraulic pump 26F that pressurizes the brake fluid in a brake fluid reservoir tank 25F, and the P port is connected to the reservoir tank 25F.

Further, the hydraulic pump 26F and the 3-port 3
A pressure switch 27 is provided in a line between the position electromagnetic directional control valves 22FL and 22FR, and the accumulator 2
8 is connected, and the brake fluid pressurized by the hydraulic pump 27 is stored in the accumulator 28. Further, the accumulator 28 is connected to a reservoir 25F via a relief valve 29. The signal from the pressure switch 27 is input to a braking pressure control device 16 described later. When the brake fluid pressure falls below a first predetermined value P ₀ , the braking pressure control device 16 The hydraulic pump 26F is driven by the output hydraulic pump drive signal, and when the brake fluid pressure exceeds a second predetermined value P ₁ (> P ₀ ), the drive signal is stopped based on the signal from the switch 27. Further, when the brake fluid pressure exceeds a third predetermined value P ₂ (> P ₁ ), the brake pressure control device 16
Valve 2 from the relief valve drive signal output from the
9 is driven, and the brake fluid in the accumulator 28 is relieved to the reservoir tank 25F.

On the other hand, each of the electromagnetic directional switching valves 22FL and 22FL
In the third switching position, the FRs communicate with the plunger-type pistons 23FL, 23FR and the accumulator 28 as shown in FIG.
R is moved forward and the switching valves 21FL and 21FR are switched by the rods of the pistons 23FL and 23FR to shut off the output to the actuator 2 side, and at the same time, the brake fluid in the pistons 23FL and 23FR is supplied to the wheel cylinders 1FL and 1FR. Master cylinder 5
Increase to more than the brake fluid pressure. In the second switching position, the plunger type pistons 23FL, 23FR and the accumulator 28 are shut off, and the pistons 23F, 23FR are closed.
L and 23FR stop at that position, and the brake fluid pressure of the wheel cylinders 1FL and 1FR is held. In the normal first switching position, the plunger-type pistons 23FL, 23FR and the reservoir tank 25F are communicated and relieved, the rods of the pistons 23FL, 23FR retreat, and the wheel cylinders 1FL, 1FR are depressurized. At the same time, the switching valves 21FL and 21FR return to the normal position, and the brake fluid pressure from one actuator 2 is input to the wheel cylinders 1FL and 1FR.
These switching positions are switched and controlled by three-stage current values supplied from a braking pressure control device 16 described later. A check valve is used at the switching position of the plunger type pistons 23FL, 23FR, and the rods of the pistons 23FL, 23FR automatically advance / retreat according to the brake fluid pressure of the accumulator 28 and the brake fluid pressure of the master cylinder 5. It is like that. In the pressure increasing state, the throttle valves 24FL and 24FR are switched to the throttle side so that the plunger type pistons 23FL and 23FR move forward slowly.

On the other hand, as shown in FIG.
The steering angle of the ring wheel 10 is detected,
Zero voltage when the wheel 10 is in the neutral position,
Negative voltage according to the steering angle when turning right from the standing position,
And when turning left from the neutral position, a positive
Steering state detecting means for outputting a steering angle detection value θ as a voltage
The steering angle sensor 11 as a
Vehicle speed detection value V according to speed_XOutput speed detection means
All the vehicle speed sensors 12 are attached, and the brake pedal
Brake switch 13 for detecting the stepping state of No. 4 is attached
And each wheel cylinder 1FL, 1F
Pressure detection value P according to cylinder pressure of R, 1RL_FL,
P_FR, P_RPressure sensors 14FL, 14FR,
14R is attached, and each of the two system master cylinders 5
Pressure detection value P corresponding to the cylinder pressure of the system _MCFAnd P_MCR
Pressure sensors 14MCF and 14MCR output
The detected value of each of these sensors is
16 is input.

As shown in FIG. 5, the braking pressure control device 16 includes sensors 11, 12, 13, and 14FL to 14M.
CF, a microcomputer 19 which detected values of 14MCR is input, the control signal CS _FL1, CS _FR1 and CS _R is individually input electromagnetic direction switching actuator 2 while the aforementioned output from the microcomputer 19 Floating type constant current circuits 20FL1 and 20FR for driving solenoids of valves 3FL, 3FR and 3R
1 and 20R and the control signals CS _FL2 and CS _FR2 output from the microcomputer 19 are individually input to the electromagnetic directional control valve 2 of the other actuator 15 described above.
Floating type constant current circuits 20FL2 and 20FR2 for driving 2FL and 22FR solenoids are provided.

The microcomputer 19 includes at least
Input interface circuit 19 having A / D conversion function
a, output interface circuit 1 having D / A conversion function
9b, an arithmetic processing unit 19c and a storage device 19d,
The steering angle detection from the steering angle sensor 11 is performed by the arithmetic processing unit 19c.
Output value θ, vehicle speed detection value V from vehicle speed sensor 12_XAnd pressure
Master cylinder from sensor 14MCF, 14MCR
Pressure detection value P_MCF, P_MCR7 is executed based on
Target wheel cylinder as the target braking force for the front left and right wheels
Pressure P^* _FRAnd P^* _FLAnd calculate these target wheels.
Cylinder pressure P ^* _FRAnd P^* _FLAnd pressure sensor 14F
Cylinder pressure of R, 14FL, 14MCF and 14MCR
Detection value P_FR, P_FL, P_MCFAnd P_MCRFIG. 7 based on
Is performed, and the electromagnetic method of the one actuator 2 is performed.
Control signal CS for controlling directional control valves 3FL, 3FR_FL1,
CS_FR1And the other actuator 15
Control signal C for controlling magnetic direction switching valves 23FL and 23FR
S_FL2, CS_FR2And outputs to the electromagnetic directional control valve 3R.
For the control signal CS which is always zero_RIs output.

