JPH05185817A - Active suspension system for vehicle - Google Patents

Abstract

PURPOSE:To improve the extent of turning performance in a vehicle so sharply by setting a control distribution so as to make a steering characteristic in the vehicle come to an understeering tendency at an area where the size of a steering angle is small as well as to make the vehicle steering characteristic come to an oversteering tendency at the area where the size of the steering angle is large, respectively. CONSTITUTION:A control means controls each operation of an actuator at the front wheel and another actuator at the rear wheel side out of paired actuators capable of adjusting an increase or decrease of force supporting a car body to each wheel so as to become a control distribution set by a steering angle corresponding distribution rate setting means 100 as adjusting the control distribution between these two actuators at both front and rear wheel sides, and changes a steering characteristic in a vehicle in addition. At this time, this setting means 100 sets the control distribution so as to make the car steering characteristic become an understeering tendency at an area where size of the steering angle is small, and to make the car steering characteristic become an oversteering tendency at an area where the size of the steering angle is large, respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle active suspension device capable of increasing and decreasing the vehicle body supporting force for each wheel of a vehicle, and more particularly to a front wheel body supporting force and a rear wheel body supporting force. The present invention relates to an active suspension device for a vehicle, which can change the steering characteristic of the vehicle by adjusting the distribution.

[0002]

2. Description of the Related Art Conventionally, in the suspension portion of each wheel of a vehicle such as an automobile, an actuator capable of increasing / decreasing a vehicle body supporting force for the wheel has been provided so that the characteristics of the suspension can be positively adjusted. So-called active suspension devices have been developed. Then, in such a device, it is also considered that the steering characteristic of the vehicle body can be adjusted.

This steering characteristic can be adjusted, for example, by increasing or decreasing the vehicle body supporting force for the wheels or the damping force of the vehicle body supporting spring system. That is, if the vehicle body supporting force for the front wheels or the damping force of the vehicle body supporting spring system is increased, while the vehicle body supporting force for the rear wheels or the vehicle support spring system damping force is decreased, it is adjusted to the understeer (US) side, and conversely. ,
If the vehicle body supporting force for the front wheels or the damping force of the vehicle body supporting spring system is decreased while the vehicle body supporting force for the rear wheels or the vehicle support spring system damping force is increased, the oversteer (O
S) side is adjusted.

The configuration of the steering characteristic control system (OS / US control system) in the suspension device is, for example, as shown in FIG.
As shown in the schematic block diagram of FIG. In FIG. 12, 42 is a steering angle sensor,
Reference numeral 121 is a differentiator for differentiating the detection output from the steering angle sensor 42 with time to obtain the steering angular velocity δ _H ′.
Is a correction unit (steering angular velocity direction correction unit) that appropriately corrects the value of the steering angular velocity δ _H ′ to be positive in the steering cut-in direction, and 302 is the steering angle velocity δ _H ′ corrected in this direction. It is a distribution ratio setting unit that correspondingly sets the distribution ratio α of the front and rear wheels.

The distribution rate α is the front-rear distribution rate of the vehicle body supporting force or damping force when the vehicle body supporting force or the damping force of the vehicle body supporting spring system is constant for the entire front and rear wheels. It is set, and the distribution rate α is the distribution rate to the front wheels. Therefore, as the distribution rate α is higher, the vehicle body supporting force or damping force of the front wheels is increased, and conversely, as the distribution rate α is lower, the vehicle body supporting force or damping force of the front wheels is reduced.

The distribution rate α is calculated by the distribution rate setting unit 3
As shown in the map in the block of 02, the steering angular velocity δ
_If the value of _H ′ is large in the positive direction (cutting direction), the distribution rate α
Is set so that when the value of the steering angular velocity δ _H ′ is large in the negative direction (returning direction), the distribution rate α is increased. That is, the value of the steering angular velocity δ _H ′ increases in the turning direction when the driver starts a sharp turn, and if the distribution rate α is decreased at this time, the oversteer tendency becomes stronger and the turning performance of the vehicle (mainly (Turnability) is improved. Further, the value of the steering angular velocity δ _H ′ becomes large in the return direction when the driver wants to finish the turning motion promptly. At this time, if the distribution ratio α is increased, the understeer tendency becomes stronger and the vehicle goes straight ahead. The running stability is improved, and the turning motion of the vehicle can be quickly converged.

