JP2874427B2 - Active suspension system for vehicles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an active suspension system for a vehicle which can increase or decrease the force of each wheel of the vehicle for supporting the vehicle body, and more particularly to a vehicle when traveling on a slippery road surface (low μ road). The present invention relates to an active suspension device for a vehicle that controls suspension characteristics according to a road surface.

[0002]

2. Description of the Related Art Conventionally, an actuator capable of increasing / decreasing a vehicle supporting force or the like with respect to a wheel is provided in a suspension portion of each wheel of a vehicle such as an automobile, so that characteristics of the suspension can be positively adjusted. So-called active suspension devices have been developed. As such an apparatus, an apparatus that suppresses a roll of a vehicle body has been developed.

For example, FIG. 24 is a block diagram schematically showing the configuration of a roll control system (anti-roll control system) in such a suspension apparatus. In this example, the suspension is controlled by adding steering control to roll control. It has become. In FIG. 24, a roll control gain setting unit 140 receives detection outputs from the lateral G sensor 41 and the vehicle speed sensor 43 and sets a control gain corresponding to, for example, each data (lateral G, vehicle speed, etc.). Are integrated and output as a roll control gain K _R for each of the left and right wheels.

A front and rear wheel gain distribution ratio setting unit 141 receives detection outputs from a steering wheel angle sensor 42, a vehicle speed sensor 43, and the like, and outputs, for example, respective data (the steering wheel angle, the steering wheel angle, and the like).
The distribution ratio α of the roll control gains of the front and rear wheels is set in accordance with the vehicle speed and the like, and is output. The roll stiffness ratio of the front and rear wheels is adjusted by the distribution ratio α of the front and rear wheels, and the steer characteristics of the vehicle are controlled to the oversteer side and the understeer side.

[0007], 142 is a control amount calculation unit, and a distribution ratio α and roll control gain K _R of the above, the wheels [front right wheel (FR), left front wheel (FL), rear right wheel (RR), Roll control amount (roll control gain) for the left rear wheel (RL)] is calculated and output. In this way, by setting the roll control amount for each wheel in consideration of the gain distribution ratio α of the front and rear wheels and controlling the operation of the actuator of each wheel, it is possible to suppress the roll and adjust the steering characteristics as well. .

[0006]

In the above-described conventional active suspension device for a vehicle, the above-described roll control amount is set irrespective of the state of the road surface. For this reason, various problems have occurred. For example, even if the vehicle travels on a slippery road surface (low μ road) having a small friction coefficient μ, the roll of the vehicle body will be suppressed to almost zero roll, and the driver will be able to drive the vehicle on the low μ road. It is difficult to detect that you are driving.

Further, when the vehicle is running on a low μ road, the running stability of the vehicle is likely to be lost. Therefore, it is desired to improve the running stability of the vehicle in the control regarding the steering characteristic.
The present invention has been made in view of the above-described problems, and has as its object to provide an active suspension device for a vehicle that can reflect a road surface state in suspension control.

[0008]

According to a first aspect of the present invention, there is provided an active suspension system for a vehicle, which is interposed between each wheel of the vehicle and the vehicle body to support the vehicle body on each wheel. An actuator capable of increasing / decreasing a force to be applied, a distribution setting means for setting a control distribution state of a left-wheel actuator and a right-wheel actuator among the actuators so as to suppress the roll of the vehicle, and the distribution setting. Control means for controlling the operation of the actuator in accordance with the control distribution state set by the means ;
Steering angle detecting means for detecting a steering angle of the vehicle;
Vehicle speed detecting means for detecting the vehicle speed of the vehicle;
To detect the operating state of the power steering device
ー Steering operation state detection means and the vehicle body
An actual lateral acceleration detecting means for detecting an acting lateral acceleration;
The steering angle detected by the steering angle detection means described above and the vehicle speed detection
Calculate the calculated lateral acceleration based on the vehicle speed detected by the gear.
Lateral acceleration calculating means, and the actual lateral acceleration and the calculated lateral acceleration.
Determines the state of the road surface on which the vehicle travels based on the acceleration
The first road surface state determining means and the steering angle detecting means
Steering angle to be detected and power steering operation state detection
Means of operation of the power steering device detected by the means
A second road for determining a state of a road on which the vehicle travels based on the second road
Surface state determination means, and the distribution setting means
The first road surface state determination unit and the second road surface state determination unit
When at least one of them determines that the road surface is in a slippery state, a control distribution state capable of reducing roll suppression of the vehicle is set.

Further, in the vehicle active suspension device according to the second aspect of the present invention, the force for supporting the vehicle body with respect to each wheel can be increased or decreased by being interposed between each wheel of the vehicle and the vehicle body. An actuator; distribution setting means for setting a control distribution state of a front wheel actuator and a rear wheel actuator among the actuators so as to change a steering characteristic of the vehicle; and control set by the distribution setting means. Control means for controlling the operation of the actuator according to the distribution state; and detecting the steering angle of the vehicle.
Steering angle detecting means for outputting, and a vehicle for detecting the vehicle speed of the vehicle
Speed detecting means and a power steering provided for the vehicle.
Steering to detect the operating state of the steering device
A state detecting means, and a lateral acceleration acting on the vehicle body of the vehicle.
Actual lateral acceleration detecting means for detecting, and the above steering angle detecting means
And the vehicle speed detected by the vehicle speed detecting means.
Acceleration calculation means for calculating a calculated lateral acceleration based on
Based on the actual lateral acceleration and the calculated lateral acceleration.
First road surface condition determination for determining the condition of the road surface on which the vehicle travels
And the steering angle detected by the steering angle detection means.
The power detected by the power steering operation state detecting means
-The vehicle is running based on the operating state of the steering system.
A second road surface state determining means for determining the state of the road surface to be traveled.
In addition, the distribution setting means is configured to perform the first road surface state determination
At least one of the step and the second road surface state determining means.
When the road surface is determined to be slippery, a control distribution state is set such that the steering characteristic of the vehicle can be adjusted toward the understeer side.

[0010]

In the above-described active suspension device for a vehicle according to the first aspect of the present invention, the actuators respectively interposed between each wheel of the vehicle and the vehicle body increase or decrease the vehicle body supporting force for each wheel. , The distribution setting means,
The control distribution between the left wheel side actuator and the right wheel side actuator among the actuators is set so as to suppress the roll of the vehicle, and the control means operates the actuator in accordance with the set control distribution state. Control.

Further , the first road surface condition determining means includes an actual lateral
Lateral acceleration acting on the vehicle body detected by the speed detecting means
Degree, steering angle and vehicle speed detecting means detected by the steering angle detecting means
Is calculated by the lateral acceleration calculating means based on the vehicle speed detected by
Road surface on which the vehicle is traveling based on the calculated lateral acceleration
And the second road surface condition determining means determines the steering angle.
The steering angle detected by the gear and the power steering operation status
Operating state of the power steering device detected by the
The state of the road surface on which the vehicle travels is determined based on. The distribution setting means includes a first road surface state determination means and a second road state determination means.
When at least one of the surface state determination means determines that the road surface is in a slippery state, the control distribution is set so as to reduce roll suppression of the vehicle. For this reason, if the traveling road surface of the vehicle is a normal road surface, the roll of the vehicle body is suppressed, but if the traveling road surface of the vehicle becomes a slippery road surface, the vehicle body rolls. Claim 2 of the present invention described above
In the vehicle active suspension device, the actuator interposed between each wheel of the vehicle and the vehicle body increases or decreases the vehicle body supporting force on each wheel. At this time, the distribution setting means adjusts the steering characteristic of the vehicle. The control distribution between the front-wheel-side actuator and the rear-wheel-side actuator among the actuators is set, and the control means controls the operation of the actuator in accordance with the set control distribution state.

