JPH03112710A - Control device for vehicle roll - Google Patents

Abstract

PURPOSE:To improve the control performance of body roll by reducing roll rigidity for a rear wheel side with the increase of a front and rear wheel steering angle ratio in the same phase direction, and setting the roll rigidity higher for a rear wheel side, upon detection of a transient turning state. CONSTITUTION:A hydraulic fluid is supplied to the hydraulic fluid chambers 2FR and 2FL of actuators 1FR and 1RL provided between right and left front wheels (rear wheel side not shown herein) and a body, through a high pressure passage 18 connected to the delivery side of a pump 6 via pressure control valves 32 and 34. Also, the fluid in each of the hydraulic fluid chambers 2FR and 2FL can be discharged to a tank via a low pressure passage 38. In this case, a control device not shown herein controls each of the pressure control valves 32 and 34, in such a way that roll rigidity for a rear wheel side is decreased with the increase of a front and rear wheel steering angle ratio in a four-wheel steering device wherein the aforesaid ratio is being changed in the same phase direction from a reverse phase direction, depending upon a speed increase, while the roll rigidity for the rear wheel side is increased upon detection of a transient turning state.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a roll control device for a vehicle such as an automobile, and more particularly to a roll control device for a vehicle equipped with a four-wheel steering device.

[Prior Art] For the purpose of improving the turning performance of vehicles such as automobiles in low vehicle speed ranges and improving the steering stability in medium and high vehicle speed ranges, for example, Japanese Unexamined Patent Publication No. 17185/1985 discloses As described above, a vehicle speed-sensitive four-wheel steering system is already known that steers the front and rear wheels so that as the vehicle speed increases, the front and rear wheels' steering angle ratio changes from a higher value in the anti-phase direction to a higher value in the in-phase direction. It is being According to such a four-wheel steering system, turning performance can be optimally controlled compared to a vehicle in which only the front wheels are steered.

[Problems to be Solved by the Invention] However, in such a four-wheel steering system, as the vehicle speed increases, the steering angle of the rear wheels increases in the in-phase direction, which makes it easy for the vehicle body to roll quickly and When the vehicle is running at high speed, the front and rear wheel steering angle ratios are set to a high value in the same phase direction, and the US-O8 characteristic is set to an understeer characteristic, so the problem is that the transient response of the steering is poor when the vehicle is running at high speed. There is.

In view of the above-mentioned problems in vehicles incorporating conventional four-wheel steering systems, the present invention aims to improve transient turning performance, especially transient turning performance during high-speed driving, while ensuring steering stability during high-speed driving. It is an object of the present invention to provide an improved vehicle roll control device with improved performance.

[Means for Solving the Problems] According to the present invention, the above-mentioned object is to provide a vehicle equipped with a four-wheel steering device configured to change the steering angle ratio of front and rear wheels from anti-phase to in-phase as the vehicle speed increases. The roll control device includes front wheel and rear wheel roll stiffness control means for controlling the roll stiffness of the front and rear wheels, respectively, a means for determining a front and rear wheel steering angle ratio, and a means for detecting a transient turning state. and a control means for controlling the roll stiffness control means, and the control means reduces the roll stiffness of the rear wheels as the front and rear wheel steering angle ratio increases in the same phase direction, and reduces the roll stiffness of the rear wheels during a transient turn and during a steady turn. This is achieved by a vehicle roll control device configured to set the roll stiffness of the rear wheels to be higher than that of the rear wheels.

[Operation of the invention] According to the above-described configuration, as the front and rear wheel steering angle ratio increases in the same phase direction, the roll stiffness on the rear wheel side is reduced, and the roll stiffness on the rear wheel side is reduced during a transient turn compared to a steady turn. is set high.

Therefore, when the vehicle is running at high speed, the US-O8 characteristics can be set to understeer characteristics without increasing the steering angle of the rear wheels, which prevents the vehicle from rolling quickly, thereby improving the vehicle's roll control performance. is improved. In addition, the US-OS characteristics during transient turns during high-speed driving of the vehicle have a reduced degree of understeer characteristics compared to the characteristics during steady turning, so responsiveness during transient turns during high-speed driving is improved. . Furthermore, since the US-OS characteristic during steady turning while the vehicle is running at high speed is maintained at a predetermined understeer characteristic, the steering stability during steady turning while running at high speed is not impaired.

