JPH05193332A - Steering angle and rolling integrated control device for vehicle - Google Patents

Abstract

PURPOSE:To change a steering angle with a steering angle control device with out changing a rolling mode by a rolling control device in a vehicle provided with the steering angle control device and the rolling control device. CONSTITUTION:When a characteristic correction request is made from a steering angle controller, variable gains KF and KR for increasing a roll rigidity burden on the front wheel side are set (Step 37), a steering angle change amount DELTAdeltaR is calculated from rear wheel steering angle detection values deltaR of the previous time and the present time (Step 30), and tilting angle to the ground theta1 and theta2 in the lateral direction link are calculated as a roll direction instantaneous rotation center (Step 31). And a correction pressure DELTAP corresponding to a roll moment by a rear-wheel steering-angle change is calculated based on the rear wheel steering angle change amount DELTAdeltaR and the tilting angle to the ground theta1 and theta2 (Step 32), pressure command values VRL and VRR on the rear wheel side corresponding to a lateral acceleration with this correction pressure DELTAP are corrected so that they are subtracted on the outer wheel side and added on the inner wheel side (Step 33) and a roll moment is generated so as to offset the roll moment amount due to the rear wheel steering angle change.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle steering angle / roll comprehensive control device, and more particularly, to control the control characteristics of the steering angle control device and the roll control device provided in the vehicle in cooperation with each other. , A device capable of controlling a steering angle without changing a roll mode of a vehicle.

[0002]

2. Description of the Related Art Conventionally, as a control device relating to the steering angle and roll rigidity of a vehicle, for example, the one described in Japanese Patent Application Laid-Open No. 3-164313 previously proposed by the present applicant (the title of the invention is "vehicle" Roll rigidity distribution and rudder angle integrated control device ") is known. This conventional device includes a roll rigidity control device capable of controlling front and rear distribution of roll rigidity, and a steering angle control device capable of assisting steering of at least one of front wheels and rear wheels (both in the embodiment). Of both control devices, control characteristic changing means for changing the control characteristic of one control device, and control characteristic correction for correcting the control characteristic of the other control device in response to the change of the control characteristic by the control characteristic changing means And a configuration including means.

[0003]

However, such a conventional control device is configured to change the control characteristic of the roll stiffness control device in response to the change of the control characteristic of the four-wheel steering device. Therefore, when the lateral force of the rear wheels is increased (or decreased) by the four-wheel steering system, the front wheel side distribution of roll rigidity can be decreased (or increased), and the steer characteristic of the vehicle can be controlled well. However, there is an unsolved problem that the roll mode is changed at this time.

The present invention has been made by paying attention to the unsolved problem of the above-mentioned conventional example. In a vehicle having a steering angle control device and a roll control device, the roll mode is not changed by the roll control device. An object of the present invention is to provide a comprehensive steering angle / roll control device for a vehicle, which can change the steering angle by the steering angle control device.

[0005]

In order to achieve the above object, a vehicle steering angle / roll total control system according to the present invention is
As shown in FIG. 1, in a vehicle including a steering angle control device capable of assisting steering of at least one of front wheels and rear wheels, and a roll control device capable of at least transiently controlling a roll of the vehicle, A rotation center calculation means for calculating a roll direction instantaneous rotation center in a vehicle traveling state based on a suspension geometry of the vehicle, a roll direction instantaneous rotation center of the rotation center calculation means, and a steering angle control change amount of the steering angle control device. A roll moment amount calculating means for calculating the roll moment amount generated in the suspension link based on the steering angle control, and a roll control for correcting the control by the roll control device so as to cancel the roll moment amount of the roll moment amount calculating means. It is characterized by comprising a correction means.

[0006]

When the steering angle amount of the steering angle control device is changed by steering, a roll moment is momentarily generated in the suspension link in the transitional state of the change of the steering angle, and the roll mode is changed. The roll moment amount at this time is calculated by the roll moment amount calculation means from the roll direction instantaneous rotation center calculated from the vehicle traveling state based on the suspension geometry and the steering angle change amount, and the roll moment amount is offset. The roll control correction means corrects the control by the roll control device to prevent the roll mode from being changed due to a change in the steering angle.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a schematic configuration diagram showing an embodiment in which the present invention is applied to a four-wheel drive vehicle in which steering angles of four wheels can be assisted by steering. In this embodiment, a steering angle control device 4 capable of assisting steering of the four wheels and a hydraulic active suspension 5 as a roll rigidity control device are provided.

In FIG. 2, 2FL and 2FR are left and right front wheels, and 2RL and 2RR are left and right rear wheels. First, the steering angle control device 4 will be described. Each of the wheels 2FL to 2RR is rotatably supported by a knuckle 6 which is horizontally swingably supported on the vehicle body. Of these, the front wheels 2FL and 2FR are connected between the knuckles 6 by tie rods 8 and 8 by a rack shaft 10A of a rack and pinion type steering gear 10. A steering shaft 12 meshes with the rack shaft 10A via a pinion, and the front wheel can be mechanically steered by rotating the steering wheel 14.

The gear case of the steering gear 10 is connected to the piston rod 14a of the single rod cylinder 14 via an elastic body.
With the stroke of 4a, the steering gear 10 can be assisted by steering. The cylinder 14 is provided with a piston rod 14a and a piston 14b which are integral with each other.
It is divided into 4L and 14R, and each pressure chamber 14
Coil springs 15L, 15R for returning the piston rod 14a to the neutral position, that is, the neutral position where the front wheels 2FL, 2FR are in the non-steered state are inserted in the L, 14R, and the pressure chamber 1
The piston rod 14a is stroked in the left (or right) direction according to the amount of pressure oil supplied to the 4L, 14R, and the front wheels 2FL, 2FR are steered left (or right) accordingly.

For the rear wheels 2RL and 2RR, both knuckles 6
The piston rod 20a of the double-acting double-acting cylinder 20 is connected as a steering shaft for steering the rear wheels via tie rods 16 and 16, respectively. The double-acting cylinder 20 is
It is divided into left and right pressure chambers 20L and 20R by a piston 20b which is integral with the piston rod 20a, and
Coil springs 21L and 21R are inserted in the pressure chambers 4L and 4R to return the piston rod 20a to the neutral position, that is, the neutral position where the rear wheels 2RL and 2RR are in the non-steering state.
The piston rod 20a is stroked in the left (or right) direction according to the amount of pressure oil supplied to the pressure chambers 20L, 20R, and the rear wheels 2RL, 2RR are steered left (or right) accordingly.

