JP3409601B2 - Vehicle behavior control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control car speed at a high responsiveness for preventing the behavior of a vehicle from becoming unstable when steering is excessively operated. SOLUTION: A means F determines a target yaw rate (d/dt)ϕ* based on the steering angle θ detected by a means A and the car body speed V detected by a means B, and A means H determines the target yaw moment M[ϕ]* for making the yaw rate (d/dt)ϕ detected by a means G equal to a target value (d/dt)ϕ*. A means C determines the limit value ϕmax for steering angle from the car speed V detected by the means B and the estimated coefficient μ of friction with the road face, a means D determines the excessive steering quantity, Δθ, which is the excessive quantity over this limit value θmax , and a means E calculates a target reduced speed Xc * for preventing the turning behavior of the vehicle from uncontrollability according to Δθ. A means I individually controls the pressure of the brake liquid of each wheel to realize both of the target values M=[ϕ]4x and Xc *.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a behavior control device that prevents the turning behavior of a vehicle from becoming unstable even if steering is excessively operated.

[0002]

2. Description of the Related Art Conventionally, as a behavior control device of this type, as described in, for example, Japanese Patent Laid-Open No. 3-45453, a tire grip limit vehicle speed is obtained from a wheel steering amount, and the wheel steering amount and the tire grip limit are determined. Calculate the target yaw rate of the vehicle that should be obtained under the vehicle speed, and when the vehicle speed exceeds the tire grip limit vehicle speed, reduce the vehicle speed to the tire grip limit vehicle speed in such a manner that the actual yaw rate approaches the above target yaw rate. Therefore, there is known a structure in which the inner and outer wheels are individually braked in the turning direction.

[0003]

However, in the conventional behavior control device, the limit at which the turning behavior of the vehicle is broken is regarded as the tire grip limit vehicle speed, and steering operation is performed to reach a vehicle speed range that exceeds the tire grip limit vehicle speed. Since the vehicle is decelerated when the speed becomes low, it takes a relatively long time from the steering operation to the determination of the deceleration, which is disadvantageous in terms of responsiveness.

If the vehicle speed is reduced to the tire grip limit vehicle speed in such a manner that the actual yaw rate approaches the target yaw rate, the target yaw rate is also calculated from the tire grip limit vehicle speed and the wheel steering amount. In reality, it was confirmed that it is difficult to achieve the desired behavior control because a physically impossible target behavior is set, which exceeds the area of the friction circle between the tire and the road surface.

It is an object of the present invention to propose a vehicle behavior control device which can solve at least the former problem and at the same time solve the latter problem.

[0006]

In order to solve the former problem, a behavior control apparatus according to a first aspect of the present invention is directed to a steering operation amount detecting means for detecting a steering operation amount by a driver, and at least a steering operation amount detecting means. Based on the steering operation amount detected by the means, a target behavior determining means for determining a desired behavior of the vehicle, an actual behavior detecting means for detecting an actual behavior of the vehicle, and a vehicle detected by the means. In a vehicle including vehicle behavior control means for operating the vehicle behavior control unit so that the actual behavior of the vehicle approaches the determined target behavior of the vehicle, the traveling state detection for detecting at least one of the vehicle body speed and the road surface friction coefficient. Means and a limit operation amount setting for setting a limit value of the steering operation amount corresponding to at least one of the vehicle speed and the road surface friction coefficient detected by the means Stage, steering operation amount detection means for detecting the current steering operation amount, and when the steering operation amount detected by the means exceeds the set steering operation amount limit value, it is determined that the steering operation is excessive. ingredients and operation determining means, and a vehicle deceleration means for reducing the vehicle speed at the time of determination of the excess operation by said means
The excessive operation determining means calculates an excessive operation amount based on the steering operation amount detected by the steering operation amount detecting means, and the vehicle principle means calculates the target deceleration of the vehicle from the calculated excessive operation amount. It is characterized in that the vehicle speed is reduced to obtain the target deceleration.

For the same purpose, a behavior control device according to a second aspect of the present invention provides a steering operation amount detecting means for detecting a steering operation amount by a driver and at least steering operation amount detected by the means. Originally, a target behavior determining means for determining a behavior to be a target of the vehicle, an actual behavior detecting means for detecting an actual behavior of the vehicle,
In a vehicle including vehicle behavior control means for operating a vehicle behavior control unit so that the actual behavior of the vehicle detected by the means approaches the determined target behavior of the vehicle, at least one of a vehicle body speed and a road surface friction coefficient. A traveling state detecting means for detecting the vehicle speed, a limit behavior calculating means for calculating a limit value of the vehicle behavior that can be constantly achieved in correspondence with at least one of the vehicle speed and the road surface friction coefficient detected by the means, When the determined target behavior of the vehicle exceeds the calculated vehicle behavior limit value, an excessive operation determination means for determining an excessive operation of the steering wheel, and a vehicle deceleration means for reducing the vehicle speed when the excessive operation by the means is determined. The excessive operation determination means calculates an excessive operation amount based on the target behavior and a vehicle behavior limit value, and the vehicle principle means calculates the excessive operation amount. Seeking target deceleration Luo vehicle, it is characterized in that it has a configuration to reduce the vehicle speed to the target deceleration occurs.

According to a third aspect of the present invention, in the first or second aspect of the invention, the target behavior determining means determines the vehicle operation based on at least the detected steering operation amount. The target yaw rate is determined as the target behavior, and the actual behavior detection means is
The actual yaw rate of the vehicle is detected as the actual behavior of the vehicle, and the vehicle behavior control means responds to signals from these means so that the detected actual yaw rate of the vehicle approaches the determined target yaw rate of the vehicle. It is characterized in that the behavior control unit of the vehicle is operated.

Further, a fourth invention according to claim 4 is the rudder for controlling a steering angle of at least one of a rear wheel and a front wheel as the behavior control unit of the vehicle according to any one of the first invention to the third invention. An angle control unit, a wheel braking / driving force control unit that individually controls the braking / driving force of each wheel to control the yaw moment of the vehicle, and a suspension control unit that changes the longitudinal rigidity balance of the wheel suspension to change the steering characteristics. It is characterized in that at least one of the above is used.