The roll stiffness control means in the present invention may have any structure as long as it can change the roll stiffness of the front wheels and the rear wheels independently of each other. It may be an active suspension configured to control roll stiffness, an active stabilizer device configured to variably control roll stiffness, or the like.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention will be explained in detail below by way of example embodiments with reference to the accompanying figures.

[Embodiment] FIG. 1 is a schematic configuration diagram showing a fluid circuit of one embodiment of a roll control device according to the present invention, in which a hydraulic active suspension is employed as roll stiffness control means. The fluid circuit of the illustrated roll control device includes actuators I FR and IF provided corresponding to the front right wheel, front left wheel, rear right wheel, and rear left wheel of the vehicle, which are not shown in the figure, respectively.
These actuators have working fluid chambers 2PR, 2FL, and 2FL, respectively.
It has RR and 2RL.

Further, in the figure, 4 indicates a reserve tank that stores hydraulic oil as a working fluid, and the reserve tank 4 is connected to a suction flow path 10 in which a filter 8 for removing foreign matter is provided in the middle.
It is connected in communication with the suction side of the pump 6. A drain passage 12 is connected to the pump 6 for collecting working fluid leaked inside the pump 6 into the reserve tank 4. The pump 6 is rotationally driven by an engine 14, and the rotation speed of the engine 14 is detected by a rotation speed sensor 16.

A high pressure flow path 18 is connected to the discharge side of the pump 6.

A check valve 20 is provided in the middle of the high-pressure flow path 18 to allow only the flow of working fluid from the pump toward each actuator, and between the pump 6 and the check valve 20, the working fluid discharged from the pump is provided. An attenuator 22 is provided to absorb pressure pulsations and reduce pressure changes. The high pressure flow path 18 includes a front wheel high pressure flow path 18F and a rear wheel high pressure flow path 1.
8R is connected to one end, and accumulators 24 and 26 are connected to these high pressure channels, respectively.

Each of these accumulators has a high pressure gas sealed therein so as to absorb pressure pulsations of the working fluid and perform a pressure accumulating function.

Also, the high pressure channels 18F and 18R include a high pressure channel 18FR for the right front wheel, a high pressure channel 18PL for the left front wheel, and a high pressure channel 181 for the right rear wheel, respectively. l? , one end of the left rear wheel high pressure flow path 18RL is connected. High pressure flow path 18FR.

18PL, 181? R, 181? There are filters 28PR, 28PL, 28RR, 28RL in the middle of L, respectively.
are provided, and the other ends of these high-pressure channels are connected to the P boat of the pilot-operated three-boat switching control valve 40.42.44.46 of the pressure control valve 32.34.36.38, respectively. There is.

The pressure control valve 32 is connected to the switching control valve 40 and the high pressure flow path 18P.
It consists of a flow path 50 that communicates and connects the low pressure flow path 48PR for the right front wheel, and a fixed throttle 52 and a variable throttle 54 provided in the middle of the flow path.

A low pressure passage 48PR is connected to the R port of the switching control valve 40, and a connection passage 56 is connected to the A boat. The switching control valve 40 has a fixed throttle 52 and a variable throttle 54.
This is a spool valve that takes in the pressure Pp in the flow path 50 between the two and the pressure Pa in the connecting flow path 56 as pilot pressure, and when the pressure Pp is higher than the pressure Pa, it connects the boat P and the boat A for communication. Switched to switching position 40a,
When the pressures Pp and Pa are equal to each other, the switch is switched to the switching position 40b which cuts off communication between all boats, and the pressure P
When p is lower than pressure Pa, the switch is switched to a switching position 40c that connects boat R and boat A in communication. Further, the variable throttle 54 changes the effective passage cross-sectional area of the throttle by controlling the current supplied to the solenoid 58, and thereby works together with the fixed throttle 52 to create a pressure Pp.
It is designed to change the

Similarly, pressure control valves 34 to 38 are each pressure control valve 32
pilot-operated three-boat switching control valves 42, 44, 46 corresponding to the switching control valve 4o, flow passages 60, 62.64 corresponding to the flow passage 50, and fixed throttles 66, 68 corresponding to the fixed throttle 52; .70 and variable apertures 72, 74, and 76 corresponding to the variable aperture 54, and the variable apertures 72 to 76 have solenoids 78, 80, and 82, respectively.