Furthermore, each of the cylinders 14 and 20 divides the hydraulic oil of a predetermined pressure from the hydraulic pressure supply device 22 into the flow dividing valve 2.
4 and the control valve 26 or 28 to receive them in both chambers L and R. The hydraulic pressure supply device 22 also serves as a hydraulic pressure source of an active suspension, which will be described later, and has a dual pump that is driven by the vehicle engine to discharge the hydraulic oil in the tank, and one of the discharge circuits has a supply side pipe. It is connected to the input port of the shunt valve 24 via a line 29. The flow dividing valve 24 performs a flow dividing function for the control valves 26 and 28. As shown in FIG. 3, the shuttle spool 24a is elastically supported by springs 24b and 24c at a neutral position, and pressure chambers 24d are provided at both ends of the spool 24a. , 24e are defined. Further, the pressure chambers 24d and 24e are formed in the spool 24a and have orifices 24f and 24 having different diameters.
g to communicate with the pipeline 29, and the spool 2
The horizontal holes 24h and 24i formed in 4a and the output port 24
The conduits 30 and 32 are communicated with each other via j and 24k.
Therefore, the horizontal holes 24h and 24i and the output ports 24j and 2 are
The degree of communication with 4k is adjusted by the stroke amount of the spool 24a that responds to the pressure in the pressure chambers 24d and 24e, respectively.

Here, the required flow rate Q _f of the pipe 30 is represented by the product A · v (= Q _f ) of the piston pressure receiving area A of the front wheel side cylinder 14 and the piston moving speed v. The moving speed v is
Assuming that the stroke of the cylinder 14 is δ and the front wheel auxiliary steering frequency is f, v = 2π · f · δ, so the required flow rate Q _f of the conduit 30 is Q _f = A · 2π · f · δ. Similarly, the required flow rate Q _r of the rear wheel side conduit 32 is Q _r = A · 2π
・ F · δ. The total discharge amount Q ₀ of the pump is Q ₀ = Q _f
It is set to + Q _r , and the diameters of the orifices 24g and 24f are set corresponding to the ratios of Q _f / Q ₀ and Q _f / Q ₀ . Therefore, the flow dividing valve 24 inputs the flow rate Q _0.
Is distributed to the required flow rates Q _f and Q _r and supplied to the pipelines 30 and 32, respectively. When the line pressure of the pipe lines 30 or 32 decreases due to load disturbance or the like, the spool 24a moves rightward or leftward in FIG. 4 to reduce the opening degree of the lateral hole 24i or 24k, so that the pressure is reduced in the system. Hydraulic fluid is supplied to prevent the flow rate distribution ratio from collapsing and prevent pressure fluctuations in one system from affecting the other.

One of the output ports 24k
Is connected to the pump port P of the control valve 26 on the front wheel side via the line 30, and the other port 24j is connected to the pump port P of the control valve 28 on the rear wheel side via the line 32. Each tank port T is connected to the drain side of the hydraulic pressure supply device 22 via the return side pipe line 34. The control valves 26 and 28 are each composed of a 4-port 3-position, spring center type electromagnetic directional control valve, and a command current I, which is supplied from a steering angle controller 36 to the electromagnetic solenoids thereof.
Takes an offset position according to I. This control valve 26, 2
Both cylinder ports A and B of No. 8 are connected to both chambers 14L and 14R or 20L and 20R of the cylinder 14 or 18, respectively.

Therefore, each of the control valves 26 and 28 is in the neutral position when the command currents I and I are both off, and the entire supply flow rate is returned to the drain pipe 34, and both chambers 14L of the cylinder 14 or 20 are supplied. , 14R or 20L, 20R is set to zero. Further, when any one of the command currents I and I is turned on, the hydraulic oil is supplied to the cylinder chamber L or R at a predetermined offset position.

A steering angle sensor 38 for outputting two kinds of pulse signals corresponding to the steering angle and the rotating direction of the steering wheel 14 is provided, and a vehicle speed sensor 40 for outputting a pulse signal according to the vehicle speed of the vehicle. And one side of each of the front and rear wheels, for example 2FL and 2
The RL is provided with steering angle sensors 42F and 42R that output a steering direction signal, a neutral position signal, and a pulse signal corresponding to the steering angle, and as shown in FIG. 3, in each suspension on the rear wheel side. Lateral link 44F, 44
Vehicle height sensors 46L and 46R for detecting a rotation angle corresponding to the vehicle height change are disposed on the R-side mounting portion of the vehicle body.

The steering angle controller 36 is constructed by mounting a microcomputer, for example, and normally reads the steering angle detection signal Dθ from the steering angle sensor 38 and the vehicle speed detection signal DV from the vehicle speed sensor 40, as shown in FIG. The four-wheel steering control for the front and rear wheels is executed, and the rear wheel steering angle δ _R at that time is sent to the roll rigidity controller 60 described later.

The active suspension 5 includes attitude control hydraulic cylinders 50FL to 50RR respectively interposed between the vehicle body side member and the wheel side members of the wheels 2FL to 2RR, and the attitude control hydraulic cylinders 50FL to 50RR. The operating pressure is the command current i
Pressure control valves 52FL to 52RR that are individually adjusted in accordance with the above. Each of the attitude control hydraulic cylinders 50FL to 50RR is configured by a single rod type double acting cylinder as shown in FIG. 5, and is specifically a cylinder separated by a piston 50b having a communication hole in a cylinder tube 50a. The chamber RM is formed, the lower end of the cylinder tube 50a is attached to the wheel side member, and the upper end of the piston rod 50c is attached to the vehicle body side member, and a predetermined thrust is generated by the pressure receiving area difference between the upper and lower surfaces of the piston 50b. The hydraulic cylinders 50FL to 50RR are provided with a coil spring 51 that has a relatively low spring constant and supports a static load of the vehicle body.