[0007]

By the way, in the above-mentioned conventional vehicle active suspension device, control is performed in accordance with the steering angular velocity δ _H ′. Steer is not adjusted in the steering angle state. For this reason, the steering is not adjusted during steady turn, and the steer characteristics when straight ahead are maintained. Further, since the steer characteristic during straight traveling is generally set to the understeer tendency, there is a problem that the understeer tendency is maintained during the steady turn and the turning performance during the steady turn cannot be improved.

The present invention was devised in view of the above-mentioned problems, and provides an active suspension device for a vehicle, which can improve the turning performance including the steady turning of the vehicle while ensuring the straight running stability of the vehicle. The purpose is to

[0009]

Therefore, the vehicle active suspension device of the present invention is interposed between each wheel of the vehicle and the vehicle body to increase or decrease the force for supporting the vehicle body with respect to each wheel. An adjustable actuator; and a control unit capable of changing the steering characteristic of the vehicle by controlling the operation of the actuator while adjusting the control distribution of the front wheel actuator and the rear wheel actuator among the actuators. Along with the steering angle detecting means for detecting the steering angle of the vehicle, the control means is provided with a distribution setting means for setting the control distribution based on the magnitude of the steering angle detected by the steering angle detecting means. The distribution setting means controls the steering so that the steer characteristic of the vehicle has an understeer tendency in a region where the steering angle is small. In area is large and the magnitude of the steering angle of the configure is characterized by being configured to set the control distribution as the steering characteristic of the vehicle is oversteer.

[0010]

In the above-described vehicle active suspension device of the present invention, the control means is an actuator capable of increasing or decreasing the force for supporting the vehicle body with respect to each wheel so that the control distribution set by the distribution setting means is achieved. Among them, the steering distribution of the vehicle is changed by controlling the operation of these actuators while adjusting the control distribution between the actuators on the front wheel side and the actuators on the rear wheel side. At this time, in the distribution setting means, the control distribution is set so that the steer characteristic of the vehicle becomes an understeer tendency in the region where the steering angle is small, and the steer characteristic of the vehicle is controlled in the region where the steering angle is large. Set the control distribution so that it tends to oversteer.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An active suspension system for a vehicle according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram schematically showing a main configuration of a control system thereof, and FIG. 3 is a schematic configuration diagram showing the mechanism of FIG. 3, FIG. 3 is a block diagram showing the overall configuration of the control system, and FIGS.
6 is a block diagram showing a concrete configuration example of the control system, FIG.
Is a map for setting the roll control amount, and FIGS. 7 to 9 are maps for setting the OS / US control amount.
Reference numeral 0 is a flow chart showing the flow of the OS / US control, and FIG. 11 is a block diagram schematically showing a main part configuration of a modified example of the control system.

The vehicle active suspension system of this embodiment is a hydraulic active suspension system which operates its actuator hydraulically. FIG. 2 is a configuration diagram of the hydraulic system. In FIG. 2, the oil pump 1 is provided so as to suck the oil stored in the reserve tank 3 via the oil passage 2 and discharge the oil to the supply oil passage 4. In the vicinity of the oil pump 1 of the supply oil passage 4, accumulators 5 and 6 for absorbing the pulsation of the discharge hydraulic pressure by the oil pump 1 are connected in series, and the accumulators 5 and 6 have different set frequencies. Is becoming Furthermore, accumulator 6
Oil filters 7 and 8 are connected on the downstream side of
A relief oil passage 10 and a pilot relief oil passage 9 are connected to the downstream side of the oil filter 8.

The pilot relief oil passage 9 is connected to a solenoid valve 11, and the solenoid valve 11 is
The discharge oil passage 12 communicating 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 which will be described later. An operation check valve 14, which operates by receiving the pressure in the pilot relief oil passage 9 as pilot pressure, is provided upstream of the solenoid valve 11 in the return oil passage 13. When the discharge oil passage 12 is in communication with the discharge oil passage 12, the vehicle height is maintained by blocking the discharge oil passage to prevent the discharge of oil, while the return oil passage 13 and the discharge oil passage 1 are held.
When the two are communicated with each other, they are opened to allow oil to be discharged, thereby enabling suspension control described later.