In addition, the switching control valves 42, 44, and 46 are switching control valves 40
The R boat has a low pressure flow path 48 PL for the left front wheel and a low pressure flow path 48 PL for the right rear wheel, respectively.
One end of the low pressure flow path 48RL for the RR and left rear wheels is connected to the A boat, and the connection flow paths 84, 86, and 88 are connected to the A boat, respectively.
is connected at one end. In addition, the switching control valves 42 to 46
are the flow paths 6 between the corresponding fixed throttle and variable throttle, respectively.
Pressure Pp within 0-64 and corresponding connection channels 84-88
It is a spool valve that takes in the pressure Pa inside as a pilot pressure, and when the pressure Pp is higher than the pressure Pa, the boat P
Switching positions 42a and 44a that communicate and connect boat A with
, 46a, and disconnects all boats when the pressures Pp and Pa are equal to each other.
b , 44b , 46b , and the pressure Pp becomes the pressure P
When it is lower than a, the switch position is switched to switching positions 42c s 44c and 46c that connect boat R and boat A in communication.

As schematically shown in FIG. 1, each actuator I PI? , IFL, IRR, IRL are cylinders 106PR, 106PL, 106RR, which define working fluid chambers 2PR, 2PL, 2RR, 2RL, respectively.
106RL, and pistons 108PR, 108PL, 108RR, 108 that fit into the corresponding cylinders, respectively.
RL, each connected to the vehicle body (not shown) through a cylinder, and connected to a suspension arm (not shown) at the tip of the rod portion of the piston. Although not shown in the internal explanation, a suspension spring is elastically loaded between an upper seat fixed to the rod portion of the piston and a lower seat fixed to the cylinder.

Also, the cylinders 106FR and 106F of each actuator
L, 106RR, and 106RL have a drain flow path 110.
112.114.116 are connected at one end. The other end of the drain passage 110, 112, 114, 116 is connected to a drain passage 118, which is connected to the reserve tank 4 via a filter 120, thereby preventing leakage from the working fluid chamber. The used working fluid is returned to the reserve tank.

Working fluid chamber 2FR, 2PL, 2R1? , 2RL are each connected to an achinimulator 132.134.136.138 via an aperture 124.126.128.130. Piston 108Pl again? , 108FL,
108RR and 108RL each have a flow path 140FI.
? , 140FL, 140RR, and 140RL are provided. These channels are respectively corresponding channels 56.
84-88 and working fluid chamber 2Pl? , 2FL, 21? I
? .

2RL, and a filter 142 is installed in the middle of each.
It has PR, 142FL, 142RR, and 142RL. Also, actuators I FR, I FL, I
At positions close to RR and IRL, vehicle heights XPRSXFL, XRR, and XRL of the parts corresponding to each wheel are displayed.
Vehicle height sensors 144PR, 144FL, 144 that detect
RR, 1441? L is provided.

Pilot-operated shutoff valves 150.152.154.156 are provided in the middle of the connecting channels 56, 84-88, respectively, and these shutoff valves are connected to corresponding pressure control valves 40.42.44.46, respectively. High pressure flow path 1 on the more upstream side
8FR, 18PL, 18RR, 181? When the pressure difference between the pressure inside L and the pressure inside the drain flow path 110.112.114.116 is below a predetermined value, the valve is kept closed. In addition, the portions of the connecting channels 56.84 to 88 between the corresponding pressure control valves and the cutoff valves are respectively connected to the flow channels 158.160.162.164 and the flow channels 50.60.62.64 of the corresponding pressure control valves. It is connected to the downstream part of the variable throttle. Relief valves 166, 168, 170.
172 are provided, and these relief valves each take in the pressure of the upstream portion of the corresponding flow path 158, 160, 162, 164, that is, the side of the corresponding connection flow path, as a pilot pressure, and the pilot pressure is When a predetermined value is exceeded, the valve is opened to guide a portion of the working fluid in the corresponding connection flow path to the flow paths 50, 60 to 64.

The cutoff valves 150 to 156 are connected to the high pressure flow path 18PR, respectively.
18FL, 181? R, 181? The valve may be configured to maintain the closed state when the pressure difference between the pressure inside L and the atmospheric pressure is less than or equal to a predetermined value.

The other ends of the low pressure passages 48PR and 48PL are connected to one end of the low pressure passage 48F for the front wheels, and the other ends of the low pressure passages 48RR and RL are connected to one end of the low pressure passage 48H for the rear wheels. . The other ends of the low pressure channels 48F and 48R are connected to one end of the low pressure channel 48 in communication. The low pressure flow path 48 has an oil cooler 174 in the middle and a filter 176 at the other end.
It is connected to the reserve tank 4 via. A portion of the high-pressure flow path 18 between the check valve 20 and the attenuator 22 is connected to the low-pressure flow path 48 through a flow path 178 .