Next, the operation of the above embodiment will be described. First, the control principle of this embodiment will be described. As shown in FIG.
When considered as a degree of freedom, the equation of motion can be expressed by the following equations (1) and (2). _{I Z · ψ "(t)} = C f · L f -C r · L r + T f · (B FL (t) -B FR (t)) / 2 ......... (1) M · V'y ( t) = 2 ( _Cf + _Cr ) -MVx (t)) '(t) (2) where I _Z is the vehicle yaw moment of inertia, ψ' (t) is the yaw rate, and _Lf is The distance between the vehicle center of gravity and the front axle, L _r is the distance between the vehicle center of gravity and the rear axle, T _f is the front wheel tread,
B _FL (t) is the left front wheel braking force, B _FR (t) is the right front wheel braking force, M
Is the vehicle weight, Vy (t) is the vehicle lateral speed, V'y (t) is the vehicle lateral acceleration, and Vx (t) is the vehicle longitudinal direction speed.
Further, _Cf and _Cr are the cornering forces of the front wheels and the rear wheels, and can be expressed by the following equations (3) and (4).

[0023] _{C f = K f {θ (} t) / N- (Vy + L f · ψ '(t)) / Vx (t)} ......... (3) C r = -K r (Vy -L r · Ψ '(t)) / Vx (t) (4) where θ (t) is the steering angle, N is the steering gear ratio, and K _f
Is front wheel cornering power, and K _r is rear wheel cornering power. Substituting Equations 3 and 4 into Equations 1 and 2 above, and considering them as differential equations relating to the yaw rate ψ '(t) and the lateral velocity Vy (t), they are expressed by the following Equations 5 and 6. Can be.

Ψ ″ (t) = a ₁₁ ψ ′ (t) + a ₁₂ · Vy (t) + b ₁ · θ (t) + b _pl · ΔB _f (t) (5) V'y (t) ) = A ₂₁ · ψ '(t) + a ₂₂ · Vy (t) + b ₂ · θ (t) (6) where ΔB _f (t) = B _FL (t) −B _FR (t) _{... (7.1) a 11 = -2} (K f · L f 2 + K r · L r 2) / (I Z · Vx) ...... (7.2) a 12 = -2 (K f · L f -K r · L _r ) / (I _Z · Vx) (7.3) a ₂₁ = −2 (K _f · L _f −K _r · L _r ) / (M · V x) −V x (7.4) a ₂₂ = − _{2 (K f + K r)} / (M · Vx) ...... (7.5) b 1 = 2 · K f · L f / (I Z · N) ...... (7.6) b 2 = 2 · K f / (M · N) ··· (7.7) b _pl = T _f / (2 · I _z ) ··· (7.8) Considering a normal vehicle, the front wheel braking force difference ΔB _f (t) is zero. the transfer function of the yaw rate ψ '(t) with respect .DELTA.B _f steering angle and ignoring the section (t) θ (t) is used differential operator S Represented by the following Formula 8.

[0025] The 8 equations transfer function is in the form of a (primary) / (secondary), the steering angle input θ larger the vehicle longitudinal direction velocity V _X becomes large
It can be seen that the generated yaw rate ψ ′ (t) with respect to (t) becomes oscillating, and the vehicle maneuverability and stability deteriorate. That is, the coefficient {− (a ₁₁ + a ₂₂ )} relating to the first-order term of the denominator of the above equation (8).
Is equivalent to the damping coefficient 制 御 of the control system, so that the coefficient ｛− (
a ₁₁ + a _22)} to the 7.2 formula and substituting a ₁₁ and a ₂₂ shown in 7.5 formula, because these a _11, a ₂₂ is always a negative value, the damping coefficient ζ is positive , And the damping coefficient ζ approaches zero as the vehicle longitudinal speed Vx increases. That is, since the damping coefficient 制 御 of the control system decreases as the vehicle front-rear direction speed Vx increases, the yaw rate ψ ′ (t) becomes vibrating (hard to attenuate).

Therefore, for example, if the target yaw rate ψ'r (t) is a first-order lag system without overshoot and undershoot with respect to the steering angle input θ (t), and the steady-state value is set equal to that of a normal vehicle, , The target yaw rate ψ'r (t) is 9
It can be represented by an equation. _{ψ'r (t) = H 0 ·} θ (t) / (1 + τt) ......... (9) where, H ₀ is the steady yaw rate gain, by using a stability factor A, it is defined by the following 10 formula .

H ₀ = Vx / ｛(1 + A · Vx ² ) · L · N) (10) where L is the wheel base, and the stability factor A is represented by the following equation (11). . Next, a method of making the generated yaw rate ψ ′ (t) of the vehicle equal to the target yaw rate ψ′r (t) using the braking force difference ΔB _f (t) between the left and right front wheels will be described. The differential value ψ ″ r (t) of the target yaw rate can be obtained by the following equation (12) obtained by modifying the equation (9).

Ψ “r (t) = H ₀ · θ (t) / τ−ψ′r (t) / τ (12) Difference between steering angle input θ (t) and left and right front wheel braking force ΔB _f ( Assuming that the generated yaw rate ψ '(t) due to t) coincides with the target yaw rate ψ'r (t), each differential value ψ "(t), ψ" r (t)
Also matches. Therefore, ψ "r (t) = ψ" (t), ψ'r (t) = ψ '
(t), and the lateral velocity Vy (t) at the time when the above assumption is satisfied is defined as Vyr (t), and these are substituted into the above formulas (5) and (6). Equation 14 can be obtained.

