JPS6261811A - Suspension controller for vehicle - Google Patents

Abstract

PURPOSE:To suppress the chassis vibration when the spring constant is varied, by setting the damping force according to the result of judgement by a chassis vibration judging means, in a suspension device having the variable spring constant and damping force. CONSTITUTION:When each output of a front ground clearance sensor 1 and a rear ground clearance sensor 2 is input into a controller 35, a calculation processing unit 39 calculates the housing shift Hb and the pitching shift Hp according to a prescribed program, and when a spring-constant varying spring device 6 is soft, the filter treatment according to the band width in the vicinity of the housing characteristic frequency obtained on the basis of the spring constant on the front and rear soft sides for the housing shift Hb is performed and the vibration judgement is carried out, and then the damping force 7 is controlled. In case of hard, the digital processing is performed and vibration judgement is carried out, and thus the damping force 7 is controlled. With such constitution, the chassis vibration suppressing force can be improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is capable of adjusting both the damping force of a variable damping force shock absorber and the spring constant of a variable spring constant spring device included in a suspension device according to the running condition of a vehicle. The present invention relates to an improvement of a suspension control device for a vehicle that can be changed, and in particular to a vehicle suspension control device that changes the damping force of a variable damping force shock absorber in consideration of the spring constant of a variable spring constant spring device. .

[Conventional technology]

As a suspension control device for a vehicle equipped with both a conventional variable damping force shock absorber and a variable spring constant spring device, for example, rMITSUBISIll
New model car manual GALANT ETERNAΣ.

Published by Mitsubishi Motors Corporation, August 1983.

The one disclosed on pages 111 to 137 is known.

With this conventional device, both the damping force and spring constant can be changed in two stages, soft and hard, and auto mode and hard mode can be selected. The damping force and spring constant are automatically set to the soft side or the hard side at the same time, and in the hard mode, the damping force and spring constant are fixed to the hard side.

Further, as a suspension control device for a vehicle, there is one described in Japanese Patent Application No. 138567/1989, which is an earlier application filed by the present applicant.

This device changes at least one of the damping force or the spring constant, but it detects the vertical vibration of the vehicle body, extracts vibration components with a predetermined amplitude or more from the detected vertical vibration signal, and calculates the vibration component. When the frequency of is within a predetermined bandwidth, at least one of the damping force or the spring constant is changed to the hard side.

[Problem that the invention seeks to solve]

However, in such a vehicle suspension control device, in order to determine pitching or bouncing of the vehicle body based on the vertical vibration of the vehicle body, the frequency band width through which the detection signal of the vehicle body vertical vibration is passed is determined by a spring constant. It is constant regardless of whether the spring is on the soft or hard side, and it is based on the spring constant of the soft side. Therefore, if the spring constant is manually set to the hard side, or when the vehicle turns or accelerates or decelerates in automatic operation, the spring constant will change to the hard side. When the spring constant is changed, the natural frequency of pitching or bouncing changes, so there is a problem in that it becomes difficult to determine whether to control pitching or bouncing after changing the spring constant to the hard side.

To explain this with reference to Fig. 8, the vehicle body mass is m1, the pitching moment of inertia for the center of gravity is 11, the front and rear spring constants are 1, and the distance between the center of gravity G and the front suspension and rear suspension is 1. The distance of 1
．． and Il, the vertical displacement of the center of gravity G is X, and the pitching angle around the center of gravity 0 of the vehicle body is θ. Regarding bouncing, m M + (k (+ k J x = 0 holds, and the characteristic of bouncing The frequency f, is fb=(1/2
π) b; B; 7 guns were obtained, and regarding pitching, ■σ+C1rkr+! , kl) θ=0 holds, and the pitching natural frequency rp is fp-(
1/2π) f, +j? Kotofu T is obtained.

In a spring constant variable spring device, if the front and rear spring constants can be changed from the soft side kf3 and krs to the hard side and krN, and the hard side is twice the soft side, the soft side and hard side The natural frequency of bouncing ``5.'' and fbH are r b H = (i-r), and similarly, the natural frequencies f93 and f□ of pitching on the soft side and hard side are r, - pressure f1. .

Generally, the hard side spring constant is the soft side spring constant n
When doubled, the natural frequencies of bouncing and pitching become five times.

