JPH03189220A - Coordinated control device for active suspension of car with rear wheel steering - Google Patents

Abstract

PURPOSE:To prevent reduction of the cornering force resulting from the grounding load difference between the inner and outer wheels about cornering, by furnishing a means to correct the suspension characteristic so that shift of the grounding load between the inner and outer wheels is suppressed when the rear wheel steering angle is set in the opposite phase. CONSTITUTION:A fluid cylinder device 23 is interposed between a car body 1 and each wheel 2 (2FL-2RL), and pressure fluid from a hydraulic pump 28 is supplied to and exhausted from the liquid pressure chambers 23c by a proportional flow control valve 29, and thereby it is made possible to vary the stroke of each cylinder device 23. This proportional flow control valve 29 is controlled by a control unit U2 on the basis of output signals from the mentioned flow control valve 29, and a steering angle sensor 13, car speed sensor 14, car height sensor 34, vertical acceleration sensor 35, etc. Therein the suspension characteristics shall be corrected so that shift of the grounding load between the inner and outer wheels about cornering is suppressed when he rear wheel steering angle is set in opposite phase in the rear wheel steering device for ex. in the initial period of cornering during high speed running.

Description

[Detailed Description of the Invention] The present invention relates to a cooperative control device for rear wheel steering and active suspension of a vehicle, and more specifically,
A rear wheel steering device is equipped with a phase reversal control means that can temporarily set the rear wheel steering angle to an opposite phase at the beginning of a turn of a vehicle running at high speed, and the suspension characteristics can be changed as desired. The present invention relates to a cooperative control device with an active suspension device.

A known rear wheel steering device for a vehicle is configured to variably set the steering ratio of the rear wheels to the steering angle of the front wheels based on the vehicle speed or the steering angle of the front wheels. ing(
For example, Japanese Patent Laid-Open No. 61220972, etc.).

In such a rear wheel steering system, when driving at a high speed exceeding a predetermined vehicle speed, for example, 40 km/h, the following formula; KR: A rear wheel steering device equipped with a phase reversal control means for steering the rear wheels based on a constant determined by the characteristics of the vehicle has been proposed (Japanese Patent Application No. 134698).

According to this phase reversal control means, at the beginning of a turn, the yaw rate φ is still small and the second term in the above equation does not have a large effect on the target steering angle TGθ8 of the rear wheels. is set negative, that is, in opposite phase, and when the yaw rate φ increases as the vehicle turns, the target steering angle TGθ is set positive, that is, in the same phase, due to the influence of the second term in the above equation. Therefore, at the beginning of a turn while driving at high speed, the rear wheel steering angle is temporarily set in the opposite phase to ensure the desired yawing, thereby sufficiently achieving the turning performance of the vehicle required by the driver. becomes possible.

Furthermore, in recent years, a fluid cylinder device is provided between the sprung weight and the unsprung weight, and the suspension characteristics can be changed as desired by controlling the amount of working fluid supplied to and discharged from the fluid cylinder device. Suspension devices called active suspensions have been proposed that are capable of achieving this (for example, Japanese Patent Publication No. 59-14365, Japanese Patent Application Laid-Open No. 63-130418, etc.).

Generally, there are three types of vehicle vibration: bounce, pitch, and roll, and such active suspension systems include a fluid cylinder device for each wheel.
The above-mentioned three types of vibrations of the vehicle are detected by a displacement detection means for detecting displacement of the vehicle, and a fluid cylinder device of each wheel is installed so that riding comfort and running stability are improved according to the detected values of these detection means. Supply and discharge of working fluid to
The attitude of the vehicle is controlled by controlling the opening degree of the flow rate control valve of each wheel using a predetermined control gain.

However, in a vehicle that is equipped with both a rear wheel steering device equipped with the phase reversal control means described above and the active suspension device described above, the rear wheel steering device does not change the phase at the beginning of a turn when traveling at high speed. The target steering angle TGθ3 of the rear wheels is set in the opposite phase by the reversal control means so as to encourage yawing of the vehicle;
On the other hand, the active suspension device discharges working fluid from the fluid cylinder device of the wheel on the inner wheel side of the turn and supplies the working fluid to the fluid cylinder device of the wheel on the outer wheel side of the turn, so as to suppress the roll of the vehicle due to centrifugal force. . In other words, the rear wheel steering device steers the rear wheels in the opposite phase to change the direction of the vehicle, while the active suspension device shifts the ground load between the inner turning wheel and the outer turning wheel. The suspension characteristics are changed to increase the difference in ground load between the inner turning wheel and the outer turning wheel, thereby reducing the cornering force of the entire vehicle. As described above, as a result of the rear wheel steering device having the phase reversal control means and the active suspension device performing control that contradicts each other, in a vehicle equipped with both devices, the steering performance of the vehicle that should be obtained by the phase reversal control device is reduced. was not fully achieved.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and its object is to provide a phase shifter that allows the rear wheel steering angle to be set transiently in the opposite phase at the beginning of a turn during high-speed driving. In a vehicle equipped with a rear wheel steering device equipped with a reversal control means and an active suspension device that controls suspension characteristics so as to cancel the displacement of the vehicle based on the detection result of the displacement detection means that detects the displacement of the vehicle. Another object of the present invention is to provide a control device that can suitably ensure the turning performance of a vehicle at the beginning of a turn, which is obtained by reverse phase steering of the rear wheels using a phase reversal control means.

The above object of the present invention is to provide a rear wheel steering device equipped with a phase reversal control means that can temporarily set the rear wheel steering angle to an opposite phase at the beginning of a turn during high speed driving, and In a vehicle equipped with an active suspension device that controls suspension characteristics so as to cancel displacement of the vehicle based on the detection result of the displacement detection means, the rear wheel steering angle is set to have an opposite phase by the phase reversal control means. Cooperative control of rear wheel steering and active suspension of a vehicle, characterized in that the vehicle is equipped with a cooperative control means for modifying suspension characteristics so as to suppress the load transfer of ground load between the inner turning wheel and the outer turning wheel when the vehicle is turned. achieved by the device.

According to the cooperative control device for rear wheel steering and active suspension of a vehicle according to the present invention, when the phase reversal control means of the rear wheel steering device sets the steering angle of the rear wheels to the opposite phase according to a predetermined condition, The cooperative control means modifies the suspension characteristics set by the active suspension device to suppress roll of the vehicle, suppresses the load transfer of the ground load between the inner turning wheel and the outer turning wheel, and Prevents the difference in ground load between the outer rings from increasing. Therefore, reduction in cornering force caused by the difference in ground load between the inner turning wheel and the outer turning wheel is prevented, and the vehicle
It is possible to suitably ensure the turning performance of the vehicle at the beginning of a turn, which is obtained by reverse-phase steering of the rear wheels.

In a preferred embodiment of the present invention, when the phase reversal control means sets the rear wheel steering angle to the opposite phase, the cooperative control device adjusts the flow rate '4B amount to the fluid cylinder device of the wheel on the inner wheel side of the turn. , the settings are changed so that the working fluid is supplied to the fluid cylinder device. Thereby, the ground load of the wheel on the inner wheel side of the turning can be increased transiently, and the load shift of the ground load between the inner wheel and the outer wheel of the turning can be effectively suppressed.

Below, embodiments of the present invention will be described in detail based on the accompanying drawings.

FIG. 1 is a schematic overall configuration diagram of a rear wheel steering device using a cooperative control device according to an embodiment of the present invention.

In FIG. 1, the vehicle 1 has left and right front wheels 2FL and 2F.
R is linked by a front wheel steering mechanism A, and the left and right rear wheels 2RL and 2RR are linked by a rear wheel steering mechanism B.

The front wheel steering mechanism A includes a pair of knuckle arms 3FL and 3F.
R and tie rods AFL and 4FR, and a relay rod 5F that connects these tie rods 4FL and 4FR to each other.
It is roughly composed of. A rank-and-pinion type steering mechanism C is linked to the front wheel steering mechanism A, and includes a steering wheel (not shown) connected to a relay rod 5F and a pinion 6 connected to a steering shaft 7. The front wheel steering mechanism A controls the amount of operational displacement of the handle 8;
That is, the relay rod 5F is displaced left and right according to the steering angle of the steering wheel, and the left and right front wheels 2FL and 2FR are steered.

The rear wheel steering mechanism B includes a pair of knuckle arms 3RL and 3R.
R and tie rods 4FL and 4FR, and a relay rod 5 that connects these tie rods 4RL and 4RR to each other.
R, a servo motor 10 that serves as a drive source for steering the left and right rear wheels 2RL and 2RR, and a servo motor 10.
The relay rod 5R is displaced from side to side via the linkage mechanism 11 by rotating the servo motor 10 in the forward or reverse direction. , left and right rear wheels 2RL, 21?
It is configured to steer R.