[0029] ψ "r (t) = a 11 · ψ'r (t) + a 12 · Vyr (t) + b 1 · θ (t) + b pl · ΔB f (t) ......... (13) Vyr '( t) = a ₂₁ · ψ′r (t) + a ₂₂ · Vyr (t) + b ₂ · θ (t) (14) Then, if the above equation (13) is substituted into the above equation (14), the control of the left and right front wheels is obtained. The power difference ΔB _f (t) can be obtained by the following equation: ΔB _f (t) = (ψ ″ r (t) −a ₁₁ · ψ′r (t) −a ₁₂ · Vyr (t) −b ₁ · θ (t)) / b _pl (15) In order to generate the braking force difference ΔB _f (t) between the left and right front wheels determined by the equation (15), a differential pressure is applied to the wheel cylinder pressures of the left and right front wheels. The relationship between the wheel cylinder pressure P and the braking force _Bf can be obtained by ignoring the moment of inertia of the wheels.
It can be obtained by the following equation (16).

[0030] _{B f = 2 · μ p ·} A p · r p · P / R = k p · P ......... (16) k p = 2 · μ p · A p · r p / R ......... ( 17) However, k _p is a proportionality constant between the wheel cylinder pressure and the braking force, mu _p brake pad and the disc rotor friction coefficient between, a _p is the wheel cylinder area, r _p is the disc rotor effective radius, R represents the tire Radius.

Therefore, if the target differential pressure of the wheel cylinder pressures of the left and right front wheels is ΔP (t), the target differential pressure ΔP
(t) can be represented by ΔP (t) = ΔB _f (t) / k _p (18) Then, since the target differential pressure ΔP determined in the 18 formula (t) and the master cylinder pressure P _{MC F} (t), such that the total braking force is not changed, i.e., the sum of the left and right front wheels of the wheel cylinder pressure master cylinder The target wheel cylinder pressures P ^* _FL (t) and P ^* _FR (t) for the left and right front wheels are set according to the following equations (19) and (20) so as to be twice the pressure.

[0032] _{^{P * FL (t) = max}} (P MCF (t) + ΔP (t) / 2,0) ......... (19) P * FR (t) = max (P MCF (t) -ΔP (t ) / 2, 0) (20) where max (A, B) in the above equations (19) and (20) means that the maximum value of A and B is selected. Further, the present invention is characterized in that an upper limit value corresponding to the master cylinder pressure generated by the depression force of the brake pedal is provided for the target wheel cylinder pressure, but in this embodiment, the upper limit value is set to the master cylinder pressure. Doubled. Accordingly, the target wheel cylinder pressure of each wheel is set by the following equations 21, 22, and 23.

P ^* _FL (t) = min [ _2PMCF (t), max ( _PMCF (t) + ΔP (t) / 2, 0)] (21) P ^* _FR (t) = min [ 2P _MCF (t), max (P _MCF (t) -ΔP (t) / 2, 0)] ... (22) P ^* _R (t) = 2P _MCR (t) ... (23) In Equations 21 to 23, min (A, B) means that the minimum value of A and B is selected.

Therefore, the above-mentioned calculation is executed by the processing unit 19c of the microcomputer 19 to execute the target wheel cylinder pressure calculation processing of FIG. 7 and the braking force control processing of FIG. By controlling, the yaw rate of the vehicle can be made to coincide with the target yaw rate. That is, the target wheel cylinder pressure calculation process of FIG. 7 is executed as a timer interrupt process for each predetermined period ΔT (for example, 5 msec). First, in step S1, the steering angle sensor 1
1 and the detected vehicle speed V of the vehicle speed sensor 12
_X is read, and then the process proceeds to step S2 to calculate the above-mentioned formula 7.2 from the vehicle speed detection value V and the preset vehicle data.
The calculation of equation 7.6 is performed to calculate coefficients a _{11 to} a ₂₂ .
Here, the constant portion is determined by the specifications of the vehicle in the 7.2 Formula 7.6 Formula a _11V ~a _22V is below 24.1
It is calculated in advance by Equations 24.4 to 24.4.

A_11V= -2 (K_f・ L_f ^Two+ K_r・ L_r ^Two) / I_Z …… (24.1) a_12V= -2 (K_f・ L_f-K_r・ L_r) / I_Z …… (24.2) a_21V= -2 (K_f・ L_f-K_r・ L_r) / M …… (24.3) a_22V= -2 (K_f+ K_r) / M (24.4) Next, the process proceeds to step S3, where the detected vehicle speed value Vx is set as follows:
The stability feasibility calculated in advance based on the above equation (11)
Wheel base determined by the specifications of the
Based on the gear ratio L and the steering gear ratio N,
Calculation is performed to determine the steady yaw rate gain H₀When calculating
And the calculated steady-state yaw rate gain H ₀Based on previous
By performing the calculation of Equation 12, the target yaw rate can be finely adjusted.
Calculate the partial value ψ "r (n), and further calculate the calculated differential value ψ" r
(n) and the previous value of the target yaw rate ψ'r (n-1)
Calculate the current target yaw rate ψ'r (n) according to equation 5,
This is stored in the target yaw rate storage area formed in the storage device 19d.
Update and store in the area.