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

An oil cooler 16 is provided in the discharge oil passage 12.
Further, the oil filter 17 is interposed in series, and a relief valve 18 is provided in parallel with the oil filter 17 for compensation when the oil filter 17 is clogged. Further, the supply oil passage 4 is branched to a front wheel side oil passage 4F and a rear wheel side oil passage 4R at a downstream side of a branch portion with the relief oil passage 10, and line pressures are respectively applied to the oil passages 4F and 4R. Accumulators 19F and 19R for holding and check valve 20
F and 20R are interposed, and each check valve prohibits the flow of oil from the downstream side to the upstream side. An oil filter 21 is provided upstream of the accumulator 19R in the rear wheel side oil passage 4R. The oil passages 4F and 4R have check valves 20F and 20F, respectively.
On the downstream side of R, an oil passage is branched for each wheel, and suspension units 22FL, 22FR, 22RL, 22RR provided for each wheel are connected to each oil passage. In addition, each suspension unit 22FL,
22FR, 22RL, 22RR are check valves 23FL, 2 for prohibiting the flow of oil from the downstream side to the upstream side.
Return oil passage 13 through 3FR, 23RL, 23RR
Check valve 23F on the front wheel side
The upstream sides of the L and 23FR are communicated with each other via the throttle 24F,
A throttle 2 is attached to the check valves 23RL and 23RR on the rear wheel side.
4RL and 24RR are provided in parallel. The throttles 24F, 24RL, 24RR are provided to average the internal pressures of the actuators of the wheels when the vehicle height is maintained as described above.

An accumulator 25 for preventing pulsation of the return oil passage is provided in the rear wheel return oil passage 13R.
Is provided between the return oil passage 4R on the rear wheel side and the supply oil passage 13R on the rear wheel side, and a relief valve 26 for preventing high pressure in the return oil passage and a cock 27 for maintenance. 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 the hydraulic actuator 30
1 and the oil supply passage 4F and the oil discharge passage 13F through the control valve 32 interposed between the hydraulic actuator 1
The supply and discharge of hydraulic pressure to and from the hydraulic chamber 4 is controlled. A proportional solenoid valve is used as the control valve 32, and the hydraulic actuator 1 is proportional to the supply current by controlling the valve opening according to the supplied current.
The pressure in 4 can be controlled. An oil passage 32 is also connected to the hydraulic actuator 30, and the 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 the hydraulic chamber of the hydraulic actuator 30 via a throttle 33. The throttle 33 exerts a vibration damping effect and is enclosed in the accumulator 34. The gas spring 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. Further, the oil passage 31 is provided with a pressure sensor 36 for detecting the internal pressure of the hydraulic actuator 30.

The operation of each control valve 32, each damping force control valve 33 and solenoid valve 11 is controlled by a controller 40 which is composed of a microcomputer.
When it is necessary to control the operating state of the hydraulic actuator 30, the return oil passage 13 and the discharge oil passage 1 are changed from the state shown in FIG.
2 is allowed to discharge oil from the hydraulic actuator 30, and when it is not necessary to control the operating state of the hydraulic actuator 30 such as during parking, the hydraulic actuator 30 is switched to the state shown in FIG.
The vehicle height is maintained by prohibiting the discharge of oil from the vehicle.

The controller 40, as shown in FIG.
In addition to the detection output of the pressure sensor 36 described above, a detection output from a lateral G sensor 41 that detects the lateral acceleration acting on the vehicle body, and a steering angle sensor 42 that detects the steering angle of the steering wheel.
Speed sensor 43 that detects the detection output of the vehicle and the traveling speed of the vehicle
Detection output, a front-rear G sensor 44 detection output for detecting longitudinal acceleration acting on the vehicle body, a brake switch 45 detection output for detecting a brake pedal operation, and a throttle sensor 46 detection for an engine throttle opening. Output, detection output of a stroke sensor 47 that detects the vertical stroke state of each wheel, detection output of a vertical G sensor 48 that is provided for each wheel and that detects vertical acceleration that acts on the vehicle body, and the state of the road surface in front of the vehicle. The detection outputs of the preview sensor 49 are input, and the controller 40 controls the operating states of the control valve 32 and the damping force switching valve 35 for each wheel based on the detection outputs of these sensors. It has become.

The schematic structure of the controller 40 is shown in the control block diagram of FIG. As shown in FIG. 3, in the controller 40, a control unit (steering control unit) 40A for adjusting the steering stability of the vehicle and a control unit (attitude control unit) 40B for adjusting the posture of the vehicle. And 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 section 40A includes an anti-roll control section 50 and an OS / US control section (steer control section) 51.
The posture control unit 40B includes an anti-pitch control unit 52, and the riding comfort control unit 40C includes a composite control unit 56 and a preview control unit 59. The anti-roll controller 50 includes a pressure sensor 36, a lateral G sensor 41,
The detection outputs of the steering angle sensor 42, the vehicle speed sensor 43, and the front-rear G sensor 44 are input, and a control amount for supporting the load movement amount during steering and suppressing a posture change in the roll direction of the vehicle body is output. It has become.

