JP2761662B2 - Suspension control device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suspension control device, and more particularly, to a suspension control device provided with a suspension means capable of changing characteristics such as a generation pattern of a damping force and a spring constant. The present invention relates to a suspension control device that changes characteristics of suspension means based on a state.

2. Description of the Related Art As a suspension control device of this type, a change rate of a damping force of a shock absorber, which is a signal having extremely excellent response, is detected. It is known that when the damping force suddenly changes due to a brake operation or the like, the generation pattern of the damping force with respect to the movement of the shock absorber is quickly switched to a smaller value side (for example, JP-A-64-67407).

By the way, if the suspension characteristics are simply made soft based on the displacement of the suspension device, the type, squat and roll generation or the tilting of the vehicle due to the unwinding that is the reaction to it can be sufficiently achieved during sudden acceleration / deceleration or turning. Cannot be suppressed. In this case, the grounding properties of the wheels are impaired, and steering stability is also reduced. Therefore, when detecting a driving state (sudden accelerator, brake or steering operation, vehicle speed, etc.) that results in a change in the vehicle attitude, such as a dive or roll, a reference value for determining whether or not to switch the characteristics of the suspension system to software. Is corrected to be higher to suppress the occurrence of dives and rolls. In addition, there has been proposed a system in which the characteristics of the suspension device are controlled independently for each wheel.

[Problems to be Solved by the Invention] Such a device is capable of suppressing the inclination of the posture of the vehicle at the time of traveling and is excellent in steering stability. Since the value is corrected, the dependence on the road surface condition is high, and there has been a problem that the characteristics of the suspension device may be too soft during rapid acceleration / deceleration or turning at high speed. In particular, if the suspension of each wheel is controlled independently, the characteristics of the suspension of all the wheels may become soft during sudden turning during rapid acceleration / deceleration. It was considered that the properties became insufficient. On the other hand, when the characteristics of the entire suspension device are forcibly fixed at the time of acceleration / deceleration or turning, the ride comfort may be insufficient.The suspension control device of the present invention solves the above-described problems, It is an object of the present invention to achieve both riding comfort and steering stability even in a driving state that results in the inclination of the vehicle attitude.

Configuration of the Invention The configuration of the present invention that achieves the above object will be described below.

[Means for Solving the Problems] The suspension control device of the present invention is provided between each wheel and the vehicle body as illustrated in FIG. 1 and has characteristics such as a generation pattern of a damping force and a spring constant. Independently variable suspension means
M1; vibration state detection means M2 for detecting a vibration state of the vehicle; and the suspension means M1 based on the detected vibration state.
A suspension control device comprising a suspension characteristic control means M3 for controlling the characteristics of the vehicle, an operation state detection means M4 for detecting an operation state of the vehicle that causes the inclination of the vehicle posture, and an operation state predicted from the detected operation state of the vehicle. Posture determining means M5 for determining whether the degree of the posture inclination is equal to or greater than a predetermined value.If the posture inclination predicted by the posture determination means M5 is determined to be a predetermined value or more, With respect to one of the pair of wheel suspension means M1 disposed along the direction of inclination, the control of the characteristics by the suspension characteristic control means M3 to the software side is prohibited, and the combination of the wheel suspension means M1 is prohibited. Regarding the other of M1, the control of the characteristics by the suspension characteristic control means M3 to the software side is permitted, and if it is determined that the inclination is less than a predetermined value, all of the wheel suspension means M1 in the set are related. And a prohibition unit M6 for permitting the control of the characteristics by the suspension characteristic control unit M3 to the software side.

[Operation] With the suspension control device of the present invention having the above configuration, the vibration state detecting means M2 detects the characteristics such as the generation pattern of the damping force and the spring constant of the suspension means M1 provided between the wheel and the vehicle body. The suspension characteristic control means M3 controls the vehicle based on the vibration state of the vehicle.
The following control is performed based on the driving state of the vehicle which causes the inclination of the vehicle posture detected by the control.