In the conventional device described above, in practice, when the vehicle body is experiencing bouncing or pitching resonance,
It is preferable to change the damping force to the hard side while maintaining the spring constant on the soft side to damp vibration.
When the spring constant is set to the hard side by manual operation,
When turning or accelerating or decelerating during automatic operation, the spring constant is changed to the hard side to suppress changes in the vehicle's roll or pitching posture, and the damping force is changed to the soft side from the perspective of emphasizing ride comfort. Maintaining control is preferred. Particularly when the latter type of control is being performed, bouncing and pitching occur when the road surface is undulating. If the bandwidth for extracting this bouncing and pitching vibration is constant regardless of whether the spring constant is on the soft or hard side, such bouncing or pitching can be detected accurately and the damping force can be changed to the hard side. It becomes difficult to control the situation.

This invention was made by focusing on these conventional problems, and is capable of accurately controlling vehicle body vibration even when the spring constant changes in a vehicle suspension control device that can change both the damping force and the spring constant. It is an object of the present invention to provide a vehicle suspension control device that can detect vibrations caused by vibrations of the vehicle and suppress the vibrations of the vehicle body.

[Means for solving problems]

Therefore, as shown in FIG. 1, the vehicle suspension control device according to the present invention includes a variable damping force shock absorber that can change the damping force in at least two stages, a soft side and a hard side, and a spring constant that can be changed at least on the soft side. a suspension device including a variable spring device with a variable spring constant that can be changed into two stages: hard side and hard side; a vehicle body vibration detection means for detecting vehicle body vibration; and a frequency component of a predetermined bandwidth extracted from the vehicle body vibration detection signal. Vehicle body vibration determination means that determines the amplitude of a frequency component or extracts a vibration component with a predetermined amplitude or more from the vehicle body vibration detection signal and determines whether the frequency of the vibration component is within a predetermined bandwidth. and;
In a vehicle suspension control device comprising a damping force setting means for setting a damping force of a variable damping force shock absorber according to a determination result of the vehicle body vibration determining means, the vehicle body vibration is determined according to a spring constant of a variable spring constant spring device. The present invention is characterized by comprising a bandwidth setting means for setting the bandwidth of the determination means.

[Effect]

The function of the vehicle suspension control device according to the present invention is to set the bandwidth of the vehicle body vibration determination means according to the spring constant of the variable spring constant spring device, and to detect the frequency component of the set bandwidth from the vehicle body vibration detection signal. or extracting a vibration component having a predetermined amplitude or more from the vehicle body vibration detection signal and determining whether the frequency of the vibration component is within a predetermined bandwidth, and making the determination. The damping force of the variable damping force shock absorber is set according to the results.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

First, to explain the configuration, in FIG. 2, numeral 1 is a front vehicle height sensor that detects the vehicle height at the front of the vehicle body, and 2 is a rear vehicle height sensor that detects the vehicle height h1 at the rear of the vehicle body.

These front vehicle height sensor 1 and rear vehicle height sensor 2 are used, for example, to measure the distance between the mounting section of sensors 1 and 2 using ultrasonic waves and the road surface, or to measure the distance between the shock absorber section and the vehicle body side. An appropriate device is used, such as one that detects relative displacement on the wheel side as a change in coil inductance.

3 is a wheel, and a suspension device 4 is interposed between the wheel 3 and the vehicle body (not shown), and the suspension device 4 includes, for example, a suspension member such as a suspension arm 5, and a variable spring constant spring device 6. , and a variable damping force shock absorber 7.

The variable spring constant spring device 6 and the variable damping force shock absorber 7 are preferably used for each of the front, rear, left and right wheels 33 to 3.
d and the vehicle body, but is not limited thereto.

The variable spring constant spring device 6 shown in FIG. 2 is capable of changing the spring constant in two stages, a soft side and a hard side, and can be freely expanded and contracted in the vertical direction between the vehicle body and the variable damping force shock absorber 7. An elastic body 9 made of rubber or the like surrounds and forms an air chamber F therein, an auxiliary tank 10 forms an auxiliary air chamber K with a fixed volume inside, and the air chamber F communicates with the auxiliary air chamber. A switching valve 12 is installed between the conduit 11 and the conduit 11 to open and close the conduit 11 and to switch the air chamber F and the auxiliary air chamber to either a communicating state or a blocking state. It consists of:

FIG. 3 shows an example of a variable damping force shock absorber 7 in which the damping force can be changed to two levels: a soft side and a hard side.

