JPH0616117A - Wheel longitudinal force control method in vehicle - Google Patents

Abstract

(57) [Summary] [Purpose] To maximize the performance of each wheel while maintaining a good vehicle posture. A total front-rear force, which is the sum of front-rear forces applied to a plurality of wheels, is detected or set, a share load ratio for each of the plurality of wheels with respect to a total vehicle weight is obtained, and the total front-rear force is calculated according to the share load ratio. The target wheel longitudinal force to be applied to each wheel is set by distributing to each wheel, and the longitudinal force of each wheel is controlled based on the target wheel longitudinal force.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle longitudinal force control method for controlling a longitudinal force of each wheel in a vehicle capable of individually controlling longitudinal forces applied to a plurality of wheels.

[0002]

2. Description of the Related Art Conventionally, a braking force as a wheel longitudinal force is individually controlled for each of a plurality of wheels, for example, Japanese Patent Laid-Open Nos. 1-178062 and 1-237.
No. 252, etc.

[0003]

By the way, in controlling the braking force or the driving force as the wheel longitudinal force for each of a plurality of wheels, it is necessary to maximize the ability of each wheel while maintaining a good posture of the vehicle. It is necessary to properly distribute the load to each wheel, but in the above-mentioned conventional publication,
No such control is disclosed.

The present invention has been made in view of the above circumstances, and provides a wheel longitudinal force control method for a vehicle in which the posture of the vehicle is kept in a good condition and the ability of each wheel can be maximized. The purpose is to

[0005]

In order to achieve the above object, according to the invention of claim 1, the total longitudinal force, which is the sum of the longitudinal forces applied to the plurality of wheels, is detected or set, and the total vehicle force is detected. A target wheel longitudinal force to be applied to each wheel is set by obtaining a shared load ratio for each of the plurality of wheels with respect to weight and distributing the total longitudinal force to each wheel according to the shared load ratio. The longitudinal force of each wheel is controlled based on the force.

According to the second aspect of the invention, in addition to the configuration of the first aspect of the invention, the shared load of each wheel in a stationary state of the vehicle is set, and the longitudinal acceleration and the lateral acceleration of the vehicle are respectively set. The apparent moving direction and the moving amount of the vehicle center of gravity position are detected to correct the set shared load based on the apparent moving direction and the moving amount of the vehicle center of gravity position, and each wheel is based on the corrected shared load. Calculate the shared load ratio for each.

According to the invention of claim 3, in addition to the structure of the invention of claim 2, the longitudinal force is a braking force, and the target deceleration of the vehicle determined based on the total longitudinal force, and the detection The total longitudinal force is corrected based on the deviation from the deceleration of the vehicle. Further, according to the invention of claim 4, in addition to the configuration of the invention of claim 1, the target turning amount of the vehicle is determined based on the steering operation amount, and the actual turning amount of the vehicle is detected to detect each wheel. The distribution of the target longitudinal force between the two is changed based on the deviation between the target turning amount and the actual turning amount so that the sum thereof becomes constant.

[0008]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 14 show a first embodiment of the present invention, FIG. 1 is a diagram showing a braking system of a vehicle, FIG. 2 is a block diagram showing a configuration of a control device, and FIG. 3 is a brake pedal force. Showing the setting map of total brake hydraulic pressure according to
4 is a diagram for explaining the apparent movement of the center of gravity along the front-rear direction of the vehicle, FIG. 5 is a diagram for explaining the apparent movement of the center of gravity along the left-right direction of the vehicle, and FIG. 6 is a center of gravity. FIG. 7 is a diagram for explaining an apparent change in position on the XY coordinates, FIG. 7 is a diagram showing a correction factor corresponding to the vehicle speed, and FIG. 8 is a diagram showing a correction factor corresponding to the X coordinate of the changed center of gravity position. , Fig. 9
Is a diagram showing a correction factor corresponding to the Y coordinate of the changed center of gravity position, FIG. 10 is a block diagram showing the configuration of the yaw control amount computing means, FIG. 11 is a diagram showing a reference yaw rate corresponding to the vehicle speed,
12 is a diagram showing a correction factor corresponding to a vehicle speed, FIG. 13 is a diagram showing a correction factor corresponding to a longitudinal acceleration, and FIG. 14 is a diagram showing a correction factor corresponding to a lateral acceleration.

First, in FIG. 1, a right front wheel W _FR of a four-wheeled vehicle is a right front wheel brake B _FR , a left front wheel W _FL is a left front wheel brake B _FL , and a right rear wheel W _RR is a right rear wheel. The wheel brake B _RR and the left rear wheel W _RL are equipped with the left rear wheel brake B _RL , and the respective brakes B _FR , B _FL , B _RR , B _RL.
Have the same specifications.

The tandem master cylinder 1 has a pair of outputs.
Equipped with ports 1a and 1b, one output port 1a
Is a modulator 2 that can control hydraulic pressure_FRRight front wheel through
Brake B_FRConnected to modulator 2_RL
Brake for the left rear wheel via _RLConnected to the other output
Port 1b is modulator 2_FLFor the left front wheel
Key B_FLConnected to modulator 2_RRThrough
B brake for right rear wheel _RRConnected to.

The operation of each modulator 2 _FR , 2 _FL , 2 _RR , 2 _RL , that is, the brake hydraulic pressure acting on each brake B _FR , B _FL , B _RR , B _RL is individually controlled by the controller C ₁ .