In order to solve the latter problem, the behavior control device according to a fifth aspect of the present invention is the behavior control device according to any one of the first to fourth aspects, wherein the target behavior determining means is the vehicle. The target behavior is modified according to the degree of decrease in vehicle speed by the speed reduction means.

According to a sixth aspect of the present invention, in any one of the first aspect, the third aspect, and the fifth aspect, the limit operation amount setting means is the detected vehicle speed and road surface. It is characterized in that the maximum value of the steering operation amount capable of maintaining a steady turn is set as the limit value from at least one of the friction coefficients.

Further, according to a seventh aspect of the present invention, in the sixth aspect of the invention, the excessive operation determination means is the current steering operation amount detected by the steering operation amount detection means and the steering operation amount. The vehicle deceleration means is configured to calculate a difference from the maximum value to obtain an excessive operation amount, and the vehicle deceleration means obtains a target deceleration of the vehicle from the calculated excessive operation amount, and a vehicle speed so that the target deceleration occurs. It is characterized in that it is configured to reduce.

According to the eighth aspect of the present invention, the third aspect
In any one of the inventions through the fifth inventions, the limit behavior calculation means sets, as the vehicle behavior limit value, a maximum value of a yaw rate that can be constantly generated from at least one of the detected vehicle speed and road surface friction coefficient. Configured as
The excessive operation determination means is configured to determine an excessive operation of the steering when the determined target yaw rate exceeds the maximum yaw rate value.

According to the ninth aspect of the present invention, the eighth aspect
In the invention, the excessive operation determining means is configured to calculate a difference between the determined target yaw rate and the maximum yaw rate to obtain an excessive yaw rate when determining the excessive operation of steering, and the vehicle decelerating means. Is characterized in that a target deceleration of the vehicle is obtained from the calculated excess yaw rate and the vehicle speed is reduced so that the target deceleration occurs.

[0015]

According to the first aspect of the present invention, the target behavior determining means determines the target behavior of the vehicle based on at least the steering operation amount detected by the steering operation amount detecting means. The control means operates the behavior control section of the vehicle such that the actual behavior of the vehicle detected by the actual behavior detection means approaches the determined target behavior of the vehicle.

In parallel with the above, the running state detecting means detects at least one of the vehicle body speed and the road surface friction coefficient, and the limit operation amount setting means operates the steering operation corresponding to at least one of the vehicle body speed and the road surface friction coefficient. Set the limit of quantity. Then, when the current steering operation amount detected by the steering operation amount detection means exceeds the set steering operation amount limit value, the excessive operation determination means determines that the steering operation is excessive and the current steering operation amount is determined. Based on the calculated excessive operation amount, the vehicle deceleration means calculates a target deceleration of the vehicle from the calculated excessive operation amount, and reduces the vehicle speed so that the target deceleration occurs.

Therefore, while maintaining the vehicle behavior as the target behavior corresponding to the steering operation amount, the unstable vehicle turning behavior due to the excessive steering operation can be suppressed by decelerating the vehicle.

In the first aspect of the invention, the limit at which the turning behavior of the vehicle is broken is regarded as the steering operation amount limit value, not the tire grip limit vehicle speed as in the conventional case, and the steering operation excess region exceeding the limit value is set. Since the vehicle decelerates when the vehicle enters, it takes a relatively short time to judge the deceleration after entering the excessive steering operation area, and therefore, it is very advantageous in terms of responsiveness, which is a problem in the conventional device. It is possible to solve the problem regarding the responsiveness.

In the second aspect of the invention, in the same manner as in the first aspect of the invention, while the behavior control for making the actual behavior of the vehicle closer to the target behavior is performed, the running state detecting means causes the vehicle speed and the road surface friction coefficient to change. Of the vehicle target, the limit behavior calculating means calculates a limit value of the vehicle behavior that can be steadily achieved in correspondence with at least one of the detected vehicle speed and road surface friction coefficient, and the target of the vehicle. When the behavior exceeds the calculated vehicle behavior limit value, the excessive operation determination means determines that the steering operation is an excessive operation, calculates the excessive operation amount based on the current steering operation amount, and decelerates the vehicle when the excessive operation is determined. The means obtains a target deceleration of the vehicle from the calculated excessive operation amount and reduces the vehicle speed so that the target deceleration occurs.

Therefore, as in the first aspect of the present invention, while maintaining the vehicle behavior at the target behavior corresponding to the steering operation amount, the excessive vehicle turning behavior due to the excessive steering operation can be suppressed by decelerating the vehicle. .

Also in the second aspect of the invention, the limit at which the turning behavior of the vehicle is broken is regarded as the vehicle behavior limit value instead of the tire grip limit vehicle speed as in the conventional case, and steering operation in which the behavior exceeding the limit value occurs Since the vehicle is decelerated when it becomes excessive, the time required to judge the deceleration after entering the excessive steering range can be relatively short. Therefore, it is very advantageous in terms of responsiveness. It is possible to solve the problem of responsiveness that has been a problem in the device.

In the third invention, the first invention or the second invention
The target behavior determining means in the invention determines the target yaw rate as the behavior to be the target of the vehicle based on at least the detected steering operation amount, and the actual behavior detecting means determines the actual behavior of the vehicle as the actual behavior of the vehicle. The yaw rate is detected, and the vehicle behavior control means operates the vehicle behavior control section so as to respond to the signals from these means and bring the actual yaw rate of the vehicle to the target yaw rate.

In this case, the yaw rate, which is the most representative of the vehicle behavior, can be brought close to the target value, which is very useful.

According to a fourth aspect of the invention, as a vehicle behavior control section according to any of the first to third aspects, a steering angle control section for controlling the steering angle of at least one of the rear wheels and the front wheels,
At least one of a wheel braking / driving force control unit that individually controls the braking / driving force of each wheel to control the yaw moment of the vehicle, and a suspension control unit that changes the longitudinal rigidity balance of the wheel suspension to change the steering characteristics. The use of technology already established today
The above-described effects of the invention through the third invention can be easily achieved.