Ψ′r (n) = ψ′r (n−1) + ψ ″ r (n) · ΔT (25) where ΔT is a timer interrupt cycle. Then, the process proceeds to step S4. Then, the coefficient a calculated in step S2
₂₁ and the a _22, lateral acceleration Vyr '(n from the calculated target yaw rate ψ'r (n) and the lateral velocity of the previous value Vyr (n-1) and carries out an operation of the equation (14) in step S3 ) Is calculated, and the current lateral velocity Vyr (n) is calculated from the calculated lateral acceleration Vyr '(n) and the previous value of the lateral velocity Vyr (n-1) by the following equation (26). Calculate and store this in the storage device 19
The data is updated and stored in the lateral speed storage area d.

Vyr (n) = Vyr (n−1) + Vyr ′ (n) · ΔT (26) Next, the process proceeds to step S5, and the braking force difference ΔB _f between the left and right front wheels is calculated according to the above equation (15). Then, the calculated braking force difference ΔB _f and a proportional constant k calculated in advance according to equation (17).
_The target differential pressure ΔP is calculated by performing the calculation of Expression 18 based on _p .

Next, the process proceeds to step S6, where
By performing the calculations of Equations 1 to 23, the left front wheel target wheel is obtained.
Cylinder pressure P^* _FLTo (P_MC+ ΔP / 2) or 0
And the master cylinder pressure P_MCFDouble value of 2
P_MCFAnd set the right front wheel target wheel
Cylinder pressure P^* _FRTo (P_MC-ΔP / 2) or 0
If the deviation is large and the master cylinder pressure P_MCFDouble value of
2P_MCFAnd set the rear wheel target wheel
Cylinder pressure P^* _RIs the master cylinder pressure P _MCRSet in
After the setting, the timer interrupt processing ends.

In the processing of FIG. 7, the processing of step S3 corresponds to the target yaw rate setting means.
Steps 2, 4 to 6 correspond to the target braking force calculating means. Therefore, if it is assumed that the vehicle is traveling straight ahead, the vehicle speed detection value Vx from the vehicle speed sensor 12 is a value corresponding to the vehicle speed, but the steering angle detection value θ from the steering angle sensor 11 is zero. , And the previous value of the target yaw rate ψ'r (n-
1) and the previous value Vyr (n-1) of the lateral speed are also zero. For this reason, the steady yaw rate gain H ₀ calculated in step S3 is a value corresponding to the vehicle speed, but the differential value ψ ″ r (n) of the target yaw rate is the steering angle detection value of the first term on the right side of the equation (12). θ is zero and the previous value of the target yaw rate ψ'r
Since (n-1) is also zero, the current value ψ'r (n) of the target yaw rate also becomes zero. Accordingly, the lateral acceleration Vyr (n) and the lateral velocity Vyr (n) calculated in step S4 become zero, and the left and right front wheel braking force difference ΔB _f and the target differential pressure ΔP calculated in step S5 also become zero. In the following step S6, since the vehicle is in the non-braking state, master cylinder pressure P detected by pressure sensor 14MCF is detected.
_MCF is zero, and target wheel cylinder pressures P ^* _FL and P
^* _FR is set to zero.

[0040] However, when the transition from the straight running state to the braking state by depressing the brake pedal 4, by the master cylinder pressure P _MCF of the master cylinder 5 rises, the target wheel cylinder pressure P of the left and right wheels in step S6
^* _FL and P ^* _FR are set equal to the master cylinder pressure _PMCF . On the other hand, when the vehicle is turned leftward, for example, by turning the steering wheel 10 leftward from the straight traveling state at a constant speed, the steering angle sensor 11 correspondingly increases in the forward direction according to the steering angle of the steering wheel 10. Is output, the current value 、 "r (n) of the differential value of the target yaw rate calculated in step S3 is determined by the steady yaw rate gain H ₀ corresponding to the vehicle speed and the steering angle detection value θ. And the current value of the target yaw rate ψ'r (t) also increases in the positive direction, and accordingly, the current value V of the lateral acceleration calculated in step S4.
yr ′ (n) changes in the positive or negative direction depending on the vehicle specifications and the vehicle speed, and accordingly, the current value Vyr (n) of the lateral speed also changes in the positive or negative direction.

At step S5, the braking force difference ΔB _f between the left and right front wheels and the target differential pressure ΔP are calculated based on the above values. Based on the calculated values, the target cylinder pressure P ^* _FL for the front left wheel is calculated at step S6 by (P
_MC + ΔP / 2) or 0, whichever is greater, or the double value 2P _MCF of the master cylinder pressure P _MCF , whichever is smaller, and sets the target cylinder pressure P ^* _FR of the front right wheel to (P _MC −
ΔP / 2) or 0, whichever is greater, or the double value 2P _MCF of the master cylinder pressure P _MCF , whichever is smaller, and set the target cylinder pressure P ^* _R for the rear wheels to the master cylinder pressure P _MCR By setting and controlling the cylinder pressure of each of the wheel cylinders 1FL, 1FR and 1R in accordance with these settings, it is possible to generate an appropriate yaw rate according to the vehicle speed, the steering angle, and the load movement.

Next, when the steering wheel 10 is turned rightward from the straight running state to the right turning state, the steering angle detection value θ of the steering angle sensor 11 becomes a negative value, so that the differential value of the target yaw rate is obtained. ψ "r (n) and the target yaw rate ψ'r (n) have negative values, but are controlled basically in the same manner as in the left turn. On the other hand, the braking force control processing of FIG. Similar to the target cylinder pressure calculation processing, the processing is individually executed on the left and right wheels as a timer interruption processing of a predetermined period ΔT. Fig. 8 shows only the braking force control processing for the left front wheel side wheel cylinder 1FL.