Each of the pressure control valves 52FL to 52RR is a conventionally known three-port proportional electromagnetic pressure reducing valve (for example, Japanese Patent Laid-Open No. 64-7).
4111), the supply port and the return port are connected to the discharge side and the drain side of the hydraulic pressure supply device 22 via the supply side pipe 54 and the return side pipe 56, respectively, and the output port is connected to the pipe 58. Through hydraulic cylinder 50FL
It is connected to the cylinder chamber RM of ˜50 RR. The pressure control valves 52FL to 52RR supply control pressure P, which changes as shown in FIG. 6, to the cylinder chamber RM in response to the command current i supplied from the roll stiffness controller 60 to the proportional solenoid. That is, the control pressure P also becomes zero when the command current i is zero, and linearly increases from this state in proportion to the command current i, and at the maximum command current i _MAX , the maximum control pressure corresponding to the set line pressure. It becomes P _MAX . In the figure, i _N is the neutral command current and P _N is the neutral control pressure.

The roll rigidity controller 60 is a steering angle controller.
A microcomputer is installed like the tracker 36
Wheel speed signals of the wheel speed sensors 62FL to 62RR configured
DN _FL~ DN_RR, Lateral acceleration signal G of the lateral acceleration sensor 64
_YAnd perform normal roll stiffness control as shown in Fig. 8.
In addition, a determination circuit 63 and a steering angle controller described later
Signal α from 36₀₁, Α₂Also for the low shown in Figure 9
Control is performed, and the rear wheel steering angle δ_RAnd vehicle height sensor
Rotation angle θ from 46L, 46R_L,θ_RRear wheel rudder based on
Angle δ_RThe roll moment generated according to the change in
A roll rigidity correction process for killing is also executed. Where wheel speed
Sensors 62FL to 62RR are installed corresponding to each wheel 2FL to 2RR
Pulse signal corresponding to the rotation speed of the wheels 2FL to 2RR
The lateral acceleration sensor 64 outputs the weight of the vehicle body.
Equipped at the core position, etc.
Electric signal G according to_YIs output.

Further, in this embodiment, as a characteristic request mechanism for the steering angle controller 36 and the roll rigidity controller 60, a manual switch 65 and a judgment circuit 63 are used.
Is equipped with. The manual switch 65 is operated by the will of the occupant, and the switch signal S output from the switch 65 to the judgment circuit becomes zero at the "normal running" position which is the neutral position, and the tail slide (oversteer tendency) is generated. The value becomes a positive predetermined value at the "higher steering effectiveness" position where the driver is slightly running, and further becomes a negative predetermined value at the "stable running" position, which aims for more stable running (understeer tendency). Here, the selection of "higher steering effect" position and "stable running" position is always "normal running".
It is carried out through the position.

The judgment circuit 63 inputs the switch signal S
The content of the steer characteristic instructed by the occupant is determined according to the value of ∘ and the command is given to the steering angle controller 36 or the roll rigidity controller 60. That is, when the switch signal S is zero, no instruction is given to both the controllers 36 and 60, and when the switch signal S is a negative predetermined value, the roll rigidity controller 60 outputs a determination signal α ₀₁ of a predetermined value, while the switch signal S When S has a positive predetermined value, the steering angle controller 36 outputs a determination signal α ₀₂ having a predetermined value.

The principle of total control according to this embodiment will be described with reference to FIG. The two curves A and B in the figure
Is a steer characteristic-a characteristic example of steering effectiveness relating to two control units A (corresponding to a steering angle control device in this embodiment) and B (corresponding to an active suspension which is a roll rigidity control device in this embodiment). Show. In general, regarding the relationship between the steering characteristic and the steering effectiveness, as shown in FIG. 7, the steering effectiveness becomes worse as the understeer (US) is set. Since the steer characteristic has a desirable zone and the steering effect has a required level, the desirable performance region that satisfies both is the shaded area in the figure.

Now, replace unit A with A₁Point, unit B
B₁Controlled by points, total performance is C ₁When you are at the point
Depending on driving conditions, driver's intention, etc.
It is assumed that the characteristics of the duster (US) side are required. this
In that case, it is better to control the unit B to the US side for better efficiency.
Unit B, for example, B₂Controlled by points
Then, the total performance is C₁’
Tear characteristics can be obtained. However, the effectiveness of the rudder has deteriorated
To control the unit A₂Move to
Total performance is C₂Need to Similarly, the effectiveness of the rudder
When you need to improve the
Since the degree is good, set the control point of unit A to A ₁From eg A
₂Move to the point and total performance is C₁I'm at the point
It This improves the effectiveness of the rudder, but
(A) The characteristics deviate from the shaded area.
For example B₁To B₂Move to the point, and total performance is C₂To the point
Need to move the steering characteristics to the US side.
It

As described above, when there is a request for changing the characteristics of the steering characteristic and the steering effect, the unit having the highest sensitivity for changing the characteristics (in the present embodiment, the steering characteristic is the unit B, and the steering effect is the unit). In A), it becomes desirable to respond to the request, and to control the other units in the direction of compensating for the characteristics according to the change of the unit whose control is changed.

Next, the operation of the above embodiment will be described with reference to the flow charts of FIGS. 8 and 9 showing examples of the processing procedure of the steering angle controller 36 and the roll rigidity controller 60, respectively. The rudder angle controller 36 is operated for a fixed time (for example, 2
The timer interrupt process shown in FIG. 8 is executed every 0 msec.

First, the steering angle controller 36 is
At step S1, the vehicle speed signal DV and the steering angle signal Dθ are read.
Then, the vehicle speed V and the steering angle θ are calculated from these values, and step S
Move to 2. In this step S2, a conventionally known method is used.
(See, for example, JP-A-60-161266)
Auxiliary steering angle δ for rear wheels 2FL, 2FR, 2RL, 2RR_F, Δ
_RAre calculated respectively. This calculated value δ_F, Δ_RIs normal
This embodiment corresponds to running, and in this embodiment, the steering angle control of FIG.
Control Point A in Curve A for Device 4 (Unit A) ₁Characteristics of
Is the value that determines.