In the same figure, 14 is our parosodo 15 and lower rod 1.
6, and its upper end is fixed to the vehicle body side. 17 is a tube whose lower end is fixed to the wheel 3 side; 18 is a piston which is fixed to the lower end of the lower rod 16 and slides along the inner peripheral surface of the tube 17; and 19 is a tube 17 fixed to the bottom side of the tube 17.
It is a free piston that slides along the inner peripheral surface of the piston. Inside the tube 17, above the piston 18 there is a piston upper chamber A, the piston 18 and a free piston 19.
A lower piston chamber B and a gas chamber C are formed below the free piston 19, respectively, and the upper piston chamber A and the lower piston chamber B are filled with oil, and the gas chamber C is filled with high pressure gas. .

20 is an expansion side valve, 21 is an expansion side orifice, 22 is a contraction side valve, and 23 is a contraction side orifice. Also,
24 and 25 are through holes and cavities formed in the upper rod 15, and 26 and 27 are bypass paths and cavities formed in the lower loft 16.

A plunger 28 is disposed within the two cavities 25 and 27, and this plunger 28 is constantly pressed upward in the drawing (in the D direction) by the restoring force of a return spring 29. A solenoid 30 is disposed around the plunger 28. Actuator 31 with solenoid 30 and plunger 28
is configured.

The solenoid 30 is connected to a drive circuit 34 via a lead wire 32 passing through the through hole 24 of the upper rod 150.

In the variable damping force shock absorber 7, during the extension stroke, the extension side valve 20 opens and the piston upper chamber A and the piston lower chamber B communicate with each other via the extension side orifice 21, and the compression side valve 20 communicates with the piston lower chamber B through the compression side pulp 22. Orifice 23 is closed. Further, in the contraction stroke, the contraction side valve 22 opens, the piston upper chamber A and the piston lower chamber B communicate with each other via the contraction side orifice 23, and the expansion side orifice 21 is closed by the expansion side valve 20.

Returning to FIG. 2, 35 is a controller, and this controller 35 includes a microcomputer 36, a drive circuit 37 that drives the switching valve 12 of the variable spring constant spring device 6, and an actuator 31 of the variable damping force shock absorber 7. and a drive circuit 34 for driving.

The microcomputer 36 includes at least an interface circuit 38, an arithmetic processing unit 39, and a RAM.

The front vehicle height sensor 1 and the rear vehicle height sensor 2 are connected to the interface circuit 38, and the drive circuits 34 and 3 are connected to the interface circuit 38.
7 is connected.

The arithmetic processing unit 39 reads detection signals from the front vehicle height sensor 1 and the rear vehicle height sensor 2 via the interface circuit 38, and performs calculations and other processing described below based on these signals. Further, the storage device 40 stores a predetermined program necessary for executing the processing, and also stores processing results of the arithmetic processing device 39 and the like.

Next, the operation of this embodiment will be explained.

The ignition switch is turned on and controller 3
When the power of 5 is turned on, a detection signal representing the front vehicle height from the front vehicle height sensor 1 and a detection signal representing the front vehicle height from the front vehicle height sensor 2 are output.
A detection signal representing the rear vehicle height from the rear vehicle height is supplied to the interface circuit 38.

FIG. 4 shows the processing procedure carried out in the microcomputer 36, which preferably consists of 20 m
It is executed as a timer interrupt every a.

First, in step (2), the values of front vehicle height hf and rear vehicle height based on the detection signals of front vehicle height sensor 1 and rear vehicle height sensor 2 are read, and then in step (2), half of the sum of both From the difference, a bouncing displacement H5 and a pitching displacement H are calculated.

Next, in step (2), it is determined whether the spring constant of the variable spring constant spring device 6 is set to the soft side or the hard side. The spring constant of this variable spring constant spring device 6 is set to the hard side when the hard mode is set by manual operation. In the auto mode, it is normally set to the soft side to improve ride comfort, and is automatically changed to the hard side during cornering and sudden acceleration/deceleration to improve maneuverability and stability.

When the spring constant is set to the soft side, a control signal of "rL (low level or logical value "O")" is supplied from the interface circuit 38 to the drive circuit 37 in FIG. 2. In this case, no excitation current is supplied from the drive circuit 37 to the switching valve 12, and the switching valve 12 is opened.