In the fifth invention, the target behavior determining means in any one of the first invention to the fourth invention corrects the target behavior according to the degree of decrease in vehicle speed by the vehicle decelerating means, so that the tire-road surface Introducing the concept of the friction circle in, the physically possible target behavior will be set, and it is possible to surely achieve the desired behavior control. Of the problems in the conventional device described above, the latter problem. Can also be eliminated.

In the sixth invention, the limit manipulated variable setting means in any one of the first invention, the third invention, and the fifth invention maintains a steady turn from at least one of the detected vehicle speed and road surface friction coefficient. Since the maximum value of the steering operation amount to be obtained is set as the limit value, it is possible to achieve the action and effect in any one of the first invention, the third invention to the fifth invention in a mode that can maintain a steady turn, and is very useful. Is.

In a seventh aspect based on the sixth aspect, the excessive operation determining means calculates a difference between the current steering operation amount detected by the steering operation amount detecting means and the maximum steering operation amount value. The vehicle deceleration means obtains the excessive operation amount, the vehicle deceleration means obtains the target deceleration of the vehicle from the calculated excessive operation amount, and reduces the vehicle speed so that this target deceleration occurs. Can be something.

According to an eighth aspect of the present invention, in any one of the third to fifth aspects, the limit behavior calculation means can constantly generate the maximum yaw rate that can be generated from at least one of the detected vehicle speed and road friction coefficient. A value is set as the vehicle behavior limit value, and when the determined target yaw rate exceeds the yaw rate maximum value, the excessive operation determination means determines that the steering operation is excessive, and therefore the existing yaw rate feedback control signal is used. Therefore, it is possible to determine the excessive operation of the steering wheel at low cost.

According to a ninth invention, in the eighth invention,
When the excessive operation determination means determines that the steering operation is excessive, the excess yaw rate is calculated by calculating the difference between the determined target yaw rate and the maximum yaw rate, and the vehicle deceleration means calculates the excess yaw rate from the calculated excess yaw rate. Since the target deceleration of the vehicle is calculated and the vehicle speed is reduced so that this target deceleration is generated, the vehicle speed reduction can be made appropriate in accordance with the actual situation.

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will now be described with reference to the drawings.
It will be described in detail based on. FIG. 1 shows an embodiment of the present invention.
Vehicle brake system showing a behavior control device
Where 1 is the brake pedal that the driver operates by depressing,
2 is the front mass of the hydraulic pressure according to the brake pedal pressure.
Turcylinder pressure line 3_FAnd rear master cylinder pressure
Pipeline 3_ROutput to master cylinder, 4_FLIs for the left front wheel
Brake caliper, 4_FRIs the brake caliper of the right front wheel,
Four_RLIs the brake caliper on the left rear wheel, 4 _RRIs the blur of the right rear wheel
-Indicates each caliper.

The master cylinder hydraulic pressure output from the master cylinder 2 to the front master cylinder pressure line 3 _F and the rear master cylinder pressure line 3 _R is boosted by a well-known hydraulic booster 5, and the hydraulic booster 5 further includes a brake pedal. It is assumed that the automatic brake pressure is output to the automatic brake pressure line 6 regardless of the pedaling force.

Left front wheel brake caliper 4_FLAnd the right front wheel
Brake caliper 4_FRFront brake pressure extending from
Pipeline 7_FIs the switching valve 8_FFront master through Siri
Pressure line 3_FAnd connected to the automatic brake pressure line 6,
Left rear wheel brake caliper 4_RLAnd the right rear wheel brake
Lipa 4_RRRear brake pressure line 7 extending from_RSwitch
Valve 8_RRear master cylinder pressure line 3 via _Rand
Connect to the automatic brake pressure line 6.

[0033] Here, at the respective switching valves 8 _F and 8 _R is OFF, through the corresponding pipe 7 to _F and 7 _R in the master cylinder pressure line 3 _F and 3 _R, ON at the corresponding conduits 7 _F and 7 _R shall be switched and connected to the automatic brake pressure line 6.

Front brake pressure line 7_FInside left and right
Front wheel brake caliper 4_FLAnd 4 _FROn the entrance side of
Distribute the booster valve 9_FLAnd check valve 10_FLParallel pipelines,
Booster valve 9_FRAnd check valve 10_FRInsert the parallel conduit of
Yabrake pressure line 7_RSome of the left and right rear wheel brake carriers
Par 4_RLAnd 4_RRAre installed on the inlet side of the
_RLAnd check valve 10_RLParallel line, booster valve 9 _RRAnd vice versa
Stop valve 10_RRInsert the parallel pipelines of the
Pressure reducing valve 11 between the brake caliper_FL, 11_FR，
11_RL, 11_RRAnd the pressure sensor
12_FL, 12_FR, 12_RL, 12_RRAre connected and provided.

The pressure increasing valves 9 _FL , 9 _FR , 9 _RL , and 9 _RR are normally-open solenoid valves, respectively, and these check valves are normally operated through these valves.
With the non-return function of 0 _FL , 10 _FR , 10 _RL , and 10 _RR ,
The brake fluid pressure is supplied to the corresponding brake calipers 4 _FL , 4 _FR , 4 _RL , 4 _RR , but when it is ON, it is closed and the supply of the brake fluid pressure is stopped.

The pressure reducing valves 11 _FL , 11 _FR , 11 _RL and 11 _RR are normally closed solenoid valves, respectively, which are opened when they are turned on and the brake fluid pressures of the corresponding brake calipers 4 _FL , 4 _FR , 4 _RL and 4 _RR are stored in the reservoir 13. _F, 13 shall decrease to escape to _R, the accumulated pressure in the reservoir 13 _F, 13 _R at the same time, a pump 14 _F, 14 _R driven by a motor M, corresponding master cylinder pressure line 3 _F, 3 _R Shall be returned to.