The attitude determining means M5 determines whether the degree of the inclination of the attitude predicted from the detected driving state is equal to or more than a predetermined value.
With regard to one of the suspension means M1 of the pair of wheels arranged along the direction of the inclination, the suspension characteristic control means
Prohibits the control of characteristics by M3 to the software side. That is,
If it is determined that the predicted inclination of the vehicle posture is equal to or greater than a predetermined value, the pair of wheel suspension means M1 arranged along the direction of the inclination, such as one set on the left and right, and one set on the front and back, One is not controlled by software. In this case, the prohibition means
M6 relates to the other of the pair of wheel suspension means M1,
Control of the characteristics by the suspension characteristic control means M3 to the software side is permitted.

For example, when the vehicle turns, the posture tilts in the left and right direction.However, it is necessary to prohibit the control of the suspension means M1 on the turning outer wheel side to the software side and permit the control of the suspension means M1 on the turning inner wheel side to the software side. Thus, the steering stability of the vehicle can be ensured. Conversely, if the control of the suspension means M1 on the turning inner wheel side to the software side is prohibited, and the control of the suspension means M1 on the turning outer wheel side to the software side is permitted, a change in the attitude of the vehicle can be suppressed.

On the other hand, when it is determined that the inclination is less than the predetermined value, the prohibition unit M6 controls the suspension characteristics control unit M3 to control the characteristics of the wheels on the software side for all of the suspension units M1 of the paired wheels. To give permission. Therefore, in a normal driving state in which a large inclination of the vehicle posture is not caused, it is possible to ensure the riding comfort of the vehicle.

Incidentally, the prohibiting means M6, of the wheels making the set,
With respect to the suspension means M1 of the wheel on which the load moves due to the inclination of the posture, if the control to the software side is prohibited, the following is achieved. That is, in this case, since the suspension means M1 on the side where the load moves is hardly controlled, the steering stability is further improved.

Embodiment In order to further clarify the configuration and operation of the present invention described above, a preferred embodiment of a suspension control device of the present invention will be described below.

FIG. 2 is a schematic configuration diagram showing the entire configuration of the suspension control device 1. FIG. 3 (A) is a cross-sectional view of the shock absorber partially cut away, and FIG. 3 (B) is an essential diagram of the shock absorber. It is a part enlarged sectional view.

As shown in FIG. 2, the suspension control device 1 of the present embodiment includes shock absorbers 2FL, 2FR, 2RL, and 2RR capable of changing the damping force in two stages, and is connected to each of these shock absorbers to control the damping force. And an electronic control unit 4. Each shock absorber 2FL, 2FR, 2RL, 2R
R is provided between the suspension lower arms 6FL, 6FR, 6RL, 6RR of the left and right front and rear wheels 5FL, 5FR, 5RL, 5RR and the vehicle body 7 together with coil springs 8FL, 8FR, 8RL, 8RR.

As described later, the shock absorbers 2FL, 2FR, 2RL, 2RR are a piezo load sensor that detects the force acting on the shock absorbers 2FL, 2FR, 2RL, 2RR, and a shock absorber.
A piezo actuator for switching the setting of the generation pattern of the damping force in 2FL, 2FR, 2RL, and 2RR is incorporated in each one set.

Next, the structure of each of the shock absorbers 2FL, 2FR, 2RL, and 2RR will be described.
Since the structures of 2RL and 2RR are all the same, here the left front wheel 5
A description will be given using the shock absorber 2FL on the FL side as an example. In the following description, the reference numerals of the respective members provided on the respective wheels indicate the left front wheel 5FL, the right front wheel 5FR, and the left rear wheel 5R as necessary.
L, suffixes FL, FR, RL, RR corresponding to the right rear wheel 5RR shall be added, and if there is no difference between the respective wheels, the suffix shall be omitted.

As shown in FIG. 3 (A), the shock absorber 2 is fixed to the suspension lower arm 6 via an axle-side member 11a at the lower end on the cylinder 11 side, while the upper end of a rod 13 inserted into the cylinder 11 , Is fixed to the vehicle body 7 together with the coil spring 8 via the bearing 7a and the vibration isolating rubber 7b.