A relief valve 180 is provided in the middle of the flow path 178 and is set to a predetermined pressure in advance.

In the illustrated embodiment, the high pressure channel 18R and the low pressure channel 4
8R is a flow path 188 that has a filter 182, a throttle 184, and a normally open electromagnetic on-off valve 186 that can adjust the flow rate.
are connected to each other by. The electromagnetic on-off valve 186 is configured to open by energizing seven solenoids 190 and changing the excitation current, and to adjust the flow rate of the working fluid passing through the valve. Also, high pressure flow path 18R
and low pressure channel 48)? are connected to each other by a flow path 194 having a pilot-operated on-off valve 192 in the middle. The on-off valve 192 takes in the pressure on both sides of the throttle 184 as a pilot pressure, and maintains the closed position 192a when there is no differential pressure on both sides of the throttle 184, and when the pressure on the high pressure flow path 18R side with respect to the throttle 184 is high. The valve is switched to the open position 192b. Thus aperture 1
84, the electromagnetic on-off valve 186 and the on-off valve 192 cooperate with each other to selectively communicate and connect the high-pressure flow path 18R and the low-pressure flow path 48R1, and therefore the high-pressure flow path 18 and the low-pressure flow path 48, to direct the low-pressure flow from the high-pressure flow path. A bypass valve 196 is configured to control the flow rate of the working fluid flowing into the passage.

Further, in the illustrated embodiment, pressure sensors 197 and 198 are provided in the high-pressure flow path 18R and the low-pressure flow path 48R, respectively, and these pressure sensors measure the pressure PS and pressure of the working fluid in the high-pressure flow path, respectively. The pressure Pd of the working fluid in the low pressure flow path is detected. In addition, pressure sensors 19 are provided in the connecting channels 56, 84, 86, and 88, respectively.
9PR, 199PL, 1991? J? , 199RL
are provided, and these pressure sensors detect the pressures in the working fluid chambers 2FR, 2PL, 2RR, and 2RL, respectively. Furthermore, reserve tank 4
A temperature sensor 195 is provided to detect the temperature T of the working fluid stored in the tank.

The vehicle to which the illustrated embodiment is applied has a steering angle ratio of the front and rear wheels that changes depending on the vehicle speed, as shown in FIG.
In addition, there is a normal mode W-〇 that changes from opposite phase to in-phase in relatively high and low vehicle speed ranges, and a sports mode Wags that changes from opposite phase to in-phase in relatively high vehicle speed ranges, using a changeover switch installed in the cabin. It incorporates a vehicle speed-sensitive four-wheel steering system that is configured to switch between the two modes.

The electromagnetic on-off valve 186 and the pressure control valves 32-38 are controlled by an electric control device 200 shown in FIG. Electrical control device 200 includes a microcomputer 202 .

The microcomputer 202 may have a general configuration as shown in FIG. 2, and includes a central processing unit (CPU) 204 and a read-only memory (ROM) 2.
06, random access memory (RAM) 208,
An input port device 210 and an output port device 212 are connected to each other by a bidirectional common bus 214.

The input port device 210 includes a signal indicating the rotation speed N of the re-engine 14 from the rotation speed sensor 16, a signal indicating the temperature T of the working fluid from the temperature sensor 195, and pressure sensors 197 and 19.
Signals indicating the pressure Ps in the high-pressure flow path and the pressure Pd in the low-pressure flow path from 8, pressure sensors 199FL, 199
PR, 199RL, 199RI? The working fluid chambers 2PL, 2PR, and 2RL, respectively.

A signal indicating the pressure P1 (1-1, 2, 3, 4) in 2RR, a signal indicating whether the ignition switch is in the on state from the ignition switch (IGSW) 216, vehicle height sensors 144FL, 144Pi? , 144RL
, respectively from 144RR left front wheel, right front wheel, left rear wheel,
Vehicle height of the part corresponding to the right rear wheel X1 (I-1, 2, 3, 4
) are respectively input.

The input port device 210 also includes a signal indicating the vehicle speed V from the vehicle speed sensor 234, a signal indicating the longitudinal acceleration Ga from the longitudinal G (acceleration) sensor 236, and a signal indicating the longitudinal acceleration Ga from the longitudinal G (acceleration) sensor 236.
A signal indicating lateral acceleration Gl from 38, steering angle sensor 240
A signal indicating the steering angle θ, a signal indicating the front and rear wheel steering angle ratio K of the four-wheel steering set by the control device of the four-wheel steering device 242, and a vehicle height control mode set by the vehicle height setting switch 248 are set to high. A signal indicating whether the mode is mode or normal mode is manually input.