That is, in step S7, the brake switch 1
3 is in the on state, and when the brake switch 13 is in the off state, it is determined that it is in the non-braking state, and the process proceeds to step S8, where a variable T representing the holding time of the control signal to be output is set. _P is set to "1", and then the process proceeds to step S9 to set the variable m representing the cycle for monitoring the error between the target cylinder pressure P ^* _FL and the actual cylinder pressure _PFL to "1".
Then, the process proceeds to step S10, in which the control signal CS _FL2 as a pressure reduction signal of “0” is output to the constant current circuit 20FL2 to the other actuator 15, and the process proceeds to step S11.

[0044] In the step S11, the variable T or _P is positive, or "0", further determines whether the negative. If T _P > 0, step S12
And the control signal CS _FL1 as a pressure increase signal of “0” is supplied to the one actuator by the constant current circuit 20F.
L1 and then the process proceeds to step S13 where the variable T
_A new coefficient _TP is calculated by subtracting "1" from _P , and this is updated and stored in a coefficient storage area formed in the storage device 19d, and then the process proceeds to step S14 to subtract "1" from the variable m. The updated value is updated and stored in a variable storage area formed in the storage device 19d as a new variable m, and then the timer interrupt processing is terminated and the program returns to the main program. On the other hand, when the determination result of step S11 is T _P = 0, the process proceeds to step S15, where the control signal CS as a holding signal of the first predetermined voltage V _S11 is sent to one of the actuators 2.
After outputting _FL1 , the process _proceeds to step S14 and returns to the main program. On the other hand, when the result of the determination in step S11 is T _P <0, the process proceeds to step S16, in which one of the actuators 2 is used as a pressure reduction signal of a second predetermined voltage V _S12 higher than the first predetermined voltage V _S11. control signal CS _FL1 outputs, then transition to the variable T _P a value obtained by adding "1" to a new variable T in step S17 in
_After being updated and stored in the variable storage area as _P , the process proceeds to step S14 and returns to the main program.

When the brake switch 14 is on in the result of the determination in step S7, it is determined that the vehicle is in the braking state, and the flow proceeds to step S18.
It is determined whether or not the target wheel cylinder pressure P ^* _FL calculated in the above-described target cylinder pressure calculation processing coincides with the master cylinder pressure _PMCF . If the two coincide, the process proceeds to step S8. Do not match, the process proceeds to step S19.

In this step S19, it is determined whether or not the variable m is positive.
0, and when m ≦ 0, the process proceeds to step S21. In step S21, target wheel cylinder pressure P ^* _FL and error P between the current cylinder pressure detection value P _{FL
^{err (= P * FL -P FL}} ) step S22 from to calculate the
Move to

In this step S22, a variable T _P is calculated in accordance with the following equation 27 in which a value obtained by dividing the error P _err by the reference value P ₀ is rounded. T _P = INT (P _err / P ₀ ) (27) Then, the process proceeds to step S23, where the variable m is set to a predetermined positive value m ₀ , and then the process proceeds to step S20.

In step S20, it is determined whether or not the target cylinder pressure P ^* _FL is equal to or higher than the master cylinder pressure _PMCF . If P ^* _{FL≥PMCF, the} routine _proceeds to step S1.
0, and when P ^* _FL < _PMCF , step S
Move to 24. In step S24, a control signal CS _FL1 as a pressure increase signal of “0” is output to the one actuator 2 to the constant current circuit 20FL1, and the process proceeds to step S25.

[0049] In the step S25, the variable T or _P is positive, or "0", further determines whether the negative. When T _P <0, step S26
Migrate outputs the control signal CS _FL2 as pressure signal increasing the "0" to the other actuator 15 to the constant current circuit 20FL2 in, then adds "1" to the variable T _P and proceeds to step S27 and to calculate the new coefficients T _P, which shifts from the updated and stored in the coefficient storage region formed in the storage device 19d to the step St 14, a new variable a value obtained by subtracting "1" from the variable m m After that, the timer interrupt processing is ended and the program returns to the main program, after updating and storing it in the variable storage area formed in the storage device 19d.
Further, when the determination result of step S25 is T _P = 0, the process proceeds to step S28, and outputs a control signal CS _FL2 as a first hold signal of a predetermined voltage V _S21 with respect to the other actuator 15 From step S14
And returns to the main program. On the other hand, when the determination result in step S25 is T _P > 0, the process proceeds to step S29, and the second predetermined voltage V _S22 higher than the first predetermined voltage V _S21 is applied to the other actuator 15.
Control signal and outputs a CS _FL2, then the after shifting the value obtained by subtracting "1" from the variable T _P in the variable storage area as a new variable T _P updated and stored in step S30 step S14 of the pressure reduction signal And returns to the main program.

Here, the processing of FIG. 8 corresponds to the braking force control means. Accordingly, when the vehicle is running in the non-braking state, the brake switch 14 is in the off state, so that the process proceeds from step S7 to step S10 via steps S8 and S9, and the control signal CS _FL2 of “0” (or CS _FR2 ) is a constant current circuit 20FL2 (or 20FR2)
Is output as a pressure reduction signal. Therefore, the constant current circuit 2
0FL2 (or 20FR2) does not output an exciting current, and the electromagnetic directional control valve 22F of the other actuator 15
L (or 22FR) maintains the normal position.