The operation of the brake system shown in FIG. 1 will be described below. Normally, the switching valves 8 _F and 8 _R and the pressure increasing valve 9
_FL , 9 _FR , 9 _RL , 9 _RR , and pressure reducing valves 11 _FL , 11 _FR ,
All of 11 _RL and 11 _RR are turned off. here,
When the driver depresses the brake pedal 1, the master cylinder 2 outputs the master cylinder hydraulic pressure corresponding to the brake pedal depressing force to the pipelines 3 _F and 3 _R under the boost of the hydraulic booster 5.

These pipelines 3_F, 3_RMaster Sirin to
Liquid pressure is the corresponding switching valve 8_F, 8 _RVia booster valve
9_FL, 9_FR, 9_RL, 9_RRVia individual brake
Lipa 4_FL, 4_FR, 4_RL, 4_RRSupply as brake fluid pressure to
The wheels can then be braked individually.

When the wheels are locked during this braking,
Booster valves for locked wheels 9 _FL , 9 _FR , 9 _RL , 9 _RR
By turning on, the brake fluid pressure of the wheel is maintained, and the pressure reducing valves 11 _FL , 11 _FR , 11 _RL and 11 _RR are also turned on to reduce the brake fluid pressure of the wheel, thereby canceling the locked state of the wheel. After unlocking the wheels, booster valve _9FL ,
9 _FR , 9 _RL , 9 _RR OFF, pressure reducing valves 11 _FL , 11 _FR ,
By turning OFF 11 _RL and 11 _RR , it is possible to execute anti-skid control in which the brake hydraulic pressure of the corresponding wheel is increased toward the master cylinder hydraulic pressure.

Next, in the behavior control of the vehicle using the brake system of FIG. 1, the switching valves 8 _F and 8 _R are turned on.
Then, the automatic brake pressure of the pipeline 6 is supplied to the front brake pressure pipeline 7 _F and the rear brake pressure pipeline 7 _R, and the brake calipers 4 _FL , 4 _FR , 4 _RL , 4 are used as pressure sources.
_The brake fluid pressure is supplied to the _RR , and these brake fluid pressures are increased by the pressure increasing valve 9 _FL ,
ON / OFF of 9 _FR , 9 _RL , 9 _RR and pressure reducing valve 11 _FL , 1
1 _FR , 11 _RL , 11 _RR are individually controlled by turning them ON and OFF, and the wheels are individually controlled by automatic braking.

Switching valve 8_F, 8_RON, OFF, booster valve
9_FL, 9_FR, 9_RL, 9_RRON, OFF, pressure reducing valve 1
1_FL, 11_FR, 11_RL, 11_RRON and OFF of the
Controlled by the trolley 20, which is why the controller
20 includes the pressure sensor 12_FL, 12_FR, 12_RL, 1
Two_RRPressure detection value from the pressure sensor group 12 consisting of
P _iInput (i = FL, FR, RL, RR)
Of the steering wheel in every calculation cycle [n]
Steering sensor 21 for detecting steering speed Δθ [n]
Signal from, wheel speed VW of each wheel_i(I = FL, FR,
RL, RR) from the wheel speed sensor group 22 for detecting
No., longitudinal acceleration X provided at the vehicle weight center point_G, Lateral acceleration
Y_G, Yaw rate (d / dt) φ are detected respectively.
Degree sensor 23, lateral acceleration sensor 24, yaw rate sensor
The signals from 25 are input respectively.

The controller 20 performs the above-mentioned anti-skid control and behavior control based on these input information. Since anti-skid control is not related to the present invention, only the behavior control will be described below with reference to FIGS. 2 to 6. The description will be made with reference.

FIG. 2 is a block diagram showing the configuration of the controller 20, and FIGS.
When 0 is configured by a microcomputer, it shows a control program to be executed by the microcomputer 20.

A (steering operation amount detecting means) The steering operation amount detecting means A in FIG. 2 performs the processing in step 31 of FIG. 3, and the steering wheel steering angle θ [n] in each calculation cycle [n].
Is detected by the following procedure. 1. The steering speed [Delta] [theta] [n] of the steering wheel [n] detected by the steering sensor 21 is read for each calculation cycle in which the left steering has a positive polarity. 2. Based on the read current steering speed Δθ [n] and the previous steering angle θ [n−1], the current steering angle θ [n] is θ [n] = θ [n−1] + Δθ [n]. Calculate by

B (Running State Detection Means) The running state detection means B in FIG.
2, the vehicle speed V and the road surface friction coefficient μ
Are calculated by the following procedure. 1. Wheel speed VW of each wheel detected by the wheel speed sensor group 22
_i (i = FL, FR, RL, RR) is read. 2. Of these wheel speeds VW _FL , VW _FR , VW _RL , VW _RR , the largest value max (VW _FL , VW _FR , VW _RL , V
W _RR ) is the vehicle speed V. V = max (VW _FL , VW _FR , VW _RL , VW _RR ) 3. Longitudinal acceleration X _G detected by the longitudinal acceleration sensor 23 and lateral acceleration sensor 24 (positive at acceleration), lateral acceleration Y
_{Read G} (positive when turning left). 4. These read longitudinal acceleration X _G and lateral acceleration Y
_{From G} , the road surface friction coefficient μ is estimated by the following equation using the friction circle between the wheel and the road surface.

[Equation 1]

C (Limit manipulated variable setting means) The limit manipulated variable setting means C in FIG. 2 performs the processing in step 33 of FIG. 3 and calculates the steering angle limit value θ _max by the following procedure. 1. The vehicle speed V and the road surface friction coefficient μ obtained as described above
Read. 2. Based on the map corresponding to FIG. 5, the coefficient f _V1 [V] for calculating the steering angle limit value θ _max is searched from the vehicle speed V. Here, the coefficient f _V1 [V] is a coefficient for obtaining the maximum value of the steering angle that can maintain a steady turn, and is obtained in advance by experiments or the like. Then, the road surface friction coefficient μ is added to the coefficient f
By multiplying _V1 [V], the steering angle limit value θ
Calculate _max . θ _max = f _V1 [V] × μ

D (Excessive operation determination means) The excessive operation determination means D in FIG.
4 is performed, the excessive steering is determined by the following procedure, and the excessive steering amount is calculated. 1. This steering angle θ [n] detected by the steering operation amount detecting means A (hereinafter, simply expressed as θ for simplicity)
Read. 2. This steering angle θ is compared with the steering angle limit value θ _max ,
When | θ |> θ _max , the excessive steering determination flag FLAG is set to
At the same time that FLAG = 1 is set, the excessive steering amount Δθ is calculated by the following equation, and when Δθ = | θ | −θ _max | θ | ≦ θ _max , the excessive steering determination flag FLAG is set to
At the same time when FLAG = 0 is reset, the excessive steering amount Δθ
Is Δθ = 0.