Further, the US / OS control section 51 receives the detection outputs of the steering angle sensor 42 and the vehicle speed sensor 43,
By increasing or decreasing the roll rigidity ratio between the front and rear wheels based on the steering angle, the steering angular velocity, and the vehicle speed calculated from the output of the steering angle sensor 42, a control amount for controlling the vehicle body steer characteristic is output. ing. This US / OS
Details of the control unit 51 will be described later.

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

Further, in the vehicle height control section 55, the detection outputs of the vehicle speed sensor 43 and the stroke sensor 47 are input, and the target vehicle height (that is, the target stroke) corresponding to the vehicle speed is obtained by integral control based on the detection outputs of the stroke sensor 47. ) Is output. Further, the composite control unit 56 includes a skyhook damper control unit and a mass increase control unit (not shown).

In the skyhook damper control section, the steering angle sensor 42, the vehicle speed sensor 43, the brake switch 4
5, the detection outputs of the throttle sensor 46 and the vertical G sensor 48 are input, and control is performed to suppress the fluffy feeling of the vehicle body by reducing the absolute sprung speed calculated from the detection output of the vertical G sensor 48. During sudden steering, high speed, braking, and acceleration, the gain relative to the absolute vertical speed is increased.

In the mass increase control section, the vehicle speed sensor 43, the stroke sensor 47 and the vertical G sensor 4
The detection output of 8 is input, and the control amount for suppressing the sprung acceleration and reducing the vibration transmission force is output. In addition to this, the riding comfort control section 40C is adapted to output a control amount for reverse spring control for reducing the spring constant to reduce the vibration transmission force during a minute stroke.

Although not shown, a stroke damper control section is also provided, and this stroke damper control section has a steering angle sensor 42, a brake switch 45, and a throttle sensor 4.
6, and the detection output of the stroke sensor 47 is input,
The control for reducing the stroke speed calculated from the detection output of the stroke sensor 47 to attenuate the vehicle body vibration is performed, and the gain with respect to the stroke speed is increased especially at the time of sudden steering, braking and acceleration.

The control amounts output from the control units 50 to 56 are input to the adder 57 for each wheel, and the adder 5
The total control amount added in 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 perform active control of the operation of the hydraulic actuator 30, thereby realizing control in which the posture change is small and a good ride comfort is obtained. It Further, the detection output of the pressure sensor 36 is input to the drive circuit 58, and constant pressure control for feedback control is performed so that the internal pressure of the hydraulic actuator 30 becomes a target control pressure (output of the adder 57).

In the preview controller 59,
When the detection outputs of the vehicle speed sensor 43 and the preview sensor 49 are input and it is detected from the outputs of the preview sensor 49 that there is a protrusion or a step ahead of the vehicle, the time when the wheel passes through the protrusion or the step is calculated in relation to the vehicle speed. The damping force switching valve 3 when passing through a protrusion or a step
By outputting a control signal to the drive circuit 60 so as to bring the opening 5 into the open state, the vibration transmission at the time of passing over the protrusion is reduced.

The details of the US / OS control section 51 will now be described. The US / OS control section 51 is configured as shown in FIG. 1, and the distribution rate of the roll control amount (roll rigidity ratio between the front and rear wheels) α Is set. The distribution ratio α is the front-rear distribution ratio of the vehicle body support force or the damping force when the vehicle body support force or the damping force of the vehicle body support spring system is constant for the entire front and rear wheels, and here, the front wheel is mainly set. Therefore, α (0 ≦ α ≦ 1) is the distribution ratio to the front wheel side. Further, the distribution ratio to the rear wheel side is 1-α. Therefore, as the distribution rate α is higher, the vehicle body supporting force or damping force of the front wheels is increased, and conversely, as the distribution rate α is lower, the vehicle body supporting force or damping force of the front wheels is reduced.

In FIG. 1, 99 is a steering angle sensor 42.
Is an absolute value calculation unit that calculates the magnitude (absolute value) of the steering angle δ _H detected in step 1, and 100 is the distribution of the roll control amount based on the calculated steering angle magnitude | δ _H | Rate α
It is a steering angle corresponding distribution rate setting unit that sets 1. The steering angle corresponding distribution ratio setting unit 100 sets the front-rear distribution ratio α1 based on a map as shown in FIG. 7, for example. In this map, the distribution rate α1 is set to be large when the steering angle δ _H is small, and the distribution rate α1 is set to be gradually reduced when the steering angle δ _H is increased.

