JPH11198624A - Vehicle behavior operation device and vehicle suspension device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately detect vehicle behavior from a wheel speed signal even if a vehicle speed changes by providing a means to arithmetically operate the vehicle behavior from the wheel speed signal detected by a wheel speed sensor and a means to change the vehicle behavior operation content according to a vehicle speed detected by a vehicle speed detecting means. SOLUTION: A pitch speed and a roll speed of a vehicle being vehicle behavior is found by a vehicle behavior operation means (b) from a wheel speed signal detected by wheel speed sensor (a). A change is applied by an operation content changing means (d) to change the vehicle behavior operation content to find the pitch speed and the roll speed according to a vehicle speed detected by a vehicle speed detecting means (c) at that time. Therefore, the pitch speed and the roll speed of the vehicle can be accurately detected even if the vehicle speed changes by correcting a detecting error caused when a pulse frequency and a noise component of the wheel speed sensor (a) changes according to the vehicle speed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle behavior calculation device for detecting various behaviors in a vehicle, and a vehicle suspension device to which the vehicle behavior calculation device is applied.

[0002]

2. Description of the Related Art As a vehicle behavior calculation device as described above, for example, a "suspension behavior detection device" described in Japanese Patent Application Laid-Open No. 6-48139 is known.
This conventional suspension behavior detecting device comprises a wheel speed detecting means for detecting a wheel speed, and a natural frequency of a vehicle including a resonance frequency of a sprung member and a resonance frequency of a unsprung member based on the detected wheel speed. The relative displacement speed between the sprung member and the unsprung member is calculated based on the wheel speed fluctuation amount based on the wheel speed fluctuation amount extracting means for obtaining the wheel speed fluctuation amount in the area and a predetermined relationship determined from the geometry of the suspension. And a relative displacement speed calculating means. The wheel speed signal is processed based on a predetermined relationship determined by certain high-pass and low-pass filters and suspension geometry.

[0003]

However, the conventional suspension behavior detecting device has the following problems since it is configured as described above. That is,
The wheel speed sensor that detects the wheel speed detects the number of teeth of the gear-shaped rotor integrally provided on the tire side as a pulse signal, and measures the number of detected pulse signals within a unit time to measure the number of rotations of the tire. Since the vehicle behavior is to detect how the detected pulse signal fluctuates by extracting a predetermined frequency component, the vehicle behavior component included in the pulse signal is minute. Therefore, it is difficult to accurately detect the vehicle behavior from the wheel speed signal, and the pulse wave frequency of the wheel speed sensor fluctuates depending on the vehicle speed. Further, the noise component from the road surface varies depending on the vehicle speed. Changes, it becomes more difficult to accurately detect the vehicle behavior component detected from the wheel speed variation.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and provides a vehicle behavior calculation device capable of detecting vehicle behavior accurately from a wheel speed signal even if the vehicle speed fluctuates. It is intended for.

[0005]

In order to achieve the above object, in a vehicle suspension system according to the present invention, a wheel speed sensor a for detecting a wheel speed, and a wheel speed sensor a for detecting a wheel speed. Vehicle behavior calculating means b for calculating vehicle behavior from wheel speed signals, and vehicle speed detecting means c for detecting vehicle speed
And calculation content changing means d for changing the vehicle behavior calculation content in the vehicle behavior calculation means b according to the vehicle speed of the vehicle detected by the vehicle speed detection means.
According to a second aspect of the present invention, in the first aspect, the operation content changing unit d changes the vehicle behavior operation content by switching a plurality of operation units having different operation contents according to the vehicle speed. Means. According to a third aspect of the present invention, in the first aspect, the calculation content changing unit changes the content of the vehicle behavior calculation by changing a coefficient of an arithmetic expression in the vehicle behavior calculation unit in accordance with the vehicle speed. The means are configured as follows. According to a fourth aspect of the present invention, there is provided the vehicle behavior calculation device according to the first to third aspects, wherein the vehicle behavior calculated by the vehicle behavior calculation means b includes a vertical behavior of the vehicle. The vehicle behavior calculation device according to claim 5, wherein the vehicle behavior calculation means (b) detects a pitch speed in the vehicle from a wheel speed change detected by the wheel speed sensor (a). Means are included. In the vehicle behavior calculation device according to claim 6,
The wheel speed sensor (a) according to claim 1, wherein the wheel speed sensor (a) is provided on at least one of the left and right wheels of a front wheel or a rear wheel, and the vehicle behavior calculation means (b) determines the right and left wheel speeds detected by the left and right wheel speed sensors. The means includes a roll speed detecting means for detecting a roll speed in the vehicle from the difference. In the vehicle behavior calculation device according to the seventh aspect,
In 6, the vehicle speed detecting means c is a means constituted by the wheel speed sensor a and a vehicle speed calculating means for calculating a vehicle speed of the vehicle from a wheel speed signal detected by the wheel speed sensor a. In the vehicle suspension device according to the eighth aspect, the rigidity of the vehicle suspension is controlled based on the vehicle behavior signal calculated by the vehicle behavior calculation device according to any one of the first to seventh aspects.