The human-powered boat device 210 appropriately processes the signals input thereto, and outputs the processed signals to the CPU and RAM 208 according to instructions from the CPU 204 based on a program stored in the ROM 206. ROM2
06 stores the control flows shown in FIGS. 3, 6A to 6C, and the maps shown in FIGS. 4, 5, and 7 to 16, and the CPU It is designed to process signals based on flows. Output boat device 2
12 outputs a control signal to the electromagnetic on-off valve 186 via the drive circuit 220 according to instructions from the CPU 204, and the drive circuit 22
2 to 228 to the pressure control valves 32 to 38, in particular the solenoids 58 of variable throttles 54, 72, 74, 76, respectively.
．． Output the control signal to 78, 80, 82, drive circuit 23
A control signal is output to the display 232 via 0.

The operation of the illustrated embodiment will now be described with reference to the flowchart shown in FIG.

Note that the control flow shown in FIG. 3 is started when the ignition switch 216 is closed. Further, in the flowchart shown in FIG. 3, the flag Fc indicates that the pressure Ps of the working fluid in the high pressure flow path is
This relates to whether or not the pressure Ps has ever exceeded the threshold pressure Pc that causes the valve to fully open.
The flag Fs indicates that the standby pressure Pb1 (■
-1, 2, 3, 4) standby pressure current 1b
This relates to whether or not 1 (1-1, 2, 3, 4) is set, and 1 indicates that the standby pressure current is set.

First, in step 10, a main relay (not shown in the figure) is turned on, and then in step 2
Go to 0.

In step 20, the contents stored in the RAM 208 are cleared and all flags are reset to 0, and the process then proceeds to step 30.

In step 30, a signal indicating the rotation speed N of the engine 14 detected by the rotation speed sensor 16, a signal indicating the rotation speed N of the engine 14 detected by the rotation speed sensor 16,
A signal indicating the temperature T of the working fluid detected by the pressure sensor 195, and a pressure Ps in the high pressure flow path detected by the pressure sensor 197.
A signal indicating the pressure Pd in the low pressure flow path detected by the pressure sensor 198, a pressure sensor 199FL,
A signal indicating the pressure P1 in the working fluid chambers 2PL, 2PR, 2RL, and 2RR detected by 199FR, 199RL, and 199RR, a signal indicating whether the ignition switch 216 is in the on state, and a vehicle height sensor 144P.
A signal indicating the vehicle height X1 detected by L, 144FR, 144RL, and 144RR, a signal indicating the vehicle speed V detected by the vehicle speed sensor 234, a signal indicating the longitudinal acceleration Ga detected by the longitudinal G sensor 236, a lateral G sensor 238
Lateral acceleration detected by G! , a signal indicating the steering angle θ detected by the steering angle sensor 240 , a signal indicating the front and rear wheel steering angle ratio K of the four-wheel steering set by the control device of the four-wheel steering device 242 , a vehicle height setting switch 248 A signal indicating whether the set mode is high mode or normal mode is read, and the process then proceeds to step 40.

In step 40, it is determined whether or not the ignition switch is in the off state, and when it is determined that the ignition switch is in the off state, the process proceeds to step 200, where the ignition switch is in the on state. When it is determined that this is the case, the process advances to step 50.

In step 50, whether or not the engine is being operated is determined by determining whether the engine rotation speed N detected by the rotation speed sensor 16 and read in step 30 exceeds a predetermined value. A determination is made, and when it is determined that the engine is not being operated, the process proceeds to step 90, and when it is determined that the engine is being operated, the process proceeds to step 60.

Note that whether or not the engine is being operated may be determined by determining whether or not the generated voltage of a generator (not shown in the drawings) driven by the engine is equal to or higher than a predetermined value.

In step 60, from the time when engine operation is started, in step 150, which will be described later, the pressure control valves 32 to 3 are
A timer is started for a time Ts until the standby pressure Pbl of 8 is set, after which the process proceeds to step 70. In this case, if the timer Ts has already been activated, the timer continues counting.

In step 70, the current 1b applied to the solenoid 190 of the electromagnetic on-off valve 186 of the bypass valve 196 is RO
Based on the map corresponding to the graph shown in FIG. 4 stored in M206, calculation is performed according to Ib-1b+ΔIbs, and the process then proceeds to step 80.