E (Target Deceleration Determining Means) The target deceleration determining means E in FIG. 2 performs the processing in step 35 of FIG. 3 and calculates the target deceleration of the vehicle by the following procedure. 1. The excessive steering determination flag FLAG and the excessive steering amount Δθ are read. 2. The target deceleration X _G ^* of the vehicle is calculated by the following equation according to the excessive steering determination flag FLAG. When FLAG = 1, the feedback control gain k is added to the excessive steering amount Δθ.
By multiplying by [θ], the target deceleration X _G ^* is calculated by the following equation. X _G ^* = − k [θ] × Δθ (However, since acceleration is positive, the value is −k [θ].) When FLAG = 0, it is natural that the steering state is not excessive.
The target deceleration X _G ^* is X _G ^* = 0.

F (Target Behavior Determining Means) The target behavior determining means F in FIG.
6 is performed, and the target yaw rate is calculated as the behavior of the vehicle by the following procedure. 1. The steering angle θ and the vehicle speed V are read from the means A and B. 2. Based on the steering angle θ and the vehicle speed V, a signed yaw rate reference value (d / dt) φ ^* [θ] corresponding to the driving operation of the driver
Is calculated by the following formula. (d / dt) φ ^* [θ] = f _V2 [V] × θ where f _V2 [V] is the yaw rate reference value (d / dt) φ
^* A coefficient for calculating [θ], which is obtained in advance by experiments or the like as a map as shown in FIG. 6, and is searched from the vehicle speed V. 3. Considering the target deceleration X _G ^* obtained by the means E as the physical yaw rate limit value, the maximum value (d / dt) φ of the yaw rate that can be constantly obtained from the friction circle between the tire and the road surface ^* _max is calculated by the following formula. The reference numeral is the same as the steering angle.

[Equation 2] 4. According to the excessive steering determination flag FLAG determined by the excessive operation determination means D, the following target yaw rate of the vehicle
Determine (d / dt) φ ^* . When FLAG = 0, the yaw rate reference value (d / dt) φ corresponding to the driver's driving operation
^* [Θ] is set as it is as the target yaw rate (d / dt) φ ^* , and (d / dt) φ ^* = (d / dt) φ ^* [θ]. When FLAG = 1, the maximum yaw rate that can be constantly generated (d / dt) φ ^* _max , which is the physical yaw rate limit value, is set to the target yaw rate (d
/ dt) φ ^* is defined as (d / dt) φ ^* = (d / dt) φ ^* _max .

G (Actual Behavior Detecting Means) The actual behavior detecting means G in FIG.
Is performed to obtain the actual yaw rate (d / dt) φ from the detection value of the yaw rate sensor 25. However,
This actual yaw rate (d / dt) φ is positive when turning left.

H (Vehicle Behavior Control Means) The vehicle behavior control means H in FIG.
The target yaw moment M [φ] ^* for bringing the above-mentioned actual yaw rate (d / dt) φ closer to the target yaw rate (d / dt) φ ^* is calculated as follows. 1. The target yaw rate (d / dt) φ ^* and the actual yaw rate (d / dt) φ are read from the means F and G, and the yaw rate deviation {(d / dt) φ− (d / dt) φ ^* } between them is calculated. . 2. Eliminating this yaw rate deviation (d / dt) φ = (d / dt) φ
^* The target yaw moment M [φ] ^* for the calculated by the following equation using the feedback control gain k [φ]. M [φ] ^* = − k [φ] ・ {(d / dt) φ− (d / dt) φ ^* }

I (brake control means) The brake control means I in FIG.
The target reduction of the vehicle calculated by the means E is performed by performing the processing in 9.
Speed X_G ^*And the target yaw moment M obtained by the means H
[Φ]^*In order to achieve
-Ki caliper 4 _FL, 4_FR, 4_RL, 4_RRTarget brake fluid
Pressure P_i ^*(I is FL, FR, RL, RR)
The target brake fluid pressure P is calculated individually._i ^*Is a car
Switching valve 8 so that it can be achieved for each wheel_F, 8_R, Booster valve 9
_FL, 9_FR, 9_RL, 9_RRAnd pressure reducing valve 11_FL, 11_FR, 1
1_RL, 11_RRON / OFF control. 1. First, the target deceleration X_G ^*Front wheel side to achieve
Target braking force F_F ^*And the target braking force F on the rear wheel side_R ^*The it
Front axle load W_FAnd rear axle load W_RUsing
Calculated from F_F ^*= W_F・ X_G ^* F_R ^*= W_R・ X_G ^* 2. Next, the target yaw moment M [φ]^*To achieve
For the target braking force difference ΔF between the left and right front wheels_F ^*The front wheel training
Dead T_FIs calculated by the following formula. ΔF_F ^*= M [φ]^*/ T_F 3. The above target braking force F on the front wheel side_F ^*And rear wheel target system
Power F_R ^*, And the target braking force difference ΔF between the left and right front wheels_F ^*Or
The left front wheel target braking force F_FL ^*, Right front wheel target braking force
F_FR ^*, Target left rear wheel braking force F_RL ^*, Right rear wheel target braking force F
_RR ^*Are calculated by the following equations. F_FL ^*= (1/2) (F_F ^*+ ΔF_F ^*) F_FR ^*= (1/2) (F_F ^*-ΔF_F ^*) F_RL ^*= F_RR ^*= (1/2) F_R ^* 4. This target braking force F_i ^*(I is FL, FR, RL,
RR) for each wheel, that is, the brake
Lipa 4_FL, 4_FR, 4_RL, 4_RRTarget brake fluid pressure P_i ^*
(I is FL, FR, RL, RR) is a constant k for each wheel
_Bi(Friction coefficient of brake pad, pad area, brake
(Determined by rotor diameter, etc.)
To do. P_i ^*= F_i ^*/ K_Bi 5. Target brake fluid for at least one of the left and right front wheels
When the pressure is no longer 0, the switching valve 8_FTurn on,
Pipeline 7_FTo supply the automatic brake pressure of line 6 to
The target brake fluid for at least one of the left and right rear wheels.
When the pressure is no longer 0, the switching valve 8_RTurn on,
Pipeline 7_RSo that the automatic brake pressure of line 6 is supplied to
Enables vehicle behavior control by automatic braking
To do. 6. Pressure sensor 12_FL, 12_FR, 12_RL, 12_RRby
Actual brake fluid pressure detection value P_i(I is FL, FR, RL,
RR) is read. 7. These actual brake fluid pressure detection values P_iAnd the above target
Rake fluid pressure P_i ^*Compare and between the corresponding ones,
According to the comparison result, as shown in FIG. _FL，
9_FR, 9_RL, 9_RRAnd pressure reducing valve 11_FL, 11_FR, 1
1_RL, 11_RRON / OFF control, actual brake fluid pressure P
_iCorresponding target brake fluid pressure P_i ^*To match.