That is, since the degree of turning is small when the steering angle δ _H is small, if the distribution rate α1 is increased at this time, the understeer tendency is strengthened, and the straight running stability of the vehicle can be improved. On the other hand, when the steering angle δ _H becomes large, the degree of turning becomes large, and turning performance is required rather than straight running stability. Therefore, if the distribution rate α1 is decreased at this time, the oversteer tendency becomes stronger. The turning performance (mainly turning ability) of the vehicle can be improved.
Therefore, even during steady turning, the steering is appropriately adjusted according to the steering angle.

Reference numeral 98 denotes a vehicle speed corresponding distribution ratio setting unit (vehicle speed corresponding correction amount setting unit) for setting a correction amount α2 of the front-rear distribution ratio of the roll control amount based on the vehicle speed V detected by the vehicle speed sensor 43. .. In this vehicle speed corresponding distribution ratio setting unit 98,
For example, the correction amount α2 of the front-rear distribution ratio is set based on the map as shown in FIG. In this map, the correction amount α2 is set small when the vehicle speed V is relatively low and low,
The correction amount α2 gradually increases as the vehicle speed V increases, and is set to a large value at high speed.

That is, at low and medium speeds, the steering amount is set to the oversteer side by reducing the correction amount α2, the turning performance (mainly turning performance) of the vehicle is prioritized, and the correction amount α2 increases as the vehicle speed increases. It is increased to adjust the steer characteristic to the understeer side so that the straight running stability of the vehicle is gradually given priority. In addition, 121
Is a differentiator for time-differentiating the steering angle δ _H detected by the steering angle sensor 42 to calculate the steering angular velocity δ _H ′.
Reference numeral 7 denotes a steering angular velocity corresponding distribution ratio setting unit (steering angular velocity corresponding correction amount setting unit) which sets a correction amount α3 of the roll control amount distribution ratio based on the calculated steering angular velocity δ _H ′.

The steering angular velocity-corresponding distribution rate setting unit 107 sets the distribution rate correction amount α3 based on a map as shown in FIG. 9, for example. In this map, the steering angular velocity δ
_If the value of _H ′ is large in the positive direction (cutting direction), the distribution rate α
Is set so that when the value of the steering angular velocity δ _H ′ is large in the negative direction (returning direction), the distribution rate α is increased.

That is, the value of the steering angular velocity δ _H ′ increases in the cutting direction when the driver starts a sharp turn, and when the correction amount α3 of the distribution ratio is decreased at this time,
It is when the driver wants to finish the turning motion quickly that the oversteering tendency is enhanced, the turning performance (mainly turning performance) of the vehicle can be improved, and the value of the steering angular velocity δ _H ′ increases in the return direction. When the correction amount α3 of the distribution rate is increased, the understeer tendency is strengthened, the straight running stability of the vehicle is improved, and the convergence of the turning motion of the vehicle can be accelerated.

Further, 101 is the distribution rate α1 and the correction amount α2.
Is an adder that adds the correction amount α3 to the output value α ′ from the adder 101. Also, 10
Reference numeral 9 denotes a limiter that sets the upper limit value and the lower limit value when the output value α ′ from the adder 101 exceeds the upper limit value and the lower limit value. The limiter 109 outputs the final distribution rate α. It is like this.

Here, although α2 and α3 are defined as the correction amounts of the distribution rate, all of α1 to α3 are considered as the distribution rate, and these are added by the adders 101 and 108 to obtain the final value. It may be considered that the distribution rate α is set. Then, such a US / OS control unit 51 is incorporated in the anti-roll control unit 50 in the actual control amount setting route as shown in FIGS. It is combined with the control amount W and output as the control amount of each wheel. In this example, first, the roll control amount for the right wheel is set, and then the roll control amount for the left wheel is set.

FIG. 4 shows the configurations of the US / OS control unit 51 and the anti-roll control unit 50, and FIG. 5 shows the control unit 5.
1 shows an input system to 1, 50 and an output system from the control units 51, 50. Further, in FIG. 4, the same reference numerals as those in FIG. 1 denote the same parts. In FIG. 5, reference numeral 200 denotes an input unit that takes in data from each sensor and performs A / D (analog / digital) conversion, and 201 is a conversion unit that converts the input data into a predetermined physical quantity. Further, 202 is a drift correction processing unit, and 203 is a low-pass filter. Further, 57 is an adder, and 57A is a correction unit for D / A (digital / analog) conversion by pressure-correcting the added control gain.

In FIG. 4, reference numeral 102 denotes a lateral acceleration corresponding gain setting section for setting a roll control gain corresponding to lateral acceleration from the map shown in the figure, and the control gain is increased in a region where the lateral acceleration is large. .. A speed correction unit 103 sets a gain correction value corresponding to the vehicle speed from a map shown in the figure, integrates the correction value with a set value in the lateral acceleration corresponding gain setting unit 102, and incorporates a speed corresponding element into the roll control gain. Therefore, the correction value is increased as the vehicle speed increases.

Reference numeral 121 is a differentiator for time-differentiating the steering angle δ _H to calculate the steering angular velocity δ _H ′, and 122 is a correction value K1 corresponding to the steering angle δ _H from a map as shown in the figure, for example. A correction value setting unit 120 is a correction value setting unit that sets a correction value K2 corresponding to the vehicle speed V from a map as shown in the figure, and 123 is a correction value K1 or K2 for the steering angular velocity δ _H ′. Compensation amount D
This is a calculation unit that calculates T.

Further, 124 is a correction value setting unit for setting a correction value σ for correcting the correction corresponding amount DT according to its magnitude, and 125 is a coefficient S1 according to the steering angle direction (here, in the case of right steering). A correction value setting unit that sets +1 if there is, and -1 if left steering, and 126 is a calculation unit that calculates the correction amount W _Y by integrating the correction corresponding amount DT with the correction value σ and the coefficient S1. is there.

This correction amount W_YIs the steering angular velocity δ_H′
Correction amount of the roll control gain_YTo
Each element to be determined δ_HPay attention to ′, K1, K2, σ, S1
Then, it becomes as follows. Steering angular velocity δ_H'about
Together with the coefficient S1, the correction amount W _YTo
It acts as a positive element, and when switching back, the correction amount W_YTo
Acts as a negative factor. Regarding the correction value K1
Is the correction amount W when the steering angle is small, as shown in the map in the figure.
_YActing as a negative factor to the correction amount W at a large steering angle._Y
Acts as a positive element to.

Therefore, at the start of turning (at the start of additional cutting), the correction amount W _Y is momentarily negative and the roll control gain is corrected to the decreasing side, and thereafter the correction amount W _Y is positive and the roll is increased. Correct the control gain to increase. That is, therefore, the response (turning property) of the vehicle at the start of turning is improved, and thereafter, traveling stability is ensured. However, depending on the correction value K2, the correction amount W in the middle and high speed range where the responsiveness becomes a problem
_Y is set to occur (see the map in the figure).

The correction of the roll control gain corresponding to the steering angular velocity δ _H ′ is performed by correcting the roll control gain to the increasing side at the start of steering and predicting the occurrence of a sudden lateral G. Means for increasing the rigidity may be considered. That is,
Since the actual lateral acceleration G _Y is delayed with respect to the steering operation at the time of turning suddenly or at the time of turning at a high speed, even if an attempt is made to increase the roll rigidity based on the actual lateral acceleration G _Y , it may be too late. When it is applied, by controlling in accordance with the steering angular velocity δ _H ′, the control that predicts the occurrence of the lateral G can be performed.

Then, in the adder 106, the speed correction unit 10
The roll control gain W1 output from
_Y is added and the roll control gain W is input to each wheel control amount calculation unit 104. In addition,
The roll control gain W is calculated by performing various corrections as described above. Regarding the lateral acceleration (lateral G) which is the main setting factor, the roll control gain W is divided into the inner turning wheel and the outer turning wheel, and A general tendency is shown in FIG. In FIG. 6, the solid line indicates the turning outer wheel, and the broken line indicates the turning inner wheel.

Then, the above-mentioned distribution rate α is input to the respective wheel control amount calculation section 104 together with the roll control gain W, and the roll control gain W is divided into front wheels (= α × W) and rear wheels. = (1−α) × W]. This front wheel roll control gain (α
XW) and the rear wheel roll control gain [(1-α) × W] are for the right wheel side, and the left wheel side gain setting unit 105
The right wheel gain value is multiplied by a coefficient (-1) to set the left wheel gain, and the right front wheel (FR) and left front wheel (F) are set.
L), the right rear wheel (RR), and the left rear wheel (RL), the roll control gains are output.