Therefore, the air chamber F and the auxiliary air chamber are in communication, and the spring constant is determined by the sum of the volume of the air chamber F and the volume of the auxiliary air chamber. The spring constants are kfs and krs on the soft side.

In addition, when setting the spring constant to the hard side, the interface circuit 38 sends "H" (high level,
or a logic value "1")" control signal is supplied. In this way, a predetermined value of excitation current is supplied from the drive circuit 37 to the switching valve 12, and the switching valve 12 is closed. Therefore, there is a disconnection between the air chamber F and the auxiliary air chamber, and the spring constant is determined only by the volume of the air chamber F. Therefore, the front and rear spring constants are hard side kvo (
>krs) and □(>krs).

If it is determined in step (■) that the spring constant is on the soft side, the process proceeds to step (2), and the front and rear soft side spring constants kf3 and kr are determined for the bouncing displacement Hb determined in step (2). The natural frequency of bouncing obtained based on 15. Bandpass filter processing is performed using a nearby bandwidth to obtain the amplitude Fb of bouncing that passes through that bandwidth.

This band-pass filter processing uses a digital filter processing method as described in, for example, Japanese Patent Application No. 160984/1984 related to the applicant's earlier application. 3 in the control cycle
Using the values of the bouncing displacement H1, a coefficient is determined according to the cutoff frequency of the bandwidth to be passed, and the bouncing amplitude Fb is obtained by calculation.

Next, proceeding to step (2), similarly using the digital filter processing method, the pitching displacement H2 obtained in step (2) is calculated based on the front and rear soft side spring constants kf, and A bandpass filter process is performed using a bandwidth around the natural frequency f2s of the pitching obtained, and the amplitude FP of the pitching that passes through that bandwidth is obtained.

If it is determined in step ■ that the spring constant is on the hard side, then proceed to step ■, and similarly use the digital filter processing method to calculate Perform band-pass filter processing using a bandwidth around the natural frequency fbH of bouncing obtained based on 0 and □ on the front and rear hard side spring constants to obtain the amplitude Fb of bouncing that passes through that bandwidth. .

Next, proceeding to step (2), using the same digital filter processing method, the pitching displacement H2 obtained in step (2) is calculated based on the front and rear hard side spring constants kfH and . A band-pass filter process is performed using a bandwidth around the pitching natural frequency r□ obtained by the pitching, and the pitching amplitude Fp passing through that bandwidth is obtained.

Next, the process moves to step (2), where the absolute value of the bouncing amplitude F obtained in step (2) or (2) is compared with a predetermined judgment level Δb, and if 1Fbl≧Δb, it is determined that the bouncing is large, and the next step is Then, proceed to step (3), and set the damping force of the variable damping force shock absorber 7 to the hard side.

When setting the damping force of the variable damping force shock absorber 7 to the hard side, the interface circuit 38 of the microcomputer 36 inputs rH (high level or logical value "1").
A control signal “)” is supplied to the drive circuit 34. In this way, as shown in FIGS. 2 and 3, a predetermined value of excitation current is supplied from the drive circuit 34 to the solenoid 30 of the actuator 31, so that the solenoid 30 becomes excited, and the electromagnetic force of the solenoid 30 causes the plunger 28 to rotate. - The lower end of the plunger 28 enters the bypass passage 26 against the restoring force of the spring 29, and the communication between the upper piston and the lower piston chamber B is cut off. Therefore, the variable damping force shock absorber 7
The damping force is set to the hard side. Therefore, the bouncing vibration of the vehicle body is attenuated.

Returning to Fig. 4, the next step [phase] is entered, and after the point in time when the bouncing amplitude is attenuated to a small value as a result of the judgment in step A timer t for maintaining the damping force on the hard side for a predetermined time T0 is set to a predetermined value corresponding to the predetermined time T0, and the process returns to the main program.

In step ■, if it is determined that IFbl<Δb, then proceed to step ■, and compare the absolute value of the pitching amplitude Fp obtained in step ■ or ■ with a predetermined judgment level Δp. and IF, l≧Δp
If so, it is determined that the pitching is large, and the next step ■
Then, the damping force of the variable damping force shock absorber 7 is set to the hard side to attenuate pitching.