Further , the first road surface condition determining means includes an actual lateral
Lateral acceleration acting on the vehicle body detected by the speed detecting means
Degree, steering angle and vehicle speed detecting means detected by the steering angle detecting means
Is calculated by the lateral acceleration calculating means based on the vehicle speed detected by
Road surface on which the vehicle is traveling based on the calculated lateral acceleration
And the second road surface condition determining means determines the steering angle.
The steering angle detected by the gear and the power steering operation status
Operating state of the power steering device detected by the
The state of the road surface on which the vehicle travels is determined based on. The distribution setting means includes a first road surface state determination means and a second road state determination means.
When at least one of the surface state determination means determines that the road surface is in a slippery state, the control distribution is set so as to adjust the steering characteristic of the vehicle toward the understeer side. For this reason, when the traveling road surface of the vehicle becomes a slippery road surface, the steering characteristic of the vehicle is adjusted to the understeer side, and the traveling stability is improved.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring now to the drawings, an active suspension system for a vehicle according to an embodiment of the present invention will be described. FIG. 1 is a schematic configuration showing a main configuration of a roll control system (including an OS / US control system). FIG. 2, FIG. 2 is a schematic configuration diagram showing the mechanism of the device, FIG. 3 is a block diagram showing the overall configuration of the control system, FIGS. 4 to 11 are control gain maps for the control, and FIG. FIG. 13 is a schematic configuration diagram schematically showing a portion related to low-μ road control of the roll control system (including the OS / US control system), and FIG. 14 is a schematic diagram of the roll control system (OS / US control). 15 is a flowchart of the characteristic of the roll control amount, FIG. 16 is a characteristic diagram of the roll state of the vehicle body, and FIG. 17 is a comparison of the characteristics of each control gain that changes with the steering angle. FIG. 18 is a diagram comparing the characteristics of the respective control gains that vary with the vehicle speed, and FIGS. 19 to 21 are flowcharts relating to a modification of the low μ road control of the roll control system (including the OS / US control system). FIG. 22 is a graph for explaining the data phase correction performed for the road surface state determination, and FIG. 23 is a determination map for the road surface state determination.

The vehicle active suspension device of this embodiment is a hydraulic active suspension device that operates its actuator by hydraulic pressure. FIG. 2 is a configuration diagram of the hydraulic system. In FIG. 2, an oil pump 1 is provided to suck oil stored in a reserve tank 3 through an oil passage 2 and discharge the oil to a supply oil passage 4. In the vicinity of the oil pump 1 in the supply oil passage 4, accumulators 5 and 6 for absorbing the pulsation of the discharge hydraulic pressure from the oil pump 1 are connected in series, and the accumulators 5 and 6 have different set frequencies. Has become. Further, the accumulator 6
Oil filters 7 and 8 are connected to the downstream side of
A relief oil passage 10 and a pilot relief oil passage 9 are connected downstream of the oil filter 8.

The pilot relief oil passage 9 is connected to a solenoid valve 11, and the solenoid valve 11
The discharge oil passage 12 communicated with the reserve tank 3 is selectively communicated with a return oil passage 13 of a control valve or a pilot relief oil passage 9 described later. On the upstream side of the return oil passage 13 from the solenoid valve 11, an operation check valve 14 that operates by receiving the pressure of the pilot relief oil passage 9 as pilot pressure is interposed. When the drain oil passage 12 is in communication with the drain oil passage 12, the oil passage is closed to prohibit oil discharge, thereby maintaining the vehicle height.
2 is communicated with the control valve 2 and is opened to permit the discharge of oil, thereby enabling suspension control described later.

The relief oil passage 10 is connected to a discharge oil passage 12 downstream of the solenoid valve 11, and a relief valve 15 is interposed in the relief oil passage 10. When the upstream oil pressure of the relief valve 15 becomes equal to or higher than a predetermined pressure, oil discharged from the oil pump 1 is discharged to the reserve tank 3 side.
Further, the relief valve 15 receives the pilot pressure from the pilot relief oil passage 9, and the above-mentioned set pressure changes according to the state of the solenoid valve 11 that changes the pressure of the pilot relief oil passage 9. When the vehicle height is maintained while the oil passage 9 and the discharge oil passage 12 are communicated with each other, the set pressure is reduced to reduce the load on the pump 1.

The discharge oil passage 12 has an oil cooler 16.
The oil filter 17 is interposed in series, and a relief valve 18 is provided in parallel with the oil filter 17 to compensate for clogging of the oil filter 17. Further, the supply oil passage 4 is branched downstream into a front oil passage 4F and a rear oil passage 4R on the downstream side of a branch point with the relief oil passage 10, and line pressures are applied to the oil passages 4F and 4R, respectively. Accumulators 19F and 19R for holding and check valve 20
F, 20R are interposed, and each check valve prohibits the oil flow from the downstream side to the upstream side. Note that an oil filter 21 is provided upstream of the accumulator 19R of the rear wheel side oil passage 4R. Each oil passage 4F, 4R is connected to a check valve 20F, 20 respectively.
On the downstream side of R, the vehicle is branched into oil passages for the respective wheels, and suspension units 22FL, 22FR, 22RL, 22RR provided for the respective wheels are connected to the respective oil passages. Also, each suspension unit 22FL,
22FR, 22RL, 22RR are check valves 23FL, 2 which prohibit oil flow from the downstream side to the upstream side.
Return oil passage 13 via 3FR, 23RL, 23RR
Is connected to the front wheel side check valve 23F.
The upstream side of L, 23FR is communicated via a throttle 24F,
A throttle 2 is provided for the check valves 23RL and 23RR on the rear wheel side.
4RL and 24RR are provided in parallel. The throttles 24F, 24RL, and 24RR are provided for equalizing the internal pressures of the actuators of the respective wheels when the vehicle height is maintained.

The return oil passage 13R on the rear wheel side has an accumulator 25 for preventing pulsation of the return oil passage.
A relief valve 26 for preventing the return oil passage from becoming high pressure and a cock 27 for maintenance are provided between the return oil passage 4R on the rear wheel side and the supply oil passage 13R on the rear wheel side. Are provided in parallel. Since each suspension unit has the same structure, the suspension unit 22FL for the left front wheel will be described. A single-acting hydraulic actuator 30 is provided between the vehicle body and the wheels in parallel with a suspension spring (not shown). Oil passage 3 communicating with the hydraulic chamber of hydraulic actuator 30
1 and the control valve 32 interposed between the supply oil passage 4F and the discharge oil passage 13F.
The supply and discharge of the hydraulic pressure to and from the hydraulic chamber 4 are controlled. As the control valve 32, a proportional solenoid valve is used. By controlling the valve opening in accordance with the supplied current, the hydraulic actuator 1 is controlled in proportion to the supplied current.
4 can be controlled. An oil passage 32 is also connected to the hydraulic actuator 30 so that oil leaking from the hydraulic chamber is sent to the discharge oil passage 12.

An accumulator 34 is connected to an oil passage 31 communicating with a hydraulic chamber of the hydraulic actuator 30 through a throttle 33. The throttle 33 exhibits a vibration damping effect and is sealed in the accumulator 34. The gas exerts a gas spring action. Further, a damping force control valve 35 is provided in parallel with the throttle 33, and the damping force can be set softly by driving the damping force control valve 35 to the open position. The oil passage 31 is provided with a pressure sensor 36 for detecting an internal pressure of the hydraulic actuator 30.

The operation of each control valve 32, each damping force control valve 33, and the solenoid valve 11 is controlled by a controller (control means) constituted by a microcomputer.
2), and the solenoid valve 11 is used to control the operation state of the hydraulic actuator 30 from the state shown in FIG.
When the operation state of the hydraulic actuator 30 does not need to be controlled such as during parking, the state is switched to the state shown in FIG. The discharge of oil from the hydraulic actuator 30 is prohibited to maintain the vehicle height.

As shown in FIG. 3, the controller 40
Lateral G sensor (actual lateral acceleration detecting means) for detecting the lateral acceleration acting on the vehicle body in addition to the detection output of the pressure sensor 36 described above.
A detection output from 41, a steering angle sensor for detecting the steering angle of the steering wheel (steering angle detecting means) A detection output from 42, a vehicle speed sensor for detecting the running speed of the vehicle (vehicle speed detecting means)
Step) a detection output of 43, a detection output of a longitudinal G sensor 44 for detecting longitudinal acceleration acting on the vehicle body, a detection output of a brake switch 45 for detecting operation of a brake pedal,
The detection output of a throttle sensor 46 for detecting the throttle opening of the engine, the detection output of a stroke sensor 47 for detecting the vertical stroke state of each wheel, the vertical G sensor 4 provided for each wheel and detecting the vertical acceleration acting on the vehicle body.
8 and a detection output of a preview sensor 49 for detecting the state of the road surface in front of the vehicle, and the controller 40 controls the control valve 32 and the damping force based on the detection outputs of these sensors. The operation state of the switching valve 35 is controlled for each wheel.

The schematic configuration inside the controller 40 is as shown in the control block diagram of FIG. As shown in FIG. 3, the controller 40 includes a control unit (operation control unit) 40A for adjusting the steering stability of the vehicle and a control unit (posture control unit) 40B for adjusting the posture of the vehicle. A control unit (vehicle height control unit) 55 for adjusting the vehicle height of the vehicle;
A control unit (ride comfort control unit) 40C for adjusting the ride comfort of the vehicle is provided.

The operation control unit 40A is provided with distribution setting means.
An anti-roll control unit 50 and an OS / US control unit (steer control unit) 51 are provided, and the attitude control unit 40B includes an anti-pitch control unit 52 and a ride comfort control unit 40.
C has a composite control unit 56 and a preview control unit 59. The anti-roll control unit 50 includes a pressure sensor 3
6, lateral G sensor 41, steering angle sensor 42, vehicle speed sensor 4
The detection outputs of the third and the front and rear G sensors 44 are input, and a control amount for supporting the amount of load movement during steering and suppressing a change in the posture of the vehicle body in the roll direction is output. The details of the anti-roll control unit 50 will be described later.

Further, the detection outputs of the steering angle sensor 42 and the vehicle speed sensor 43 are input to the US / OS control unit 51,
The control amount for controlling the vehicle body steering characteristic is output by increasing or decreasing the roll rigidity ratio between the front and rear wheels based on the steering angular speed and the vehicle speed calculated from the output of the steering angle sensor 42. That is, the US / OS control unit 5
1 is configured to be combined with the anti-roll control unit 50.

The anti-pitch control unit 52 includes a vehicle speed sensor 43, a front / rear G sensor 44, a brake switch 4
5, and the detection output of the throttle sensor 46 is input,
Based on the output of the front and rear G sensor 44, a control amount for supporting a load movement amount during acceleration and deceleration and suppressing a change in the attitude of the vehicle body in the pitching direction is output. The gain increases.

The vehicle height control unit 55 receives the output of the vehicle speed sensor 43 and the output of the stroke sensor 47, and performs control for obtaining a target vehicle height corresponding to the vehicle speed by integration control based on the output of the stroke sensor 47. The amount is output. Further, the composite control unit 56
Although not shown, a skyhook damper control unit and a mass increase control unit are provided.

In the skyhook damper control unit, a steering angle sensor 42, a vehicle speed sensor 43, a brake switch 4
5, the detection output of the throttle sensor 46 and the upper and lower G sensor 48 is input, and control is performed to reduce the sprung absolute speed calculated from the detection output of the upper and lower G sensor 48 to suppress the fluffiness of the vehicle body. At the time of sudden steering, high speed, braking, and acceleration, the gain with respect to the vertical absolute speed increases.

In the mass increase control section, a vehicle speed sensor 43, a stroke sensor 47, and a vertical G sensor 4
8, the control amount for suppressing the sprung acceleration and reducing the vibration transmission force is output. In addition, the ride comfort control unit 40C outputs a control amount for reverse spring control for reducing the spring constant during a small stroke to reduce the vibration transmission force.

Although not shown, a stroke damper control unit is also provided. In the stroke damper control unit, a steering angle sensor 42, a brake switch 45, a throttle sensor 4
6, and the detection output of the stroke sensor 47 is input,
Control is performed to reduce the stroke speed calculated from the detection output of the stroke sensor 47 to attenuate the vehicle body vibration, and the gain with respect to the stroke speed is increased particularly during sudden steering, braking and acceleration.

Each control amount output from each of the control units 50 to 56 is input to an adder 57 for each wheel.
The total control amount added at 7 is input to the drive circuit 58. Then, the drive circuit 58 outputs a current corresponding to the input control amount to the control valve 32 to actively control the operation of the hydraulic actuator 30, thereby realizing a control in which a change in posture is small and a good ride is obtained. You. Further, the detection output of the pressure sensor 36 is input to the drive circuit 58, and constant pressure control is performed to perform feedback control so that the internal pressure of the hydraulic actuator 30 becomes a target control pressure (output of the adder 57).

In the preview control section 59,
When the detection outputs of the vehicle speed sensor 43 and the preview sensor 49 are input and the presence of a projection or a step in front of the vehicle is detected from the output of the preview sensor 49, the time at which the wheel passes through the projection or the step is calculated in relation to the vehicle speed. And the damping force switching valve 3
By outputting a control signal to the drive circuit 60 so as to bring the 5 into the open state, the transmission of vibration when the vehicle goes over the protrusion is reduced.

The active suspension system for a vehicle has a roll control amount and an OS / OS ratio depending on the road surface condition.
Means for correcting the US control amount is provided. FIG. 13 schematically shows these road surface correction means. In FIG. 13, reference numeral 82 denotes a road surface state determination unit (road surface state determination unit) that determines whether the traveling road surface is a low μ road (a slippery road surface), and 50A denotes a main part of an anti-roll control unit. 51A is a main part of the OS / US control unit (steer control unit).

Reference numeral 142 denotes a low μ from the road surface state determination unit 82.
Upon receiving the road information is a roll control correction unit for outputting as a roll control gain K _R performs the road surface condition-dependent correction (low μ road correction) to the roll control amount. The OS 143 receives the low μ road information from the road surface state determination unit 82, performs a road surface state corresponding correction (low μ road correction) on the distribution ratio α ′ as the OS / US control amount, and outputs the result as the distribution ratio α. / US control correction unit.

Reference numeral 87 denotes a control amount calculation unit which calculates each of the wheels [right front wheel (FR), left front wheel (FL), right rear wheel (RR), based on the roll control gain K _R and the distribution ratio α. Roll control amount (roll control gain) for left rear wheel (RL)]
Is calculated and output. Such a road surface correction means includes an anti-roll control unit 50 as shown in FIG.
Here, details of the anti-roll control unit 50 will be described together with the road surface correction means.

In FIG. 1, an actual lateral acceleration signal G _Y detected from the lateral G sensor 41 is input to a lateral G gain setting device 61, and a control gain K corresponding to the lateral acceleration G _Y is obtained based on a map shown in FIG. _G times. Horizontal G gain setting device 61
The gain K _G to be set has a lateral acceleration G _Y has become a decrease gently with fairly large area, set to warn of dangerous conditions to the driver by increasing the rolling amount at the high G turning in .

The output of the lateral G gain setter 61 is input to the steering angular velocity gain setter 62 and multiplied by Kθ '. The control gain Kθ ′ in the steering angular velocity gain setting device 62 is
The steering angular velocity signal θ ′ obtained by differentiating the steering angle signal θ detected by the steering angle sensor 42 with the differentiator 63 is variably set as shown in FIG. That is, the steering angular velocity θ ′
The control gain Kθ ′ is constant until the control gain Kθ ′ reaches a predetermined value. However, when the control gain Kθ ′ exceeds a predetermined value, the control gain Kθ ′ decreases with an increase in the steering angular velocity θ ′. 'Is set to be constant. Thus, at the actual lateral acceleration G _Y phase delay of occurrence is greater steering angular velocity theta 'is large area to the steering operation, and is assumed that the gain of the roll control amount to the actual lateral acceleration signal G _Y decreases.

The output of the steering angular velocity setting unit 62 is K _V multiplied are input to the vehicle speed gain setting unit 64. The control gain K _V in the vehicle speed gain setting device 64 is variably set by the vehicle speed signal V detected from the vehicle speed sensor 43 as shown in FIG. That is, the control gain K _V is constant until the vehicle speed V reaches a predetermined value. However, when the vehicle speed V exceeds a predetermined value, the control gain K _V decreases as the vehicle speed V increases. _V is set to be constant. Thus, the actual lateral acceleration G _Y at high speeds the phase delay becomes large generator to the steering operation, and is assumed that the gain of the roll control amount to the actual lateral acceleration signal G _Y decreases.

The load gain setting device 65 disposed downstream of the vehicle speed gain setting unit 64, an output of the vehicle speed gain setting unit 64 serves as multiplied by K _L, in accordance with an increase ΔL of the load acting on the wheel the control gain K _L as shown in FIG. 7 has become a set variably. That is, a compensates that easily roll occurs load shift amount when the roll is increased at the time of load increase by increasing the control gain K _L with increasing load.

The load increase signal ΔL input to the load gain setting unit 65 is calculated by the load change calculator 66 based on the detection outputs of the steering angle sensor 42, the vehicle speed sensor 43, the pressure sensor 36, and the front and rear G sensor 44. The detected load increase amount ΔL is calculated through the processing shown in the flowchart of FIG. That is, the steering angle θ is 10 ° or less, the longitudinal acceleration G _X is 0.15 G or less, and the vehicle speed is 20 °.
The output P of the left and right pressure sensor average at or less miles / h, by subtracting the reference value P _O from the average value P _A, which is intended to load increment ΔL is calculated. Therefore, the load increase amount ΔL is obtained independently for the front wheel and the rear wheel.

On the other hand, the calculated lateral acceleration calculation section (lateral acceleration calculation section )
Means 67 receives the detection signal θ of the steering angle sensor 42 and the detection signal V of the vehicle speed sensor 43 and calculates the calculated lateral acceleration G _YB by the following equation. Calculated lateral acceleration G calculated by calculated lateral acceleration calculation section 67
_YB is input to the horizontal G ′ gain setting unit 68 and multiplied by K _GB . Control gain K in lateral G 'gain setting device 68
_GB is variably set as shown in FIG. 8 according to a change rate (differential value) G _YB ′ of the calculated lateral acceleration obtained by differentiating the calculated lateral acceleration G _YB by the differentiator 69. That is, the control gain K _GB is 0 until the calculated lateral acceleration change rate (differential value) G _YB 'reaches a predetermined value, but when the calculated gain exceeds the predetermined value, the calculated lateral acceleration change rate (differential value) G _YB ' is exceeded. Control gain K _GB with increase
Has increased. As a result, when the change rate (differential value) G _YB ′ of the calculated lateral acceleration whose output phase is faster than the calculated lateral acceleration G _YB is large, the control gain for the calculated lateral acceleration G _YB whose output is faster than the actual lateral acceleration G _Y is increased. When a sudden occurrence of the lateral G is predicted, a control amount corresponding to the calculated lateral acceleration G _YB can be output quickly.

The output of the lateral G 'gain setting unit 68 is supplied to a steering angular velocity gain setting unit 70 and a vehicle speed gain setting unit 71 in parallel. The control gain Kθ _B ′ in the steering angular velocity gain setter 70 is variably set as shown in FIG. 9 by the steering angular velocity signal θ ′ obtained from the differentiator 63, and the output of the lateral G ′ gain setter 68 in the steering angular velocity gain setter 70. Is multiplied by Kθ _B ′. That is, as the steering angular velocity θ 'increases, the steering angular velocity θ' changes from an area where Kθ _B 'is 0 to an area where Kθ _B ' increases with the steering angular velocity θ 'and an area where Kθ _B ' becomes a constant value. K with the increase of
It shifts to a region where θ _B ′ decreases. As a result, the control gain with respect to the calculated lateral acceleration G _YB at the time of sudden steering is increased, and the effect of suppressing the initial roll can be improved.
At the time of ultra-rapid steering in which the occurrence of the actual lateral G is greatly delayed, the control gain for the calculated lateral acceleration G _YB can be reduced to maintain the balance with the control corresponding to the actual lateral G.

The control gain K _VB in the vehicle speed gain setter 71 is the vehicle speed signal V detected by the vehicle speed sensor 43.
Is variably set as shown in FIG.
At 1, the output of the horizontal G 'gain setting unit 68 is multiplied by K _VB .
That is, with the increase of the vehicle speed V, from the region K _VB is 0, the area K _VB increases with the vehicle speed V, through the region K _VB becomes a constant value, K _VB decreases with increasing vehicle speed V region It has been shifted to. As a result, the control gain for the calculated lateral acceleration G _YB is increased in a region where a phase delay is likely to occur in the generation of the actual lateral G, the effect of suppressing the initial roll can be improved, and the calculation is performed at an extremely high speed where the occurrence of the actual lateral G is greatly delayed. Reduce the control gain for the lateral acceleration G _YB to reduce the actual lateral G
Can be kept in balance with the control corresponding to.

The outputs of the steering angular velocity gain setter 70 and the vehicle speed gain setter 71 are input to an adder 72, added, and then input to a load gain setter 73. Adder 72
Is input to the weight gain setting unit 73 and is multiplied by _KLB . The load gain setting unit 73 is provided with the aforementioned load change calculating unit 66.
The control gain _KLB is variably set as shown in FIG. That is, by decreasing the control gain K _LB as the load increases, the phase of the actual lateral acceleration is delayed when the load increases, and the phase difference between the control corresponding to the actual lateral acceleration G _Y and the control corresponding to the calculated lateral acceleration G _YB. To prevent the occurrence of an imbalance in the control due to the increase in the control.

The output of the load gain setter 65 and the output of the load gain setter 73 are added by the adder 74 and output to the adder 57 in FIG. 3 as a roll control amount. . Note that the roll control amount output from the adder 74 is set such that the inner pressure of the hydraulic actuator 30 increases in the same direction as the direction in which the occurrence of the lateral G is detected or predicted, Is a control amount for controlling the control valve 32 in the direction in which the internal pressure of the hydraulic actuator 30 decreases in the direction opposite to the direction in which the wheel is detected or predicted to suppress the roll generated on the vehicle body.