Next, in step S3, the controller 36 inputs the determination signal α ₀₂ from the determination circuit 63, and the process proceeds to step S4. In step S4, the determination signal α
Check whether ₀₂ is on or not, and select manual switch 65
Then, it is judged whether or not there is a request for characteristic change, that is, a request from "normal running" to "running with increased steering effectiveness". If it is determined that the signal α ₀₂ is off and there is no request to change the characteristic, the process proceeds to step S5 and the correction signal α ₁ from the roll rigidity controller 60 is read. Next, the process proceeds to step S6, and it is determined whether or not the characteristic correction of the steering angle control device 4 is performed by checking whether or not the read correction signal α ₁ is ON.

In step S6, the correction signal α ₁
When the switch is off, there is no request for characteristic correction, so in the end, it is judged that the command of the driving performance given by the driver via the manual switch 65 is "normal driving", and the outputs of steps S7 and S8 are output. Execute the process. That is, in step S7, the correction signal α ₂ = OFF output to the roll rigidity controller 60 is maintained, and in step S8, the steering command value D _F corresponding to the auxiliary steering angles δ _F and δ _R calculated in step S2. _, D _R to the built-in solenoid drive circuit, respectively.

As a result, the solenoid drive circuit, that is, the steering angle controller 36 supplies the on / off command currents I _DF and I _DR to the solenoids of the control valves 26 and 28, respectively. Take an offset position. Therefore, the hydraulic oil is supplied to the cylinder chamber L (or R) of the cylinders 14 and 20, and the hydraulic oil of the cylinder chamber R (or L) is discharged to the drain side, and the rods 14A and 18 of the cylinders 14 and 20 are moved to the right. (Or left). As a result,
The front wheels 2FL and 2FR are turned left (or right) as an auxiliary
The rear wheels 2RL and 2RR are steered to the right (or to the left) in an auxiliary manner, and the auxiliary steering angle control in normal traveling that is preset with respect to the main steering of the steering wheel 14 is performed.
The characteristic at the control point A ₁ is obtained.

On the other hand, when the read judgment signal α ₀₂ is ON in step S4 while repeating the above-mentioned timer interruption processing, a request for changing the characteristic for increasing the steering effect is issued to the steering angle control device 4. It is judged that it is being done against. Therefore, in this case, the processes of steps S9 and S10 are sequentially performed. That is, in step S9, the steering angle controller 36 adds to the auxiliary steering angle δ _{R the} auxiliary steering angle increment Δδ _R ′ that increases the rear wheels 2RL, 2RR, that is, sets the steer characteristic to a predetermined oversteer side to enhance the steering effect. To do. here,
The increment Δδ _R ′ changes the control points of the curve A in FIG. 11 from A ₁ to A ₂
Is set to the value to be transferred to. Further, in response to this, in step S10, the auxiliary steering angle δ _F = δ _F −Δδ for correcting the yaw rate gain by cutting back the front wheels 2FL, 2FR.
Calculate _F ′.

After that, the process goes to step S11, the steering angle controller 36 turns on the correction signal α ₂ for requesting the roll rigidity controller 60 to correct the roll rigidity, and the process goes to step S8. As a result, since the steering angle is controlled in the same manner as described above, the steering angles of the rear wheels 2RL, 2RR are increased by a predetermined value to enhance the steering effect, and the steering angles of the front wheels 2FL, 2FR are increased by a predetermined value. It is cut back to correct the yaw rate gain and spin is prevented. After all, the effectiveness of the rudder by the rudder angle control device 4 depends on the control point A _{2 in} FIG.
It becomes the characteristic of.

Further, while repeating the above-described processing, it is determined in step S6 that only the characteristic correction of the steering angle control is required when the input correction signal α ₁ is ON. The request for such characteristic correction is made when the driver requests the steer characteristic of “stable running (US tendency)” to the active suspension 5 via the manual switch 62, as in the principle of the invention described above. In this state, the steer characteristic is changed to the understeer side by the active suspension 5 as described later, and the effectiveness of the rudder is about to deteriorate.

Therefore, the process proceeds to steps S12 and S13 and is processed in the same manner as steps S9 and S10 described above.
That is, in step S12, the auxiliary steering angle δ for increasing the rear wheels 2RL and 2RR by performing the calculation of δ _R = δ _R + Δδ _R ″.
Calculate _R. Here, the increment Δδ _R ″ is the curve A in FIG.
Is set to a value for shifting the control point of A from A ₁ to A ₃ . In response to this, in step S13, the front wheels 2FL, 2FL
Auxiliary steering angle δ that corrects yaw rate gain by switching back FR
_F = δ _F −Δδ _F ″ is calculated, where Δδ _R ″ <Δ
δ _R ′, Δδ _F ″ <Δδ _F ′.

Thereafter, the process proceeds to step S8 without requesting the roll stiffness controller 60 to correct the roll stiffness. As a result, the circulating control loop between the control devices 4 and 5 is broken, and the steering angle is controlled in the same manner as when the characteristics are changed as described above. The effectiveness of the steering by the steering angle control device 4 is determined by the control points in FIG. It becomes the characteristic of A ₃ . Next, the processing of the roll rigidity controller 60, which is executed in parallel with the above-described processing by the steering angle controller 36, will be described. This roll rigidity controller 60 is used for a certain time (for example, 2
The timer interrupt process shown in FIG. 9 is performed every 0 msec.

First, the roll stiffness controller 60 determines the wheel speed signals DN _{FL to} DN _RR in step S21 of FIG.
And the wheel speeds N _{FL to} N _RR are calculated based on the signals DN _{FL to} DN _RR . Then, the process proceeds to step S22, The rotation difference ΔN between the left and right wheels is calculated from the following equation.

Then, the process proceeds to step S23, where the controller
Of the decision circuit 64 from the decision circuit 64₀₁Enter
Control goes to step S24. In step S24, the judgment
Signal α₀₁Switch to see if it is on or not.
From the request of characteristic change from Chi 62, that is, from "normal running"
Was there a request for "stable driving (understeering)"?
Determine whether or not. The signal α₀₁Is off and special
If there is no request for sex change, move to step S25.
Correction request signal α from the steering angle controller 36 ₂Read
To be crowded. Next, the process proceeds to step S26, and the read correction
Request signal α₂The active type by checking whether the
It is determined whether or not the characteristic correction of the Pension 5 is necessary.