In step ■, if it is determined that IF,, 1<Δp, move to step [phase], determine whether the value of timer t is 0, and if not, proceed to step 0. Then, the value of timer t is decremented by 1, and the process returns to the main program.

If the timer is t-Q in step 0, the process moves to step [phase] and the damping force of the variable damping force shock absorber 7 is set to the soft side.

When setting the damping force of the variable damping force shock absorber 7 to the soft side, the interface circuit 38 of the microcomputer 36 inputs rL (low level or logical value).
0'')'' is supplied to the drive circuit 34. 2 and 3, no excitation current is supplied from the drive circuit 34 to the solenoid 30 of the actuator 31, so that the solenoid 30 becomes de-energized, and the plunger 28 is moved by the restoring force of the return spring 29. The plunger 28 is pushed upward (in the D direction), the lower end of the plunger 28 comes off the bypass passage 26, and the piston upper chamber A and the piston lower chamber B are brought into communication via the bypass passage 26. Therefore, the variable damping force shock absorber 7 The damping force is set to the soft side.

Returning to FIG. 4, after setting the damping force to the soft side in step (2), return to the main program.

According to such control of bouncing and pitching, depending on whether the spring constant of the variable spring constant spring device 6 is on the soft side or the hard side, the natural frequency of bouncing and pitching based on the spring constant 'b3r f bH
The amplitudes Fb and F of the resonance of bouncing and pitching are extracted according to the bandwidth around rps+fpH, and the damping force of the variable damping force shock absorber 7 is determined depending on whether the amplitude values are equal to or higher than a predetermined judgment level Δb or 69. is set on the hardware or software side. Therefore, regardless of whether the spring constant of the variable spring constant spring device 6 is on the soft side or the hard side, large vibrations due to bouncing and pitching are attenuated by changing the damping force of the variable damping force shock absorber 7 to the hard side. will be done.

FIG. 6 shows a specific example of bouncing (or pitching) vibration control according to the present invention, and FIG. 7 shows a specific example of conventional bouncing (or pitching) vibration control.

In FIG. 6, the spring constant is set to the soft side in the past and to the hard side thereafter.

) <Unsinging vibration (or pitching vibration) occurs at time t1
Both occur before and after, but the frequencies of the vibrations are different. In this invention, the bandwidth around the natural frequency of the vehicle body based on the spring constant is set for each case where the spring constant is on the soft side and when the spring constant is on the hard side. The bouncing amplitude Fb (or the pitching amplitude Fp) of both the vibration on the hard side and the vibration on the hard side
is extracted, and the damping force is set to the hard side at time ('r+ +7'0) and time (T2 + T11), so that the bouncing vibration (both before and after time t1) is
or pitching vibration) is attenuated.

On the other hand, in the conventional case shown in FIG. 7, the amplitude F, (or F,) of the bouncing vibration (or pitching vibration)
Since the bandwidth for extracting is constant for both the soft and hard sides of the spring constant, the amplitude Fb (or F,) of the vibration before time t1 is extracted, and the damping force is At time (TI +'l', ), the vibration is damped by setting it to the hard side, but at time 1.
The amplitude F, (or F,) of the subsequent vibrations could not be extracted, and the damping force remained on the soft side, so the vibrations could not be damped.

FIG. 5 shows a procedure of processing executed in the microcomputer 36 as a modification of the above embodiment. This modified example is based on the patent application filed in 1986-138 listed at the beginning as a conventional example.
This invention is applied to the process in the specification of No. 567.

The processing in this modified example will be briefly explained below. This processing is applied to bouncing vibration control, but in step O it is determined whether the spring constant is set to the soft side or the hard side. If it is set to the side, the process moves to step [phase], and a predetermined setting value T and T for determining the count value cM of a counter that measures the time during which the bouncing vibration to be damped is generated. , is set as TA-TA3 and TI "Tm3, and if it is set on the hardware side, the step [phase] is shifted and TA-T□ (>TAs) and TI-Tm
Set as u(>Tm5).

Then, in step 2, the neutral position HN of the vehicle height obtained in advance and the vehicle height H read in step [phase]
It is determined whether the absolute value of the difference between the values (that is, the amplitude of the vehicle height H) is equal to or greater than a predetermined bouncing determination level H1°1.