In FIG. 2, the controller C ₁ includes a pedal effort detection sensor 3 for detecting a brake pedal effort F _B as a brake operation amount by a brake pedal (not shown), a vehicle speed sensor 4 for detecting a vehicle speed V, and a vehicle. Longitudinal acceleration detection sensor 5 for detecting the longitudinal acceleration G _SX of the vehicle and lateral acceleration detection sensor 6 for detecting the lateral acceleration G _SY of the vehicle.
A steering angle detection sensor 7 that detects a steering angle θ as a steering operation amount by a steering handle (not shown) and a yaw rate detection sensor 8 that detects a yaw rate Y _A as an actual turning amount of the vehicle are connected.

Thus, the control device C₁Is the pedal effort detection sensor 3
Based on the detected value of the total brake hydraulic pressure P of all four wheels_T
Total front / rear force setting means 9 for setting
Total brake hydraulic pressure P obtained by force setting means 9_TReduced
Speed control amount P_GCompensation with 1st compensation total brake fluid
Pressure P_T1Deceleration correction means 10 for obtaining
Brake oil pressure P_T1Gain correction is added to the second correction rotor
Lebrake hydraulic pressure P_T2Gain correction means 11 for obtaining
Directional acceleration G_SXAnd lateral acceleration G_SYBased on car
Calculate the apparent movement direction and movement amount of both barycentric positions
Center of gravity position calculation means 12 and total brake hydraulic pressure
P_T, Vehicle speed V, longitudinal acceleration G_SX, Lateral acceleration G
_SY, Steering angle θ and detected yaw rate Y_ABased on
Yaw control amount Y_CYaw control amount calculation means 13 for calculating
And the center of gravity position calculation means 12 and the yaw control amount calculation means 1
Share load ratio R of each four wheels based on the calculation amount of 3_FR, R_FL，
R_RR, R_RLA shared load ratio calculation means 14 for calculating
Corrected total brake hydraulic pressure P_T2And the shared load ratio R
_FR, R_FL, R_RR, R_RLBased on the target longitudinal force of each wheel based on
Then brake B for each wheel_FR, B_FL, B_RR, B_RLThe goal of blur
Key hydraulic pressure P_FR, P_FL, P _RR, P_RLRight front to calculate individually
Brake hydraulic pressure calculator for wheels, left front wheel, right rear wheel and left rear wheel
Step 15_FR, 15_FL, 15_RR, 15_RLAnd the target break
Hydraulic pressure P_FR, P_FL, P_RR, P_RLBased on each modular
2_FR, 2_FL, 2_RR, 2_RLDriving hands that individually operate
Step 16_FR, 16_FL, 16_RR, 16_RLWith.

A total longitudinal force setting means 9 is provided for each of the four wheels.
Total braking, which is the sum of the wheel longitudinal forces that act separately
Brake pedal force F_BIt is set according to. Physics
And all four wheels W_FR~ W_RLB brake with the same specifications_FR, B
_FL, B_RR, B_RL, If they are installed,
Rake B_FR, B_FL, B_RR, B_RLThe braking force exerted by
Modulator 2_FR, 2_FL, 2_RR, 2_RLIndividually controlled by
It is proportional to the brake hydraulic pressure
The total braking force as the rear force is equal to the total brake hydraulic pressure.
Since it is possible to calculate it as shown in FIG.
Brake pedal force F _BBased on a map that is predetermined according to
And each brake B_FR, B_FL, B_RR, B_RLAct on
Total brake hydraulic pressure P_TIs the total longitudinal force setting means 9
Will be set by.

The total brake oil pressure P _T obtained by the total longitudinal force setting means 9 is input to the target deceleration setting means 17, and the target deceleration setting means 17 determines the target deceleration speed according to the total brake oil pressure P _T. G _O is set.
Further, the vehicle speed V obtained by the vehicle speed sensor 4 is input to the differentiating means 54, and the deceleration of the vehicle obtained by differentiating the vehicle speed V by the differentiating means 54 and the target deceleration G _O are controlled. The deceleration control amount P _G is calculated based on the deviation between the target deceleration G _O and the detected deceleration of the vehicle.

The deceleration correction means 10 receives the total brake oil pressure P _T and the deceleration control amount P _G, and by adding the deceleration control amount P _G to the total brake oil pressure P _T , 1 Correction total brake hydraulic pressure P _T1
Is obtained.

The center-of-gravity position calculating means 12 receives the longitudinal acceleration G _SX obtained by the longitudinal acceleration sensor 5 and the lateral acceleration G _SY obtained by the lateral acceleration sensor 6, respectively. Then, the center-of-gravity position calculating means 12 calculates the apparent moving direction and the moving amount of the center-of-gravity position due to the load change, when the coordinates of the center-of-gravity position in the stationary state of the vehicle are (G _X0 , G _Y0 ). In addition, based on the calculated value, the coordinates (G _X ,
G _Y ) is calculated.

In FIG. 4, when the height of the center of gravity from the ground contact road surface is H and the gravity is G = 1, the apparent movement amount ΔX of the center of gravity along the longitudinal direction of the vehicle, that is, the X direction.
Is obtained by ΔX = G _SX × H.

Further, in FIG. 5, when the height of the center of gravity from the ground contact road surface is H and the gravity is G = 1, the apparent movement amount Δ of the center of gravity along the lateral direction of the vehicle, that is, the Y direction, is shown.
Y is obtained by ΔY = G _SY × H.