[0006]

In the vehicle behavior calculation device according to the first aspect of the present invention,
The vehicle behavior calculation means b calculates the vehicle behavior from the wheel speed signal. At this time, the calculation content change means d changes the vehicle behavior calculation content in the vehicle behavior calculation means b according to the vehicle speed. Thus, the detection error caused by the pulse frequency and the noise component of the wheel speed sensor fluctuating in accordance with the vehicle speed is corrected, so that accurate vehicle behavior can be detected even if the vehicle speed fluctuates. it can. In the vehicle behavior calculation device according to claim 2,
By changing a plurality of calculation means having different calculation contents according to the vehicle speed, the vehicle behavior calculation content is changed, whereby the detection error is corrected and the accuracy is increased. In the vehicle behavior calculation device according to the third aspect, the content of the vehicle behavior calculation is changed by changing the coefficient of the calculation formula according to the vehicle speed, thereby reducing the cost of the vehicle behavior calculation means. In the vehicle behavior calculation device according to the fourth aspect, the vehicle behavior calculation means b calculates the vertical behavior of the vehicle according to the wheel speed signal and the vehicle speed.
It is possible to accurately detect the vertical behavior of a vehicle that is strongly affected by changes in vehicle speed, and in a vehicle equipped with an anti-skid control device, the vertical behavior of the vehicle can be detected without adding a new vertical acceleration sensor. Can be detected. In the vehicle behavior calculation device according to the fifth aspect, the vehicle behavior calculation means b calculates the pitch speed of the vehicle according to the wheel speed signal and the vehicle speed. In the vehicle equipped with the anti-skid control device,
The pitch speed of the vehicle can be detected without newly adding a longitudinal acceleration sensor or the like. In the vehicle behavior calculation device according to the sixth aspect, the vehicle behavior calculation means b calculates the roll speed of the vehicle in accordance with the wheel speed signal and the vehicle speed. The roll speed of the vehicle can be detected without adding a lateral acceleration sensor or the like. In the vehicle behavior calculation device according to the seventh aspect, the vehicle speed of the vehicle is calculated from the wheel speed signal detected by the wheel speed sensor a. Thus, in the vehicle equipped with the anti-skid control device, the vehicle speed sensor is newly provided. The vehicle behavior can be detected without adding. In the vehicle suspension device according to the eighth aspect, by performing stiffness control of the vehicle suspension based on the vehicle behavior signal calculated by the vehicle behavior calculation means according to any one of the first to seventh aspects,
Conventionally, suspension rigidity control, which required multiple vertical acceleration sensors, has been changed to a vehicle behavior signal equivalent to the vehicle behavior determined by the vertical acceleration sensor without installing a new sensor in vehicles equipped with an anti-skid control device. Thus, an inexpensive suspension system can be obtained while maintaining the same performance as the conventional one.