To explain the processing of FIG. 4, the left front wheel target brake hydraulic pressure P _FL ^* is read in step 41, and the actual brake hydraulic pressure P _FL is read in step 42. Next, at step 43, the magnitude relationship between the two is judged, and if P _FL > P _FL ^* , that is, the actual brake fluid pressure P _FL
Is higher than the target brake fluid pressure P _FL ^* , step 4
At 4 and 45, the pressure increasing valve 9 _FL is turned on (shut off) and the pressure reducing valve 11 _FL is turned on (communication). As a result, the actual brake fluid pressure P _FL is reduced, and this can be brought close to the target brake fluid pressure P _FL ^* .

On the contrary, in step 43, P_FL<P_FL ^*Judge
If so, that is, the actual brake fluid pressure P _FLIs the target brake fluid
Pressure P_FL ^*If lower, in steps 46 and 47,
Pressure reducing valve 11_FLOFF (shut off) and booster valve 9
_FLTurn off (communicate). With these, the actual brake fluid
Pressure P_FLWill be raised, and this will be the target brake fluid.
Pressure P_FL ^*Can be approached to.

Then, in step 43, P_FL= P_FL ^*Judge
If so, that is, the actual brake fluid pressure P _FLIs the target brake fluid
Pressure P_FL ^*If it matches with the step 48, 49
Pressure increase valve 9_FLON (shut off) and pressure reducing valve 1
1_FLIs turned off. With these, the actual brake fluid
Pressure P_FLIs maintained at the current value without increasing or decreasing
And the actual brake fluid pressure P_FLIs the target brake fluid pressure P_FL ^*
It is possible to maintain the state of being consistent with.

The same processing as described above is also applied to the brake fluid pressure control of the three wheels other than the left front wheel in step 50, and the actual brake fluid pressures of these three wheels are individually applied to the target brake. Can be matched to hydraulic pressure.

By the way, since the target target brake fluid pressure P _i ^* is determined as described above, as a result, the following actions can be obtained in the present embodiment. That is, the target behavior determination means F determines the target yaw rate of the vehicle based on the steering angle θ detected by the steering operation amount detection means A and the vehicle body speed V detected by the traveling state detection means B.
(d / dt) φ ^* , and the vehicle behavior control means H determines the actual yaw rate (d / dt) φ of the vehicle detected by the actual behavior detection means G,
Eliminating the yaw rate deviation {(d / dt) φ- (d / dt) φ ^* } from the target yaw rate (d / dt) φ ^* , (d / dt) φ =
(d / dt) target yaw moment of the order to φ ^* M [φ] ^*
The brake control means I individually controls the brake fluid pressure of each wheel to generate this target yaw moment M [φ] ^*, and the target yaw rate (d / dt) φ ^* is automatically controlled by each wheel. Can be achieved.

At the same time, the limit manipulated variable setting unit C obtains a limit value θ _max of the steering angle that can maintain a steady turn from the vehicle speed V and the road friction coefficient μ detected by the traveling state detecting unit B. When the steering steering angle θ detected by the steering operation amount detecting means A exceeds the steering steering angle limit value θ _max , the excessive operation determining means D obtains the steering excessive operation amount Δθ from the difference between the two. The target deceleration determining means E calculates a target deceleration X _G ^* for preventing the turning behavior from being damaged by such steering operation in accordance with the excessive operation amount Δθ, and the brake control means I By controlling the brake fluid pressure of each wheel individually to generate this target deceleration X _G ^* , the breaking of the turning behavior can be prevented by the automatic braking of each wheel.

Accordingly, while the actual yaw rate (d / dt) φ of the vehicle is made to coincide with the target yaw rate (d / dt) φ ^* , it is possible to prevent the vehicle turning behavior from being unstable or unstable due to the excessive steering operation. Can be achieved by individual automatic braking of the wheels.

By the way, in the present embodiment, the limit at which the turning behavior of the vehicle is broken is regarded as the steering operation amount limit value (steering angle limit value) θ _max instead of the tire grip limit vehicle speed as in the conventional case. Since the vehicle is decelerated when it enters the excessive steering operation area that exceeds the limit value, the time required to judge the deceleration after entering the excessive steering operation area is relatively short, and therefore the responsiveness Is very advantageous, and the problem of responsiveness, which has been a problem in the conventional device, can be solved.