In step S11, since T _P > 0, the flow proceeds to step S12 in which the control signal CS of "0" is set.
_FL1 (or CS _FR1 ) is a constant current circuit 20FL1 (or 2
0FR1) as a pressure increase signal. Therefore, no exciting current is output from the constant current circuit 20FL1 (or 20FR1), the electromagnetic directional control valve 3FL (or 3FR) of one actuator 2 maintains the normal position, and the front wheel-side wheel cylinder 1FL (or 1FR). Are in communication with the master cylinder 5. At this time, since the brake pedal 4 is not depressed, the cylinder pressure output from the master cylinder 5 is zero, and the cylinder pressure of each wheel cylinder 1FL (or 1FR) is also zero, so that a braking force is generated. And the non-braking state is continued.

In this state, the brake pedal 4 is depressed.
Assuming that the braking state is established, the steps from step S7 in FIG.
The process proceeds to S18 and is calculated by the target cylinder pressure calculation process of FIG.
Target wheel cylinder pressure P^* _FL(Or P^* _FR)But
Master cylinder pressure P of each master cylinder 5_MCFWhen
It is determined whether they match. This judgment indicates that the vehicle is running straight
To determine whether the vehicle is in a running state or a turning state.
In the straight running state, as described above, the processing in FIG.
The target wheel cylinder pressure P^* _FL(Or P ^* _FR)
Is the master cylinder pressure P_MCFIs set equal to
The process moves from step S18 to step S8, and the
Control signal CS as in braking state_FL1(Or CS_FR1)
Both are set to zero and solenoid directional control valve 3FL (or 3FR) is turned off.
The master cylinder 5 and each
The communication with the wheel cylinder 1FL (or 1FR)
Of each wheel cylinder 1FL (or 1FR)
Pressure P_FL(Or P_FR) Is the master cylinder pressure P_MCFWhen
Up to the same value, and both wheel cylinders 1FL and
An equal braking force is generated at 1FR.

However, when the vehicle is in a braking state while turning.
When turning or turning in the braking state,
7, the target wheel cylinder pressure P^* _FL (or
Is P ^* _FR) Is the master cylinder pressure P_MCFTarget difference
A value obtained by adding half the pressure ΔP / 2, or “0”,
Or 2P_MCFIs set to
In the process for 1FL (or 1FR),
The process proceeds from step S18 to step S19, and
Variable m is set to “0” in the process of step S14
Then, the process proceeds to step S21. Therefore, each goal
Wheel cylinder pressure P^* _FL (Or P^* _FR) And pressure sensor
Pressure detection value P of 14FL (or 14FR)_FL(Or
P_FR) And error P_errIs calculated (step S21).
Set value P indicating the allowable range₀Divided by T_PCalculate
(Step S22), and then set the variable m to a positive predetermined value m₀
Is set (step S23) and the process proceeds to step S20.
Run.

Then, the target wheel cylinder pressure P^* _FL (or
Is P^* _FR) Is the master cylinder pressure P _MCFIf
Shifts to step S10, where the control signal CS_FL2(Or
CS _FR2) To zero and depressurize the other actuator 15
Mode, and the process proceeds to step S11. At this time,
Pressure detection value P of pressure sensor 14FL (or 14FR) _FL
(Or P_FR) Is the target wheel cylinder pressure P^* _FL(Or P
^* _FR), The variable T_PIs a positive value
Therefore, the process proceeds to step S12 and the control signal CS
_FL1(Or CS_FR1) To zero and one actuator
The pressure increasing mode of the fuel cell 2 is continued. This turning state and braking state
Is repeated and this step is repeated, step S
Variable T at 13_PIs decremented by “1” at step S14.
The variable m is decremented by "1" by_PIs zero
Then, the process moves from step S11 to step S15 and
1 predetermined voltage V_S11Control signal CS_FL1(Or C
S_FR1) To the constant current circuit 20FL1 (or 20FR1).
Output as a holding signal. Therefore, the constant current circuit 20F
A predetermined voltage V from L1 (or 20FR1)_S11Encouragement according to
Magnetic current is output to the electromagnetic directional control valve 3FL (or 3FR).
As a result, these electromagnetic directional control valves 3FL (or 3
FR) is switched to the second switching position, and the wheel cylinder is switched.
Between 1FL (or 1FR) and master cylinder 5
It is shut off and the wheel cylinder 1FL (or 1FR)
Cylinder pressure P_FL(Or P_FR) Is maintained at a constant value
Mode, and this holding mode is a variable
The process is continued until m becomes “0”.

[0055] Then, the variable m is "0", the process proceeds to step S21 again, the variable T _P calculated in less than half the step S22 of the error pressure P _err is the set pressure P ₀ at this time The value becomes "0", and the flow proceeds from step S11 to step S15 to be in the above-mentioned holding mode without going through the pressure increasing mode, and the cylinder pressure P _FL (or P _FR ) of the wheel cylinder 1FL (or 1FR) becomes the target wheel cylinder pressure P ^* _FL (or P ^* _FR ) is maintained.

Each wheel cylinder 1FL (or 1
FR) Cylinder pressure P_FL(Or P_FR) Is the target wheel
Linda pressure P^* _FL(Or P^* _FR) If higher,
Error P calculated in step S21_errIs negative
And the variable T_PIs also a negative value, and
The process proceeds to step S16 and the predetermined voltage V_S12Control signal CS
_FL1(Or CS_FR1) Is output as a pressure reduction signal.
From the constant current circuit 20FL1 (or 20FR1).
Pressure V_S12Exciting current corresponding to the electromagnetic directional control valve 3FL (or
Is supplied to the third switching position.
Is switched. Therefore, the wheel cylinder 1FL (or
1FR) is connected to the master cylinder 5 via the hydraulic pump 7F.
To the wheel cylinder 1FL (or
Is the cylinder pressure P of 1FR)_FL(Or P_FR) Is decompressed
The decompression mode is set, which is determined by the variable T_PTill becomes “0”
Will be maintained.