Further, assuming that the total vehicle weight is WT _T , the shared loads of the right front wheel W _FR , the left front wheel W _FL , the right rear wheel W _RR and the left rear wheel W _RL when the vehicle is stationary are WT _FR , WT _FL , WT _RR. , WT _RL
(WT _T = WT _FR + WT _FL + WT _RR + WT _RL ) and, as shown in FIG. 6, when the wheel base is L _B and the tread is L _T , the X-coordinate G _X0 of the center of gravity in the stationary state of the vehicle. is represented by _{G X0 = {L B · (} WT FR + WT FL) / WT T} -L B / 2, Y coordinates G _Y0 of the center of gravity position of the vehicle stationary _{state, G Y0 = {L T ·} ( represented by _{WT RR + WT RL) / WT} T} -L T / 2.

Thus, the X coordinate at the apparent displacement point at the position of the center of gravity due to the load variation during vehicle running is G _X = G _X0 +
ΔX, and the Y coordinate is G _Y = G _Y0 + ΔY.

Referring again to FIG. 2, the vehicle speed V obtained by the vehicle speed sensor 4 is input to the vehicle speed corresponding correction rate setting means 19, and the vehicle speed corresponding correction rate setting means 19 sets a preset map as shown in FIG. Based on, the correction factor C _G1 corresponding to the vehicle speed V is set, and the maximum value of this correction factor C _G1 is “1”.
Is.

Further, the X-coordinate G _{X of the} position of the center of gravity obtained by the center-of-gravity position calculation means 12 in the load fluctuation state is input to the longitudinal acceleration-corresponding correction factor setting means 20, and the longitudinal acceleration-corresponding correction factor setting means 20. Then, as shown in FIG. 8, the correction factor C _G2 corresponding to the X coordinate G _X is set based on a preset map. Here, in the above map, the X coordinate G _X governs the front-rear distribution of the braking force and depends on the front-rear force-load characteristics of the tire. The maximum value of the correction rate C _G2 is “1”.

Further, the load obtained by the center-of-gravity position calculation means 12
Y coordinate G of the position of the center of gravity in the state of heavy fluctuation _YAcceleration in the lateral direction
Input to the correction factor setting means 21 corresponding to the degree,
In the speed-corresponding correction factor setting means 21, as shown in FIG.
Y coordinate G based on the map set for_YCorresponding to
Correction factor C_G3Is set. Here, the above map is Y seat
Mark G_YControl the distribution of braking force to the left and right,
-Based on the fact that it depends on the longitudinal force characteristics
Is determined in consideration of the weight balance of the vehicle.
Yes, correction rate C_G3The maximum value of is 1.

The correction factors C _G1 , C obtained in this way
_G2 and C _G3 are input to the averaging calculation means 22, which averages the correction rate C by dividing the sum of the correction rates C _{G1 to} C _{G3 by} the number of correction elements, that is, 3.
_GA1 is obtained. The correction factor C _GA1 is input to the gain correction means 11, and the gain correction means 11
In the above, by multiplying the first corrected total brake hydraulic pressure P _T1 by the correction rate C _GA1 , the gain corrected second corrected total brake hydraulic pressure P _T2 is obtained.

In the gain correction, the braking force becomes weaker as the correction rate C _GA1 becomes smaller, and the wheels are hard to lock.
Further, since the cornering force is maintained and the stability of the vehicle body is improved, the maps of FIGS. 7 to 9 may be adjusted depending on whether the braking force is important or the stability is important.

Further, by incorporating a correction map corresponding to the brake pedal force, the brake pedal force change speed, etc., it is possible to improve the brake feeling by more precise gain correction, and further to partially correct each of the above-mentioned correction elements. If not, the correction factor of the correction element may be set to "1".

In FIG. 10, the yaw control amount calculation means 13
Is a reference yaw rate calculation unit 22 that calculates a reference yaw rate Y _B as a target turning amount based on the vehicle speed V obtained by the vehicle speed sensor 4 and the steering angle θ obtained by the steering angle detection sensor 7, and the yaw rate detection sensor 8 in the deviation calculating section 23 for calculating a deviation [Delta] Y between the actual yaw rate Y _B is detected and the reference yaw rate Y _B, a control amount calculation unit 24 that calculates a yaw control amount Y _E by the PID calculation based on the deviation [Delta] Y, Vehicle speed V obtained by vehicle speed sensor 4
Correction rate C _G4 corresponding to the vehicle speed corresponding correction rate setting unit 25, and longitudinal acceleration corresponding correction rate setting that sets the correction rate C _G5 corresponding to the longitudinal acceleration G _SX obtained by the longitudinal acceleration sensor 5 And a correction rate setting section 27 for setting a correction rate C _G6 corresponding to the left-right acceleration G _SY obtained by the left-right acceleration sensor 6, and the correction rates C _G4 , C _G5 , C an averaging calculation unit 28 to obtain averaged correction factor C _GA2 to _G6, yaw control correction factor C _GA2 amount Y _E
The gain correction unit 29 that performs gain correction by multiplying by and the brake hydraulic pressure control based on the total brake hydraulic pressure P _T obtained by the total longitudinal force setting means 9 and the gain-corrected yaw control amount Y _EC are combined. And a complex computing unit 30 that computes the yaw control amount Y _C.

The reference yaw rate calculator 22 calculates a yaw rate transfer function for each of a plurality of vehicle speeds V set at intervals of, for example, 10 km / h for each input steering angle θ, as shown in FIG. A standard map yaw rate Y _B is obtained by setting a different map and interpolating according to the input vehicle speed V, whereby a suitable standard yaw rate Y _B can be obtained even during a brake operation with a large speed change. .