In step S26, when the correction request signal α ₂ is off, there is no request for characteristic correction, so the driver's command of the running performance via the manual switch 62 is eventually "normal running". Then, the processing of the following steps S27 to S31 is executed. First, in step S27, it is stored in advance,
Variable gains K _F and K _R for each of the front and rear wheels are set according to the absolute value of the left and right wheel difference ΔN obtained in step S2 with reference to the storage table corresponding to the a and a characteristics in FIG. The variable gains K _F and K _R take values from zero to “1”,
The calculation of pressure command values V _{FL to} V _RR , which will be described later, is a factor that determines the front and rear roll rigidity distribution ratios. In addition, in FIG.
The a characteristic is that the variable gains K _F and K _R are predetermined values β _1F and β _1R (β _1F > β _1R ) in proportion to the left-right wheel difference | ΔN |
From β _1F + β _1R = 1), the constant and the same rate of change increase and decrease, and the predetermined values β _1F and β _1R are control points B in the curve B for the active suspension (unit B) in FIG. It is set to a value that gives ₁ . Also, K _F
> K _R is for obtaining understeer characteristics.

Further, in step S28, the output of the correction request signal α ₁ to the steering angle controller 36 is stopped. This is because a control loop circulating between the control devices 4 and 5 is not formed. Further, at step S29, the controller 60 causes the steering angle detection signal Dθ _R of the steering angle sensor 42R, the angle detection signals θ _L, θ _R from the vehicle height sensors 46L to 46R _, and the lateral acceleration signal G _Y from the lateral acceleration sensor 64. Is read and these values are temporarily stored as a rear wheel steering angle detection value, an angle detection value, and a lateral acceleration detection value, respectively. Further, in step S30, the absolute value of the difference between the previous rear wheel steering angle δ _R (n-1) and the current rear wheel steering angle δ _R (n) is calculated as the rear wheel steering angle change amount Δ.
It is calculated as δ _R (= | δ _R (n-1) −δ _R (n) |).
Next, in step S31, the vehicle height sensor 46
Based on the rotational angles θ _{L and} θ _R from L and 46 _R , the ground inclination angles θ _{1 and} θ ₂ of the lateral links 44 L and 44 _R are calculated from the equation of the plane four-bar mechanism.

Next, in step S32, the rear wheel steering change amount Δδ _R and the lateral directional links 44L and 44R.
The hydraulic cylinder on the rear wheel side required to generate the roll moment that cancels the roll moment caused by the change amount of the rear wheel steering angle by performing the calculation of the following equation (1) based on the ground inclination angles θ _{1 and} θ _2. The correction pressure ΔP for 50RL and 50RR is calculated.

[0040] Here, t _r is the tread, t _r 'is the hydraulic cylinder 50R
Distance between L and 50RR, S is hydraulic cylinder 50RL and 50RR
Effective cylinder area, Cp _{1 and} Cp ₂ are rear wheels 2RL, 2
This is the cornering power of RR.

The reason why the roll moment generated by the rear wheel steering angle change amount can be canceled by the equation (1) will be described below. In a four-wheel steering vehicle, for example, in order to improve the yaw convergence in a lane chain gage at the time of high speed running,
When the rear wheels are in the so-called in-phase steering state, a differential value Δδ / Δt is generated in the tire slip angle δ, and as shown in FIG. 3, a roll occurs in the vehicle body and a lateral suspension is used in the case of a strut suspension from a preset suspension geometry. It is assumed that the roll center tilt angles represented by the tilt angles θ _{1 and} θ ₂ of the directional links 44L and 44R are generated.

At this time, the tire lateral force ΔC _F is the product of the cornering power Cp and the rear wheel steering angle change amount Δδ _R Cp · Δ
Since it can be expressed by δ _R , the vertical reaction force of the tire is Δf
Can be expressed by _{Δf = ΔC F · tan θ =} Cp · Δδ R · tan θ ............ (2). Therefore, the roll moment Δu instantaneously generated at the lateral links 44L and 44R.
It is represented by _{Δu = t r · Δδ R (} Cp 2 · tan θ 2 -Cp 1 · tan θ 1) / 2 ............ (3). In the case of in-phase steering, the roll moment Δu acts vertically upward on the outer wheel side and vertically downward on the inner wheel side.

On the other hand, the left and right hydraulic cylinders 50RL and 50RR on the rear wheel side generate the roll moment Δu represented by the following equation (4) by applying the correction pressures ΔP and −ΔP to the inner and outer wheels. You can Δu = t _r ′ · ΔP · S (4) By solving these equations (3) and (4) as simultaneous equations, the lateral direction link 44 represented by the above equation (1) is obtained.
It is possible to calculate the correction pressure ΔP for canceling the roll moment Δu that occurs instantaneously at L and 44R.

Next, in step S33, the variable gains K _F and K _R set in step S27, the lateral acceleration detection value G _Y read in step S29, and the correction pressure ΔP calculated in step S32 are used. , The pressure command values V _{FL to} V _RR for the front left wheel to the rear right wheel are V _FL = V _N + K _F · K · G _Y ………… (5) a V _FR = V _N −K _F · K · G _Y ………… (5) b V _RL = V _N + K _R · K · G _Y + ΔP ………… (5) c V _RR = V _N −K _R · K · G _Y −ΔP ………… ( 5) From each equation in d, calculate so that the left and right wheels have opposite phases. Here, K is a fixed value control gain, and V _N is a neutral pressure command value for securing the vehicle height, but it is not necessarily a neutral value.

Next, in step S34, the pressure command values V _{FL to} V _RR obtained in step S33 are output to the built-in solenoid drive circuit. Therefore, the command currents i _{FL to} i _RR corresponding to the pressure command values V _{FL to} V _RR are supplied from the solenoid drive circuit, that is, the controller 60 to the solenoids of the pressure control valves 52 _{FL to} 52 _RR . Therefore,
The pressure control valve 52FL~52RR, respectively, in proportion to the supplied command current i _FL through i _RR, the corresponding hydraulic cylinders 50FL
Control the working pressure P of ˜50 RR.