In step 80, the current calculated in step 70! By energizing the solenoid 190 of the electromagnetic on-off valve 186, the bypass valve 196 is driven in the closing direction, and the process then proceeds to step 90.

In step 90, it is determined whether the pressure Ps in the high-pressure flow path is equal to or higher than the threshold value Pc, and when it is determined that Ps≧Pc is not satisfied, the process proceeds to step 120, where Ps≧ When it is determined that it is Pc, the process advances to step 100.

In step 100, flag Fc is set to 1, and then the process proceeds to step 110.

In step 110, in order to control the ride comfort of the vehicle and the posture of the vehicle body, the process proceeds to step 30, as will be explained in detail later with reference to FIGS. 6A to 6C and FIGS. 7 to 16. By performing active calculations based on various signals read in, the variable throttle 5 of each pressure control valve
4. The current 1ul to be energized to the solenoids 58, 78, 80, 82 of 72 to 76 is calculated, and then step 1
Proceed to 70.

In step 120, it is determined whether the flag Fc is 1 or not, and it is determined that the flag Fc is Fc -1, that is, the pressure Ps of the working fluid in the high pressure flow path is equal to or higher than the threshold suppressing pressure Pc. If it is determined that the value has become lower than this after the initial pressure is determined, the process proceeds to step 110, and it is determined that the pressure is not Fc-1, that is, it is determined that the pressure PS has never exceeded the threshold suppression pressure Pc. When this has been performed, the process advances to step 130.

In step 130, it is determined whether the flag Fs is 1, and when it is determined that it is Fs -1, the process proceeds to step 170, and it is determined that it is not Fs -1. If so, the process proceeds to step 140.

In step 140, it is determined whether or not the time Ts has elapsed, and when it is determined that the time Ts has not elapsed, the process proceeds to step 170, where it is determined that the time Ts has elapsed. When this has been performed, the process advances to step 150.

In step 150, the operation of the Ts timer is stopped, and the pressure Pl read in step 30 is stored in the RAM 208 as the standby pressure Pbl, and the pressure Pl read in the step 30 is stored in the RAM 208 as shown in FIG. Based on the map corresponding to the graph shown in FIG. Fluid chamber 2PL, 2PR, 2RL
, 2RR, the variable restrictor 72. of the pressure control valve 34.32.38.
54.76.74 solenoid 78.58.82.80
The current 1bl (1-1, 2, 3, 4) to be applied to is calculated, and then the process proceeds to step 160.

In step 160, the flag Fs is set to 1, and then the process proceeds to step 170.

In step 170, it is determined whether the current 1b calculated in step 70 is greater than or equal to the reference f11bo, and when it is determined that Ib≧lbo is not satisfied, the process returns to step 30. , when it is determined that Ib≧Ibo, the process advances to step 180.

In step 180, it is determined whether the pressure Ps of the working fluid in the high pressure flow path read in step 30 is equal to or higher than the reference value Pso, and it is determined that Ps≧Pso is not satisfied. When it has been carried out, the process returns to step 30 and Ps≧
When it is determined that it is Pso, step 19
Go to 0.

In step 190, the current I calculated in step 150 or the current 1ui calculated in step 110 is applied to the variable throttle solenoid 58.7 of each pressure control valve.
8 to 82, each pressure control valve is driven and its control pressure is controlled, and then the process returns to step 30 and the above-described steps 30 to 190 are repeated.

In step 200, the bypass valve 1 is turned off by stopping the power supply to the trail 190 of the electromagnetic on-off valve 186.
96 is opened, and the process then proceeds to step 210.

In step 210, the main relay is turned off, thereby ending the control flow shown in FIG. 3 and stopping power supply to the electric control device 200 shown in FIG. Ru.

Claims (1)

[Claims] A front wheel roll control device for a vehicle equipped with a four-wheel steering device configured to change the front and rear wheel steering angle ratio from opposite phase to in-phase as the vehicle speed increases, and controlling the roll stiffness of the front wheels and rear wheels, respectively. and a control means for controlling the roll stiffness control means, a means for determining a front and rear wheel steering angle ratio, a means for detecting a transient turning state, and a control means for controlling the roll stiffness control means. The roll of the vehicle is configured to reduce the roll stiffness of the rear wheels as the front and rear wheel steering angle ratio increases in the same phase direction, and to set the roll stiffness of the rear wheels higher during transient turns than during steady turns. Control device.