Since the vehicle active suspension device as one embodiment of the present invention is configured as described above, the anti-roll control unit 50 and the OS / US control unit 51 are, for example, as shown in FIG. , Control is performed. That is, first, the steering angle sensor 42 and the vehicle speed sensor 4
3. Read the detection output from the sensor such as the lateral G sensor 44 (step S1), and determine whether the anti-roll control is necessary by the steering angle determination (step S2) and the lateral G determination (step S3). To be done.

The steering angle δ _H is the set steering angle (for example, 5 deg)
If the lateral G (G _Y ) is equal to or greater than the set lateral G (for example, 0.1 G), the process proceeds to step S4, and the roll control amount (roll control gain) W is determined, for example, as shown in FIG.
Then, the distribution rate α1 is set from the map (see FIG. 7) corresponding to the steering angle δ _H (step S5), and the distribution rate α is set.
1 is added with the correction amount α2 obtained from the map (see FIG. 8) corresponding to the vehicle speed V to perform the correction (step S6),
Further, the correction amount α3 obtained from the map (see FIG. 9) corresponding to the steering angular velocity δ _H ′ is added to perform the correction to determine the distribution rate α (step S7).

Further, in step S8, the distribution rate α is combined with the above-described roll control amount W to obtain and output the roll control amount of each wheel. As a result, the distribution rate α added to the roll control amount W is set corresponding to the steering angle δ _H based on the map as shown in FIG. 7, so that the steering angle δ _H is small. When the turning degree is small, the understeer tendency is strengthened, and the straight running stability of the vehicle can be improved. On the other hand, when the steering angle δ _H becomes large, the degree of turning becomes large, and turning performance is required rather than straight running stability, but at this time, the distribution rate α is reduced and the oversteer tendency is strengthened. The turning performance (mainly turning ability) of the vehicle can be improved. Therefore, even during steady turning, the steering is appropriately adjusted according to the steering angle.

Further, the distribution ratio α is set (corrected) in accordance with the vehicle speed V based on the map as shown in FIG. 8 so that the turning performance is required to be lower than the straight running stability. At times, the steer characteristic is set to the oversteer side, and the turning performance (mainly turning ability) of the vehicle is prioritized. Further, as the vehicle speed increases, straight running stability is required rather than turning performance, but the steer characteristic is adjusted to the understeer side as the vehicle speed increases, and the straight running stability of the vehicle gradually becomes priority. To be done. Therefore, the optimum steering characteristic can always be obtained according to the vehicle speed.

Further, the distribution rate α is set (corrected) in accordance with the steering angular velocity δ _H ′ based on the map shown in FIG. 9, so that the oversteer is performed when the driver starts a sharp turn. When the driver wants to finish the turning motion promptly, the understeer tendency increases and the straight running stability of the vehicle improves and the turning motion of the vehicle converges faster. Be done.

In this embodiment, the distribution rate α is set in correspondence with the three elements of the steering angle δ _H , the vehicle speed V and the steering angular velocity δ _H ′, but as shown in FIG. The distribution rate α may be set so as to correspond only to the steering angle δ _H. Although not shown, the distribution ratio α is set to the steering angle δ.
_It may be configured so as to correspond to _H and the vehicle speed V, or to correspond to the steering angle δ _H and the steering angular velocity δ _H ′.

The device of the present invention itself is not limited to the above embodiment, the characteristics of the map in the embodiment are not limited to this, and it is widely applied to the vehicle active suspension device of other mechanisms. It goes without saying that various modifications can be applied without departing from the scope of the present invention.

[0055]

As described above in detail, according to the active suspension system for a vehicle of the present invention, the force that is interposed between each wheel of the vehicle and the vehicle body to support the vehicle body with respect to each wheel. And a control means capable of changing the steer characteristic of the vehicle by controlling the operation of the actuator while adjusting the control distribution of the front wheel side actuator and the rear wheel side actuator among the actuators. And a steering angle detecting means for detecting a steering angle of the vehicle, and a distribution setting means for setting the control distribution to the control means based on the magnitude of the steering angle detected by the steering angle detecting means. And the distribution setting means controls such that the steer characteristic of the vehicle has an understeer tendency in a region where the steering angle is small. By setting the minute and setting the control distribution so that the steering characteristic of the vehicle becomes an oversteer tendency in the region where the magnitude of the steering angle is large, while securing the straight running stability of the vehicle, Steer can be adjusted appropriately according to the steering angle, including during steady turning, which has the advantage of significantly improving the turning performance of the vehicle.