Further, the means for correcting the road control amount of the roll control amount incorporated in the anti-roll control unit 50 will be described. This correction means includes a calculated lateral acceleration calculation unit 6
A phase delay unit 81 for delaying the phase of the calculated lateral acceleration G _YB calculated in step 7, and a road having a low μ road (a slippery road)
, A correction gain setting unit 83 for setting a correction gain Kμ ₁ corresponding to the road surface state, and a correction gain Kμ for the roll control amount output from the adder 74. A road surface condition correction unit 84 that accumulates ₁ is provided.

The phase delay section 81 delays the phase of the calculated lateral acceleration G _YB calculated by the calculated lateral acceleration calculating section 67 by a predetermined amount β and outputs the delayed signal. For example, a low-pass filter (1 having a cut-off frequency of 5 Hz). Next low-pass filter). This is because the vehicle behavior is delayed with respect to steering, so that a time difference occurs between the calculated lateral acceleration G _YB and the actual lateral acceleration G _Y , for example, as shown in FIG. If the levels of G _YB and the actual lateral acceleration G _Y are compared, accurate road surface determination cannot be performed.
Therefore, the phase delay is performed as described above. By this phase delay processing, for example, as shown in FIG. 22B, the time difference between the lateral acceleration G _YB and the actual lateral acceleration G _Y is eliminated.

The calculated lateral acceleration G _YB and the actual lateral acceleration G _Y
Is a phase angle of, for example, about 40 to 70 degrees. Therefore, the phase delay amount β is 40 to 70 deg.
Set to a value of the order. The road condition determining unit 82 determines a road condition based on the lateral acceleration (the first road condition).
Judgment Means) A judgment unit (second road condition judgment unit) that judges the road surface condition from 82A and the relationship between the steering angle θ and the power steering pressure Pst
Step) 82B is provided.

The determination unit 82A determines the phase of the actual lateral acceleration (actual lateral acceleration) G _Y detected by the lateral G sensor 41 and the calculated lateral acceleration G _YB calculated by the calculated lateral acceleration calculating unit 67 by the phase delay unit 81. by comparing the calculated lateral acceleration G _YB1 delayed, judges that the larger fixed amount (d) above than the delay calculated lateral acceleration G _YB1 the actual lateral acceleration G _Y, road surface has a low μ road.

The determination by the determination section 82A is based on the ratio G _Y / G between the actual lateral acceleration G _Y and the delay calculation lateral acceleration G _YB1.
May be done by _YB1 . That is, as shown in the map of FIG. 23, if the value of G _Y / G _YB1 is in an area of m (m <1) or less, it is determined that the traveling road surface is a low μ road. The determining unit 82B includes a power steering pressure sensor (power steering).
Power state pressure P detected by operating state detecting means) 80
If st is smaller than a predetermined amount according to the steering angle θ, it is determined that the traveling road surface is a low μ road. For example, the determination unit 82B
In the determination of, the traveling road surface state can be determined based on which region on the map the power steering pressure Pst with respect to the steering angle θ is located, using a map as shown in FIG. This is a low μ
On the road, the fact that the steering reaction force with respect to the steering angle θ decreases and the power steering pressure Pst adjusted according to the steering reaction force also decreases with respect to the steering angle θ is used.

Then, the road surface state determining section 82 of this embodiment
In one of the two determination sections 82A and 82B, if the traveling road surface is determined to be a low μ road, the traveling road surface becomes low μ.
Decide that it is a road. Conversely, if both of the two determination units 82A and 82B determine that the traveling road surface is not a low μ road, it is determined that the traveling road surface is not a low μ road. Then, a result of determining whether or not the traveling road surface is a low μ road is output to the correction gain setting unit 83 as an electric signal.

The correction gain setting unit 83 sets the correction gain Kμ ₁ to 1 so that actual correction is not performed when it is determined by the output signal from the road surface state determination unit 82 that the traveling road surface is not a low μ road. Then, when the traveling road surface is determined to be a low μ road, the roll control gain (roll control amount)
The correction gain Kμ ₁ is set to a value appropriately smaller than ₁ so as to reduce. However, this correction gain Kμ
₁ is set to a value that can detect that the driver is traveling on a low μ road due to an increase in the roll amount, but does not significantly impair the stability of the vehicle due to the increase in the roll amount.

The road surface condition correcting section 84 integrates the correction gain Kμ ₁ set by the correction gain setting section 83 with the roll control amount output from the adder 74, and calculates the integrated roll control gain. Output. On the other hand, in the roll control amount output from the roll control unit 50, the respective wheels [right front wheel (FR), left front wheel (FL), right rear wheel (RR),
The left rear wheel (RL)] is output as a roll control amount (roll control gain).

[0053] That is, in the front-rear distribution ratio setting unit 51A of the OS / US control unit 51 sets the front-rear distribution ratio α of the roll control amount K _R from the steering angle θ and the vehicle speed V. And the operation unit 8
7, the front and rear distribution ratio α is added to the roll control amounts K _R of the left and right wheels.
The multiplied, and calculates FR, FL, RR, the roll control amount K _R of the wheel RL. Regarding the setting of the front-rear distribution ratio α, the road surface condition is also considered. That is,
The front-rear distribution ratio α ′ set and output by the front-rear distribution ratio setting unit 51A is taken into the road surface condition correction unit 86.
On the other hand, a signal from the above-described road surface condition determination unit 82 is sent to the correction gain setting unit 85, and the correction gain setting unit 85 uses the output signal from the road surface condition determination unit 82 to determine whether the traveling road surface is low. When it is determined that the road is not a μ road, the correction gain Kμ ₂ is set to 1 so that actual correction is not performed. When the traveling road surface is a low μ road, the steering characteristic of the vehicle is set to the understeer side. Is set to the correction gain Kμ ₂ .

The road surface condition correcting unit 86 integrates the correction gain Kμ ₂ set by the correction gain setting unit 85 with the front and rear distribution ratio α ′ output from the front and rear distribution ratio setting unit 51A, and obtains the front and rear distribution ratio α. Is output. Then, the arithmetic unit 87, by thus appropriately corrected longitudinal distribution ratio alpha, it has become to calculate FR, FL, RR, the roll control amount K _R of the wheel RL.

The active suspension device for a vehicle according to one embodiment of the present invention is configured as described above, and operates as follows. In FIG. 15, the upper part shows the time change between the calculated lateral acceleration G _YB and the change rate (differential value) G _YB ′ of the calculated lateral acceleration. G _YB and G _YB ′ are calculated values and the phase lag is Since it does not occur, in order to facilitate understanding, the description will be made assuming that the time change characteristics of G _YB and G _YB ′ are constant.

First, the calculated lateral acceleration G _YB in FIG. 15 corresponds to the steering operation of the steering wheel, and the actual lateral acceleration G _Y indicated by the one-dot chain line in FIG. 15 occurs without much delay to the steering operation. In such a situation, since the steering angular velocity θ ′ is slow and the vehicle speed V is also slow, the control gains Kθ _B ′ and K _VB become 0 as shown in FIGS. 9 and 10, and the control amount corresponding to the calculated lateral acceleration G _YB is 0, the actual lateral acceleration G
_The control amount corresponding to _Y is directly output from the adder 74 as a control amount for roll control indicated by a dashed line. Then, in this situation, since the phase delay of the actual lateral acceleration G _Y for steering operation is small, the occurrence of proper body roll without roll generation of swirling initial becomes a problem is suppressed.

Next, when the steering angular velocity theta 'and the vehicle speed V is the phase delay of the actual lateral acceleration G _Y for steering operation as indicated by the bold line is greater in FIG. 15 rises, the control gain K
θ _B ′ and K _VB increase to generate a thick line control amount corresponding to the calculated lateral acceleration G _YB, which is added to the thick line control amount corresponding to the actual lateral acceleration G _Y , and the phase lag changes little. The roll control amount indicated by a thick line with a small amount is output from the adder 74. In such a situation, the occurrence of roll at the beginning of turning can be effectively prevented because the phase delay of the roll control amount is small, and the roll stability is also improved because the change in roll control amount is small.

[0058] Moreover, it is further increased phase lag of the actual lateral acceleration G _Y for steering operation, as shown by thin lines in FIG. 15 and the like steering angular velocity theta 'and live load increase or vehicle speed V is further increases The above-mentioned calculated lateral acceleration G
_When the control amount indicated by the thick line corresponding to _YB is used, the roll control amount output from the adder 74 fluctuates greatly as shown by the dotted line, and the roll amount and the roll speed as shown by the dotted line in FIG. Of the vehicle may increase, which may cause inconvenience to the occupant.

Therefore, in this embodiment, when the detected steering angular velocity θ ′ and vehicle speed V are particularly large or when the load increases, the control gains Kθ _B ′, K _VB and K _VB corresponding to the calculated lateral acceleration G _YB are obtained. K _LB is, the control gain Kθ corresponding to the actual lateral acceleration G _Y ', with respect to K _V and K _L, are relatively reduced properties. Accordingly, in the above situation, the control amount corresponding to the calculated lateral acceleration G _YB is reduced as shown by the thin line in FIG. 15, and the roll control amount output from the adder 74 has a small phase lag as shown by the thin line. The change of the control amount becomes gentle. Therefore, the actual lateral acceleration G _Y
Even in a situation where the phase delay is extremely large, it is possible to exhibit a stable roll suppression effect of the vehicle body as shown by the solid line in FIG.

[0060] That is, as in the above embodiment shown in FIG. 17, the steering angular velocity theta ₁ 'in the region where the phase lag is not a major problem of the actual lateral acceleration G _Y below the control gain K [theta _B' becomes 0 The output from the gain setting device 70 is 0
From becoming appropriate roll control is performed based on mainly the actual lateral acceleration G _Y is a low steering angular velocity region.
Further, in a region where the phase lag is a problem of higher actual lateral acceleration G _Y than the steering angular velocity theta ₁ ', in particular the steering angular velocity theta
₁ in the region of 'through? _3', calculated lateral acceleration G _YB control gain Kθ corresponding to _B increase the relative magnitude with increasing steering angular velocity with respect to 'the control gain Kθ corresponding to the actual lateral acceleration G _Y' By doing so, the specific gravity of the control corresponding to the calculated lateral acceleration G _YB is increased, and the initial roll is prevented very effectively. Further, 'in a region where the phase difference is a problem with the high calculated lateral acceleration G _YB and actual lateral acceleration G _Y than, corresponding to compute the lateral acceleration G _YB control gain K [theta _B' steering angular velocity theta ₄ actual lateral acceleration by reducing the relative size with respect to G _Y control gain corresponding to the K [theta 'with increasing steering angle velocity, stabilizing the vehicle body posture during roll control by suppressing the fluctuation of the control amount while obtaining suppression effect of the initial roll It can be done.

[0061] Further, as shown in FIG. 18, the vehicle speed is from the gain setting device 71 is a control gain K _VB is 0 in a region where the phase lag is not a major problem of the actual lateral acceleration G _Y in V ₁ below output from becoming 0, the appropriate roll control mainly based on the actual lateral acceleration G _Y is a low vehicle speed region is performed. Further, the vehicle speed is higher actual lateral acceleration than V ₁ G
_In a region where the phase delay of _Y is a problem, especially when the vehicle speed is V
_{In the range of 1 to} V ₃ , the relative magnitude of the control gain K _VB corresponding to the calculated lateral acceleration G _YB to the control gain K _V corresponding to the actual lateral acceleration G _Y is increased as the vehicle speed increases. The specific gravity of the control corresponding to the calculated lateral acceleration G _YB is increased to prevent the initial roll extremely effectively. Further, in a region where the vehicle speed is higher than V ₄ and the phase difference between the calculated lateral acceleration G _YB and the actual lateral acceleration G _Y becomes a problem, the control gain K _VB corresponding to the calculated lateral acceleration G _YB is
By reducing the relative magnitude to the control gain K _V corresponding to the actual lateral acceleration G _Y with an increase in the vehicle speed,
While obtaining the effect of suppressing the initial roll, it is possible to stabilize the vehicle body posture during roll control by suppressing the fluctuation of the control amount.

Further, with respect to an increase in load, which is another factor causing a phase delay of the actual lateral acceleration G _Y , FIGS.
The control gain K _LB corresponding to compute the lateral acceleration G _YB, as shown in 1, since the relative size is set smaller with increasing load on the control gain K _L corresponding to the actual lateral acceleration G _Y, calculated it can be improved roll stability even phase difference between the lateral acceleration G _YB and actual lateral acceleration G _Y is increased by suppressing the variation of the roll control amount, the control gain K _L corresponding to the actual lateral acceleration G _Y Is set to be larger with an increase in the load, so that the roll can be appropriately suppressed with respect to the increase in the load.

Then, in addition to such roll control,
Depending on whether or not the traveling road surface of the vehicle is slippery (low μ road condition), reduction control of the roll control amount (roll control gain) is performed, for example, in a flow as shown in the flowchart of FIG. That is, data from each sensor is input (step S1), and the vehicle speed V is set to a set value (for example, 3 km) in each of steps S2 to S5.
/ H) or greater, or the lateral acceleration is greater than or equal to the set value a1;
It is determined whether the steering angle θ _H is equal to or greater than a set value (eg, 5 deg) or the power steering pressure Pst is equal to or greater than a set value (eg, 5 kg / m). When these are satisfied, that is, the steering operation is performed during traveling. When the lateral acceleration occurs, the roll control amount is reduced based on the determination by the road surface state determination unit 82.

That is, the calculated lateral acceleration G _YB is calculated from the steering angle δ _H and the vehicle speed V by the calculated lateral acceleration calculator 67 (step S6), and the phase of the calculated lateral acceleration G _YB is filtered by the phase delay unit 81 by filtering. Delay and calculate delay lateral acceleration G _YB1
(Step S7), and the determination unit 82A determines that the delay calculation lateral acceleration G _YB1 is more than the actual lateral acceleration G _Y by a predetermined amount (d).
It is determined whether or not it is larger than the above (step S8).
When _YB1 is greater than a predetermined amount than the G _Y, road surface is low μ
Assuming that the road is a road (a slippery road surface), the roll control gain (roll control amount) is reduced (step S11).

The determination section 82B compares the relationship between the power steering pressure Pst and the steering angle θ with the map and the surface state (step S9), and determines whether the relationship between the power steering pressure Pst and the steering angle θ is on the low μ road side. It is determined whether or not it is (step S10). If the relationship between the power steering pressure Pst and the steering angle θ is on the low μ road side, the roll control gain (roll control amount) is reduced (step S11).

That is, if one of the judging sections 82A and 82B determines that the traveling road surface is a low μ road, it is determined that the traveling road surface is a low μ road, and this determination information is used as the correction gain setting value. It is sent to the units 83 and 85, and the roll control amount and the front-rear distribution ratio are corrected. Note that, as described above, the determination unit 82
If the traveling road surface is a low μ road on one of the roads A and 82B, the traveling road surface is determined to be a low μ road, so that the low μ road determination is reliably performed without any omission in the determination. This is suitable for a case where it is desired to perform control at a time.

The correction gain setting section 83 sets the correction gain K so as to reduce the roll control gain (roll control amount).
Set μ ₁ to a value appropriately smaller than ₁ . Then, the road surface condition correcting unit 84 integrates the correction gain Kμ ₁ set by the correction gain setting unit 83 with the roll control amount output from the adder 74 to obtain the roll control gain K.
Output _R ′.

The correction gain setting section 85 sets a correction gain Kμ ₂ so that the steer characteristic of the vehicle is on the understeer side. Then, the OS /
The front-rear distribution ratio α ′ set by the front-rear distribution ratio setting unit 51A of the US control unit 51 is multiplied by the correction gain Kμ ₂ to calculate the front-rear distribution ratio α. Further, the arithmetic unit 87, thus from appropriately corrected and the roll control gain K _R 'by longitudinal distribution ratio alpha, calculates FR, FL, RR, the roll control amount K _R of the wheel RL.

[0069] Consequently, the correction gain Kmyu _1, roll control gain, as shown by the solid line at the bottom of FIG. 15 K _R
Is reduced as indicated by the roll control gain K _R ′ indicated by the dashed line, and when the running road surface of the vehicle is on a low μ road, the roll restriction of the vehicle body is released. For example, the roll amount indicated by the solid line in FIG. The roll amount increases on the amount side. However, this increase in the roll amount is set to such an extent that the driver can detect that the driver is traveling on a low μ road, but does not significantly impair the stability of the vehicle. Thus, it is possible to detect that the driver is traveling on a low μ road while obtaining a certain vehicle stability.

When the traveling road surface of the vehicle is on a low μ road due to the correction gain Kμ ₂ , the steer characteristics are adjusted to the understeer side, and the running stability of the vehicle which is easily lost when traveling on the low μ road is ensured. Is done. When the road surface state determination unit 82 determines that the traveling road surface is a low μ road by both of the two determination units 82A and 82B, the traveling road surface becomes low μ.
It is also conceivable to configure so as to determine the road.

In this case, the judgment by the road surface condition judging section 82 and the roll control based on this judgment are performed, for example, according to the flow chart shown in FIG. That is, data from each sensor is input (Step S1), and in each of Steps S2 to S5, whether the vehicle speed V is equal to or more than the set value (for example, 3 km / h) or whether the lateral acceleration is equal to or more than the set value a1 , The steering angle θ _H is a set value (for example, 5 de
g) or the power steering pressure Pst is equal to or greater than the set value (for example, 5
kg / m) or more, respectively, and when these conditions are satisfied, that is, when a lateral acceleration is generated by performing a steering operation during traveling, reduction control of the roll control amount is performed based on the determination of the road surface state determination unit 82. Perform

That is, the calculated lateral acceleration G _YB is calculated from the steering angle δ _H and the vehicle speed V by the calculated lateral acceleration calculator 67 (step S6), and the phase of the calculated lateral acceleration G _YB is filtered by the phase delay unit 81 by filtering. Delay and calculate delay lateral acceleration G _YB1
(Step S7), and the determination unit 82A determines that the delay calculation lateral acceleration G _YB1 is more than the actual lateral acceleration G _Y by a predetermined amount (d).
It is determined whether or not the delay calculation lateral acceleration G _YB1 is greater than the actual lateral acceleration G _Y by a predetermined amount d or more (step S8).
The relationship between the steering angle θ and the map is compared with the surface state (step S9), and it is determined whether the relationship between the power steering pressure Pst and the steering angle θ is on the low μ road side (step S10). When the relationship between the power steering pressure Pst and the steering angle θ is on the low μ road side, it is determined here that the traveling road surface is a low μ road,
The roll control gain (roll control amount) is reduced (step S11).

As described above, since both of the judging sections 82A and 82B determine that the traveling road surface is the low μ road only when the traveling road surface is the low μ road, the low μ road conditions are made strict and unnecessary. This is suitable for a case where it is desired to avoid a low-μ road control. In addition, the road surface state determination unit 82 includes two determination units 82.
A or 82B alone may be used.

If the road surface condition judging unit 82 is constituted only by the judging unit 82A, the judgment by the road surface condition judging unit 82 and the roll control based on this judgment are performed according to the flow shown in the flowchart of FIG. 20, for example. In addition, the road surface state determination unit 82
Is constituted only by the determination unit 82B, the road surface state determination unit 82
Is determined and the roll control based on this determination is performed, for example, as shown in FIG.
Is performed according to the flow shown in the flowchart of FIG. Since the steps in the flowcharts in FIGS. 20 and 21 are the same as those in FIGS. 14 and 19,
Description is omitted.

It should be noted that the present invention is not limited to the above embodiment at all, and the gain setting units 64, 65, 71, 73
Can be abolished. It is also possible to change the form of each control gain map and the like. Further, a sensor for directly detecting the steering angular velocity may be used as the means for detecting the steering angular velocity. In any case, it goes without saying that various modifications can be made without departing from the spirit of the present invention.

[0076]

As described in detail above, claim 1 of the present invention
According to the active suspension system for a vehicle, steering
Angle, vehicle speed, operating state of power steering device, lateral acceleration
Determining road conditions reliably based on existing information such as degrees
And the road surface is judged to be slippery.
In this case, since the roll suppression of the vehicle is reduced, it is possible to detect that the driver is traveling on a low μ road while performing the roll suppression, and it is possible to greatly improve the driving feeling while improving the running performance of the vehicle. .

According to the vehicle active suspension device of the second aspect of the present invention, the steering angle, the vehicle speed, and the power
Existing operating conditions such as steering device operating status and lateral acceleration
The road condition can be reliably determined based on the information.
If it is determined that the surface is slippery,
Since the steering characteristic is adjusted to the understeer side, the running stability of the vehicle which is easily lost when traveling on a low μ road is secured, and the running performance of the vehicle can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating a main configuration of a roll control system (including an OS / US control system) of a vehicle active suspension device as one embodiment of the present invention.

FIG. 2 is a schematic configuration diagram showing a mechanism of an active suspension device for a vehicle as one embodiment of the present invention.

FIG. 3 is a block diagram showing the overall configuration of a control system of the vehicle active suspension device as one embodiment of the present invention.

FIG. 4 is a control gain map for controlling an active suspension device for a vehicle as one embodiment of the present invention.

FIG. 5 is a control gain map relating to control of the active suspension device for a vehicle as one embodiment of the present invention.

FIG. 6 is a control gain map relating to control of the active suspension device for a vehicle as one embodiment of the present invention.

FIG. 7 is a control gain map for controlling the active suspension device for a vehicle as one embodiment of the present invention.

FIG. 8 is a control gain map for controlling the active suspension device for a vehicle as one embodiment of the present invention.

FIG. 9 is a control gain map for controlling an active suspension device for a vehicle as one embodiment of the present invention.

FIG. 10 is a control gain map relating to control of the active suspension device for a vehicle as one embodiment of the present invention.

FIG. 11 is a control gain map for controlling an active suspension device for a vehicle as one embodiment of the present invention.

FIG. 12 is a determination map for determining a road surface state of the active suspension device for a vehicle as one embodiment of the present invention.

FIG. 13 is a schematic configuration diagram schematically showing a portion related to low μ road control of a roll control system (including an OS / US control system) of the active suspension device for a vehicle as one embodiment of the present invention.

FIG. 14 is a flowchart relating to low μ road control of a roll control system (including an OS / US control system) of the active suspension device for a vehicle as one embodiment of the present invention.

FIG. 15 is a characteristic diagram of a roll control amount of the active suspension device for a vehicle as one embodiment of the present invention.

FIG. 16 is a characteristic diagram showing a roll state of a vehicle body by the active suspension device for a vehicle as one embodiment of the present invention.

FIG. 17 is a diagram comparing the characteristics of each control gain that changes with respect to the steering angle by the active suspension device for a vehicle as one embodiment of the present invention.

FIG. 18 is a diagram comparing the characteristics of each control gain that changes with the vehicle speed by the active suspension device for a vehicle as one embodiment of the present invention.

FIG. 19 is a flowchart relating to a first modification of the low μ road control of the roll control system (including the OS / US control system) of the active suspension device for a vehicle as one embodiment of the present invention.

FIG. 20 is a flowchart relating to a second modification of the low μ road control of the roll control system (including the OS / US control system) of the active suspension device for a vehicle as one embodiment of the present invention.

FIG. 21 is a flowchart related to a third modification of the low μ road control of the roll control system (including the OS / US control system) of the active suspension device for a vehicle as one embodiment of the present invention.

FIG. 22 is a graph illustrating a phase correction of data performed for determination of a road surface state of the active suspension device for a vehicle as one embodiment of the present invention.

FIG. 23 is a determination map according to a road surface state determination of the active suspension device for a vehicle as one embodiment of the present invention.

FIG. 24 is a schematic configuration diagram schematically showing a portion related to low-μ road control of a roll control system (including an OS / US control system) of a conventional active suspension device for a vehicle.

[Explanation of symbols]

Reference Signs List 1 oil pump 2 oil passage 3 reserve tank 4, 4F, 4R supply oil passage 4F front wheel side oil passage 4R rear wheel side oil passage 5, 6 accumulator 7, 8 oil filter 9 pilot relief oil passage 10 relief oil passage 11 solenoid valve 12 Drain oil passage 13, 13F, 13R Return oil passage 14 Operate check valve 15 Relief valve 16 Oil cooler 17 Oil filter 18 Relief valve 19F, 19R Accumulator 20F, 20R Check valve 22FL, 22FR, 22RL, 22RR Suspension unit 23FL, 23FR, 23RL , 23RR check valve 24F, 24RL, 24RR aperture 25 accumulator 26 the relief valve 27 cock 30 hydraulic actuator (actuator) 31 oil passage 32 control Rubarubu 33 aperture 34 accumulator 35 damping force control valve 36 pressure sensor 40 controller (control means) 40A steering stability controller 40B posture control section 40C riding comfort control unit 41 the lateral G sensor (actual lateral acceleration detecting means) 42 steering angle sensor (steering Angle detecting means) 43 Vehicle speed sensor (vehicle speed detecting means) 44 Front and rear G sensor 45 Brake switch 46 Throttle sensor 47, 47A to 47D Stroke sensor 48 Vertical G sensor 49 Preview sensor 50 Anti-roll control unit (distribution setting unit) 50A Main part of roll control part 51 OS / US control part (distribution setting means) 51A Main part of OS / US control part (steer control part) 52 Anti-pitch control part 55 Vehicle height control part 56 Composite control part 57 Adder 58 Drive circuit 59 Preview control unit 60 Drive circuit 67 Calculation lateral acceleration calculation unit (lateral acceleration calculation means) 80 Power steering pressure sensor (power steering operation state)
Detection means) 81 phase delay unit 82 road surface state determination unit (road surface state determination unit) 82A determination unit (first road surface state determination unit) 82B determination unit (second road surface state determination unit) 83, 85 correction gain setting unit 84, 86 Road surface condition correction unit 87 Operation unit 142 Roll control correction unit 143 OS / US control correction unit

Continued on the front page (72) Inventor Yasutaka Taniguchi 5-33-8 Shiba, Minato-ku, Tokyo Inside Mitsubishi Motors Corporation (72) Inventor Akihiko Togashi 5-33-8 Shiba, Minato-ku, Tokyo Mitsubishi Motors Inside the Industrial Co., Ltd. (72) Inventor Tadao Tanaka 5-33-8 Shiba, Minato-ku, Tokyo Inside the Mitsubishi Motors Corporation (56) References JP-A-2-3511 (JP, A) JP-A-4- 345517 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) B60G 17/015

Claims (2)

(57) [Claims] An actuator that is interposed between each wheel of the vehicle and the vehicle body to increase or decrease a force for supporting the vehicle body with respect to each wheel; and an actuator that controls a roll of the vehicle. Distribution setting means for setting a control distribution state between the left wheel side actuator and the right wheel side actuator among the actuators; and control means for controlling the operation of the actuator according to the control distribution state set by the distribution setting means. Steering angle detecting means for detecting a steering angle of the vehicle, vehicle speed detecting means for detecting a vehicle speed of the vehicle, and operation of a power steering device provided in the vehicle
Power steering operating state detecting means for detecting the state
And the actual lateral acceleration for detecting the lateral acceleration acting on the vehicle body of the vehicle.
Degree detection means, the steering angle detected by the steering angle detection means, and the vehicle speed detection
Calculate the calculated lateral acceleration based on the vehicle speed detected by the means
The vehicle acceleration is calculated based on the actual lateral acceleration and the calculated lateral acceleration.
A first road surface condition determining means for determining the condition of the road surface on which both vehicles are traveling
Steering angle and the Pawasu detecting stage and said steering angle detecting means
Power steering detected by the tearing operation state detecting means
Road surface on which the vehicle travels based on the operating state of the
And a second road surface state determining means for determining the state of the vehicle.
When at least one of the second road surface state determination means determines that the road surface is in a slippery state, a control distribution state capable of reducing roll suppression of the vehicle is set. , Active suspension equipment for vehicles. 2. An actuator interposed between each wheel of the vehicle and the vehicle body to adjust a force for supporting the vehicle body with respect to each wheel, and an actuator capable of changing a steering characteristic of the vehicle. Distribution setting means for setting a control distribution state between a front wheel actuator and a rear wheel actuator among the actuators; and control means for controlling the operation of the actuator according to the control distribution state set by the distribution setting means. A steering angle detecting means for detecting a steering angle of the vehicle, a vehicle speed detecting means for detecting a vehicle speed of the vehicle, and an operation of a power steering device provided in the vehicle
Power steering operating state detecting means for detecting the state
And the actual lateral acceleration for detecting the lateral acceleration acting on the vehicle body of the vehicle.
Degree detection means, the steering angle detected by the steering angle detection means, and the vehicle speed detection
Calculate the calculated lateral acceleration based on the vehicle speed detected by the means
The vehicle acceleration is calculated based on the actual lateral acceleration and the calculated lateral acceleration.
A first road surface condition determining means for determining the condition of the road surface on which both vehicles are traveling
Steering angle and the Pawasu detecting stage and said steering angle detecting means
Power steering detected by the tearing operation state detecting means
Road surface on which the vehicle travels based on the operating state of the
And a second road surface state determining means for determining the state of the vehicle.
When at least one of the second road surface state determination means determines that the road surface is in a slippery state, a control distribution state capable of adjusting the steering characteristic of the vehicle to the understeer side is set. Characteristic active suspension device for vehicles.