[0007]

Embodiments of the present invention will be described with reference to the drawings. FIG. 2 is a configuration explanatory view showing a vehicle suspension device to which the vehicle behavior calculation device according to the embodiment of the present invention is applied. The vehicle suspension device is interposed between a vehicle body and four wheels, and is provided with four shock absorbers SA _FL and SA _FL . _FR , SA _RL , SA _RR (In addition, when explaining the shock absorber, these four
When referring to them collectively and when describing their common configuration, they are simply denoted by SA. Also, the lower right sign indicates the wheel position, _FL is the front left wheel, _FR is the front right wheel,
_RL indicates the rear wheel left, and _RR indicates the rear wheel right. ) Is provided. Each of the front left wheel and the front right wheel is provided with a wheel speed sensor 1 _FL , 1 _FR for detecting a wheel speed Wv _FL , Wv _FR , respectively. A vertical acceleration sensor (hereinafter, referred to as a vertical G sensor) 2 for detecting vehicle speed, a vehicle speed sensor 5 for detecting a vehicle speed Vs of the vehicle from a drive system such as a mission, and a position near the driver's seat. Left and right wheel speed sensors 1 _FL , 1 _FR , up and down G sensors 2,
A control unit 4 is provided which receives a signal from the vehicle speed sensor 5 and outputs a drive control signal to the pulse motor 3 of each of the shock absorbers SA _FL , SA _FR , SA _RL , and SA _RR .

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. The interface circuit 4a includes the left and right wheel speed sensors 1 Wheel speed Wv _FL and Wv _FR signals from _FL , 1 _FR , upper and lower G
The vertical acceleration G signal from the sensor 2 and the vehicle speed Vs signal from the vehicle speed sensor 5 are input, and the control unit 4 uses the shock absorbers SA (SA _FL , SA _FR , SA _RL , SA _RR ) is performed.

Further, the control unit 4 includes:
The wheel speed Wv from the left and right wheel speed sensors 1 _FL, 1 _{FR
The FL} and Wv _FR signals, the vertical acceleration G signal from the vertical G sensor 2, and the vehicle speed Vs signal from the vehicle speed sensor 5 are input. The control unit 4 receives the bounce speed and pitch of the vehicle based on these input signals. A signal processing circuit (FIG. 14) for determining the speed and the roll speed is provided. The details of this signal processing circuit will be described later.

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 portion of the piston 31. As shown in FIG. 5, the piston 31 has through holes 31a and 31b formed therein, and A compression-side damping valve 20 and an extension-side damping valve 12 for opening and closing 31a and 31b, respectively, are provided. A stud 38 that penetrates the piston 31 is screwed and fixed to a 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. Note that the adjuster 40 is provided with the pulse motor 3.
Is rotated through the control rod 70 (see FIG. 4). Also, studs 38
A first port 21, a second port 13, a third port 18, a fourth port 14, and a fifth port 16 are formed in this 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, and the second port 13, the vertical groove 23, and the fifth port 16. Then, the extension-side check valve 17 is opened to open the extension-side third flow path F leading to the lower chamber B, and a bypass reaching 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 a fluid can flow during 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 force 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.
The state in which both pressure sides are soft (hereinafter, soft area SS
When the adjuster 40 is rotated counterclockwise from
When the damping force characteristic can be changed in multiple stages only on the extension side and the compression side is a region fixed to the low damping force characteristic (hereinafter referred to as the extension side hard region HS). Conversely, when the adjuster 40 is rotated clockwise, Only the compression side has a structure in which the damping force characteristic can be changed in multiple stages, and the extension side is a region fixed to the low damping force characteristic (hereinafter referred to as a compression side hard region SH).

In FIG. 7, the KK section, the LL section, the MM section, and the NN section in FIG. 5 when the adjuster 40 is arranged at the position of, respectively. 8, 9 and 10 and the damping force characteristics at each position are shown in FIGS.

[0016] Next, among the control operations of the control unit 4, the wheel speed Wv _FL, Wv _FR signals from said respective left and right wheel speed sensors 1 _FL, 1 _FR, vertical acceleration G signals from the vertical G sensor 2, and , The vehicle speed Vs from the vehicle speed sensor 5
The configuration of a signal processing circuit (vehicle behavior calculation means, calculation content changing means) for obtaining the vehicle bounce speed GVb, pitch speed GVp and roll speed GVr based on the signal will be described with reference to the block diagram of FIG.

First, at B1, the left and right wheel speed sensors 1
The total value Wvp (= Wv _FL + Wv _FR ) of the two wheel speed Wv _FL and Wv _FR signals detected by _FL , 1 _FR is obtained, and in B2, the total value Wvp (= Wv _FL + W) of the wheel speed signal values is obtained.
v _FR ) and an arithmetic expression Gp _(S) (G
_{p 1 (S), Gp 2} (S), ····, the Gp _{n (S))} and a predetermined gain, pitch rate GVp of the vehicle is determined.

On the other hand, at B3, the difference value Wvr (= Wv _FR -Wv _FL ) between the two wheel speeds Wv _FL and Wv _FR signal values detected by the left and right wheel speed sensors 1 _FL and 1 _FR is obtained.
4, the difference value Wvr (= Wv _FR
−Wv _FL ) and an arithmetic expression Gr _(S) (Gr ₎ corresponding to the vehicle speed Vs.
_{1 (S)} , Gr _{2 (S)} ,..., Gr _{n (S)} ) and a predetermined gain determine the roll speed GVr of the vehicle.

On the other hand, in B5, a phase delay compensation equation is used,
The sprung vertical acceleration G signal detected by the vertical G sensor 2 is converted into a bounce speed GVb signal. The general expression of the phase delay compensation can be expressed by the following transfer function expression (1). G _(S) = (AS + 1) / (BS + 1) (1) (A <B) Then, the frequency band (0.5 Hz to 3
Hz), has the same phase and gain characteristics as the case of integration (1 / S), and as a phase lag compensation equation for lowering the gain on the low frequency side (up to 0.05 Hz), the following transfer function equation (2 ) Is used. Gb _(S) = ((0.001 S + 1) / (10S + 1)) × r (2) where r is a signal and gain characteristic when the speed is converted by integration (1 / S). This is a gain for matching, and is set to r = 10 in the embodiment of the present invention. As a result, as shown in the gain characteristic of the solid line in FIG. 15A and the phase characteristic of the solid line in FIG. 15B, the frequency band (0.5 Hz to 3 Hz) required for damping force characteristic control is obtained.
2), only the gain on the low frequency side is reduced without deteriorating the phase characteristics. Note that FIG.
Dotted lines (a) and (b) show the gain characteristic and phase characteristic of the sprung vertical velocity signal that has been velocity-converted by integration (1 / S).

Next, among the control operations of the control unit 4, the wheel speed Wv _FL, Wv _FR signals from said respective left and right wheel speed sensors 1 _FL, 1 _FR, vertical acceleration G signals from the vertical G sensor 2, and , The vehicle speed Vs from the vehicle speed sensor 5
The contents of the signal processing circuit for obtaining the damping force characteristic control signal V based on the signal will be described with reference to the flowchart of FIG. 16 and the time chart of FIG.

First, in step 201 of the time chart of FIG. 16, the wheel speed Wv _FL and Wv _FR signals from the left and right wheel speed sensors 1 _FL and 1 _FR , the vertical acceleration G signal from the vertical G sensor 2, and The vehicle speed Vs signal from the vehicle speed sensor 5 is read.

In the following step 202, it is determined whether or not the vehicle speed Vs is in a low vehicle speed range (0 <Vs ≦ Vs1).
If S, the process proceeds to step 203, where the low vehicle speed region arithmetic expression G
The pitch speed GV of the vehicle based on p _{1 ( S)} and Gr _{1 (S)}
Calculation of p and roll speed GVr. After doing 1,
Proceed to step 207. On the other hand, if NO, step 2
Go to 04.

In step 204, it is determined whether or not the vehicle speed Vs is in the middle vehicle speed range (Vs1 <Vs ≦ Vs2).
If YES, the process advances to step 205, for a medium speed range operation expression Gp 2 _(S) and Gr 2 _(S) calculation of pitch rate GVp and roll speed GVr of the vehicle based on. After performing step 2, the process proceeds to step 207. On the other hand, if NO, the process proceeds to step 206.

In step 206, the processing for calculating the pitch speed GVp and the roll speed GVr of the vehicle is performed based on the arithmetic expressions Gp _{3 (S)} and Gr _{3 (S)} for the high vehicle speed range. After performing step 3, the process proceeds to step 207 _. In this step 207,
Using a phase lag compensation formula, the sprung vertical acceleration G signal detected by the vertical G sensor 2 is converted into a bounce speed GVb signal, and based on the following formulas (3), (4), (5), and (6). , Control signals V (V _FL , V _FR , V _RL , V _RR ) at each wheel position are obtained. _{V FL = K BF · GVb +} K PF · GV P -K RF · GV R ············· (3) V FR = K BF · GVb + K PF · GV P + K RF · GV R · _{············ (4) V RL = K} BR · GVb-K PR · GV P -K RR · GV R ············· (5) _{V RR = K BR · GVb-} K PR · GV P + K RR · GV R ············· (6) in addition, K _BF front wheel side bouncing gain, K _BR are the rear wheels Bounce gain, _KPF is a front-wheel pitch gain, _KPR is a rear-wheel pitch gain, _KRF is a front-wheel roll gain, and _KRR is a rear-wheel roll gain.

Next, the content of the damping force characteristic control operation of the shock absorber SA in the control unit 4 will be described with reference to the flowchart of FIG. In addition,
This damping force characteristic control is performed by each of the shock absorbers SA _FL , S
This is performed for each of A _FR , SA _RL , and SA _RR .

[0026] At step 101, the control signal V is determined whether it exceeds the positive dead zone V _NC, each shock absorber SA proceeds to step 102 if YES and control the extension phase hard region HS, NO Then step 10
Proceed to 3.

[0027] At step 103, the control signal V is determined whether or not below the negative dead zone -V _NC, the shock absorbers proceeds to step 104 if YES SA
To the pressure side hard area SH, and if NO, the routine proceeds to step 105.

Step 105 is a process performed when NO is determined in steps 101 and 103, that is, when the value of the control signal V is within the range from the negative dead zone -V _NC to the positive dead zone V _NC. At this time, each shock absorber SA is controlled to the soft area SS.

Next, the operation of the damping force characteristic control will be described with reference to the time chart of FIG. When the control signal V changes as shown in this figure, as shown in the figure, the control signal V
When the value is within a range from negative dead zone -Vnc to a positive dead zone V _NC controls the shock absorber SA to the soft region SS.

When the value of the control signal V exceeds the positive dead zone V _NC , the compression-side damping force characteristic is controlled to the expansion-side hard region HS to fix the compression-side damping force characteristic to the soft characteristic, while the expansion-side damping force characteristic ( The target damping force characteristic position P _T ) is changed in proportion to the control signal V based on the following equation (7). P _T = (V−V _NC ) / (V _H −V _NC ) × P _T−max (7) where V _H is the extension side proportional area, P _{T -max} is the extension-side maximum damping force characteristic position. That is, the target damping force characteristic position _PT on the extension side is variably controlled to the hardware characteristic side in proportion to the value of the control signal V.

When the value of the control signal V becomes a negative value,
The compression side hard region SH is controlled to fix the extension side damping force characteristic to the soft characteristic, while the compression side damping force characteristic (target damping force characteristic position P _C ) is set to the control signal V based on the following equation (8). Change proportionally. P _C = (V−V _NC ) / (V _H −V _NC ) × P _C-max (8) where V _H is the pressure side proportional area, P _{C− max} is the pressure-side maximum damping force characteristic position. That is, the target damping force characteristic position P _C of the compression side in proportion to the control signal V value is variably controlled in the hard characteristics side.

Next, among the damping force characteristic control operations of the control unit 4, mainly a switching operation state of the control region of the shock absorber SA will be described with reference to a time chart of FIG.

In the time chart of FIG.
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). At this time, the relative speed is still a negative value (the stroke of the shock absorber SA is At this time, the shock absorber S is determined based on the direction of the control signal V.
A is controlled to the extension side hard region HS, and therefore, in this region, the pressure stroke side which is the stroke of the shock absorber SA at that time has the soft characteristic.

An area b is an area where the control signal V remains positive (upward) and the relative speed is switched from a negative value to a positive value (the stroke of the shock absorber SA is on the extension stroke side). Therefore, 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. The extension stroke, which is the stroke of the absorber SA, has hardware characteristics proportional to the value of the control signal V.

Area c is a state where the control signal V is reversed from a positive value (upward) to a negative value (downward).
At this time, the relative speed is still a positive value (shock absorber S
Since the stroke A is 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. Therefore, in this region, The extension stroke side of the shock absorber SA has soft characteristics.

The region d is a region where the control signal V remains negative (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 area SH based on the direction of the control signal V, and the stroke of the shock absorber is also the compression stroke,
Therefore, in this area, the shock absorber SA at that time is
The pressure stroke side, which is the stroke of the above, has hardware characteristics proportional to the value of the control signal V.

As described above, in the embodiment of the present invention, when the control signal V based on the sprung vertical speed and the relative speed have the same sign (region b, region d), the stroke of the shock absorber SA at that time. Side 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, which is the same as the damping force characteristic control based on the skyhook theory. Control will be performed. Further, in the embodiment of the present invention, when the stroke of the shock absorber SA is switched, that is, when shifting from the area a to the area b and from the area c to the area d (from the soft characteristic to the hard characteristic),
Since the damping force characteristic position on the stroke side to be switched has already been switched to the hard characteristic side in the previous areas a and c, the switching from the soft characteristic to the hard characteristic is performed without time delay.

As described above, in the vehicle suspension system according to the embodiment of the present invention, the vehicle speed which is the vehicle behavior is determined from the wheel speed Wv _FL and Wv _FR signals detected by the wheel speed sensors 1 _FL and 1 _FR . Pitch speed GVp and roll speed GVr
As described above, the wheel speed sensors 1 _FL and 1 _FR for detecting the wheel speed detect the number of teeth of the gear-shaped rotor integrally provided on the tire side as a pulse signal, and output the unit. A sensor that measures the number of rotations of a tire by measuring the number of detection pulse signals in time, and detects vehicle behavior by extracting a predetermined frequency component as to how the detection pulse signal fluctuates. Therefore, the vehicle behavior component included in the pulse signal is very small. Therefore, it is difficult to accurately detect the vehicle behavior from the wheel speed Wv _FL and Wv _FR signals, and the wheel speed sensors 1 _FL and 1 _FL pulse frequency of the _FR varies depending on the vehicle speed Vs, further, since the noise component from the road surface by the vehicle speed Vs are different, the car is to be detected from the wheel speed variation when the vehicle speed Vs is changed It becomes more difficult to detect the behavior component accurately.

Therefore, in the embodiment of the present invention, when determining the pitch speed GVp and the roll speed GVr of the vehicle, which is a vehicle behavior, from the wheel speed Wv _FL and Wv _FR signals, the pitch speed GVp is determined according to the vehicle speed Vs at that time. Expression G to be found
_{p (S) (Gp 1 (} S), Gp 2 (S), ····, Gp n (S)) and calculation equations Gr for obtaining the roll speed _{GVr (S) (Gr 1 (} S),
By changing and applying Gr _{2 (S)} ,..., Gr _{n (S)} , the pulse frequency and noise component of the wheel speed sensors 1 _FL and 1 _FR fluctuate according to the vehicle speed Vs. Since the detection error caused by the vehicle speed is corrected, accurate vehicle behavior (pitch speed GVp and roll speed G
Vr) can be detected.

Although the embodiments of the present invention have been described above, the specific configuration is not limited to the embodiments of the present invention, and even if there is a design change or the like within a range not departing from the gist of the present invention, the present invention is not limited thereto. Included in the invention.

For example, in the embodiment of the present invention, when the damping force characteristic of one of the expansion stroke and the compression stroke is controlled to the hard characteristic side, the damping force characteristic of the other stroke side is controlled to the soft characteristic. Although an example using a shock absorber with a structure fixed to the characteristics has been shown, the present invention can be applied to a system using a shock absorber with a structure in which the damping force characteristics of the extension stroke and the compression stroke change in the same direction. it can.

In the embodiment of the present invention, the vehicle speed of the vehicle is detected by the vehicle speed sensor. However, the vehicle speed may be calculated from the wheel speed signal.

In the embodiment of the present invention, the calculation means is switched according to the vehicle speed. However, the cost can be reduced by changing the coefficients in the calculation formula according to the vehicle speed.

Further, in the embodiment of the present invention, the bounce speed of the vehicle is obtained from the vertical acceleration signal detected by the vertical G sensor, but it can be calculated from the wheel speed signal.

[0045]

As described above, the first aspect of the present invention is as follows.
In the vehicle suspension device described above, as described above, a vehicle behavior calculation unit that calculates a vehicle behavior from a wheel speed signal detected by a wheel speed sensor, a vehicle speed detection unit that detects a vehicle speed of the vehicle, and a vehicle speed detection unit. And a calculation content changing means for changing the content of the vehicle behavior calculation in the vehicle behavior calculation means in accordance with the detected vehicle speed, so that the pulse frequency and the noise component of the wheel speed sensor correspond to the vehicle speed. Since the detection error caused by the fluctuation is corrected, it is possible to obtain an effect that accurate vehicle behavior can be detected even if the vehicle speed fluctuates. In the vehicle behavior calculation device according to claim 2, the calculation content changing unit includes:
By changing a plurality of calculation means having different calculation contents in accordance with the vehicle speed to change the vehicle behavior calculation content, the correction accuracy of the detection error can be improved. In the vehicle behavior calculation device according to claim 3,
By configuring the calculation content changing means to change the content of the vehicle behavior calculation means by changing the coefficient of the calculation formula in the vehicle behavior calculation means according to the vehicle speed, it is possible to reduce the cost of the vehicle behavior calculation means. become able to. In the vehicle behavior calculation device according to the fourth aspect, since the vehicle behavior calculated by the vehicle behavior calculation means includes the vertical behavior of the vehicle, the vertical behavior of the vehicle strongly affected by the change in the vehicle speed can be accurately determined. In addition to being able to detect well, in a vehicle equipped with an anti-skid control device, the vertical behavior of the vehicle can be detected without adding a new vertical acceleration sensor or the like. Claim 5
In the vehicle behavior calculation device described above, since the vehicle behavior calculation means includes a pitch speed calculation means for detecting a pitch speed in the vehicle from a wheel speed change detected by the wheel speed sensor, an anti-skid control device is provided. In a vehicle, the pitch speed of the vehicle can be detected without newly adding a longitudinal acceleration sensor or the like. 7. The vehicle behavior calculation device according to claim 6, wherein the wheel speed sensors are provided on at least one of left and right wheels of a front wheel or a rear wheel, and the vehicle behavior calculation means detects the left and right wheels detected by the left and right wheel speed sensors. Since a roll speed detecting means for detecting the roll speed of the vehicle from the speed difference is included, in a vehicle equipped with an anti-skid control device, the roll speed of the vehicle is detected without newly adding a lateral acceleration sensor or the like. Will be able to In the vehicle behavior calculating device according to the seventh aspect, the vehicle speed detecting means includes the wheel speed sensor and a vehicle speed calculating means for calculating a vehicle speed of the vehicle from a wheel speed signal detected by the wheel speed sensor. Therefore, in the vehicle equipped with the anti-skid control device, the vehicle behavior can be detected without adding a new vehicle speed sensor. In the vehicle suspension device according to the eighth aspect, the rigidity of the vehicle suspension is controlled based on the vehicle behavior signal calculated by the vehicle behavior calculation according to any one of the first to seventh aspects. For vehicles equipped with an anti-skid control device, rigidity control of a suspension that required a vertical acceleration sensor can be obtained with a vehicle behavior signal equivalent to the vehicle behavior required by the vertical acceleration sensor without installing a new sensor. Accordingly, an effect is obtained that an inexpensive suspension system can be obtained while maintaining the same performance as the conventional one.