On the other hand, if the target cylinder pressure P ^* _FL (or P ^* _FR ) is equal to or higher than the master cylinder pressure _PMCF , the process _proceeds from step 20 to step S24, where the control signal CS _FL1 (or CS _FR1 ) is set to zero. One of the actuators 2 is set to the pressure increasing mode, and the process proceeds to step S25.
At this time, if the detected pressure value P _FL (or P _FR ) of each pressure sensor 14FL (or 14FR) has not reached the target cylinder pressure P ^* _FL (or P ^* _FR ), the routine proceeds to step 22.
In so calculated variable T _P is a positive value step S2
9, the control signal CS _{FL2 of} the second predetermined voltage V _S22 (or CS
_FR2 ) is output as a pressure increase signal, whereby the exciting current corresponding to the predetermined voltage V _S22 is supplied from the constant current circuit 20FL2 (or 20FR2) to the electromagnetic directional control valve 22FL (or 22F).
R), this is switched to the third switching position. Accordingly, the brake fluid in the accumulator 28 is supplied under pressure to the plunger-type piston 23FL (or 23FR), and the rod of the piston 23FL (or 23FR) switches the switching valve 21FL (or 21FR) to switch the wheel cylinder 1FL (or 1FR). And one actuator 2 are cut off, and at the same time, the plunger-type piston 23FL is attached to the wheel cylinder 1FL (or 1FR).
When the brake fluid in (or 23FR) is supplied under pressure, the cylinder pressure P _FL (or P _FR ) of the wheel cylinder 1FL (or 1FR) is increased so as to be in the pressure increasing mode.

[0058] With this flow with the turning state and braking state is continuously repeated, the variable T _P in step S30 is "1" is one by subtraction, the variable m in Step S14 "1"
Each time the variable T _P becomes zero, step S is performed.
25, the process proceeds to step S28, where the first predetermined voltage V
The control signal CS _FL2 (or CS _FR2 ) of _S21 is output to the constant current circuit 20FL2 (or 20FR2) as a holding signal. Therefore, the constant current circuit 20FL2 (or 20FR
By exciting current corresponding 2) to a predetermined voltage V _S21 is output to the electromagnetic directional control valve 22FL (or 22FR), these directional control valve 22FL (or 22FR) is switched to the second switching position, the plunger Type piston 2
3FL (or 23FR) and the accumulator 28 are cut off, the rod of the piston 23FL (or 23FR) and the switching valve 21FL (or 21FR) are held at that position, and the cylinder pressure P of the wheel cylinder 1FL (or 1FR) is maintained. This is a holding mode in which _FL (or P _FR ) is maintained at a constant value, and this holding mode is continued until the variable m becomes “0” in step S14.

[0059] Then, the variable m is "0", the process proceeds to step S21 again, the variable T _P calculated in less than half the step S22 of the error pressure P _err is the set pressure P ₀ at this time The value becomes "0", the process proceeds from step S25 to step S28, and the above-described holding mode is set without passing through the pressure increasing mode, and the cylinder pressure P _FL (or P _FR ) of the wheel cylinder 1FL (or 1FR) becomes the target wheel cylinder pressure P ^* _FL (or P ^* _FR ) is maintained.

Each wheel cylinder 1FL (or 1
FR) Wheel cylinder pressure P_FL(Or P_FR) Is the target
Eel cylinder pressure P^* _FL(Or P^* _FR) If higher
Is the error P calculated in step S21._errIs negative and
So the variable T_PIs also a negative value, and the step S25
Then, the process proceeds to step S26, where the control signal CS_FL2(Or C
S_FR2) As zero, the electromagnetic directional control valve 22FL (or 2
2FR) to the normal first switching position. This
Re-plunger type piston 23FL (or 23FR)
The reservoir tank 25F is communicated and relieved.
The rod of Ston23FL (or 23FR) retreats
The switching valve 21FL (or 21FR) is in the steady position
Is switched to Therefore, the wheel cylinder 1FL (also
Is the cylinder pressure P of 1FR)_FL(Or P_FR) Is decompressed
The decompression mode is set, and this is the variable T _PTill becomes “0”
Will be maintained. Vehicle using braking force control device of this embodiment
Turned quickly and quite deeply while braking at
FIG. 9 shows time-braking characteristics and FIG. 1 shows time-driving characteristics.
0 is shown. In these figures, the solid line does not control the braking force.
(Control OFF), the dashed line indicates the upper limit of the target braking force.
Not provided (no limit), dashed line indicates upper limit for target braking force
1 shows a braking force control device of the present invention provided (with limitations). Ma
FIG. 9A shows the steering angle, FIG. 9B shows the right front wheel braking force,
9c shows the left front wheel braking force, and FIG. 10a shows the acceleration.
10b shows the speed, and FIG. 10c shows the generated yaw rate.
Is shown. It should be noted that in FIGS.
The cylinder pressure was set to 10.

First, as shown in FIG. 9, immediately after the start of turning, the sum of the right front wheel braking force and the left front wheel braking force is twice or more the master cylinder pressure as shown in FIG. on the other hand,
In the present invention with limitation, the sum of the right front wheel braking force and the left front wheel braking force does not exceed twice the master cylinder pressure. From the result of FIG. 9, as shown in FIG. 10a, in the case of the unlimited vehicle, a sudden change in acceleration (deceleration) occurs immediately after the start of turning, and the behavior of the vehicle becomes unstable. In the invention, there is no acceleration fluctuation, and the behavior of the vehicle is stable. Also, it can be seen that the livability is improved by the amount of no rapid acceleration fluctuation.

Further, as shown in FIG. 10B, the vehicle speed changes due to the rapid change of the acceleration in the case where there is no limit, and the actual driver must finely adjust the brake operation and the steering operation according to the change in the vehicle speed. This is not necessary in the limited invention, as it must be. As further shown in FIG.
It can be seen that the overshoot of the yaw rate in the initial stage of turning is smaller than that of F.

Although the upper limit of the target cylinder pressure is set to twice the master cylinder pressure in the above embodiment, the upper limit is not necessarily limited to this value. In the above embodiment, the case where the yaw rate characteristic control is performed only when the vehicle is in the braking state has been described. However, the present invention is not limited to this. For example, by using an actuator for traction control, However, yaw rate characteristic control can be performed.

Further, in the above-described embodiment, the case has been described in which the braking force difference between the left and right wheels on the front wheel side is controlled. However, the present invention is not limited to this. It may be. Further, in the above embodiment, the steering angle sensor 11 is used as the vehicle steering state detecting means.
Is described, but the present invention is not limited to this. Instead of the steering angle sensor, the actual wheel turning angle (actual steering angle) may be detected. In this case, The steering gear ratio N in Equations (3), (7.6) and (7.7) is omitted.

Further, in the above embodiment, the case where the vehicle speed sensor 12 is applied as the speed detecting means has been described. However, the present invention is not limited to this, and the vehicle speed is calculated by detecting the wheel speed, the vehicle longitudinal acceleration and the like. You can also.
Still further, in the above embodiment, the braking pressure control device 1
Although a case where a microcomputer is applied as 6 has been described, the present invention is not limited to this, and may be configured by combining electronic circuits such as a comparison circuit, an arithmetic circuit, and a logic circuit.

Although the above embodiment has been described with reference to the feedforward control as shown in FIG. 11, the present invention is also effective for a control system using feedback compensation as shown in FIG. Is a feedback compensator that detects, for example, the generated yaw rate and reduces the error from the target yaw rate so that the proportional element P and the proportional +
It can be composed of an integral element PD, a proportional + integral + differential element PDI, a robust compensator and the like.

[0067]

As described above, according to the braking force control apparatus of the present invention, the target yaw rate is calculated based on the detected value of the steering state of the vehicle and the speed in the longitudinal direction of the vehicle. Calculate and calculate a target braking force that causes a braking force difference between the left and right braking force control means by performing a calculation based on a vehicle model set by vehicle specifications and a motion equation so as to match the yaw rate generated in the vehicle. When the target braking force on the pressure-increasing side is equal to or more than the upper limit value corresponding to the braking force generated by the pedaling force, the target braking force is set to the same upper limit value, so that unnecessary increase in the braking force is prevented, There is an effect that the steering stability of the vehicle is improved and the transient braking characteristics are improved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a basic configuration of the present invention.

FIG. 2 is a system diagram showing one embodiment of the present invention.

FIG. 3 is a hydraulic system diagram of one actuator in FIG. 2;

FIG. 4 is a hydraulic system diagram of the other actuator in FIG.

FIG. 5 is a block diagram illustrating an example of a braking pressure control device.

FIG. 6 is an explanatory diagram of a motion model of a vehicle.

FIG. 7 is a flowchart illustrating an example of a processing procedure for setting a target yaw rate and calculating a target braking force in the braking pressure control device.

FIG. 8 is a flowchart illustrating an example of a processing procedure of target braking force control in the braking pressure control device.

FIG. 9 is a time-brake characteristic diagram of an actual vehicle.

FIG. 10 is a time-running characteristic diagram of an actual vehicle.

FIG. 11 is a block diagram of a feedforward control system.

FIG. 12 is a block diagram of a feedback control system.

[Explanation of symbols]

 1FL to 1RR are wheel cylinders (braking means) 2 is an actuator 3FL to 3R are electromagnetic direction switching valves 4 are brake pedals 5 are master cylinders 11 are steering angle sensors (steering state detecting means) 12 are vehicle speed sensors (speed detecting means) 13 Is a brake switch 14FL-14MCR is a pressure sensor (braking pressure detecting means) 15 is an actuator 16 is a braking pressure control device 21FL, 21FR is a switching valve 22FL, 22FR is an electromagnetic direction switching valve 23FL, 23FR plunger type piston 24FL, 24FR is a throttle valve 25F is a reservoir tank 26F is a hydraulic pump 27 is a pressure switch 28 is an accumulator

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B60T 8/58 B60T 8/24

Claims (1)

(57) [Claims] 1. A steering state detecting means for detecting a steering state of a vehicle, a speed detecting means for detecting a forward / rearward speed of the vehicle, and a signal from the steering state detecting means and the speed detecting means to input a target of the vehicle. Target yaw rate setting means for setting a yaw rate, left and right braking means disposed on at least one of a front wheel and a rear wheel, braking pressure detecting means for detecting a braking pressure of each of the braking means, and the target yaw rate setting means In order to achieve the target yaw rate set in the vehicle to be controlled, the left and right target braking forces of at least one of the front wheels and the rear wheels are calculated by a calculation based on a vehicle model set in advance by vehicle specifications and equations of motion. The calculated target braking force calculating means and the braking force of the left and right braking means are independently controlled so as to match the target braking force calculated by the target braking force calculating means. A braking force control device comprising: a braking force control device for controlling the braking force control device; A braking force control device for limiting the same target braking force to the same upper limit value.