JP3342606B2 - Loading status judgment device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a loading state judging device for detecting a changing state of a loading amount in a vehicle.

[0002]

2. Description of the Related Art Conventionally, as a vehicle suspension device for controlling a damping force characteristic of a shock absorber, for example, Japanese Patent Laid-Open Publication No. Hei.
One described in Japanese Patent No. 500490 is known.

In this conventional vehicle suspension system, a dynamic vehicle running state is detected by a sensor, and a control signal for controlling a semi-active shock absorber provided on each wheel of the vehicle is formed. The vehicle control is performed according to the actual value of the force.

[0004]

However, in the conventional apparatus, since the change in the loading state in the vehicle is not considered at all, there are the following problems.

That is, in this conventional apparatus, the shock absorber is attenuated in each wheel in consideration of a fixed loading state, that is, a vehicle weight and a wheel load acting on each wheel, and a wheel load balance between a front wheel and a rear wheel. The control gain for performing the force characteristic control is set. However, when the vehicle weight and the wheel load balance between the front and rear wheels are changed from the state at the time of design, the control gain for the running state of the vehicle is changed. May not be appropriate, and optimum ride comfort and steering stability may not be obtained.

[0006] By using a vehicle height sensor separately, it is possible to detect a change in the loading state from a change in the vehicle height of the vehicle, but there is another problem that the cost increases.

[0007] The present invention has been made in view of the above-mentioned conventional problems, and without providing a separate vehicle height sensor,
It is an object of the present invention to provide a loading state determination device capable of detecting a change in a loading state of a vehicle from vehicle state quantities at two places in the vehicle front-rear direction detected by a vehicle state quantity detecting unit.

[0008]

In order to achieve the above-mentioned object, a loading state judging device according to a first aspect of the present invention has a structure as shown in FIG.
As shown in the claim correspondence diagram, a pair of vehicle state quantity detection means a ₁ , a 2 provided at a predetermined distance at least in the longitudinal direction of the vehicle and detecting the state quantity of the vehicle, respectively.
_2, and the instantaneous rotation center position calculating means b for calculating the distance from the reference position than the vehicle state quantity of two positions obtained by said pair of vehicle state quantity detecting means a _1, a ₂ to instantaneous rotation center position of the body A moving average value calculating means c for obtaining a moving average value of a distance from the reference position obtained by the instantaneous rotation center position calculating means b to the instantaneous rotation center position of the vehicle body; and a moving average value calculating means c for obtaining the moving average value. And means for determining a change in the load capacity of the vehicle by comparing the moving average value with a predetermined reference value.

Further, in the loading state judging device according to the second aspect, a pair of vehicle state amount detecting means a provided at a predetermined distance at least in the longitudinal direction of the vehicle and detecting the state amount of each vehicle. ₁ and a ₂ and the vehicle state quantity obtained by the pair of vehicle state quantity detection means a ₁ and a ₂ , both positive and negative peak values of the vehicle state quantity at each detection position are obtained, and both positive and negative values at each detection position are obtained. A peak value change amount calculating means e for obtaining a change amount of both peak values, and a comparison value calculating means f for obtaining a comparison value of both peak value change amounts at both detection positions obtained by the peak value change amount calculating means e. Moving average value calculating means g for calculating a moving average value of both peak value change amount comparison values at both detection positions obtained by the comparison value calculating means f, and a moving average value of the comparison value obtained by the moving average value calculating means g. The moving average value is a predetermined standard And a load amount change determining means h for determining a change in the load amount of the vehicle by comparing the value with the value.

Further, in the loading state judging device according to the third aspect, the vehicle state quantity detecting means is constituted by a sprung vertical speed detecting means for detecting a sprung vertical speed of the vehicle. Also,
In the loading state judging device according to the fourth aspect, the vehicle state quantity detecting means is constituted by a sprung vertical acceleration detecting means for detecting a sprung vertical acceleration of the vehicle.

Further, in the loading state judging device according to the fifth aspect, the vehicle state quantity detecting means is constituted by a relative speed detecting means for detecting a relative speed between a sprung and unsprung state of the vehicle. Further, in the loading state judging device according to claim 6, the vehicle state quantity detecting means is constituted by relative acceleration detecting means for detecting a relative sprung unsprung acceleration of the vehicle.

[0012]

According to the loading state determining device of the first aspect of the present invention,
As described above, the state quantities of the vehicle at the two detection positions having a predetermined distance at least in the front-rear direction of the vehicle are detected, and the vehicle state quantities at the front and rear two points are used to determine the distance from the reference position to the instantaneous rotation center position of the vehicle body. A moving average value of the distance is calculated.