Inside the cylinder 11, an internal cylinder 15, a connecting member 16, and a cylindrical member 17 connected to the lower end of the rod 13, and a main piston 18 slidable along the inner peripheral surface of the cylinder 11,
It is arranged. A piezo load sensor 25 and a piezo actuator 27 are housed in the internal cylinder 15 connected to the rod 13 of the shock absorber 2.

The main piston 18 is externally fitted to the cylindrical member 17,
A seal member 19 is interposed on the outer periphery fitted to the cylinder 11. Therefore, the main piston 18
Thus, a first liquid chamber 21 and a second liquid chamber 23 are defined. A backup member 28 is screwed into the distal end of the cylindrical member 17, and a spacer 29 and a leaf valve 30 are provided between the cylindrical member 17 and the main piston 18 on the cylindrical member 17 side. The collar 32 is pressed and fixed to the backup member 28 side. Further, a main valve 34 and a spring 35 are provided between the leaf valve 31 and the backup member 28.
The leaf valve 31 is connected to the main piston 18
Biased in the direction.

When the main piston 18 is stopped, the leaf valves 30 and 31 close the extension side and the contraction side passages 18a and 18b provided on the main piston 18 on one side, respectively. It opens to one side as it moves in the A or B direction. Accordingly, the hydraulic oil filled in the two liquid chambers 21 and 23 moves between the two liquid chambers 21 and 23 through one of the two passages 18a and 18b as the main piston 18 moves. In the state where the movement of the hydraulic oil between the two liquid chambers 21 and 23 is limited to the two passages 18a and 18b, the damping force generated for the movement of the rod 13 is large, and the characteristics of the suspension become hard. .

Piezo load sensor 25 housed inside internal cylinder 15
3 (A) and 3 (B).
As shown in FIG. 1, an electrostrictive element laminate is obtained by laminating piezoelectric ceramic thin plates with electrodes interposed therebetween. Each electrostrictive element of the piezo load sensor 25 is polarized by a force acting on the shock absorber 2, that is, a damping force. Therefore, the piezo load sensor
If the output of 25 is taken out as a voltage signal by a circuit having a predetermined impedance, the rate of change of the damping force can be detected.

The piezo actuator 27 is formed by laminating electrostrictive elements that expand and contract with good responsiveness when a high voltage is applied, and increases the amount of expansion and contraction, and directly drives the piston 36. When the piston 36 is moved in the direction of arrow B in FIG. 3 (B), the plunger 37 and the spool 41 having an H-shaped cross section are also moved in the same direction via the hydraulic oil in the oil-tight chamber 33. Thus, the spool 41 at the position (origin position) shown in FIG.
Move in the direction B in the drawing, the sub-flow path 16c connected to the first liquid chamber 21 and the sub-flow path 3 of the bush 39 connected to the second liquid chamber 23
It will be communicated with 9b. The sub flow path 39b is further connected to the cylindrical member 1 through an oil hole 45a provided in the plate valve 45.
When the spool 41 moves in the direction of the arrow B, the first liquid chamber 21 and the second liquid chamber 21
The flow rate of the working oil flowing between the liquid chamber 23 and the liquid chamber 23 increases. That is, the shock absorber 2 is
When the voltage is extended by applying a high voltage, the damping force characteristic is switched from a large damping force (hard) state to a small damping force (soft) side, and when the electric charge is discharged and contracted, the damping force characteristic is changed to a large damping force (hard). Return to the state.

The amount of movement of the leaf valve 31 provided on the lower surface of the main piston 18 is regulated by a spring 35 as compared with the leaf valve 30. The plate valve 45 has an oil hole
An oil hole 45b having a diameter larger than 45a is provided outside the oil hole 45a, and when the plate valve 45 moves toward the bush 39 against the urging force of the spring 46, the hydraulic oil passes through the oil hole 45b. And can be moved. Therefore, irrespective of the position of the spool 41, the hydraulic oil flow rate when the main piston 18 moves in the direction of arrow B becomes larger than when the main piston 18 moves in the direction of arrow A. That is, the damping force is changed depending on the moving direction of the main piston 18, thereby further improving the characteristics as a shock absorber. Also,
A hydraulic oil supply passage 38 is provided between the oil-tight chamber 33 and the first liquid chamber 21 together with a check valve 38a to keep the flow rate of the hydraulic oil in the oil-tight chamber 33 constant.