Here, the processing of step S31 of FIG. 9 corresponds to the rotation center calculating means, the processing of step S32 corresponds to the roll moment amount calculating means, and the processing of step S33 corresponds to the roll control correcting means. .. Therefore,
When traveling straight on a good road, the left-right wheel difference | ΔN | is almost zero, so the variable gains K _F , K _{R of the} front and rear wheels are both set to predetermined values β _1F , β _1R , while The acceleration G _{Y is} also “0”, the rear wheel steering angle δ _R is also zero, the rear wheel steering angle change amount Δδ _R is also maintained at “0”, and the correction pressure ΔP is also “0”.
Therefore, after all, the calculated pressure command value V _{FL to} V _RR =
It becomes V _N. Therefore, the command current i _FL through i _RR supplied to the pressure control valve 52FL~52RR is neutral value i _N becomes corresponding to the neutral pressure command value V _N, each cylinder pressure corresponding to the neutral command current i _N Neutral The pressure is controlled to P _N. As a result, the vehicle body is maintained in a flat posture with the vehicle height value based on the cylinder pressure P _N.

When the straight traveling state is shifted to the left turning traveling state, for example, a left / right wheel difference | ΔN | is obtained according to the turning radius, and correspondingly, the variable gain becomes larger on the front wheel side. While K _F and K _R are set, a lateral acceleration G _Y (a positive value when turning to the right and a negative value when turning to the left) is obtained according to the turning speed or the like. When the vehicle is in the left-turning traveling state, as described above, the rear wheel steering angle δ _R is calculated in the four-wheel steering control process of FIG. 8, and the rear wheel steering hydraulic cylinder is calculated based on the rear wheel steering angle δ _R. Since the control valve 28 of the control valve 20 is controlled to the right offset position, the steering shaft 18 moves left and the rear wheels 2RL, 2RR are steered to the left from the neutral position. This rear wheel actual steering angle δ _R is detected by the steering angle sensor 42R, and the lateral direction link 4 by the roll of the vehicle at the time of turning.
The rotation angles θ of 4L and 44R are detected by vehicle height sensors 46L and 46R.

Therefore, the compensation calculated in step S32
The positive pressure ΔP has a positive value, and the inner ring side is determined in step S33.
Is the neutral value V_NCommand value V lower than_FL, V_RL(or
Is V _FR, V_RR) Is calculated and the neutral value V is calculated on the outer ring side._NThan
Command value V that also increases_FR, V_RR(Or V_FL, V_RL)But
Calculated, and its value is the front wheel side command value V_FL, V_FRof
Neutral value V_NFrom the rear wheel side command value V_RL, V_RR
And the roll by the rear wheel steering on the rear wheel side
Corrected pressure ΔP corresponding to the moment is on the outer ring side
Since the wheel reduces pressure and the inner wheel on the left side increases pressure, rear wheel operation
Roll Momen that offsets the roll moment of the rudder
Can be generated and their value V _FL~ V_RRAccording to
Command current i_FL~ I_RRThat is, the hydraulic cylinders 50FL to 50
The operating pressure P of RR is controlled.

Therefore, the right wheel hydraulic cylinders 50FL, 50RL (or 50FR, 50RR), which are the outer wheel side, generate a biasing force against the sinking of the vehicle body, and the left wheel hydraulic cylinders 50FR, 50RR, which are the inner wheel side. (Or 50FL, 50R
Since the operating pressure of (L) does not promote lifting of the vehicle body, roll rigidity that resists the roll of the vehicle body is obtained as a whole, and the roll moment due to the steering of the rear wheels is reliably offset, resulting in a substantially flat body posture. Retained.

The roll rigidity distribution ratio of the front and rear wheels in this posture control state is larger on the front wheel side by the amount corresponding to the variable gain K _F > K _R , so the left and right load movement amount on the front wheel side is Greater than that on the side. That is, the sum of the cornering forces of the front wheels becomes smaller than the sum of the cornering forces of the rear wheels, the grip force on the front wheel side becomes smaller than the grip force on the rear wheel side, and the steering corresponding to the control point B ₁ in FIG. 11 is performed. The characteristics and the effectiveness of the rudder are obtained.

On the other hand, while repeating the timer interrupt processing of FIG. 9, "YES" in the step S24, that is,
Suppose that the judgment signal α ₀₁ is detected to be ON, and the characteristic requirement for “stable running (understeering)” is further confirmed. In this case, after performing the processes of steps S35 and S36, the processes of steps S29 to S34 described above are performed. That is, in step S35, in step S27
Similarly, the variable gains K _F and K _R of the front and rear wheels are set by referring to the storage table corresponding to the lines c and c in FIG. Here, in the c and c characteristics of the same figure, the variable gains K _F and K _R are proportional to the left-right wheel difference | ΔN | and the predetermined values β _2F and β _2R (β _2F > β).
_2R , which increases and decreases from β _2F + β _2R = 1) at a constant and the same rate of change, and the predetermined values β _2F and β _2R
Is set to such a value that the control point B ₂ in the curve B of FIG. 11 can be obtained. Further, in step S35, the steering angle control device 4
The correction request signal α ₁ for the steering angle controller 36 is turned on in order to request the characteristic correction for

Therefore, the above steps S35 and S36 are performed.
In the processing through, the lateral acceleration G _Y =
Since it becomes 0, the pressure command values V _{FL to} V _RR calculated in step S33 become equal to the neutral value V _N in the same manner as described above. Therefore, the substantially flat vehicle body posture based on the neutral value V _N is as described above. can get. However, at the time of turning, the roll rigidity corresponding to the lateral acceleration G _Y is obtained based on the variable gains K _F and K _R , the posture variation is appropriately suppressed, and the distribution ratio of the roll rigidity to the front wheels is obtained. As compared with the processing that goes through the step S27, that is, the case where the characteristic is neither changed nor corrected, the understeer characteristic corresponding to the control point B ₂ in FIG. 11 and the effect of the dull rudder are obtained.