In addition, when the target behavior determining means F calculates the target yaw rate (d / dt) φ ^* , the target deceleration X _G ^* is read from the means E as shown in FIG. From the friction circle between the tire and the road surface, calculate the maximum value (d / dt) φ ^* _max of the yaw rate that can be constantly generated,
When the excessive operation flag FLAG is 1, the yaw rate reference value (d / dt) φ ^* [θ] corresponding to the driver's driving operation is not set, but the maximum yaw rate value (d / dt) φ ^* _max is set. Since the target yaw rate (d / dt) is φ ^* , the target yaw rate (d / d
t) φ ^* is set to a physically possible value by introducing the concept of a friction circle between the tire and the road surface, and a physically impossible target behavior that exceeds the area of the friction circle. However, it is possible to solve the problem of the conventional device that this is set, and surely realize the desired behavior control.

In the above-described embodiment, the vehicle behavior control unit uses the braking system that individually controls the automatic braking force of each wheel to control the yaw moment of the vehicle. However, instead of this, Along with this, it is possible to use a steering angle control system that controls the steering angle of at least one of the rear wheels and the front wheels, or use a suspension control system that changes the front-rear rigidity balance of the wheel suspension to change the steering characteristics. These are all
It is a system already established today, and the above-mentioned effects can be achieved easily and inexpensively.

7 and 8 show another embodiment of the present invention, in which the means C, D and E in FIG. 2 are replaced by means C ', D'and E', respectively. In addition, FIG. 8 is obtained by replacing steps 33, 34, and 35 of FIG. 3 with steps 33 ′, 34 ′, and 35 ′, respectively.

C '(limit behavior calculation means) The limit behavior calculation means C'in FIG. 7 performs the processing in step 33' in FIG. 8 to limit the limit value (d / dt) φ _max is calculated by the following procedure. 1. The vehicle speed V and the road surface friction coefficient μ detected by the traveling state detecting means B as described above are read. 2. From the read vehicle speed V and road surface friction coefficient μ, the yaw rate limit value (d / dt) φ _max is calculated by the following equation. (d / dt) φ _max = μ / V

D '(Excessive operation determining means) The excessive operation determining means D'in FIG. 2 performs the processing in step 34' in FIG. 3 to determine the excessive steering according to the following procedure, and to determine the excessive steering accompanying the excessive steering. The yaw rate is calculated. 1. The yaw rate reference value (d / d
t) Read φ ^* [θ]. 2. The yaw rate reference value (d / dt) φ ^* [θ] is compared with the yaw rate limit value (d / dt) φ _max from the means C ′,
When | (d / dt) φ ^* [θ] |> (d / dt) φ _max , the excessive steering determination flag FLAG is set to FLAG = 1, and at the same time, the excess yaw rate Δ (d / dt) φ is calculated by the following equation. Δ (d / dt) φ = | (d / dt) φ [θ] | − (d / dt) φ _max | (d / dt) φ ^* [θ] | ≦ (d / dt) φ _At the time of _max , the excessive steering determination flag FLAG is reset to FLAG = 0, and at the same time, the excess yaw rate Δ (d / dt) φ is set to Δ (d / dt) φ = 0.

E '(target deceleration determining means) The target deceleration determining means E'in FIG. 2 performs the processing in step 35' in FIG. 3 and calculates the target deceleration of the vehicle by the following procedure. . 1. The excessive steering determination flag FLAG and the excessive yaw rate Δ (d / dt) φ are read. 2. The target deceleration X _G ^* of the vehicle is calculated by the following equation according to the excessive steering determination flag FLAG. When FLAG = 1, the excess yaw rate Δ (d / dt) φ is applied to the feedback control gain k [θ] similar to that in the target deceleration determining means E.
And the target deceleration X _G ^* is calculated by the following formula. When X _G ^* = − k [θ] × Δ (d / dt) φ FLAG = 0, it is natural that there is no excessive steering,
The target deceleration X _G ^* is X _G ^* = 0.

Therefore, in the present embodiment, the excessive steering operation is performed by the yaw rate reference value (d / dt) φ ^* [θ] corresponding to the driver's operation and the yaw rate limit value (d / dt) φ _max, and the target deceleration X _G ^* required to decelerate the vehicle so that the turning behavior is not impaired despite excessive operation,
The yaw rate reference value (d / dt) φ ^* [θ] and the yaw rate limit value (d / dt) φ _max are determined according to the yaw rate deviation Δ (d / dt) φ. It is possible to achieve the same operational effect as in the above-described embodiment.

In addition, the limit of the turning behavior of the vehicle is
It should be regarded as the yaw rate limit value (d / dt) φ _max instead of the tire grip limit vehicle speed as in the past, and the vehicle should be decelerated when the steering operation becomes excessive, which causes a yaw rate that exceeds the limit value. Therefore, it takes a relatively short time to judge the deceleration after entering the excessive steering operation range, and therefore it is very advantageous in terms of responsiveness, which is a problem in the conventional device as in the above-described embodiment. It is possible to solve the problem of responsiveness.

[Brief description of drawings]

FIG. 1 is a hydraulic brake system diagram of a vehicle showing a behavior control device according to an embodiment of the present invention.

FIG. 2 is a functional block diagram showing a portion of the controller that controls the brake hydraulic pressure of the hydraulic brake system, which is responsible for vehicle behavior control.

FIG. 3 is a flow chart showing a program relating to behavior control when the controller is configured by a microcomputer.

FIG. 4 is a subroutine showing a brake fluid pressure control process in the program.

FIG. 5 is a diagram showing a change characteristic of a coefficient used when obtaining a steering angle limit value.

FIG. 6 is a diagram showing a change characteristic of a coefficient used when obtaining a yaw rate reference value.

FIG. 7 is a functional block diagram similar to FIG. 2, showing a behavior control device according to another embodiment of the present invention.

FIG. 8 is a flowchart showing a program relating to behavior control according to the same embodiment.

[Explanation of symbols]

1 brake pedal 2 master cylinder 3 _F front side master cylinder pressure line 3 _R rear side master cylinder pressure line 4 _FL left front wheel brake caliper 4 _FR right front wheel brake caliper 4 _RL left rear wheel brake caliper 4 _RR right rear wheel brake Caliper 5 Hydraulic booster 6 Automatic brake pressure line 8 _F Front wheel side brake pressure switching valve 8 _R Rear wheel side brake pressure switching valve 9 _FL Left front wheel pressure increasing valve 9 _FR Right front wheel pressure increasing valve 9 _RL Left rear wheel pressure increasing valve 9 _RR Right rear wheel Pressure increasing valve 11 _FL Left front wheel pressure reducing valve 11 _FR Right front wheel pressure reducing valve 11 _RL Left rear wheel pressure reducing valve 11 _RR Right rear wheel pressure reducing valve 12 Pressure sensor group 20 Controller 21 Steering sensor 22 Wheel speed sensor group 23 Longitudinal acceleration sensor 24 Lateral acceleration sensor 25 Yaw rate sensor

Continuation of front page (56) Reference JP-A-8-183436 (JP, A) JP-A-7-223520 (JP, A) JP-A-9-240458 (JP, A) JP-A-6-127354 (JP , A) JP 10-29517 (JP, A) JP 3-45453 (JP, A) JP 62-83247 (JP, A) JP 7-69190 (JP, A) JP 7-164913 (JP, A) International Publication 96/016848 (WO, A1) (58) Fields investigated (Int.Cl. ⁷ , DB name) B60T 8/00 B60T 8/32-8/96

Claims (9)

(57) [Claims] 1. Steering operation amount detecting means for detecting a steering operation amount by a driver, and target behavior determining means for determining a behavior to be a target of a vehicle based on at least the steering operation amount detected by the means. And an actual behavior detecting means for detecting an actual behavior of the vehicle, and a vehicle behavior control means for operating the behavior control section of the vehicle so that the actual behavior of the vehicle detected by the means approaches the determined target behavior of the vehicle. In a vehicle equipped with: a traveling state detecting means for detecting at least one of a vehicle body speed and a road surface friction coefficient, and a limit value of a steering operation amount corresponding to at least one of a vehicle body speed and a road surface friction coefficient detected by the means. Limit operation amount setting means for setting the steering operation amount, steering operation amount detecting means for detecting the current steering operation amount, Steering operation amount that has been found when exceeding the set steering operation amount limit value, an excess operation determining means for determining a steering excessive operation, and a vehicle deceleration means for reducing the vehicle speed at the time of determination of the excess operation by said means The excessive operation determination means detects the steering operation amount.
Excess based on steering operation amount detected by
The operation amount is calculated, and the vehicle deceleration means calculates a vehicle amount from the calculated excessive operation amount.
Calculate the target deceleration of
A vehicle behavior control device having a structure for reducing speed . 2. Steering operation amount detecting means for detecting a steering operation amount by a driver, and target behavior determining means for determining a behavior to be a target of the vehicle based on at least the steering operation amount detected by the means. And an actual behavior detecting means for detecting an actual behavior of the vehicle, and a vehicle behavior control means for operating the behavior control section of the vehicle so that the actual behavior of the vehicle detected by the means approaches the determined target behavior of the vehicle. In a vehicle equipped with: a running state detection means for detecting at least one of the vehicle body speed and the road surface friction coefficient, and a steady state attainment corresponding to at least one of the vehicle body speed and the road surface friction coefficient detected by the means. Limit behavior calculating means for calculating a limit value of the obtained vehicle behavior; and when the determined target behavior of the vehicle exceeds the calculated vehicle behavior limit value, The excessive operation determining means for determining the excessive operation of the alling, and the vehicle decelerating means for reducing the vehicle speed when the excessive operation is determined by the means.
And the vehicle deceleration means calculates a target deceleration of the vehicle from the calculated excessive operation amount, and reduces the vehicle speed so that the target deceleration is generated. Characteristic vehicle behavior control device. 3. The target behavior determining means according to claim 1 or 2, wherein the target yaw rate is determined as a behavior to be targeted by the vehicle based on at least the detected steering operation amount. The behavior detection means is configured to detect the actual yaw rate of the vehicle as the actual behavior of the vehicle, and the vehicle behavior control means responds to signals from these means, and the detected actual yaw rate of the vehicle is the target of the determined vehicle. A vehicle behavior control device characterized in that a vehicle behavior control unit is operated so as to approach a yaw rate. 4. The behavior control unit of the vehicle according to claim 1, wherein a steering angle control unit that controls a steering angle of at least one of a rear wheel and a front wheel, and a braking / driving force of each wheel is provided individually. At least one of a wheel braking / driving force control unit for controlling the yaw moment of the vehicle and a suspension control unit for changing the steering characteristics by varying the front-rear rigidity balance of the wheel suspension is used. The vehicle behavior control device. 5. The vehicle according to claim 1, wherein the target behavior determining means is configured to correct the target behavior according to a degree of decrease in vehicle speed by the vehicle decelerating means. Behavior control device. 6. The steering operation amount according to claim 1, wherein the limit operation amount setting means can maintain a steady turn from at least one of the detected vehicle speed and road surface friction coefficient. The vehicle behavior control device is characterized in that the maximum value of the above is set as the limit value. 7. The excessive operation determining means according to claim 6, wherein the excessive operation determining means calculates a difference between the current steering operation amount detected by the steering operation amount detecting means and the maximum steering operation amount value. The vehicle deceleration means obtains a target deceleration of the vehicle from the calculated excessive operation amount, and reduces the vehicle speed so that the target deceleration is generated. Behavior control device. 8. The limit behavior calculation means according to claim 3, wherein the limit behavior calculation means sets the maximum value of the yaw rate that can be constantly generated from at least one of the detected vehicle speed and road surface friction coefficient to the maximum value. A vehicle behavior characterized in that it is configured to be set as a vehicle behavior limit value, and the excessive operation determination means is configured to determine an excessive operation of steering when the determined target yaw rate exceeds the maximum yaw rate value. Control device. 9. The excessive operation determination means according to claim 8, when the excessive operation of the steering is determined, the excess yaw rate is calculated by calculating a difference between the determined target yaw rate and the maximum yaw rate. The vehicle deceleration means is configured to obtain a target deceleration of the vehicle from the calculated excess yaw rate and reduce the vehicle speed so that the target deceleration is generated.