In the correction rate setting unit 25 for vehicle speed,
As shown in the figure, the vehicle speed V is compared with the preset map.
Corresponding correction factor C_G4Is set, and correction for longitudinal acceleration
The rate setting unit 26 is preset as shown in FIG.
Longitudinal acceleration G based on the map_SXCorrection factor corresponding to
C_G5Is set, and the correction factor setting unit 27 corresponding to the lateral acceleration is set.
Then, based on the preset map as shown in FIG.
Left and right acceleration G _SYCorrection factor C corresponding to_G6Is set
Be done.

Each correction factor C thus obtained_G4, C
_G5, C_G6Is input to the averaging calculator 28, and this averaging performance is
Correction factor C in the calculation unit 28_G4~ C_G6Divide the sum of by 3
Correction factor C averaged by_GA2And the correction factor C
_GA2To the yaw control amount Y in the gain correction unit 29._ERiding on
Yaw control amount Y that has been gain-corrected by calculating
_ECIs obtained.

In the composite calculation unit 30, the calculation Y _C = Y _EC × (2 / P _T ) is executed based on the gain-corrected yaw control amount Y _EC and the total brake hydraulic pressure P _T , and the brake hydraulic pressure control is performed. The yaw control amount Y _C combined with is output from the composite calculation unit 30.

The shared load ratio calculating means 14 calculates the shared load of each of the four wheels after the load changes, and also calculates the yaw control amount Y.
By calculating the distribution of _C to each of the four wheels and further combining them, the shared load ratios R _FR , R _FL , R _RR , R of the four wheels are calculated.
_{Establish RL} .

That is, the load WT _F on both front wheels W _FR , W _FL is WT _F due to the apparent variation of the position of the center of gravity.
_{= (0.5 × L B + G} X) × WT T / L B , and the addition the rear wheels W _RR, the load WT _R of W _RL side, WT _R = (WT _T
-WT _F ). Thus, the shared load of the right front wheel W _FR , the left front wheel W _FL , the right rear wheel W _RR and the left rear wheel W _RL after the load change is W
_Letting T _FR ′, WT _FL ′, WT _RR ′, WT _RL ′, these WT _FR ′, WT _FL ′, WT _RR ′, WT _RL ′ are expressed as follows.

WT _FL ′ = (0.5 × L _T + G _Y ) × WT _F / L _T WT _FR ′ = WT _F −WT _FL ′ WT _RL ′ = (0.5 × L _T + G _Y ) × WT _R / L _T WT _RR ′ = WT _R −WT _RL ′ Also, the distribution amount of the right front wheel W _FR , left front wheel W _FL , right rear wheel W _RR, and left rear wheel W _RL of the yaw control amount Y _C is Y _CFR , Y _CFL , Y
_{If CRR} and Y _CRL , they are Y _CFR , Y _CFL ,
Y _CRR and Y _CRL are expressed as follows.

Y _CFR = Y _C × {WT _FR ′ / (WT _FR ′ + WT _RR ′)} Y _CFL = Y _C × {WT _FL ′ / (WT _FL ′ + WT _RL ′)} Y _CRR = Y _C × { WT _RR ′ / (WT _FR ′ + WT _RR ′)} Y _CRL = Y _C × {WT _RL ′ / (WT _FL ′ + WT _RL ′)} Furthermore, the shared loads WT _FR ′, WT _FR ′, WT _RR ′,
WT _RL ′ and the distribution amounts Y _CFR , Y _CFL , Y _CRR , Y
_{Combining CRL} , right front wheel W _FR , left front wheel W _FL , right rear wheel W _RR
And the shared load ratios of the left rear wheel W _RL R _FR , R _FL , R _RR , R _RL
Is calculated as follows.

R _FR = (WT _FR ′ + Y _CFR ) / WT _T R _FL = (WT _FL ′ −Y _CFL ) / WT _T R _RR = (WT _RR ′ + Y _CRR ) / WT _{T RL RL} = (WT _RL ′) -Y _CRL ) / WT _T Therefore, the sum of the shared load ratios R _FR , R _FL , R _RR , and R _RL is always “1”.

The shared load ratios R _FR , R _FL , R _RR , R _RL obtained by the shared load ratio calculation means 14 are input to the corresponding brake hydraulic pressure calculation means 15 _FR , 15 _FL , 15 _RR , 15 _RL , respectively. , Each brake hydraulic pressure calculation means 15 _FR , 15 _FL , 15
_{In RR} and 15 _RL , the second corrected total brake hydraulic pressure P _T2 is multiplied by the shared load ratios R _FR , R _FL , R _RR , and R _RL , respectively, to obtain the target brake hydraulic pressure P _FR , which is the target longitudinal force of each wheel. P _FL , P _RR , P _RL are calculated for each wheel brake, and the drive means 16 _FR , 16 _FL , 16 _RR , 16 _RL respond based on the target brake oil pressures P _FR , P _FL , P _RR , P _RL. Activate the modulators 2 _FR , 2 _FL , 2 _RR , 2 _RL .

Next, the operation of the first embodiment will be described. The total brake oil pressure P _T corresponding to the total braking force exerted by the wheel brakes B _{FR to} B _RL individually mounted on the wheels W _{FR to} W _RL is given. Set each wheel W _FR
~ _Find the shared load ratios R _FR , R _FL , R _RR , R _RL for each W _RL ,
Shared load ratio of the second correction total braking pressure P _T2 determined based on the total brake pressure P _T R _FR, R _FL,
By distributing according to R _RR and R _RL , the target brake oil pressures P _FR , P _FL , P _RR and P of the wheel brakes B _{FR to} B _RL are distributed.
Defining a _RL by which is adapted to control the modulator _{2 FR, 2 FL, 2 RR} , 2 RL, also remain stable during braking when there is an imbalance in weight due to cargo or passengers of increase or decrease, also the nose Dive etc. can be reduced.

Moreover, since the loads on the wheels W _{FR to} W _RL can be properly distributed, the brakes B _FR , B _FL ,
Not only can the excessive heat load of B _RR and B _RL be avoided, but also the durability can be improved, and each wheel W
It can be equalized tire wear in _FR to _W-RL.

Further, the longitudinal and lateral accelerations G _SX and G _SY of the vehicle are respectively detected to obtain the apparent movement direction and movement amount of the vehicle center of gravity position, and the apparent movement direction and movement amount of the center of gravity position are obtained. based on the vehicle and set at rest by correcting the shared load of the wheels W _FR to _W-RL, the corrected shared load WT _FR '~WT _RL' the wheels W _FR ~ based on
Since the shared load ratios R _FR , R _FL , R _RR , and R _RL for each W _RL are obtained, it is possible to use the longitudinal acceleration sensor 5 and the lateral acceleration sensor 6 without using a load sensor or the like. Sharing load ratio R _FR , R _FL , R _RR when changing,
R _RL can be obtained.

Further, since the total brake oil pressure P _T is corrected based on the deviation between the target deceleration G _{O of the} vehicle determined based on the total brake oil pressure P _T and the detected deceleration of the vehicle, the load sensor It is possible to perform universal acceleration / deceleration control without being affected by the increase / decrease in total weight, traveling up and downhill, etc.

By the way, when the longitudinal acceleration G _SX and the lateral acceleration G _SY increase, it is possible that almost all of the brake hydraulic pressure acts on the wheel brake on the side where the load increases. At this time, if the tire characteristics are completely proportional to the load change and the braking force can be obtained completely independently of the cornering force, there will be no problem. The increase in the upper limit of the force becomes dull in the region where the load becomes large,
Further, there is a strong correlation between the cornering force and the braking force, and when the cornering force is strong, a large braking force cannot be obtained. In other words, if the vehicle is forced to brake under such a situation, the cornering force sharply decreases. However, X of the position of the center of gravity after the load change
Since the gain correction of the first corrected total brake hydraulic pressure P _T1 is performed based on the coordinates G _X and Y coordinates G _Y , the abrupt decrease of the cornering force can be avoided.

Moreover, it is determined based on the steering angle θ.
Normative yaw rate Y_BAnd the actual yaw rate Y_ADeviation from
Yaw control amount Y determined based on_CThe shared load ratio R_FR，
R_FL, R_RR, R_RLBy adding to the calculation element of
Brake oil pressure P_FR, P_FL, P _RR, P_RLTurning target distribution
Change based on the deviation between the
And share load ratio R_FR, R_FL, R_RR, R_RLConstant sum of
I did so without changing the total braking force
Therefore, while keeping the acceleration and deceleration of the vehicle constant, brake
By distributing the hydraulic pressure, stable longitudinal acceleration and
It is possible to obtain a turning motion that is appropriate for the steering operation.
it can.

In this first embodiment, each brake B _FR ,
Although the specifications of B _FL , B _RR , and B _RL are the same, the total front-rear force setting means 9 sets the total brake oil pressure P _T as a value corresponding to the total braking force.
It is also possible to use brakes that do not have the same specifications,
In that case, distribute the total braking force by the shared load ratio,
The braking force after distribution may be converted into brake hydraulic pressure to control the brake.

In the first embodiment described above, the case where the braking force as the wheel longitudinal force is controlled for each wheel W _{FR to} W _RL has been described. However, in the present invention, the driving force as the wheel longitudinal force is applied to each wheel. The present invention is also applicable to the one for controlling every W _{FR to} W _RL . Next, an example of the driving force control will be described.

15 and 16 show a second embodiment of the present invention, FIG. 15 is a diagram showing a drive system of a vehicle, and FIG. 16 is a block diagram showing a configuration of a control device.

First, in FIG. 15, the transmission M connected to the engine E is connected to the front propulsion shaft P _RF and the rear propulsion shaft P _RR via a differential device D _FC . Further, a differential device D _FF is provided between the front propulsion shaft P _RF and the right front axle A _FR and the left front axle A _FL connected to the right front wheel W _FR and the left front wheel W _FL , respectively, and the right rear wheel W _RR and A differential device D _FR is provided between the right rear axle A _RR and the left rear axle A _RL and the rear propulsion shaft P _RR which are respectively connected to the left rear wheels W _RL .

Moreover, the front propulsion axis P _RF and the rear propulsion axis P _RF
Hydrostatic stepless transmission 3 bypassing the differential device D _FC between _RR
1 is provided, and a hydrostatic continuously variable transmission 32 is provided between the front right axle A _FR and the front left axle A _FL , bypassing the differential D _FF , and between the rear right axle A _RR and the rear left axle A _RL. Is provided with a hydrostatic continuously variable transmission 33 bypassing the differential device D _FR .

These hydrostatic continuously variable transmissions 31 to 33
Is capable of steplessly changing the gear ratio between the input and output, and by controlling the gear shifting operation of each of the hydrostatic continuously variable transmissions 31 to 33 by the control device C ₂ , each wheel W _FR ,
It becomes possible to control the driving forces of W _FL , W _RR , and W _RL , respectively.