Next, the electronic control unit 4 for switching and controlling the generation pattern of the damping force of the shock absorber 2 will be described with reference to FIG.
This will be described with reference to the drawings.

The electronic control unit 4 includes a piezo load sensor 25 of each shock absorber 2 and a steering angle η of a steering wheel (not shown) as sensors for detecting a running state of the vehicle.
Sensor 50 for detecting the vehicle speed and the traveling speed S of the vehicle
, A shift position sensor 52 for detecting a shift position of a transmission (not shown), a hydraulic sensor 53 for detecting a brake hydraulic pressure P of a brake (not shown), and detecting an opening degree θ of a throttle valve (not shown). The throttle opening sensor 54 and the like are connected.

The electronic control unit 4 that outputs a control signal to the piezo actuator 27 based on these detection signals and the like is a known electronic control unit.
The CPU 61, the ROM 62, and the RAM 64 are mainly configured as arithmetic and logic operation circuits, and input / output with the outside is performed by an input unit 67 and an output unit 68 which are connected to the arithmetic and logic circuits via a common bus 65.

The electronic control unit 4 further includes a damping force change rate detection circuit 70 connected to the piezo load sensor 25, a waveform shaping circuit 73 connected to the steering sensor 50 and the vehicle speed sensor 51,
High voltage application circuit 7 connected to piezo actuator 27
5. A so-called switching regulator type high-voltage power supply circuit 79 that receives power from a battery 77 through an ignition switch 76 and outputs a driving voltage for driving a piezo actuator, and transforms the voltage of the battery 77 to A constant voltage power supply circuit 80 for generating an operating voltage (5 V) is provided. The shift position sensor 52, the oil pressure sensor 53, the throttle opening sensor 54, the damping force change rate detection circuit 70, and the waveform shaping circuit 73 are provided at the input section 67, while the high voltage application circuit 75 and the high voltage power supply circuit 79 are provided at the output section 68. Connected to each other.

The damping force change rate detection circuit 70 is composed of each piezo load sensor 25FL, F
R, RL, and RR are provided for each of the four detection circuits, and each of the detection circuits is a voltage output from a circuit including the piezo load sensor 25 according to the acting force received by the shock absorber 2 from the road surface. It is configured to output the signal V to the CPU 61 as the damping force change rate of the shock absorber 2. Further, the waveform shaping circuit 73 includes a steering sensor
This is a circuit that shapes the detection signal from the vehicle speed sensor 51 or the vehicle speed sensor 51 into a signal suitable for processing in the CPU 61 and outputs the signal. Therefore, the CPU 61 can determine the running state of the vehicle based on the output signals from the damping force change rate detection circuit 70 and the waveform shaping circuit 73, and further from the signals from the hydraulic pressure sensor 53 and the like. The CPU 61 outputs a control signal to the high voltage application circuit 75 provided corresponding to each wheel based on the processing.

The high-voltage applying circuit 75 applies the voltage of +500 volts or -100 volts output from the high-voltage power supply circuit 79 to the CPU 6.
This is a circuit applied to the piezo actuator 27 in response to a control signal from 1. Therefore, the piezo actuator 27 expands (when +500 volts is applied) or contracts (when -100 volts is applied) by this damping force switching signal, and the hydraulic oil flow rate is switched, so that the damping force characteristic of the shock absorber 2 is soft or hard. Is switched to. That is,
The damping force characteristic of each shock absorber 2 is such that when a high voltage is applied to expand the piezo actuator 27, the first liquid chamber in the shock absorber 2 is controlled by the spool 41 (FIG. 3B) described above. When the flow rate of the hydraulic oil flowing between the second liquid chamber 23 and the second liquid chamber 23 increases, the damping force is in a small state, and when the piezo actuator 27 is contracted by discharging the electric charge by the negative voltage, the hydraulic oil flow rate Is reduced and the damping force becomes large. When the electric charge stored in the piezo actuator 27 is discharged once, even if the negative voltage is removed, the piezo actuator 27 remains in a contracted state, and the shock absorber 2 maintains a state where the damping force is large.

Next, damping force control performed by the suspension control device 1 of the present embodiment having the above-described configuration will be described with reference to the flowcharts of FIGS. The outline of the processing in each processing routine and the relationship between the two processings are as follows.

(1) Roll area determination interrupt routine (FIG. 5) This is an interrupt routine that is executed at predetermined intervals and is based on the vehicle operating state and the anticipated degree of vehicle body inclination, and anti-skid roll control. Is determined, and the flag FRL is set.

(2) Left front wheel damping force control interrupt processing routine (FIG. 6) This routine resets each flag FSR, FSL, etc. to a value of 0 in initialization processing (not shown) at the time of power-on, and then keeps a constant value. This is an interrupt routine that is repeatedly executed every time, and performs a process of switching the pattern of the damping force generated by the shock absorber 2 based on the damping force change rate V in the shock absorber 2. In such switching, the fifth
The control of the damping force generation pattern is changed with reference to the value of the flag FRL set in the roll area determination interrupt routine shown in the figure.

These processes are performed for each of the shock absorbers 2FL, FR or 2RL, RR for a pair of left and right wheels, but the processes for the front and rear wheels are the same. I do. Of course, the wheels to be assembled may be determined according to the type of inclination (roll, pitch, etc.) of the vehicle body to be controlled and the configuration of the vehicle.
It may be front and rear wheels, or three wheels such as left and right front wheels and a turning outer wheel side rear wheel.

When the processing routine shown in FIG. 5 is started, first, a process of reading operating conditions such as the steering angle η and the vehicle speed S is performed via the input unit 67 (step 90). A process for determining an area is performed (step 95). As shown in FIG. 7, the roll area is an area determined by the relationship between the vehicle speed S and the steering angle η, and the anti-roll control unnecessary area where the predicted roll is small and the vehicle speed S and the steering angle η are both It is divided into a hard fixing area where a roll is generated to some extent.

If it is determined in step 95 that the anticipated body inclination is small and the anti-roll control is not required (step 95), the value of the flag FRL is set to 0 (step 100), and this routine is temporarily terminated. I do. On the other hand, if the vehicle body posture is predicted to be somewhat large in a hard fixed region, that is, in a sharp turning or high-speed running state, the damping force setting of the shock absorber 2 is fixed to a large value, and the flag is set. FRL is set to a value of 1 (step 105), and this routine ends.

Next, a left front wheel damping force control interrupt processing routine (FIG. 6)
Will be described. This routine is executed for the left front wheel 5FL, but for the right front wheel 5FR, the flag to be referred to is changed to the one for the left front wheel 5FL (FSL) and the right front wheel is used.
The same processing is performed except that it is a 5FR one (FSR). The processing of the right front wheel 5FR will be supplemented as appropriate.

When this routine (FIG. 6) is started, first,
It is determined whether or not the value of FRL is 0 (step 110).
If the value of the flag FRL is 0, a process of reading the change rate V of the damping force of each shock absorber 2 from the damping force change rate detection circuit 70 via the input section 67 is performed (step 120).
It is determined whether or not the damping force change rate V is greater than the switching reference value Vref (step 130). This switching reference value Vre
Although f is given a predetermined initial value in an initialization routine or the like, the switching reference value Vref may be learned based on the switching frequency of the damping force setting of the shock absorber 2 and the like.

The vehicle vibration is small and the damping force change rate V is equal to the switching reference value Vref.
If it is below (step 130), it is determined whether or not the FSL indicating that the setting of the damping force of the left front wheel 5FL is being controlled by software is 1 (step 140). If not, the flag FSL is reset to a value of 0 (step 150), and then the shock absorber 2FL is hard-controlled (step 160).
Incidentally, the processing of step 160 for controlling the suspension hardly is performed immediately after the setting of the damping force of the shock absorber 2FL is switched from software to hardware. Apply a bolt to the piezo actuator 27FL to reduce it,
If the piezo actuator 27FL is already in a contracted state, the piezo actuator 27FL is held as it is.

While the flag FRL is held at the value 0, that is, while it is determined that the roll is small and the anti-roll control is not necessary from the driving state of the vehicle, the above processing is repeated, but the road surface condition becomes a bad road. , The damping force change rate V is the switching reference value Vref
If it has become larger (step 130), a process for initializing the timer, that is, a process for setting an initial value to the timer variable Tb is performed (step 170). The timer variable Tb is used for aging by software, and is a variable that determines how long the setting of the shock absorber 2FL once softened is continued after V ≦ Vref. still,
The timer variable Tb may be constant irrespective of the vehicle speed SP, or may be set to a smaller value as the vehicle speed SP increases.

After the above processing, the condition (V> Vref) for softly controlling the damping force for the left front wheel 5FL is satisfied, so the value FSL indicating this is set to 1 (step 180), and then the high voltage is applied. A high voltage of +500 volts is applied from the circuit 75 to the piezo actuator 27FL to switch and control the damping force of the shock absorber 2FL to a small state (soft) (step 190), and this routine ends.

After the damping force of the shock absorber 2FL is switched to a small state, if the damping force change rate V is greater than the switching reference value Vref, the timer variable Tb is initialized (step 170) and the damping force is kept small. Is repeated (step 190). Eventually, when the damping force change rate V becomes equal to or less than the switching reference value Vref, the determination in step 130 becomes “NO”, and then the value of the flag FSL is checked (step 140). When V ≦ Vref after the damping force change rate V of the left front wheel 5FL once exceeds the switching reference value Vref, the flag FSL is set to the value 1. Therefore, the determination in step 140 is “YES”, and then the timer variable
It is determined whether Tb has become equal to or less than 0 (step 200). The process of decrementing the timer variable Tb by 1 until the timer variable Tb becomes equal to or less than the value 0 (step 21)
0) and the process of continuously controlling the shock absorber 2FL by software (step 190) are repeated.

When the time corresponding to the timer variable Tb elapses after the damping force change rate V of the left front wheel 5FL becomes equal to or less than the switching reference value Vref (step 200), the timer variable Tb and the flag FSL are reset to 0 (steps 220 and 150). ), Shock absorber 2FL
The setting of the damping force is hardly controlled (step 160).
That is, the high voltage application circuit 75 is controlled by the control signal from the output unit 68.
-100 volts is applied to the piezo actuator 27 to reduce it. After that, the process exits to “RTN” and ends this routine.

The processing in the case where the predicted inclination (roll) of the vehicle body is small (flag FRL = 0) has been described above. In this case, the damping force of the shock absorber 2FL of the left front wheel 5FL is equal to the damping force change rate V. As soon as the value exceeds the switching reference value Vref, the state is set to a small value, and the damping force change rate V is changed to the switching reference value Vr.
ef or less, a predetermined time (timer variable Tb
The setting of the damping force is kept in the soft state as it is for the time corresponding to (1). After the elapse of this time, the shock absorber 2FL is again controlled to a state where the damping force is large (hard).

On the other hand, when the predicted inclination of the vehicle body becomes large as in the case of a sharp turn, the flag FRL is set to 1 by the roll area determination interrupt routine of FIG. 5 (step 105). When the flag FRL is set to a value of 1, the determination in step 110 in the damping force control interrupt processing routine (FIG. 6) is “NO”.
Then, a process of determining the value of the flag FSR relating to the right front wheel 5FR is performed (step 250). Flag F
Like SL, this flag FSR is set to 1 while the damping force of the right front wheel 5FR is softly controlled by a right front wheel damping force control interrupt routine (not shown).

If FSR = 0, that is, if the right front wheel 5FR is controlled hard, the process returns to step 120 to continue the normal damping force control described above. On the other hand, if the right front wheel 5FR is controlled by software, the process proceeds to steps 150 and 160, resets the flag FSL to a value of 0, controls the shock absorber 2FL hard, and ends this routine. Note that the same processing is performed for the right front wheel 5FR, and if it is determined that the region is the hard fixed region, if the shock absorber 2FL of the left front wheel 5FL is controlled by software first,
The process of fixing and controlling the shock absorber 2FR of the right front wheel 5FR is performed.

As described above, the suspension control device 1 according to the present embodiment uses the extremely responsive signal of the damping force change rate V to generate the damping force generation pattern of each shock absorber 2 of the vehicle and to change the attitude. An appropriate state could be quickly controlled according to the driving state and the vibration of the vehicle. [I] If the vehicle is traveling substantially straight or traveling at low speed and the occurrence of roll is predicted to be small, when the damping force change rate V exceeds the switching reference value Vref, the shock absorber 2 changes its damping force characteristics. Switch to the smaller state
It is maintained for a predetermined time (Tb) after the voltage falls below Vref. Therefore,
The characteristics of the suspension are quickly switched to software and are controlled stably, so that the ride quality is improved.

[II] On the other hand, if the condition that the lateral force is applied to the vehicle body by turning the steering wheel is satisfied (FRL = 1), the shock absorber 2 of the other front wheel forming the pair
Is determined, and if the software is already controlled by software, the shock absorber 2 is hard controlled and maintained for the wheel of interest.

On the other hand, if the other front wheel of the pair is in a hard state, the damping force change rate V
The characteristics are controlled based on.

As a result, one of the left and right front wheels forming a pair is always hard controlled when a roll occurs, and the other is controlled based on the damping force change rate V, thereby improving the steering stability and the vehicle riding. Comfort can be considered.
That is, in the suspension control device 1 of the embodiment, it is possible to skillfully balance the riding comfort and the steering stability of the vehicle when the vehicle turns.

Next, a description will be given of a second embodiment of the present invention. The suspension control device of the second embodiment has the same device and configuration as the first embodiment, and only a part of the damping force control interrupt processing routine is performed. Are different. That is, instead of step 250 in which the state of the damping force control of the paired opposite wheels is determined, it is determined whether or not the wheel of interest is a turning outer wheel (step 350). If the steering wheel is turned to the right and the left front wheel 5FL is the turning outer wheel,
The characteristics of the shock absorber 2FL are hard-controlled, and normal control is executed unless the wheel is a turning outer wheel.

As a result, according to this embodiment, when a predicted roll occurs, the turning outer wheel on which the load moves is always hard controlled, and there is an advantage that steering stability is further improved.

When the predicted roll occurs, the turning inner wheel may be fixed to the hard. Shock absorber 2
Since the damping force on the extension side is larger than the damping force on the contraction side due to the hardware configuration, it is preferable to make the inner ring harder, because the change in posture can be further suppressed.

In the above embodiment, the shock absorber 2 is used as the suspension means, and the piezo load sensor 25 and the electronic control unit 4 are used.
The processing of step 120 is performed by the vibration state detecting means, the processing of steps 130 to 220 of the electronic control unit 4 is performed by the suspension characteristic control means, and the processing of the steering sensor 50, the vehicle speed sensor 51, and the processing of step 90 by the electronic control unit 4 are performed by The process of step 95 of the electronic control unit 4 corresponds to the attitude determination unit, and the process of step 250 or 350 of the electronic control unit 4 corresponds to the prohibition unit.

Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments. For example, instead of controlling the setting of the damping force of the shock absorber, the spring constant of the air spring is controlled to control the suspension means. In the range that does not deviate from the gist of the present invention, such as a configuration in which the characteristics of the present invention are changed, a configuration in which at least one of a pair of front and rear wheels is hardly controlled by determining the inclination of the vehicle body in the front-back direction (dive, squat, etc.) Of course, it can be implemented in various modes.

Effects of the Invention As described in detail above, according to the suspension control device of the present invention, based on the driving state of the vehicle causing the inclination of the vehicle attitude, one of the sets arranged along the direction of the inclination The characteristic of the suspension means of the wheel is fixed to the hard side, and the characteristic of the suspension means of the other wheel can be controlled to the soft side. For this reason, in the present invention, even when the inclination of the vehicle attitude is caused, the steering stability is ensured,
Alternatively, an extremely excellent effect that a change in the attitude of the vehicle can be suppressed is achieved.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a basic configuration of the present invention, FIG. 2 is a schematic configuration diagram showing an overall configuration of a suspension control device as one embodiment of the present invention, and FIG. FIG. 3 (B) is an enlarged sectional view of a main part of the shock absorber 2, and FIG.
FIG. 5 is a block diagram showing the configuration of the electronic control unit 4 of this embodiment. FIG. 5 is a flowchart showing a roll area determination interrupt routine. FIG. 6 is a flowchart showing a left front wheel damping force control interrupt processing routine. FIG. 8 is a graph illustrating the roll area determination, and FIG. 8 is a flowchart illustrating a main part of the process of the second embodiment. 1… Suspension control device 2FL, FR, RL, RR …… Shock absorber 4 …… Electronic control device 25FL, FR, RL, RR …… Piezo load sensor 27FL, FR, RL, RR …… Piezo actuator 50 …… Steering Sensor 51 Vehicle speed sensor 53 Oil pressure sensor 54 Throttle opening degree sensor 70 Damping force change rate detection circuit 75 High voltage application circuit 79 High voltage power supply circuit

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshimichi Hara 1-1-1, Showa-cho, Kariya-shi, Aichi Japan Inside Denso Co., Ltd. (72) Inventor Eiki Matsunaga 1-1-1, Showa-cho, Kariya-shi, Aichi Japan Japan Denso Stock In-house (72) Inventor Hiroyuki Kawada 1-1-1, Showa-cho, Kariya-shi, Aichi Japan Inside Denso Co., Ltd. (72) Inventor Akira Fukami 1-1-1, Showa-cho, Kariya-shi, Aichi Japan Nihon Denso Co., Ltd. (72) Invention Person Yutaka Suzuki 1-1-1 Showa-cho, Kariya-shi, Aichi Japan Inside Denso Co., Ltd. (56) References JP-A-61-77506 (JP, A) Real-life 1986-163707 (JP, U) (58) Field (Int.Cl. ⁶ , DB name) B60G 17/015

Claims (2)

(57) [Claims] 1. Suspension means provided between each wheel and a vehicle body to independently vary characteristics such as a damping force generation pattern and a spring constant, and vibration state detection means for detecting a vibration state of the vehicle. A suspension characteristic control means for controlling characteristics of each of the suspension means based on the detected vibration state; a driving state detecting means for detecting a driving state of the vehicle causing a tilt of the vehicle attitude; Attitude determining means for determining whether or not the degree of the inclination of the attitude predicted from the detected driving state of the vehicle is equal to or greater than a predetermined value; and the inclination of the attitude predicted by the attitude determining means is equal to or more than a predetermined value. If it is determined that the suspension characteristic control means for one of the suspension means of the pair of wheels arranged along the direction of the inclination is prohibited, the control of the characteristic to the software side by the suspension characteristic control means is prohibited. In both cases, the control of the characteristics of the other wheel suspension means of the pair to the software side by the suspension characteristic control means is permitted, and if it is determined that the inclination is less than a predetermined value, the pair is formed. A suspension control device, comprising: prohibition means for permitting control of the characteristics of the suspension characteristics control means to the software side for all of the wheel suspension means. 2. The software system according to claim 1, wherein the prohibiting means prohibits the control of the wheels on the side of the pair of wheels on which the load moves due to the inclination of the posture. Item 2. The suspension control device according to item 1.