Then, in step [phase], the count value CN is compared with its predetermined set values TA and T, and T,≦cN<'r
If s, it is determined that the vehicle body is generating bouncing vibration, and the damping force is set to the hard side.

That is, the predetermined set values TA and T are for setting the bandwidth of the bouncing vibration, and the predetermined set values TA and T are set according to the spring constant at the step [phase] and 0. Therefore, in the process of this modification, the bandwidth for extracting the bouncing vibration is set in accordance with the spring constant, similar to the above-described embodiment.

In addition, in FIGS. 1 to 5, the front vehicle height sensor 1, the rear vehicle height sensor 2, and step (2).

The processes in steps ■ and [stock] and ■ provide a specific example of the vehicle body vibration detection means, and the processes in steps ]
The processing in step (2) is a specific example of the bandwidth setting means, the processing in steps (2) and (2) is a specific example of the vehicle body vibration determination means, and the processing in step (2) and step [phase] 5@ is used for the drive circuit 34 and actuator 31. Specific examples of damping force setting means are shown below.

In addition, in the above-mentioned embodiments and their variations, configurations using a microcomputer as a controller have been shown, but instead of this, addition/subtraction circuits, multiplication circuits, division circuits, timer circuits, counter circuits, comparison circuits, It is also possible to configure the controller by combining electronic circuits such as circuits, logic circuits, and command value setting circuits.

Further, although the spring constant of the variable spring constant spring device and the damping force of the variable damping force shock absorber are shown as being able to be changed in two stages, soft side and hard side, the present invention is not limited to this. For things that can be changed into multiple stages, the present invention can be applied to any two of the multiple stages.

Further, if the spring constant can be changed in multiple stages of three or more stages, the bandwidth can be set for each stage. - [Effects of the Invention] As explained above, according to the vehicle suspension control device according to the present invention, vehicle body vibrations such as bouncing vibrations or pitching vibrations are extracted according to the spring constant of the variable spring constant spring device. By setting the bandwidth of However, by detecting vehicle body vibrations such as bouncing vibrations and pitching vibrations and appropriately setting the damping force, it is possible to attenuate these vibrations.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the basic configuration of a vehicle suspension control device according to the invention, FIG. 2 is a diagram showing the configuration of an embodiment of the invention, and FIG. 3 is a variable damping force used in the invention. A vertical cross-sectional view showing an example of a shock absorber,
FIG. 4 is a flowchart showing the processing procedure executed in the microcomputer as the above embodiment, FIG. 5 is a flowchart showing the processing procedure executed in the microcomputer as a modification of the above embodiment, and FIG. Time chart showing a specific example of operation, No. 7
The figure shows a time chart showing a specific example of the operation of a conventional device.
FIG. 8 is a diagram schematically showing the vehicle body and the spring. DESCRIPTION OF SYMBOLS 1... Front vehicle height sensor, 2... Rear vehicle height sensor, 4... Suspension device, 6... Spring constant variable spring device, 7... Damping force variable shock absorber, 9...・Elastic body, 10... Auxiliary tank, 11...
・Pipeline, 12...Switching valve, 14...Piston lower chamber, 17...Tube, 18...Piston, 2
6... Bypass path, 28... Plunger, 29...
・Return spring, °30... Solenoid, 31
...Actuator, 34...Drive circuit, 35...
・Controller, 36...Microcomputer, 3
7... Drive circuit, 38... Interface circuit, 3
9... Arithmetic processing unit, 40... Storage device, A...
Upper piston chamber, B: lower piston chamber, F: air chamber, K: auxiliary air chamber.

Claims (1)

[Scope of Claims] A variable damping force shock absorber capable of changing damping force in at least two stages, a soft side and a hard side, and a variable spring constant spring device capable of changing a spring constant in at least two stages, a soft side and a hard side. a suspension device including;
a vehicle body vibration detection means for detecting vehicle body vibration; either extracting a frequency component of a predetermined bandwidth from the vehicle body vibration detection signal and determining the amplitude of the frequency component; a vehicle body vibration determining means for extracting a vibration component of the vibration component and determining whether the frequency of the vibration component is within a predetermined bandwidth; A suspension control device for a vehicle comprising a damping force setting means for setting a damping force, further comprising a bandwidth setting means for setting a bandwidth of the vehicle body vibration determining means according to a spring constant of the variable spring constant spring device. A vehicle suspension control device characterized by: