JP3182018B2 - Vehicle suspension system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle suspension system for optimally controlling a damping characteristic of a shock absorber.

[0002]

2. Description of the Related Art Conventionally, as a vehicle suspension device for controlling damping characteristics of a shock absorber, for example, Japanese Unexamined Patent Publication No.
What is described in 163011 is known.

[0003] In this conventional vehicle suspension device, the sprung vertical speed obtained from the sprung vertical acceleration detected by the sprung vertical acceleration detecting means and the direction discrimination code of the sprung / unsprung relative speed detected by the load sensor are used. The damping characteristics based on the Skyhook theory, such as making the damping characteristics hard when the same sign is used, and softening the damping characteristics when the sign is different, are performed independently for the four wheels.

[0004]

[SUMMARY OF THE INVENTION However, in the conventional apparatus described above, for which was the above-described configuration, as shown in FIG. 18, the vehicle acts lateral acceleration G _S to the vehicle When the vehicle is inclined, the acceleration detection axis of the sprung vertical acceleration sensor 1 is also inclined with the inclination of the vehicle. Therefore, when a lateral acceleration acts on the vehicle in this state, the lateral acceleration is spun as a component force. Acting in the detection axis direction of the vertical acceleration sensor 1, the sprung vertical acceleration sensor 1 may detect the value of the actual sprung vertical acceleration plus the component force g _VS of the lateral acceleration component. Therefore, there is a problem that the controllability is deteriorated at the time of turning or the like in which lateral acceleration acts on the vehicle, and sufficient vibration damping cannot be obtained.

[0005] When the characteristics of the hardware are suitable for a case where the vehicle body is moving in the bounce direction, the center of gravity of the vehicle body with respect to the sprung mass for the vehicle body movement in which bounce and pitch or roll are coupled. Since the inertia moment of the surrounding body is added, there is a problem that the control force is insufficient and the steering stability is poor.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and is directed to a vehicle suspension system capable of preventing deterioration of controllability due to a detection error even in a situation where a lateral acceleration acts on a vehicle. With the primary purpose of providing,
It is a second object of the present invention to provide a vehicle suspension device that can generate a sufficient control force even for the moment of inertia.

[0007]

In order to achieve the above-mentioned first object, a vehicle suspension system according to the present invention is provided between a vehicle body side and each wheel side as shown in a conceptual view of a claim in FIG. A shock absorber b whose damping characteristic can be changed by damping characteristic changing means a, a vehicle behavior detecting means c detecting at least a sprung vertical acceleration as a vehicle behavior, and a damping characteristic of each shock absorber b at least a sprung vertical acceleration. A control means e having a damping characteristic control unit d for performing optimal control based on a vehicle behavior detection value including a detection value, wherein the vehicle behavior detection means c detects a lateral acceleration of the vehicle. The control means e includes a lateral acceleration detecting means f, and the control means e includes upper and lower parts included in the lateral acceleration based on the lateral acceleration detection value detected by the lateral acceleration detecting means f.
In the direction of the sprung mass.
The correction control unit g is provided to obtain a corrected sprung vertical acceleration by subtracting from the output value .

According to a second aspect of the present invention, in the vehicle suspension system according to the second aspect, the damping characteristic control unit adjusts a damping characteristic of each shock absorber by a sprung vertical acceleration by a correction control unit. The bounce rate based on the sprung vertical speed obtained from the correction value of the detected value, the pitch rate detected from the front and rear sprung vertical speed difference, and the roll rate detected from the left and right sprung vertical speed difference are used as control signals. It was controlled based on.

[0009]

According to the vehicle suspension system of the present invention, when the vehicle inclines due to a lateral acceleration acting on the vehicle, such as when the vehicle is turning, or when the vehicle is being braked or accelerated, the correction control unit of the control means is used. , The lateral direction detected by each lateral acceleration detecting means
The vertical acceleration included in the lateral acceleration is
Calculate the component force and use the component value to calculate the sprung vertical acceleration detection value.
To calculate a corrected sprung vertical acceleration by subtracting the vertical acceleration from the vertical acceleration included in the lateral acceleration.
Since the detection error of the sprung vertical acceleration corresponding to the force is corrected, lateral acceleration acts on the vehicle, such as when turning, causing the vehicle to
Even in a situation where both are inclined, it is possible to prevent the controllability from deteriorating and obtain sufficient vibration damping.

Further, in the vehicle suspension device according to the second aspect,
In the attenuation characteristic control section, attenuation characteristic control based on a control signal obtained from the bounce rate, the pitch rate, and the roll rate is performed.
A sufficient control force can be generated not only for the bounce but also for the pitch and roll due to the moment of inertia.

[0011]

An embodiment of the present invention will be described with reference to the drawings. First, the configuration will be described.

FIG. 2 is a structural explanatory view showing a vehicle suspension system according to an embodiment, and is interposed between a vehicle body and four wheels.
Four shock absorbers SA ₁ , SA ₂ , SA ₃ , S
A ₄ (in describing the shock absorber, when referring to these four together, and when describing their common configuration, simply referred to as SA) is provided. And the shock absorber SA on the right rear wheel side
_Three shock absorbers SA ₁ , SA ₂ , S except 3
The vehicle body near the position of A _4, the vertical acceleration sensor for detecting a sprung mass vertical acceleration (hereinafter, referred to as vertical G sensors)
1 ₁ , 1 ₂ , 1 ₄ (in describing the upper and lower G sensors, when these four are collectively referred to, and when describing their common configuration, they are simply indicated as 1). I have. Also, on the vehicle body near the center of the roll,
A lateral acceleration sensor (hereinafter referred to as a lateral G sensor) 2 for detecting acceleration in the lateral direction of the vehicle body is provided, and a vertical G sensor 1 and a lateral G sensor 2
And a signal from the vehicle speed sensor 5 and a control unit 4 for outputting a drive control signal to the pulse motor 3 of each shock absorber SA.

FIG. 3 is a system block diagram showing the above configuration. The control unit 4 includes an interface circuit 4a, a CPU 4b, and a drive circuit 4c. , A lateral acceleration signal from the lateral G sensor 2, and a vehicle speed signal from the vehicle speed sensor 5. The interface circuit 4a includes:
As shown in (a), (b), and (c) of FIG.
A set of filter circuits is provided. That is, LPF1,
LPF2, LPF 3 is a low-pass filter circuit for converting bouncing component G _B sprung vertical acceleration to be described later, the pitch component G _P, a signal indicating the roll component G _R by integrating each sprung mass vertical velocity signal. The BPF 1 is a bandpass filter circuit that obtains a signal in a frequency range including a sprung resonance frequency. The BPF 2 is a band-pass filter circuit that obtains a signal in a frequency range including the pitch resonance frequency. The BPF 3 is a band-pass filter circuit that obtains a signal in a frequency range including the roll resonance frequency. Incidentally, in the present embodiment, the case where the sprung resonance, the pitch resonance, and the roll resonance have different frequencies is taken as an example. However, when these resonance frequencies are close to each other, only the BPF1 may be used as the bandpass filter.

Next, FIG. 4 is a sectional view showing the structure of the shock absorber SA.
A is a cylinder 30, a piston 31 that defines the cylinder 30 in an upper chamber A and a lower chamber B, an outer cylinder 33 in which a reservoir chamber 32 is formed on the outer periphery of the cylinder 30, a lower chamber B and a reservoir chamber 32. Base 34 and piston 31
A guide member 35 for guiding the sliding of the piston rod 7 connected to the outer cylinder 33, a suspension spring 36 interposed between the outer cylinder 33 and the vehicle body, and a bump rubber 37.

FIG. 5 is an enlarged sectional view showing a part of the piston 31. As shown in FIG. 5, the piston 31 has through holes 31a and 31b formed therein, and An expansion damping valve 12 and a compression damping valve 20 for opening and closing 31a and 31b, respectively, are provided. A stud 38 that penetrates the piston 31 is screwed and fixed to the bound stopper 41 screwed to the tip of the piston rod 7, and the stud 38 bypasses the through holes 31a and 31b. Communication for forming flow paths (extension-side second flow paths E, expansion-side third flow paths F, bypass flow paths G, and compression-side second flow paths J to be described later) that communicate the upper chamber A and the lower chamber B. A hole 39 is formed.
An adjuster 40 for changing the flow path cross-sectional area of the flow path is rotatably provided in 9. Also, stud 38
The communication hole 3 is formed on the outer periphery of the communication hole 3 in accordance with the direction of fluid flow.
An expansion-side check valve 17 and a compression-side check valve 22 that allow and shut off the flow on the flow path side formed by 9 are provided. The adjuster 40 is rotated by the pulse motor 3 via a control rod 70 (see FIG. 4). The first port 21, the second port 13, the third port 18, the fourth port 14, and the fifth port 16 are formed on the stud 38 in order from the top.

On the other hand, the adjuster 40 has a hollow portion 19, a first horizontal hole 24 and a second horizontal hole 25 communicating between the inside and the outside, and a vertical groove 23 formed in the outer peripheral portion. I have.

Therefore, between the upper chamber A and the lower chamber B, a through-hole 31 is formed as a flow path through which fluid can flow in the extension stroke.
b, the inside of the extension side damping valve 12 is opened to open the lower chamber B
, The second port 13, the vertical groove 23,
Via the second port 13, the vertical groove 23, and the fifth port 16 via the fourth port 14, the outer peripheral side of the extension side damping valve 12 is opened to open the outer peripheral side of the extension side damping valve 12 to reach the lower chamber B, Then, the extension side check valve 17 is opened to open the extension side third flow path F to the lower chamber B, and the bypass to the lower chamber B via the third port 18, the second horizontal hole 25, and the hollow portion 19. There are four flow paths G. In addition, as a flow path through which fluid can flow in the pressure stroke, the pressure side first valve that opens the pressure side damping valve 20 through the through hole 31a.
Channel H, hollow portion 19, first lateral hole 24, first port 21
, The pressure-side second flow path J that opens the pressure-side check valve 22 to reach the upper chamber A through the air passage, and the bypass flow that reaches the upper chamber A through the hollow portion 19, the second horizontal hole 25, and the third port 18. Road G
And three flow paths.

That is, the shock absorber SA is configured so that the damping characteristic can be changed in multiple steps by rotating the adjuster 40 with the characteristics shown in FIG. 6 on both the extension side and the compression side. That is, as shown in FIG. 7, when the adjuster 40 is rotated counterclockwise from a state where both the extension side and the compression side are soft (hereinafter, referred to as a soft area SS), the attenuation characteristic of the extension side only is multi-stepped. It is possible to change the compression side to a region where the compression side is fixed to the low attenuation characteristic (hereinafter referred to as the extension side hard region HS). Conversely, when the adjuster 40 is rotated clockwise, the attenuation characteristic of only the compression side can be changed in multiple stages. The extension side has a structure fixed to a low attenuation characteristic (hereinafter referred to as a compression side hard area SH).

FIG. 7 shows the KK section, LL section, MM section, and NN section in FIG. 8, 9 and 10 and the damping force characteristics at each position are shown in FIGS.

Next, the operation of the control unit 4 for controlling the driving of the pulse motor 3 will be described with reference to the flowchart of FIG. This control is performed separately for each shock absorber SA.

First, in step 101, a sprung vertical acceleration detection value g obtained from each vertical G sensor 1 is read, and a lateral acceleration detection value g _S in the vehicle left-right direction obtained from the horizontal G sensor 2 is read.

In the following step 102, the following equation is used to calculate the component force g _{VS of the} lateral acceleration acting (added) in the detection axis direction from the sprung vertical acceleration detection value g obtained from each vertical G sensor 1. The subtracted vertical acceleration signal G (G _FR ,
G _FL , G _RL ).

G = g−K · | g _S | where K is a component g _{VS of the} lateral acceleration from the detected lateral acceleration g _S.
Is a coefficient for obtaining. That is, as shown in FIG. 18, the detection axis of the lateral G sensor 2 also inclines when the vehicle inclines, but since the inclination angle (roll angle) θ of the vehicle is about 6 degrees at the maximum, the lateral acceleration is detected. The value g _S and the actual lateral acceleration G _{S can be} regarded as an approximate value (g _S ≒ G _S ). Then, a component force g _VS of the lateral acceleration detected by the vertical G sensor 1, it is possible to determine a formula of g _VS = g _S sin θ, as shown in FIG. 18, the lateral acceleration detected value g _S and the roll The value of a coefficient K as an approximate value of sin θ can be obtained based on a map in which the value of sin θ is correlated with the value of sin θ based on the angle θ. By multiplying the coefficient K by the lateral acceleration detection value g _S And the component g _{VS of the} lateral acceleration can be obtained (g _VS = K · | g _S |).

[0024] Step 103, using the following equation, as shown in FIG. 19, the bounce component G _B of the vehicle center-of-gravity position
And a pitch component G _P centered on the pitch center of the vehicle
And a roll component G _R centered on the roll center of the vehicle.

First, the vertical acceleration signal G (G _FR , G _FL , G _RL ) of each position by each vertical G sensor 1 can be expressed as follows.

[0026] _{G FR = G B + L 1} · G R + L 2 · G P G FL = G B -L 3 · G R + L 4 · G P G RL = G B -L 5 · G R -L 6 · G _P can therefore be determined bounce component of the vehicle based on the following equation obtained by modifying the above equation G _B, the pitch component G _P, the roll component G _R.

G _B = 1 / Δ {(L ₃ · L ₆ + L ₄ · L ₅ ) G _FR + (L ₁ · L ₆ -L ₂ · L
₅ ) + G _FL + (L ₁ · L ₄ + L ₂ · L ₃ ) G _RL } _GP = 1 / Δ {(L ₃ -L ₅ ) G _FR + (L ₁ + L ₅ ) G _FL- ( _{L 1 + L 3) G RL} } G R = 1 / Δ {(L 4 + L 6) G FR - (L 2 + L 6) G FL + (L 2 -L 4) G RL} ( Note, delta _{= L 3 · L 6 -L 2} · L 5 + L 1 · L 4 + L 2 · L 3 + L 4 · L 5 + L 1 · L 6) step 104, the bounce component G _B, the pitch component G _P, roll component G each filter circuits each signal of _R LPF
1, BPF1, LPF2, BPF2, LPF3, BPF
3 and the speed component V _B in the bounce direction and the pitch component V
_P, performs processing for calculating the roll component V _R, FIG. 20
The proportional constant α (α _f , α _{f) of} the two components V _B , V _P according to the vehicle speed signal obtained by the vehicle speed sensor 5 based on the map shown in FIG.
_r ) and β (β _f , β _r ) are set. In addition, each component V
_B , V _P and V _R are given as positive values when the sprung vertical acceleration is in the upward direction, and are given as negative values when the sprung vertical acceleration is in the downward direction.

In step 105, the control signals V (V ₁ , V ₁ , V 2) of the position of each wheel are determined based on the components V _B , V _P , V _R and the proportional constants α, β, γ using the following equations. _2, V _3, V
₄ ) This is the step of calculating.

[0029] The front wheel right _{V 1 = α f · V B} + β f · V P + γ f · V R front wheel left _{V 2 = α f · V B} + β f · V P -γ f · V R rear wheel right V ₃ = Incidentally _{α r · V B -β r ·} V P + γ r · V R rear wheel left _{V 4 = α r · V B} -β r · V P -γ r · V R, α f, β f, γ f is , _{R r} , β _r , and γ _r are the respective proportional constants of the rear wheels.

In each equation, the part bounded by the first α _f and α _r is the bounce rate, and β _f and β _r
The portion between the two is the pitch rate, γ _f , γ _r
The rolled part is the roll rate.

[0031] Step 106, the control signal V is a step equal to or larger than a predetermined threshold value [delta] _T, controls the shock absorber SA to the extension side hard region HS proceeds to step 107 is YES Then, the process proceeds to step 108 if NO.

[0032] Step 108, the control signal V is determining whether a value between a predetermined threshold value [delta] _T and the threshold - [delta _C, shock absorber proceeds to step 109 is YES The SA is controlled to the soft area SS, and the process proceeds to step 110 if NO.

Step 110 is a step displayed for the sake of convenience.
When it is determined that O is the control signal V is less than a predetermined threshold value - [delta _C, in this case, the process proceeds to step 111,
The shock absorber SA is controlled to the pressure side hard area SH.

Next, the control operation of the control unit 4 will be described with reference to the time chart of FIG.

When the control signal V based on the sprung vertical speed changes as shown in FIG. 5, when the control signal V is a value between the predetermined thresholds δ _T and −δ _C , the shock absorber SA is turned off. Control to the soft area SS.

When the control signal V becomes equal to or greater than the threshold value δ _{T, the} compression side is controlled to the expansion side hard region HS so that the compression side is fixed to a low attenuation characteristic, while the expansion side attenuation characteristic is made proportional to the control signal V. Change. At this time, the attenuation characteristic C is C = k ₁ · V
Is controlled so that Incidentally, k ₁ is a proportionality constant of the expansion side.

When the control signal V becomes equal to or smaller than the threshold value -δ _{C, the} compression side is controlled to the compression side hard area SH to fix the expansion side to low attenuation characteristics, while making the compression side attenuation characteristics proportional to the control signal V. Change. Also at this time, the attenuation characteristic C is C = k ₂
・ V is controlled to be V. Note that k ₂ is a proportional constant on the pressure side.

In the time chart of FIG.
The area a is a state in which the control signal V based on the sprung vertical speed is reversed from a negative value (downward) to a positive value (upward), but at this time, the relative speed is still a negative value (the shock absorber SA has a negative value). Since the stroke is a pressure stroke side), at this time, the shock absorber SA is controlled to the extension side hard region HS based on the direction of the control signal V.
Therefore, in this area a, the shock absorber S at that time is
The pressure stroke side, which is the stroke of A, has soft characteristics.

In the region b, the control signal V based on the sprung vertical speed remains a positive value (upward), and the relative speed changes from a negative value to a positive value (the stroke of the shock absorber SA is on the extension stroke side). At this time, the shock absorber SA is controlled to the extension-side hard region HS based on the direction of the control signal V, and the stroke of the shock absorber is also the extension stroke. In this region b, the extension stroke side, which is the stroke of the shock absorber SA at that time, has a hard characteristic proportional to the value of the control signal V.

The area c is a state where the control signal V based on the sprung vertical speed is reversed from a positive value (upward) to a negative value (downward), but at this time, the relative speed is still a positive value. (The stroke of the shock absorber SA is on the extension stroke side.) At this time, the shock absorber SA is controlled to the compression-side hard region SH based on the direction of the control signal V. In c, the softening characteristic is on the extension stroke side which is the stroke of the shock absorber SA at that time.

In the area d, the control signal V based on the sprung vertical speed remains a negative value (downward), and the relative speed changes from a positive value to a negative value (the stroke of the shock absorber SA is on the extension stroke side). At this time, the shock absorber SA is controlled to the compression-side hard region SH based on the direction of the control signal V, and the stroke of the shock absorber is also the compression stroke. Then, the pressure stroke side, which is the stroke of the shock absorber SA at that time, has a hard characteristic proportional to the value of the control signal V.

As described above, in this embodiment, when the sprung vertical speed and the relative speed between the sprung and unsprung have the same sign (region b, region d), the shock absorber S at that time is used.
A damping characteristic control based on the skyhook theory, in which the stroke side of A is controlled to a hard characteristic, and when the sign is different (regions a and c), the stroke side of the shock absorber SA at that time is controlled to a soft characteristic. The same control will be performed without detecting the relative speed between sprung and unsprung. Further, in this embodiment, when shifting from the area a to the area b and from the area c to the area d, the switching of the damping characteristic is performed without driving the pulse motor 3.

As described above, in this embodiment, the following effects can be obtained. Included in lateral acceleration
The lateral acceleration acts on the vehicle by correcting the detection error of the sprung vertical acceleration corresponding to the vertical component force.
Even when the vehicle turns inclining, it is possible to prevent the controllability from deteriorating due to the detection error and obtain sufficient vibration damping.

Since a sufficient control force can be generated not only for the bounce but also for the pitch and the roll due to the moment of inertia, a vehicle suspension system excellent in the riding comfort and the steering stability of the vehicle can be provided. .

Since the frequency of switching the damping characteristic is reduced as compared with the damping characteristic control based on the conventional skyhook theory, control responsiveness can be improved and the durability of the pulse motor 3 can be improved.

In obtaining the bounce rate, pitch rate, and roll rate, different coefficients α,
Since β and γ are used, in the vehicle, even if the sprung resonance frequency, the pitch resonance frequency, and the roll resonance frequency are different from each other, each rate can be accurately detected based on the sprung vertical speed.

Although the embodiment has been described above, the specific configuration is not limited to this embodiment, and any change in design or the like without departing from the gist of the present invention is included in the present invention.

For example, in the embodiment, a part of the proportionality constant is changed according to the vehicle speed. However, it may be set to a constant value.

Further, in the embodiment, the case where lateral acceleration in the lateral direction of the vehicle is detected as lateral acceleration has been described as an example, but lateral acceleration in the longitudinal direction of the vehicle is detected, and the sprung vertical acceleration is detected based on the detected value. By correcting the detection value, it is possible to prevent a deterioration in controllability due to a detection error and to secure a sufficient damping property even during a brake operation or acceleration in which a longitudinal acceleration acts.

Further, in the embodiment, the case where the damping characteristic control is performed based only on the sprung vertical acceleration detection value has been described. However, the case where the control is performed in combination with other vehicle behavior such as the relative speed between the sprung and the unsprung. The present invention can also be applied to

Further, in the embodiment, when the damping characteristic on one stroke side of the extension side and the compression side is variably controlled, a shock absorber having a structure in which the reverse stroke side is maintained at a predetermined low damping characteristic is used. Control using a shock absorber having a structure in which the damping characteristics of the pressure side and the compression side simultaneously change can be performed.

[0052]

As described above, according to the vehicle suspension system of the present invention, the vertical component force included in the lateral acceleration is obtained from the lateral acceleration detection value detected by the lateral acceleration detecting means.
From the detected sprung vertical acceleration value.
By providing a correction control unit that calculates the sprung vertical acceleration corrected by subtraction, the vertical
Correct the detection error of the sprung vertical acceleration corresponding to the component force, so that the lateral acceleration acts on the vehicle such as when turning.
As a result, even in a situation where the vehicle is leaning, it is possible to obtain an effect that it is possible to prevent deterioration in controllability due to a detection error and to obtain sufficient vibration damping.

The vehicle suspension system according to the second aspect of the present invention includes a bounce rate based on a sprung vertical speed obtained from a correction value of a sprung vertical acceleration detection value by a correction control unit. By controlling based on the control signal obtained from the pitch rate detected from the front and rear sprung vertical speed difference and the roll rate detected from the left and right sprung vertical speed difference, not only bounce but also inertia moment , A sufficient control force can be generated for the pitch and roll.

[Brief description of the drawings]

FIG. 1 is a conceptual view of a claim showing a vehicle suspension system of the present invention.

FIG. 2 is an explanatory diagram illustrating a configuration of a vehicle suspension device according to an embodiment of the present invention.

FIG. 3 is a system block diagram showing a vehicle suspension device according to the embodiment.

FIG. 4 is a cross-sectional view showing a shock absorber applied to the embodiment device.

FIG. 5 is an enlarged sectional view showing a main part of the shock absorber.

FIG. 6 is a damping force characteristic diagram corresponding to a piston speed of the shock absorber.

FIG. 7 is a damping characteristic diagram corresponding to a step position of a pulse motor of the shock absorber.

FIG. 8 is a perspective view of the shock absorber shown in FIG.
It is -K sectional drawing.

FIG. 9 is a perspective view of the shock absorber shown in FIG.
It is an L sectional view and MM sectional view.

FIG. 10 is a sectional view taken along line NN of FIG. 5 showing a main part of the shock absorber.

FIG. 11 is a damping force characteristic diagram when the shock absorber is on the extension side hard.

FIG. 12 is a damping force characteristic diagram of the shock absorber in a soft state on an extension side and a compression side.

FIG. 13 is a damping force characteristic diagram of the shock absorber in a pressure-side hard state.

FIG. 14 is a block diagram showing a main part of the control unit.

FIG. 15 is a flowchart showing a control operation of the control unit.

FIG. 16 is a time chart showing the control operation of the control unit.

FIG. 17 is a diagram illustrating a component force of a lateral acceleration component acting in the detection axis direction of the upper and lower G sensors.

FIG. 18 is a map showing a correlation between a detected lateral acceleration value and a value of sin θ based on a roll angle.

FIG. 19 is a diagram for explaining a method of calculating a bounce component, a pitch component, and a roll component.

FIG. 20 is a map showing variable characteristics of proportional constants α and β with respect to a vehicle speed.

[Explanation of symbols]

 a damping characteristic changing means b shock absorber c sprung vertical speed detecting means d lateral acceleration detecting means e damping characteristic control part f control means g correction control part

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B60G 17/015

Claims (2)

(57) [Claims] 1. A shock absorber interposed between a vehicle body side and each wheel side and capable of changing damping characteristics by damping characteristic changing means, a vehicle behavior detecting means for detecting at least sprung vertical acceleration as vehicle behavior, Control means having a damping characteristic control unit for optimally controlling the damping characteristic of the shock absorber based on a vehicle behavior detection value including at least a sprung vertical acceleration detection value, wherein the vehicle behavior detection means A lateral acceleration detecting means for detecting a lateral acceleration of the vehicle, wherein the control means includes a lateral acceleration detection value obtained from the lateral acceleration detection value detected by the lateral acceleration detecting means.
Calculate the vertical component force included in the directional acceleration and calculate the component
Was corrected by subtracting from the sprung vertical acceleration detection value.
A vehicle suspension device provided with a correction control unit for obtaining a sprung vertical acceleration . 2. The damping characteristic control unit calculates a damping characteristic of each shock absorber by a bounce rate based on a sprung vertical speed obtained from a correction value of a sprung vertical acceleration detection value by a correction control unit, and a front and rear sprung vertical. 2. The vehicle suspension according to claim 1, wherein the control is performed based on a control signal obtained from a pitch rate detected from the speed difference and a roll rate detected from the left and right sprung vertical speed differences.