[Brief description of drawings]

FIG. 1 is a block diagram schematically showing a configuration of a main part of a control system of a vehicle active suspension device as an embodiment of the present invention.

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

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

FIG. 4 is a block diagram showing a specific configuration example of a control system of the vehicle active suspension device as one embodiment of the present invention.

FIG. 5 is a block diagram showing a specific configuration example of a control system of the vehicle active suspension device as one embodiment of the present invention.

FIG. 6 is a diagram showing an example of a map for setting a roll control amount of the vehicle active suspension device as one embodiment of the present invention.

FIG. 7 is a diagram showing an example of a map relating to the setting of the OS / US control amount of the vehicle active suspension device as one embodiment of the present invention.

FIG. 8 is a diagram showing an example of a map relating to the setting of the OS / US control amount of the vehicle active suspension device as one embodiment of the present invention.

FIG. 9 is a diagram showing an example of a map relating to the setting of the OS / US control amount of the vehicle active suspension device as one embodiment of the present invention.

FIG. 10 is a flowchart showing a control flow of the vehicle active suspension device as one embodiment of the present invention.

FIG. 11 is a block diagram schematically showing a main part configuration of a modified example of the control system of the vehicle active suspension device as one embodiment of the present invention.

FIG. 12 is a block diagram schematically showing a configuration of a main part of a control system of a conventional vehicle active suspension device.

[Explanation of symbols]

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 Discharge 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 Throttle 25 Accumulator 26 Relief valve 27 Cock 30 Hydraulic actuator 31 Oil passage 32 Control valve 33 Throttle 34 Accumulator 35 Damping force control valve 36 Pressure sensor 40 Controller 40A Steering control part 40B Attitude control part 40C Ride comfort control part 41 Lateral G sensor 42 Steering angle sensor 43 Vehicle speed sensor 44 Front / rear G sensor 45 Brake switch 46 Throttle sensor 47, 47A ~ 47D Stroke sensor 48 Vertical G sensor 49 Preview sensor 50 Anti-roll control unit 51 OS / US control unit (steer control unit) 52 Anti-pitch control unit 55 Vehicle height control unit 56 Combined control unit 57 Adder 57A Pressure correction unit 58 drive circuit 59 preview control unit 60 drive circuit 98 vehicle speed corresponding distribution ratio setting unit (vehicle speed corresponding correction amount setting unit) 99 absolute value calculation unit 100 steering angle corresponding distribution ratio setting unit 101 adder 102 lateral acceleration corresponding gain setting unit 103 speed Correction unit 04 Each wheel control amount calculation unit 105 Left wheel side gain setting unit 106 Adder 107 Steering angular velocity corresponding distribution ratio setting unit (steering angular velocity corresponding correction amount setting unit) 108 Adder 109 Limiter 120 Correction value setting unit 121 Differentiator 122 Correction value setting Part 123 Calculation part 124 Correction value setting part 125 Correction value setting part 126 Calculation part 200 Input part 201 Data conversion part 202 Drift correction processing part 203 Low pass filter

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yasutaka Taniguchi 5-3-8 Shiba, Minato-ku, Tokyo Mitsubishi Motors Corporation (72) Inventor Akihiko Togashi 5-3-8 Shiba, Minato-ku, Tokyo Mitsubishi Automobile Industry Co., Ltd. (72) Inventor Tadao Tanaka 5-33-8 Shiba, Minato-ku, Tokyo Mitsubishi Motors Industry Co., Ltd.

Claims (1)

[Claims] 1. An actuator that is interposed between each wheel of a vehicle and a vehicle body and that can increase / decrease a force for supporting the vehicle body with respect to each wheel, an actuator on the front wheel side of the actuators, and a rear wheel. Control means for controlling the operation of the actuator while adjusting the control distribution with the actuator on the side, and with steering angle detection means for detecting the steering angle of the vehicle. Distribution means for setting the control distribution based on the magnitude of the steering angle detected by the steering angle detecting means is provided in the control means, and the distribution setting means has a small magnitude of the steering angle. In the region, the control distribution is set so that the steer characteristic of the vehicle has an understeer tendency, and in the region where the steering angle is large, the steer characteristic of the vehicle is An active suspension device for a vehicle, which is configured to set a control distribution so as to have a bastair tendency.