In FIG. 16, the control device C₂Each car
Wheel W_FR, W_FL, W_RR, W_RLTotal driving force given to
As the output torque F of the transmission M_TTotal to detect
The luke detection sensor 34 and the vehicle speed sensor 4 that detects the vehicle speed V
And the longitudinal acceleration G of the vehicle _SXLongitudinal acceleration to detect
Degree detection sensor 5 and lateral acceleration G of the vehicle_SYDetect
The horizontal acceleration detection sensor 6 and the steering angle θ
The steering angle detection sensor 7 for detecting the yaw rate Y
_AIs connected to the yaw rate detection sensor 8.

The control device C ₂ includes a gain correction means 11 'for adding a gain correction to the output torque F _T obtained by the total torque detection sensor 34 to obtain a corrected output torque F _T1 , a longitudinal acceleration G _SX and a lateral direction. A center-of-gravity position calculating means 12 for calculating an apparent moving direction and a moving amount of the center-of-gravity position of the vehicle based on the acceleration G _SY , output torque F _T , vehicle speed V, longitudinal acceleration G _SX , lateral acceleration G _SY , steering angle The yaw control amount calculation means 13 'for calculating the yaw control amount Y _C ′ based on θ and the detected yaw rate Y _A , and the calculation amounts of the center of gravity position calculation means 12 and the yaw control amount calculation means 13' for each of the four wheels. Share load ratio R _FR ′, R _FL ′,
Sharing load ratio calculating means 14 'for calculating R _RR ' and R _RL '
And the corrected output torque F _T1 and the shared load ratio R _FR ′,
The right front wheel, the left front wheel, the right rear wheel, and the right front wheel that individually calculate the target driving forces F _FR , F _FL , F _RR , and F _RL as the target longitudinal forces of the respective wheels based on R _FL ′, R _RR ′, and R _RL ′. A hydrostatic continuously variable transmission based on the left rear wheel driving force calculating means 15 _FR ′, 15 _FL ′, 15 _RR ′, 15 _RL ′ and the target driving forces F _FR , F _FL , F _RR , F _RL. Driving means 1 for operating 31, 32, 33
6 and 6.

The total torque detection sensor 34 is, for example, one that calculates the transmission torque from the torque converter characteristic and obtains the output torque of the transmission M from the gear ratio of the transmission M.

Vehicle speed corresponding correction rate setting means 19 ', longitudinal acceleration corresponding correction rate setting means 20', lateral acceleration corresponding correction rate setting means 21 ', and averaging calculation means 22'.
Correspond to the vehicle speed corresponding correction rate setting means 19, the longitudinal acceleration corresponding correction rate setting means 20, the lateral acceleration corresponding correction rate setting means 21 and the averaging calculation means 22 of the first embodiment shown in FIG. And the correction factor C _GA1 ′ obtained by the averaging calculation means 22 ′ is the gain correction means 1
1 ', and the gain correction means 11' multiplies the output torque F _T by the correction factor C _GA1 'to obtain the corrected output torque F _T1 with gain correction.

The yaw control amount calculating means 13 'is basically the same as the yaw control amount calculating means 13 shown in FIG. 2 except that the output torque F _T is used instead of the total brake oil pressure P _T. The yaw control amount Y _C ′ is output from the yaw control amount calculation means 13 ′.

The shared load ratio calculating means 14 'executes the same calculation processing as that of the shared load ratio calculating means 14 shown in FIG. That shared load ratio calculating unit 14 'is adapted to calculating the shared load of each wheel after a load change, the yaw control amount Y _C' by calculating the allocation to each Yonrin of further combining them, Load sharing ratio of each four wheels R _FR ′, R _FL ′,
R _RR ′ and R _RL ′ are determined and output.

Sharing obtained by the sharing load ratio calculating means 14 '
Load ratio R_FR′, R_FL′, R_RR′, R _RL′ Is the corresponding drive
Power calculation means 15_FR', 15_FL', 15_RR', 15_RL′
To the driving force calculation means 15_FR', 15
_FL', 15_RR', 15_RL'In the corrected output torque F_T1To
Share load ratio R_FR′, R_FL′, R_RR′, R_RL′ Respectively
By multiplying, each wheel W_FR~ W_RLAnd the target longitudinal force
Target driving force F_FR, F_FL, F_RR, F_RLEach wheel W_FR
~ W_RLThe target driving force F is calculated for each_FR, F_FL, F_RR，
F_RLThe drive means 16 is based on the
Activate ~ 33.

According to this second embodiment, each wheel W _FR , W _FR
The output torque F _T corresponding to the total driving force of _FL , W _RR , W _RL is detected, and each wheel W _FR , W _FL , W _RR , W
Shared load ratio for each _{RL R FR ', R FL'} , R RR ', R RL' seek, gain correction is performed correction output torque F _T1 the shared load ratio _{R FR ', R FL',} R RR ', by distributing accordance R _RL ', the wheels _{W FR, W FL, W RR} , W RL target driving force of each _{F FR, F FL, F RR} , defining the F _RL hydrostatic continuously variable transmission 31 to By controlling 33, the stability can be maintained during acceleration and the nose lift and the like can be reduced even if there is an imbalance in weight due to a load, an increase or decrease in occupants, or the like.

Moreover, since the loads on the wheels W _FR , W _FL , W _RR , and W _RL can be properly distributed, the wheels W _FR , W _FR ,
It is possible to equalize tire wear in W _FL , W _RR , and W _RL .

FIG. 17 shows the driving force applied to each wheel W._FR~ W_RLControl every
This is a modification of the vehicle drive system that has been made possible.
The output of speed M is P_RTransmitted to the right front wheel W_FRIn a row
Right front axle A_FRHas a propulsion axis P_RPower from is hydrostatic
The front left wheel W is transmitted through the continuously variable transmission 35._FLConnected to
Left front axle A_FLHas a propulsion axis P_RPower from the hydrostatic stepless
The right rear wheel W is transmitted through the transmission 36._RRRight after
Axle A_RRHas a propulsion axis P _RPower from the hydrostatic stepless speed change
Left rear wheel W_RLLeft rear axle
A_RLHas a propulsion axis P_RPower from the hydrostatic stepless transmission 3
8 is transmitted.

In such a drive system, the drive force of each wheel W _FR , W _FL , W _RR , W _RL is individually controlled by individually controlling the gear ratio of each hydrostatic continuously variable transmission 35-38. It becomes controllable.

FIG. 18 shows still another modified example of the vehicle drive system in which the driving force can be controlled for each of the wheels W _{FR to} W _RL . The transmission M is connected to the front via a differential device D _FC. Department propulsion axis P
Is connected to the _RF and rear propeller shaft P _RR, differential device D _FF between the right front axle A _FR and the front left axle A _FL and the front propeller shaft P _RF communicating respectively to the right front wheel W _FR and the left front wheel W _FL A differential device D _FR is interposed between the right rear axle A _RR and the left rear axle A _RL and the rear propulsion shaft P _RR, which are interposed and connected to the right rear wheel W _RR and the left rear wheel W _RL , respectively. .

Moreover, the front propulsion shaft P_RFAnd rear propulsion axis P
_RRDifferential device D between_FCThe distribution mechanism 39, 40
Provided, right front axle A_FRAnd front left axle A_FLDifferential between
Device D_FFDistribution mechanism 41, 42 is provided to bypass the
Rear axle A_RRAnd left rear axle A _RLDifferential device D between_FRDetour
The distribution mechanism 43, 44 is provided by turning.

[0065] distribution mechanism 39 includes a gear 45 that is relatively rotatably supported to the front propeller shaft P _RF, a clutch 46 which is interposed between the gear 45 and the front propeller shaft P _RF, the gear 4
5, a gear 47 meshed with the gear 5, a gear 48 fixed to the rear propulsion shaft P _RR , and a gear 49 meshed with the gear 48 integrally with the gear 47. Moreover, the radii of the gears 46 and 47 are R ₁ , the radius of the gear 49 is R ₂ , and the radius of the gear 48 is R ₃ .

In such a distribution mechanism 39, the clutch 4
When 6 is connected, N _F / N _R = the rotational speed N _F of the front propulsion shaft P _RF and the rotational speed N _R of the rear propulsion shaft P _RR =
The relationship R ₃ / R ₂ will occur. Moreover, by adjusting the adhesive force of the clutch 46, N _F / N _R can be adjusted to R
It can be freely changed between ₃ / R _{2 and} R ₂ / R ₃ .

The other distribution mechanisms 40 to 44 have basically the same structure as the distribution mechanism 39.

Therefore, by individually controlling the engagement / disengagement of the clutch 46 in each of the distribution mechanisms 39 to 44, the driving force of each wheel W _FR , W _FL , W _RR , W _RL can be individually controlled.

FIG. 19 shows a modified example of the vehicle braking / driving system in which the driving force can be controlled for each of the wheels W _{FR to} W _RL , and the transmission M has a front portion via a differential device D _FC. A right front axle A _FR and a left front axle A connected to the propulsion axis P _RF and the rear propulsion axis P _RR and connected to the right front wheel W _FR and the left front wheel W _FL , respectively.
_A differential device D _FF is provided between _FL and the front propulsion shaft P _RF, and is connected to the right rear wheel W _RR and the left rear wheel W _RL , respectively, to the right rear axle A _RR and the left rear axle A _RL, and the rear portion. A differential device D _FR is provided between the propulsion shaft P _RR and each wheel W _FR , W _FL , W _RR ,
Brakes B _FR , B _FL , B _RR , and B _RL are mounted on W _RL , respectively. Moreover, the front propulsion axis P _RF and the rear propulsion axis P _RR
Viscous joints 51, 52, 53 for providing a differential limiting effect are provided between the front right axle A _FR and the front left axle A _FL , and between the rear right axle A _RR and the rear left axle A _RL , respectively.

In such a braking / driving system, the brake B is
By individually controlling _FR , B _FL , B _RR , and B _RL , the driving force of each wheel W _FR , W _FL , W _RR , and W _RL can be controlled. That is, the brake of the wheel for which the driving force should be maximized is deactivated, and for the other brakes, the brake hydraulic pressure may be controlled so that the distributed driving force is obtained.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments, and various small design changes can be made without departing from the present invention described in the claims. It is possible to

[0072]

As described above, according to the first aspect of the present invention, the total longitudinal force, which is the sum of the longitudinal forces applied to the plurality of wheels, is detected or set, and each of the plurality of wheels with respect to the total vehicle weight is detected. The target wheel longitudinal force to be applied to each wheel is set by calculating the shared load ratio and distributing the total longitudinal force to each wheel according to the shared load ratio, and based on the target wheel longitudinal force Since the force is controlled, it is possible to optimize the load on each wheel and accordingly maximize the performance of each wheel while maintaining a good posture of the vehicle.