In addition, the rear wheel steering mechanism B is a fail-safe mechanism.
A clutch 12 that is inserted into the linkage mechanism 11 and can release the linkage between the servo motor 10 and the relay rod 5R.
, and is interposed between the relay rod 5R and the vehicle body,
It is equipped with a neutral holding means 9 having a spring 9a that always biases the relay rod 5R in the neutral direction, and in the event of a failure such as when the servo motor 10 breaks down, the clutch 12
is released, and the relay rod 5R is forcibly held in the neutral position by the neutral holding means 9, thereby moving the vehicle 1 into the 2nd position.
It is configured so that it can be driven as a WS vehicle.

The vehicle 1 also includes a steering angle sensor 13 for detecting a steering wheel angle, a vehicle speed sensor 14 for detecting vehicle speed, which are arranged front and rear on the central axis of the vehicle 1 across the center of gravity of the vehicle 1. Lateral G sensor 1 detects lateral acceleration of vehicle 1
5.16, an encoder 17 that detects the rotational position of the servo motor 10, and a rear wheel steering angle sensor 18 that detects the displacement of the relay rod 5R are provided.

Further, a steering angle sensor 13, a vehicle speed sensor 14, a lateral G sensor 15, 16, an encoder 17, and a rear wheel steering angle sensor 18
A control unit is provided which inputs the detection results and controls the rotation of the servo motor 10 based on these detection results.

The control unit UI determines that the vehicle speed V is a predetermined vehicle speed based on the steering wheel steering angle detected by the steering angle sensor 13, that is, the steering angle θ of the front wheels 2FL and 2FR, and the vehicle speed V detected by the vehicle body sensor 14. 1. For example, 40km
/h or less, the target steering angle TGθ3 of the rear wheels is determined by the following formula; % formula % (1), and based on this target steering angle TGθ, the servo motor 10 is rotated forward or reverse to rotate the left and right rear wheels. Ring 2RL,
2RR is steered in the opposite phase by a steering angle corresponding to the steering wheel steering angle θ. Note that the above Ky□ is a coefficient determined by the characteristics of the vehicle 1.

Furthermore, when the vehicle speed v exceeds the predetermined vehicle speed V1, the control unit Ul controls the steering angle θF of the front wheels 2FL and 2FR detected by the steering angle sensor 13, the vehicle speed ■ detected by the vehicle body sensor 14, and the lateral G sensor. 1
Based on the vehicle yaw rate φ calculated from the lateral acceleration of the vehicle detected by 5.16, the following formula: % Formula % (2) TGθ,: Rear wheel target steering angle θF: Front wheel steering angle ■ :Vehicle speed φ :Yaw rate KF, KR: The target steering angle TGθk of the rear wheels is set using constants determined by the characteristics of the vehicle.

Here, K2, K is the following formula; % formula % (3) ) (4) C,, C2: Cornering power of front and rear wheels W: Weight l. Two: The center of gravity of the vehicle and the front axle. distance 12: Between the center of gravity of the vehicle and the front axle distance It is determined by

At the beginning of a turn of the vehicle 1, the rear wheel target steering angle TGθ, set by the above equation (2), is determined by the second term in the equation (2), since the yaw rate φ is still at a low value at the beginning of the turn. K
Since the first term, that is, KF·θ, is larger than R−V·φ, it is set to be negative, that is, to be in reverse phase. The control unit U1 controls the servo motor 1 to steer the rear wheel steering angle in the opposite phase based on the target steering angle TGθ.
Activate 0.

On the other hand, as the vehicle 1 turns, the yaw rate φ
When TGθR increases, the value of the second term in (2) 2 increases, so the target steering angle TGθR of the rear wheels is set to be positive, that is, in phase, and the control unit U+ sets the rear wheel steering angles to be in phase. The servo motor 10 is operated to steer the vehicle.

Therefore, the rear wheels 2RR12RL are transiently steered to a reverse phase state to encourage yawing of the vehicle at the beginning of the turn, and the vehicle 1 responds to the driver's steering wheel steering in the direction steered by the driver. To quickly change the direction of a vehicle 1. Furthermore, when the yaw rate φ increases as the vehicle 1 turns,
Since the rear wheels 2RR12RL are steered in the same phase state, steering stability during high-speed turns is ensured.

The internal structure of the control unit U1 and the control at the time of failure are disclosed in the above-mentioned Japanese Patent Application No. 1-34698, so the explanation thereof will be omitted by filing this application.

FIG. 2 is a schematic overall configuration diagram of the active suspension device mounted on the vehicle shown in FIG. 1.

Although only the left side of the vehicle 1 is shown in FIG. 2, the right side of the vehicle 1 is similarly constructed. In FIG. 2, a fluid cylinder device 23 is provided between the vehicle body and the left front wheel 2FL and between the vehicle body and the left rear wheel 2RL.
．． 23 are provided.

Inside each fluid cylinder device 23, a hydraulic chamber 23C is formed by a piston 23b fitted into a cylinder body 23a. The upper end of the piston mouth/nod 23d connected to the piston 23b of each fluid cylinder 23 is connected to the vehicle body, and each cylinder body 23a is connected to the left front wheel 2FL.
Or it is connected to the left rear wheel 2RL.

The hydraulic chamber 23C of each fluid cylinder device 23 is connected to the communication passage 24.
It communicates with the gas springs 25, and each gas spring 25
is divided into a gas chamber 25f and a hydraulic chamber 25g by a diaphragm 25e, and the hydraulic chamber 25g communicates with the hydraulic chamber 23C of the fluid cylinder device 23 through the communication passage 24 and the piston 23b of the fluid cylinder device 23. ing.

A fluid passage 30 connecting the hydraulic pump 28 and each fluid cylinder device 23 so as to be able to supply fluid has a flow rate of fluid supplied to the fluid cylinder device 23 and a flow rate of fluid discharged from the fluid cylinder device 223. Proportional flow control valves 29,29 are respectively provided.

The hydraulic pump 28 is provided with a discharge pressure needle 32 that detects the discharge pressure of fluid, and is also provided with a hydraulic pressure sensor 33, 33 that detects the hydraulic pressure in the hydraulic chamber 23c of each fluid cylinder device 23. .

Further, a vehicle height sensor 34,34 is provided which detects the cylinder stroke amount of each fluid cylinder device 23 and detects the vertical displacement of the vehicle body with respect to each wheel 2PL, 2RL, that is, the vehicle height displacement. Vertical acceleration sensor 35.35. that detects the acceleration in the vertical direction, that is, the acceleration in the vertical direction on the springs of the wheels 2PL, 2RL.
35 is the left and right front wheels 2FL, 2 on a substantially horizontal plane of the vehicle 1.
There are three in total, one each above the PR and one in the center of the left and right rear wheels in the vehicle width direction.

FIG. 3 shows each fluid cylinder device 23 from the hydraulic pump 28.
2 is a circuit diagram of a hydraulic circuit that supplies fluid to or discharges fluid from each fluid cylinder device 23. FIG.

In FIG. 3, an accumulator 42 is connected to a discharge pipe 28a through which fluid is discharged from the hydraulic pump 28 to each fluid cylinder device 23, and the discharge pipe 28a is connected to a front wheel side pipe on the downstream side of the connecting portion of the accumulator 42. It branches into 43F and rear wheel side piping 43R. The front wheel side piping 43F branches into a left front wheel side piping 43FL and a right front wheel side piping 43FR on the downstream side of the branching part with the rear wheel side piping 43R.
FR is a fluid cylinder device 23F for the left front wheel, respectively.
It communicates with the hydraulic pressure chambers 23c, 23c of the fluid cylinder device 23FR for the L and right front wheels. Similarly, rear wheel side piping 4
3R branches into left rear wheel side piping 43RL and right rear wheel side piping 43RR on the downstream side of the branching part, and connects to left rear wheel side piping 43R.
L and the right rear wheel side pipe 43RR communicate with the hydraulic chambers 23c, 23c of the fluid cylinder device 23RL for the left rear wheel and the fluid cylinder device 23RR for the right rear wheel, respectively.

These fluid cylinder devices 23FL, 23FR123R
L and 23RIi each have a gas spring 25FL.

25FR125RL and 25RR are connected,
Each gas spring 25FL, 25PR125RL and 25R
R is four gas spring units 25a and 25b.

25C, 25d, these gas spring unisol l-25a to 25d are connected to a branch communication path 2 in a communication path 24 communicating with each hydraulic pressure chamber 23C of the corresponding fluid cylinder device 23FL, 23FR123RL, and 23RR.
4a, 24b, 24c, and 24d.

Also, each gas spring is 25FL.

25FR125RL, 25RR branch communication path 24a, 2
4b, 24c, and 24d are provided with orifices 45a, 45b, 45C, and 45d, respectively, and these orifices 45a, 45b.

Damping action of 45C145d and gas spring 25FL, 25
The buffering effect of the gas sealed in the gas chamber 25f of the FR125RL and 25RR is intended to reduce high frequency vibrations applied to the vehicle.

Each gas spring 25FL, 25FR, 25RL, 25RR
Gas spring units 25a, 25b, 25C1 that constitute
Of 25d, each fluid cylinder device 23FL, 23FR1
A communication path 24 is provided between the first gas spring unit 25a provided at the position closest to each hydraulic pressure chamber 23c of 23RL and 23RR and the second gas spring unit 25b adjacent thereto. By adjusting the passage area of the communication passage 24 by taking the open position and the closed position where the passage area is narrowed, the gas springs 25FL, 25FR225RI, 2
51? I? A switching valve 46 is provided to switch the damping force in two stages. FIG. 3 shows a switching valve 46.
is shown in the open position.

Accumulator 42 of discharge pipe 28a of hydraulic pump 28
An unload relief valve 48 is connected near the upstream side of the connection part, and the unload relief valve 48 is switched to the open position when the oil discharge pressure measured by the discharge pressure gauge 32 is equal to or higher than a predetermined upper limit value. The oil discharged from the hydraulic pump 28 is directly returned to the reserve tank 49, and the hydraulic pressure accumulated in the accumulator 42 is controlled to be maintained at a predetermined value. In this way, oil is supplied to each fluid cylinder device 3 by storing oil in the accumulator 42, which is maintained at a predetermined pressure storage value. FIG. 3 shows the unload relief valve 48 in the closed position.

Since the hydraulic circuits for the left front wheel, right front wheel, left rear wheel, and right rear wheel are configured in the same way, only the hydraulic circuit for the left front wheel will be explained below, and the rest will be omitted. do.

The proportional flow rate control valve 29 is a three-way valve, with a closed position where all boats are closed, a supply position where the left front wheel side piping 43FL is opened to the hydraulic pressure supply side, and a fluid cylinder device 23 of the left front wheel side piping 43FL connected to the return piping 52. It is designed to be able to take three positions, including a communicating discharge position. FIG. 3 shows the proportional flow control valve 29 in the closed position. Further, the proportional flow rate control valve 29 is connected to the pressure compensation valve 2
9a, 29a, and these pressure compensation valves 29a, 2
9a, when the proportional flow control valve 29 is in the supply position or the discharge position, the hydraulic pressure chamber 23 of the fluid cylinder device 23 is
The hydraulic pressure in c is maintained at a predetermined value.

On the fluid cylinder device 23 side of the proportional flow rate control valve 29, a pilot pressure-responsive opening/closing valve 53 that can open and close the left front wheel side piping 43FL is provided. This on-off valve 53 is connected to the left front wheel side piping 43 on the hydraulic pump 28 side of the proportional flow rate control valve 29.
When the solenoid valve 54 that guides the FL fluid pressure is opened, the fluid pressure of the solenoid valve 54 is introduced as a pilot pressure, and when this pilot pressure is equal to or higher than a predetermined value, the on-off valve 53 closes the left front wheel side piping 43.
FL is opened to enable the proportional flow rate control valve 29 to control the flow rate of fluid to the fluid cylinder device 23.

Furthermore, a relief valve 55 that opens when the hydraulic pressure in the hydraulic pressure chamber 23c of the fluid cylinder device 23 increases abnormally and returns the fluid in the hydraulic pressure chamber 23c to the return pipe 52, and a relief valve 55 located near the downstream side of the connection part of the accumulator 42 An ignition key chain valve 56 that is connected to the discharge pipe 28a of the hydraulic pump 28 and opens when the ignition is turned off to return the oil stored in the accumulator 42 to the reserve tank 49 and release the high pressure state in the accumulator 42, and a hydraulic pump. When the oil discharge pressure of the hydraulic pump 28 increases abnormally, the oil in the hydraulic pump 28 is returned to the reserve tank 49 to lower the oil discharge pressure of the hydraulic pump 28. A return accumulator 58,58 is provided in each case, which acts to accumulate pressure when the fluid is discharged from the fluid cylinder arrangement 23.

In order to control the opening degree of each proportional flow control valve 29, the active suspension device includes a control unit U2, as shown in FIG. 2, and the control unit U2 includes the discharge pressure gauge 32, a hydraulic pressure sensor 33.3
3. Vehicle height sensor 34.34, vertical acceleration sensor 35.3
5.35, and the detection signals of the steering angle sensor 13 and vehicle speed sensor 14 are input. The control unit U2 performs calculations according to a predetermined program based on the detection signals of each of these sensors, and issues a command flow rate to each proportional flow rate control valve 29, that is, a flow rate control amount QFQFR% QllL
The suspension characteristics are variably controlled by determining % Qllll and controlling the opening degree of each proportional flow rate control valve 29.

Details of the suspension characteristic control device inside the control unit U2 can be found in Japanese Patent Application No. 1-1240 filed by the present applicant.
Since it is disclosed in No. 63, a detailed explanation thereof will be omitted by citing this patent application, but the control unit U2 has a suspension characteristic control device,
The suspension characteristic control device generally includes a first control system that controls the vehicle height to a target vehicle height based on vehicle height displacement signals from vehicle height sensors 34, 34, and 34 of each wheel;
A second control system suppresses the vehicle height displacement speed based on a vehicle height displacement speed signal obtained by differentiating each of these vehicle height displacement signals, and three vertical acceleration sensors 35, 35 and 35.
A third control system that aims to reduce vertical vibration of the vehicle based on each vertical acceleration signal, and a hydraulic pressure sensor 33 for each wheel.
．． 33. Based on each pressure signal of 33, the torsion of the vehicle body is calculated and a fourth control system is configured to suppress this. Then, depending on the running state of the vehicle 1 and the running mode set by the driver, the three types of vibrations of the vehicle body, such as bounce, pitch, and roll, vertical vibration, and torsion detected by these sensors are canceled out. The first to fourth control systems each determine the flow rate control amount to each proportional flow rate control valve 29 with a predetermined gain, and further, the flow rate control amount set in each control system is added for each wheel. , the final flow rate control amount QF to each proportional flow rate control valve 29
Set L% QFII% QIIL% Qllll.

Generally, when the vehicle 1 turns, the vehicle body tends to roll due to the centrifugal force applied to the vehicle body so that the vehicle height on the inner wheel side of the turn is high and the vehicle height on the outer wheel side of the turn is low. Q y L % Q y * % Q B
L % Q II R is a proportional flow control valve 29 corresponding to the fluid cylinder device 23.23 on the inner ring side of the turn when turning.
．． 29, the proportional flow rate control valve 2 corresponding to the negative control amount and the fluid cylinder device 23.23 on the swinging outer ring side
9.29, the proportional flow control valve 29.29 on the inner wheel side of the swing discharges the working fluid from the corresponding fluid cylinder device 23.23, and controls the proportional flow rate on the outer wheel side of the swing. The valves 29.29 supply working fluid to the corresponding fluid cylinder devices 23.23 to modify the suspension characteristics to counteract body roll. As a result,
In the vehicle 1, the difference in ground load between the wheels on the inner wheel side of turning and the wheels on the outer wheel side of turning increases, and the cornering force of the entire vehicle tends to be reduced.

Here, in this example, the rear wheel steering device and the active suspension device are cooperatively controlled so as to prevent such reduction in cornering force.

That is, the control unit U1 of the rear wheel steering device controls the target steering angle TGθ8 to be negative in the above (112), that is,
When the phases are set to be opposite, as shown in FIG. 1, a signal is sent to the control unit U2 of the active suspension system indicating that the rear wheels 2RL and RR are set to be in opposite phases by the phase reversal control means. That is, the phase inversion signal S (FIGS. 1 and 2) is fully output, and the control unit U2 of the active suspension device controls the fluid cylinder device 2 on the inner wheel side of the turn based on this phase inversion signal s.
3. Correctly control the flow rate control amount Q for the proportional flow control valve 29.29 corresponding to 23.

FIG. 4 is a flowchart showing a control method for cooperative control in the control unit U2 of the active suspension device.

Based on the signal S, the control unit U2 recognizes that the rear wheels 2RL and 2RR have been set to opposite phases by the phase reversal control means, that is, that the phase has been reversed (SL), and furthermore, the steering angle sensor 13 And the acceleration applied in the lateral direction of the vehicle calculated based on the steering angle detection signal and the vehicle speed detection signal detected by the vehicle speed sensor 14, that is, the lateral G is 0.
．． 5 or less, and therefore it is determined that the vehicle is in a slow turning state or a medium turning state (S2), the hydraulic pressure in the hydraulic pressure chambers 23c, 23c of the fluid cylinder device 23.23 on the inner wheel side of the turning is increased. The proportional flow control valve 2 on the inner ring side of the swing
The flow rate control amount Q for 9.29 is set to a predetermined amount +q (S3). Here, the predetermined amount +q is determined to be a positive control amount. Therefore, the proportional flow rate control valve 29 on the inner race side of the swing.
29 is capable of discharging these fluid cylinder devices 23 without draining the working fluid from the corresponding fluid cylinder devices 23.
．． Supplying working fluid to the hydraulic pressure chambers 23c, 23c of 23,
The hydraulic pressure chambers 23c, 23c are pressurized, and as a result, the suspension characteristics are modified so that the ground contact load of the wheel on the inner wheel side of the turn is increased, thus reducing the ground contact from the wheel on the inner side of the turn to the wheel on the outer side of the turn. Load movement of the load is suppressed.

In this way, the active suspension device modifies the suspension characteristics so that the load transfer between the inner turning wheel and the outer turning wheel is reduced while the phase reversal is being performed by the phase reversal control means. It is possible to prevent an increase in the ground load difference between the inner wheel and the outer wheel during a turn, and prevent a reduction in the cornering force of the entire vehicle when the phase is reversed at the beginning of a turn.

Note that when the lateral G applied to the vehicle 1 exceeds 0.5 and it is determined that the vehicle 1 is in a sharp turning state (S2), the proportional flow control valve on the inner wheel side of the turning is 2
Without modifying the flow rate control amount Q relative to 9.29, the flow rate control amount Q is directly output to the proportional flow rate control valve 29.29. Therefore, the active suspension device has flow rate control amounts Q F L , Q F II, Q R Q,
Based on l, l, the roll of vehicle l during turning is suppressed.

As described above, in this embodiment, when the control unit U+ sets the steering angles of the rear wheels 2RL and 2RR to be in opposite phases by the phase reversal control means at the beginning of a turn during high-speed running, the control unit U.

outputs a phase inversion signal S to the control unit U2, and based on the signal S, the control unit U2 determines the flow rate control amount Q to be output to the fluid control valve 29 corresponding to the wheel on the inner wheel side of the turn. Change the setting to quantitative +q,
The flow rate control valve 29 supplies working fluid to the fluid cylinder device 23, 23 on the inner ring side of the swing. As a result, the load transfer between the ground load of the inner turning ring and the ground load of the outer turning ring is suppressed, that is, the expansion of the difference in ground load between the inner and outer wheels is suppressed, and cornering caused by the difference in ground load between the inner turning ring and the outer turning ring is suppressed. Force reduction is prevented. In this way, the vehicle 1 can suitably ensure the turning performance of the vehicle at the beginning of a turn, which is obtained by the reverse phase steering of the rear wheels by the phase inversion control means.

The present invention is not limited to the above-mentioned examples, but various modifications can be made within the scope of the invention described in the claims, and these are also included within the scope of the present invention. Needless to say.

For example, in the embodiment described above, the slow turning state or medium turning state of the vehicle is determined based on the steering angle detection signal detected by the steering angle sensor 13 and the vehicle speed detection signal detected by the vehicle speed sensor 14. A lateral G sensor that detects the lateral acceleration applied to the vehicle may be used to directly detect the lateral acceleration applied to the vehicle to determine whether the vehicle is in a slow turning state or a medium turning state.

In addition, in the embodiment described above, the flow rate control amount Q for the proportional flow rate control valve 29.29 on the inner ring side of the turning is changed to a predetermined amount +q, but a predetermined value α is added to the flow rate control amount Q, and the turning The flow rate control amount for the inner ring may be modified upward.

Further, in the embodiment described above, the flow control amount Q for both the front and rear wheels of the inner turning wheel is set, but it is also possible to change the setting of the flow control amount only for the rear wheel of the inner turning wheel. .

Further, in the above embodiment, the yaw rate of the vehicle 1 is calculated from the lateral acceleration detected by the lateral G sensor 15, 16, but the yaw rate of the vehicle 1 may be directly detected by the angular velocity sensor. good. In this case, the angular velocity sensor is preferably placed in the control box of the control unit U so as to avoid the influence of electrical noise etc. on the detection results.

According to the above configuration of the present invention, the rear wheel steering device includes a phase reversal control means that can transiently set the rear wheel steering angle to have an opposite phase at the beginning of a turn during high-speed driving; In a vehicle equipped with an active suspension device that controls suspension characteristics so as to cancel the displacement of the vehicle based on the detection result of the displacement detection means that detects the displacement of the vehicle, the phase reversal control means reverses the phase of the rear wheels. It is possible to provide a control device that can suitably ensure the turning performance of the vehicle at the initial stage of turning obtained by steering.

[Brief explanation of drawings]

FIG. 1 is a schematic overall configuration diagram of a rear wheel steering system to which a vehicle cooperative control system according to an embodiment of the present invention is applied. FIG. 2 is a schematic overall configuration diagram of an active suspension system for a vehicle to which a cooperative control system according to an embodiment of the present invention is applied. FIG. 3 is a circuit diagram of a hydraulic circuit of an active suspension device that supplies fluid from a hydraulic pump to a fluid cylinder device or discharges fluid therefrom. FIG. 4 is a flowchart showing a control method for cooperative control in the control unit Uz of the active suspension device. 1...Vehicle, 2FL...Left front wheel, 2FR...Left rear wheel, 2RL...Right front wheel, 2R1? ...Right front wheel, 3FL, 3FR13RL, 3RR...knuckle arm, 4FL, 4FR141? L, 4RR... Tie rod, 5F, 5R... Relay rod, 6... Pinion, 7... Steering shaft, 8...
Handle, 9... Neutral holding means, 0... Servo motor, ■... Interlocking mechanism, 2... Clutch, 3... Rudder Angle sensor, 4... Vehicle speed sensor, 5.16... Lateral G sensor, 7... Encoder, 8... Rear wheel steering angle sensor, 3... ...Fluid cylinder device, 3FL...Fluid cylinder device for left front wheel, 3FR.
...Fluid cylinder device for right front wheel, 23RL...
Fluid cylinder device for left rear wheel, 23RR... Fluid cylinder device for right rear wheel, 23a... Cylinder body, 23b... Piston, 23c... Hydraulic pressure chamber, 23d... ...Piston front, 24...Communication path, 24a, 24b, 24c, 24d--Branch communication path,
25...Gas spring, 25FL...Gas spring for left front wheel, 25PR...Gas spring for right front wheel, 25RL...Gas spring for left rear wheel, 25RR・80. Gas spring for right rear wheel, 25a, 25b, 25c, 25d,...Gas spring unit, 25e...Diaphragm, 25f...Gas chamber of gas spring, 25g...Liquid pressure of gas spring Chamber, 28...Hydraulic pump, 28a...Discharge pipe, 9...Proportional flow control valve, 9a...Pressure compensation valve, 0...Fluid passage , 2...Discharge pressure needle, 3...Fluid pressure sensor, 4...Vehicle height sensor, 5...Vertical acceleration sensor, 7...・Control unit, 2...
Accumulator, 3F...Front wheel side piping, 3R...Rear wheel side piping, 3FL...Left front wheel side piping, 3FR...Right front wheel side piping, 3RL...Left rear wheel side Piping, 3RR... Right rear wheel side piping, 5 a, 45 b, 45 c, 45 d--- Orifice, 6... Switching valve, 8... Unload relief Valve, 9...
Reserve tank, 2... Return piping, 3... Open/close valve, 4... Solenoid valve, 5... Relief valve, 6... Ignition key series operating valve, 7...
...Hydraulic pump relief valve, 8...Return accumulator, A...Front wheel steering mechanism, B...Rear wheel steering mechanism, U... -Rear wheel steering device Control Uniso U2・
...Active suspension device control unit. Figure 1

Claims (1)

[Claims] Based on the detection results of a rear wheel steering device equipped with a phase reversal control means that can temporarily set the rear wheel steering angle to the opposite phase at the beginning of a turn during high-speed driving, and a displacement detection means that detects displacement of the vehicle. In a vehicle equipped with an active suspension device that controls the suspension characteristics so as to cancel the displacement of the vehicle, when the rear wheel steering angle is set to have an opposite phase by the phase reversal control means, the inner turning wheel and the outer turning wheel What is claimed is: 1. A cooperative control device for rear wheel steering and active suspension of a vehicle, characterized by comprising cooperative control means for modifying suspension characteristics so as to suppress load movement of a ground load during vehicle rear wheel steering and active suspension.