Further, while repeating the timer interrupt processing of FIG. 9, in step S26, "YES", that is, the correction request signal α ₂ is detected to be ON, and the steering angle control device 4 distributes the roll rigidity to the front and rear. Suppose that it is determined that the correction of is required. In such a case, the driver sets the manual switch 65 to "Tail slide traveling (OS
11) position, the total performance of FIG. 11 is controlled at the control point C ₁ along with the oversteering by the steering angle control device 4, and the proper range is exceeded. Therefore,
In such a case, the process proceeds to step S37, and similarly to steps S27 and S35, referring to the storage table corresponding to the lines b and b in FIG. 10, the variable gain K _{F of} the front and rear wheels,
Set K _R. Here, in the b and b characteristics of the figure, the variable gains K _F and K _R are proportional to the left and right wheel difference | ΔN |
_3F , β _3R (β _3F > β _3R and β _3F + β _3R = 1) is increased and decreased at a constant and the same rate of change, and the predetermined values β _3F and β _3R are the curves in FIG. Control point B _{3 in} B
Is set to a value that can obtain. After that, the processes of steps S29 to S34 are performed as described above.

As a result, the same attitude control as described above is performed during straight traveling, while during turning, the roll rigidity corresponding to the lateral acceleration G _Y is obtained based on the variable gains K _F and K _R. The distribution ratio of the roll rigidity to the front wheels is smaller than that in the case of the characteristic change (understeering) described above, but is larger than that in the normal running, and the weak understeer characteristic corresponding to the control point B ₃ in FIG. It is a blunt rudder effect.

Next, the steering angle control device 4 and the active type suspension
Explanation of the overall operation for Option 5 based on Fig. 11.
Reveal Now, the operation position of the manual switch 65
Suppose you are in a "normal run" position. In this case, the judgment times
The path 63 is a steering angle controller 36 and a roll rigidity controller.
Judgment signal α supplied to LA 60₀₂, Α₀₁To turn off
, The steering angle controller 36 performs steps S1 to S8 in FIG.
Through the roll rigidity controller 6
0 performs the processing through steps S21 to S37 of FIG.
U Therefore, as described above, the steering angle control device 4 operates
The rudder angle control for the rudder is performed to control point A in FIG. ₁Against
It shows the corresponding steer characteristics and the effectiveness of the rudder. one
On the other hand, the active suspension 5 has a predetermined roll as described above.
While performing control, control point B in FIG.₁Corresponding to
It exhibits steer characteristics and the effectiveness of the rudder. There car
The total performance of both the two is the control point A₁, B₁In between
Point C₀The steering characteristics and the effectiveness of the rudder
Both are within the proper area (the shaded area in the figure),
Is set to a weak understeer characteristic and the rudder is effective.
To satisfy both requirements at the same time
Good driving.

From this state, it is assumed that the driver operates the position of the manual switch 65 to the "higher steering effect" position. According to this, in order to increase the effectiveness of the rudder, it is more efficient to change the control characteristic of the curve A, that is, the steering angle control device 4 among the control curves A and B of FIG. And sends a determination signal α ₀₂ to the steering angle controller 36.
As a result, the steering angle controller 36 performs the processing through steps S1 to S4, S9 to S11, S8 in FIG.
As a result, the control characteristics correspond to the control point A ₂ in FIG. 11 by increasing the number of rear wheels for the predetermined steering angle and switching back the front wheels, and the performance of the entire vehicle is between control points A ₂ and B _1. Corresponding to the intermediate point C ₁ of. That is, although the effectiveness of the rudder is increased, the steer characteristic moves to the oversteer side and extends out of the proper area. Therefore, the steering angle controller 36 outputs a correction request signal α ₂ to the roll rigidity controller 60, which causes the roll rigidity controller 60 to perform steps S21 to S26, S37, S2 in FIG.
Immediately perform the processing of 9 to S34. In this process,
Since the process of increasing the distribution ratio of the roll rigidity to the front wheels is performed and the control point is moved from B ₁ to B ₃ in FIG. 11, the performance of the entire vehicle is the intermediate point C between the control points B ₃ and A _2. It corresponds to ₁ '. As a result, the total steering effect is increased to a predetermined value as requested by the driver, and
The steer characteristics are also contained in the proper range, high turning performance and stable turning performance can be secured at the same time, and the correction pressure ΔP against the roll moment amount generated according to the additional amount of the rear wheel is calculated, Since the rear wheel side pressure command values V _RL, V _RR are corrected accordingly, the roll moment due to the rear wheel steering angle change amount can be reliably canceled.

Further, it is assumed that the switch 65 is operated from the travel at the "higher steering effect" position to select the "stable travel" position via the "normal travel" position. At this time, the control point of the entire vehicle is returned to C ₀ in FIG. 11 through the “normal traveling” position. In order to improve the stable running performance, it is more efficient for the determination circuit 64 to change the control characteristic of the curve B, that is, the active suspension 5 among the control curves A and B of FIG. Roll rigidity controller 60
To the judgment signal α ₀₁ . As a result, the roll rigidity controller 60 causes the steps S21 to S24, S3 in FIG.
5, processing through S36 and S29 to S34 is performed. As a result, as the roll rigidity front wheel distribution ratio increases by a predetermined amount, the control characteristic thereof becomes the control point B ₂ of FIG. 11 as described above.
And the performance of the entire vehicle corresponds to the midpoint C ₂ between the control points B ₂ and A ₁ . That is, although the steer characteristic is further under-steered and the turning stability is increased, the effectiveness of the rudder is lowered and the proper range is exceeded. Therefore, the roll stiffness controller 60 outputs the correction request signal α ₁ to the steering angle controller 36, which causes the steering angle controller 36 to perform steps S1 to S1 in FIG.
The processing relating to S6, S12, S13 and S8 is immediately started. In this process, the process of increasing the front wheels and the process of returning the rear wheels by a predetermined amount is performed, and the control point is moved from A ₁ to A ₃ in FIG. 11, so that the performance of the entire vehicle is controlled by the control point A ₃ ,
It corresponds to the midpoint C ₂ ′ between B ₂ . As a result, the steering characteristics are under-steered, and the total turning stability of the vehicle is increased as requested by the driver. Both can be satisfied at the same time.