[Brief description of the drawings]

FIG. 1 is a claim correspondence diagram showing a vehicle behavior calculation device of the present invention.

FIG. 2 is a configuration explanatory diagram showing a vehicle suspension device to which the vehicle behavior calculation device according to the embodiment of the present invention is applied.

FIG. 3 is a system block diagram illustrating a vehicle suspension device to which the vehicle behavior calculation device according to the embodiment of the present invention is applied.

FIG. 4 is a cross-sectional view showing a shock absorber applied to the vehicle suspension device according to the embodiment of the present invention.

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 force 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 shows a control operation of the control unit in the vehicle suspension system according to the embodiment of the present invention;
FIG. 3 is a block diagram showing the contents of a signal processing circuit for calculating a roll speed and a bounce speed.

FIG. 15 is a diagram showing a gain characteristic (a) and a phase characteristic (b) of the sprung vertical velocity signal converted by using the phase lag compensation equation.

FIG. 16 is a flowchart showing the contents of a signal processing circuit for obtaining a control signal in the vehicle suspension system according to the embodiment of the present invention.

FIG. 17 is a time chart showing a content of a signal processing circuit for obtaining a control signal in the vehicle suspension system according to the embodiment of the present invention.

FIG. 18 is a flowchart showing a damping force characteristic control operation of a control unit in the vehicle suspension system according to the embodiment of the present invention.

FIG. 19 is a time chart showing a damping force characteristic control operation of a control unit in the vehicle suspension system according to the embodiment of the present invention.

[Explanation of symbols]

 a wheel speed sensor b vehicle behavior calculation means c vehicle speed detection means d calculation content change means

Claims (8)

[Claims] A wheel speed sensor for detecting a wheel speed; a vehicle behavior calculating means for calculating a vehicle behavior from a wheel speed signal detected by the wheel speed sensor; a vehicle speed detecting means for detecting a vehicle speed of the vehicle; A vehicle behavior calculation device, comprising: calculation content changing means for changing the vehicle behavior calculation content of the vehicle behavior calculation means in accordance with the vehicle speed of the vehicle detected by the vehicle speed detection means. 2. The method according to claim 1, wherein the calculation content changing means is configured to change the vehicle behavior calculation content by switching a plurality of calculation means having different calculation contents according to the vehicle speed. 2. The vehicle behavior calculation device according to claim 1. 3. The vehicle behavior calculation content is changed by changing a coefficient of a calculation formula in the vehicle behavior calculation means according to a vehicle speed. 2. The vehicle behavior calculation device according to claim 1. 4. The vehicle behavior calculation device according to claim 1, wherein the vehicle behavior calculated by the vehicle behavior calculation means includes a vertical behavior of the vehicle. 5. The vehicle behavior calculating means includes a pitch speed calculating means for detecting a pitch speed in a vehicle from a wheel speed change detected by the wheel speed sensor. The vehicle behavior calculation device according to any one of the above. 6. The vehicle behavior calculating means is provided on at least one of the left and right wheels of a front wheel or a rear wheel based on a difference between the left and right wheel speeds detected by the left and right wheel speed sensors. The vehicle behavior calculation device according to any one of claims 1 to 5, further comprising a roll speed detection unit that detects a roll speed. 7. A vehicle speed detecting means comprising: the wheel speed sensor; and a vehicle speed calculating means for calculating a vehicle speed of a vehicle from a wheel speed signal detected by the wheel speed sensor. Item 7. A vehicle behavior calculation device according to any one of Items 1 to 6. 8. A vehicle suspension device for controlling the rigidity of a vehicle suspension based on a vehicle behavior signal calculated by the vehicle behavior calculation device according to any one of claims 1 to 7. .