According to a second aspect of the invention, in addition to the configuration of the first aspect of the invention, the shared load of each wheel in a stationary state of the vehicle is set, and the longitudinal acceleration and the lateral acceleration of the vehicle are respectively set. The apparent moving direction and the moving amount of the vehicle center of gravity position are detected to correct the set shared load based on the apparent moving direction and the moving amount of the vehicle center of gravity position, and each wheel is based on the corrected shared load. Since the shared load ratio is obtained for each, it is possible to obtain the shared load ratio by minimizing the detection target.

According to the invention of claim 3, in addition to the configuration of the invention of claim 2, the longitudinal force is a braking force, and the target deceleration of the vehicle determined based on the total longitudinal force, and the detection Since the total longitudinal force is corrected based on the deviation from the deceleration of the vehicle, it is possible to increase or decrease the total weight without using a load sensor, etc. Speed control is possible.

According to the invention of claim 4, in addition to the configuration of the invention of claim 1, the target turning amount of the vehicle is determined based on the steering operation amount, and the actual turning amount of the vehicle is detected. , Since the distribution of the target longitudinal force among the wheels is changed based on the deviation between the target turning amount and the actual turning amount so that the sum thereof becomes constant, while keeping the acceleration / deceleration constant. By distributing the longitudinal force of the wheels, it is possible to obtain a stable longitudinal acceleration and a turning motion according to the steering operation.

[Brief description of drawings]

FIG. 1 is a diagram showing a braking system of a vehicle according to a first embodiment.

FIG. 2 is a block diagram showing a configuration of a control device.

FIG. 3 is a diagram showing a setting map of total brake hydraulic pressure according to a brake pedal force.

FIG. 4 is a diagram for explaining apparent movement of the center of gravity along the front-rear direction of the vehicle.

FIG. 5 is a diagram for explaining an apparent movement of the center of gravity along the left-right direction of the vehicle.

FIG. 6 is a diagram for explaining an apparent change in the position of the center of gravity on the XY coordinates.

FIG. 7 is a diagram showing a correction rate corresponding to a vehicle speed.

FIG. 8 is a diagram showing a correction rate corresponding to the X coordinate of the changed center of gravity position.

FIG. 9 is a diagram showing a correction rate corresponding to the Y coordinate of the changed center of gravity position.

FIG. 10 is a block diagram showing a configuration of a yaw control amount calculation means.

FIG. 11 is a diagram showing a reference yaw rate corresponding to a vehicle speed.

FIG. 12 is a diagram showing a correction rate corresponding to a vehicle speed.

FIG. 13 is a diagram showing a correction rate corresponding to longitudinal acceleration.

FIG. 14 is a diagram showing a correction rate corresponding to a lateral acceleration.

FIG. 15 is a diagram showing a drive system of a vehicle of a second embodiment.

FIG. 16 is a block diagram showing a configuration of a control device.

FIG. 17 is a diagram showing a modified example of the vehicle drive system.

FIG. 18 is a diagram showing still another modification of the vehicle drive system.

FIG. 19 is a diagram showing a modification of the vehicle braking / driving system.

[Explanation of symbols]

W _FR Right front wheel W _FL Left front wheel W _RR Right rear wheel W _RL Left rear wheel

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Wataru Saito Wataru Saito 1-4-1 Chuo, Wako-shi, Saitama Honda R & D Co., Ltd. (72) Inventor Kazuya Sakurai 1-4-1 Chuo, Wako, Saitama No. Stock Company Honda Technical Research Institute

Claims (4)

[Claims] 1. A plurality of wheels (W _FR , W _FL , W _RR , W _RL )
In a vehicle in which the longitudinal force applied to the vehicle can be individually controlled, the total longitudinal force that is the sum of the longitudinal forces applied to the plurality of wheels (W _FR , W _FL , W _RR , W _RL ) is detected or set, and The plurality of wheels (W _FR , W _FL ,
The shared load ratio for each W _RR , W _RL ) is obtained, and the total longitudinal force is calculated according to the shared load ratio for each wheel (W _FR , W _FL ,
W _RR , W _RL ) to distribute each wheel (W _FR ,
W _FL , W _RR , W _RL ) is set for each target wheel longitudinal force, and the longitudinal force of each wheel (W _FR , W _FL , W _RR , W _RL ) is controlled based on the target wheel longitudinal force. A method for controlling wheel longitudinal force in a vehicle, comprising: 2. Wheels (W _FR , W _FL ,
W _RR , W _RL ) shared load is set, the longitudinal and lateral accelerations of the vehicle are detected respectively to obtain the apparent movement direction and movement amount of the vehicle center of gravity position, and the apparent movement direction of the vehicle center of gravity position is determined. And the set share load is corrected based on the moving amount, and the share load ratio for each wheel (W _FR , W _FL , W _RR , W _RL ) is calculated based on the corrected share load. 2. A wheel longitudinal force control method for a vehicle according to 1. 3. The longitudinal force is a braking force, and the total longitudinal force is corrected based on a deviation between a target deceleration of the vehicle determined based on the total longitudinal force and a detected deceleration of the vehicle. The wheel longitudinal force control method for a vehicle according to claim 2, characterized in that: 4. The target turning amount of the vehicle is determined based on the steering operation amount, the actual turning amount of the vehicle is detected, and the target front and rear of each wheel (W _FR , W _FL , W _RR , W _RL ) is set. 2. The wheel longitudinal force control method for a vehicle according to claim 1, wherein the distribution of the forces is changed based on a deviation between the target turning amount and the actual turning amount so that the sum thereof becomes constant.