It should be noted that in this embodiment, even if the steering characteristics are changed according to the left / right wheel difference | ΔN |, the overall performance is substantially within the proper range. Here, the equivalent control formula of the above-mentioned comprehensive control is shown below. Roll rigidity Front wheel ratio R _F = f ₁ (ΔN) + f ₂ [α ₀₁ ] …… (6) (or) f ₁ (ΔN) + f ₃ [α ₂ ] …… (6) ′ Rear wheel steering angle δ _R ＝ f ₄ (V, δ) + f ₅ [α ₁ ] …… (7) (or) f ₄ (V, δ) + f ₆ [α ₀₂ ] …… (7) ′ Front wheel steering angle δ _F = f ₇ (V , Δ) -f ₅ [α ₁ ] ...... (8) (or) f ₇ (V, δ) -f ₆ [α ₀₂ ] …… (8) ′ where (6), (7), ( Equation (8) is satisfied at the same time, and (6) ′,
The expressions (7) ′ and (8) ′ are satisfied at the same time, and the term f ₂ ,
f _3, f _5, f ₆ is the partial to be increased or decreased is biased signal within parentheses. Further, terms f ₁ , f ₄ , and f ₇ are basic control, terms f ₂ and f ₆ are characteristic changes by the manual switch 64, and terms f ₃ and f ₅ are characteristic corrections. Further, the second item for the front wheel steering angle θ _F is a term for adjusting the gain.

In the above-mentioned embodiment, the case where the active suspension 5 is mounted as the roll rigidity control device has been described, but the present invention is not limited to this, and, for example, a damping force variable shock absorber is mounted. That controls the damping force to adjust the roll rigidity (see, for example, Japanese Patent Application Laid-Open No. 1-95969), and a spring constant variable spring is mounted to control the spring constant and adjust the roll rigidity (for example, Japanese Patent Laid-Open No. 60-58). No. 148710), a roll rigidity variable stabilizer is mounted (see, for example, Japanese Patent Laid-Open No. 60-60024).

Further, the steering angle control device need not be limited to the four-wheel steering angle control device capable of controlling the steering angles of the front and rear wheels as in the above-described embodiment, and for example, the auxiliary steering angle of only the rear wheels. May be controlled (for example, see Japanese Patent Laid-Open No. 1-95969). Further, in the above-described embodiment, the case has been described in which the roll center instantaneous rotation center is calculated from the ground inclination angles θ _{1 and} θ _{2 of} the lateral links 44L and 44R detected by the vehicle height sensors 46L and 46R.
The present invention is not limited to this, and the roll direction instantaneous rotation center may be calculated based on the lateral acceleration detection value G _Y of the lateral acceleration sensor 64.

Furthermore, the movement of the control points relating to the control characteristic changing means and the control characteristic correcting means does not have to be set in advance as in the above-mentioned embodiment, and for example, the proper area of FIG. The control points of the respective means may be stored and stored so that the total control points fit within this area. Further, the control directions relating to the control characteristic changing means and the control characteristic correcting means do not necessarily have to be mutually opposite as described in the above-mentioned embodiment, and for example, the rear wheels are in-phase up to the control limit in the steering angle control device. If the understeer degree is still insufficient after control, it is not possible to obtain the desired control characteristics by changing the control characteristics of one controller, such as increasing the front distribution of the roll stiffness controller to further increase the understeer degree. If sufficient, the other control device may be controlled in the same direction to achieve a desired control characteristic.

[0062]

As described above, according to the present invention,
A roll control device and a rudder angle control device are provided, and a roll moment amount calculation unit calculates a roll moment amount generated by a rudder angle control change amount of the rudder angle control device, and a roll control correction unit generates a roll moment generated by a rudder angle change. Since the control by the roll control device is corrected so as to cancel the amount of moment, it is possible to reliably suppress the roll moment that is transiently generated when the steering angle change occurs by the steering angle control device. The effect that the change of the mode is prevented and the discomfort can be eliminated is obtained.

[Brief description of drawings]

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

FIG. 2 is a schematic configuration diagram showing an embodiment of the present invention.

FIG. 3 is a schematic configuration diagram on the rear wheel side in the embodiment of FIG.

FIG. 4 is a schematic sectional view showing a flow dividing valve applicable to the embodiment of FIG.

5 is a schematic sectional view of a hydraulic cylinder applicable to the embodiment of FIG.

FIG. 6 is a control pressure characteristic diagram of a pressure control valve applicable to the embodiment of FIG.

FIG. 7 is a correlation diagram for explaining the principle of the present invention between the steering characteristics and the effectiveness of the rudder.

8 is a flowchart showing an example of a processing procedure of a steering angle controller in the embodiment of FIG.

9 is a flowchart showing an example of a processing procedure of a roll rigidity controller in the embodiment of FIG.

10 is a graph showing a change in variable gain with respect to a left-right wheel difference that can be applied to the embodiment of FIG.

FIG. 11 is a correlation diagram for explaining the overall control in the embodiment of FIG. 2 between the steering characteristics and the effectiveness of the rudder.

[Explanation of symbols]

2FL to 2RR Wheels 4 Steering angle control device 5 Active suspension as a roll stiffness control device 14,20 Steering hydraulic cylinder 36 Steering angle controller 38 Steering angle sensor 40 Vehicle speed sensor 42F, 42R Steering angle sensor 44L, 44R Lateral direction link 46L, 46R Vehicle height sensor 50FL to 50RR Attitude control hydraulic cylinder 52FL to 52RR Pressure control valve 60 Roll rigidity controller 64 Lateral acceleration sensor

Continuation of front page (51) Int.Cl. ⁵ Identification number Office reference number FI technical display location B62D 113: 00 131: 00

Claims (1)

[Claims] 1. A vehicle comprising a steering angle control device capable of assisting steering of at least one of front wheels and rear wheels, and a roll control device capable of at least transiently controlling a roll of the vehicle. Based on the rotation center calculation means for calculating the roll direction instantaneous rotation center in the vehicle traveling state based on the suspension geometry, the roll direction instantaneous rotation center of the rotation center calculation means, and the steering angle control change amount of the steering angle control device. Roll moment amount calculating means for calculating the roll moment amount generated in the suspension link by steering angle control, and roll control correcting means for correcting the control by the roll control device so as to cancel the roll moment amount of the roll moment amount calculating means. An integrated steering angle / roll control device for a vehicle, characterized by being equipped with.