[0013] The occupant of the vehicle is one driver,
Looking at the moving average value when traveling with a minimum load capacity of zero in the trunk room and the fluctuation state of the moving average value when traveling with a large amount of luggage loaded in the trunk room, In addition, there is a clearly distinguishable difference between the levels of the two moving averages depending on the loading capacity. this is,
This is a phenomenon that occurs when luggage is loaded in the trunk room because the ratio of the load acting on the rear wheel side to the front wheel side increases, and the same occurs when a person gets on the rear seat side. Therefore, the loading capacity change determining means d can determine the loading capacity change state of the vehicle by comparing the moving average value with a predetermined reference value.

Further, in the loading state judging device according to the second aspect, the state quantity of the vehicle at both detection positions having a predetermined distance at least in the front-rear direction of the vehicle is detected, and the vehicle state quantity at both detection positions is detected. The comparison value between the positive and negative peak value change amounts is determined, and the level of this comparison value is clearly distinguishable depending on the load of the vehicle. This is a phenomenon that occurs when the luggage is loaded in the trunk room because the ratio of the load acting on the rear wheel side to the front wheel side increases, and the same phenomenon occurs when a person gets on the rear seat side. Therefore, the loading capacity change determining means h can determine the loading capacity change state of the vehicle by comparing the comparison value with a predetermined reference value.

[0015]

An embodiment of the present invention will be described with reference to the drawings. (First Embodiment) FIG. 2 is a structural explanatory view showing a vehicle suspension system to which a loading state judging device according to a first embodiment of the present invention is applied. Shock absorbers SA _FL , SA _FR , SA _RL , SA _RR (Note that 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. The vehicle body at a position (tower position) in the vicinity of the front left and right shock absorbers SA _FL and SA _FR and the rear left and right shock absorbers SA _RL and SA _RR includes:
A vertical acceleration sensor (hereinafter, referred to as a vertical G sensor) _1FL , _1FR , _1RL , _1RR for detecting a vertical acceleration G is provided, and each vertical G sensor 1 ( 1 _FL , 1 _FR , 1 _RL , 1 _RR )
A control unit 4 for outputting a drive control signal to the pulse motor 3 of each shock absorber SA is provided.

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, and the upper and lower G sensors 1 _FL are provided in the interface circuit 4a. , 1 _FR , 1 _RL , 1 _RR , the sprung vertical acceleration G _FL ,
The _GFR , _GRL , and _GRR signals are input. 14, the sprung vertical speeds Δx _FL , Δx _FR , Δx _RL , at each tower position from the sprung vertical accelerations G _FL , G _FR , G _RL , and G _RR signals, as shown in FIG. Δx _RR and sprung-unsprung relative speed (Δx-Δx ₀ ) _FL ,
(Δx−Δx ₀ ) _FR , (Δx−Δx ₀ ) _RL , (Δx−Δ
x ₀ ) A signal processing circuit for _{obtaining the RR} and a signal processing circuit for _obtaining a determination signal for determining a change state of the load on the vehicle are provided as shown in FIG. The details of both signal processing circuits 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. 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, 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 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 such 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. 8, 9 and 10 and the damping force characteristics at each position are shown in FIGS.

Next, of the control operation of the control unit 4, the configuration of the signal processing circuit for obtaining the sprung vertical speed Δx and the sprung-unsprung relative speed (Δx-Δx ₀ ) is shown in FIG. Description will be made based on the drawings.

First, in B1, a phase delay compensation equation is used,
Each vertical G sensors _{1 (1 FL, 1 FR,} 1 RL, 1 RR) on each spring is detected by the vertical acceleration _{G (G FL, G FR,} G RL, G RR)
Is converted into a sprung vertical speed signal at each tower position. 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) required for damping force characteristic control
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.

G _(S) = (0.001 S + 1) / (10S + 1) × γ (2) where γ is a signal and gain characteristic when speed conversion is performed by integration (1 / S). , And is set to γ = 10 in this embodiment. As a result, FIG.
The gain characteristic of the solid line in FIG.
As shown by the solid line phase characteristics in (b), only the low-frequency gain is reduced without deteriorating the phase characteristics in the frequency band (0.5 Hz to 3 Hz) necessary for damping force characteristic control. . Note that the dotted lines in (a) and (b) in FIG.
9 shows gain characteristics and phase characteristics of a sprung vertical speed signal whose speed is converted by integration (1 / S).

In B2, a band-pass filter process for cutting off components other than the target frequency band to be controlled is performed. That is, the band-pass filter BPF is composed of a second-order high-pass filter HPF (0.3 Hz) and a second-order low-pass filter LPF (4 Hz), and has a sprung vertical velocity that targets a sprung resonance frequency band of the vehicle. Δx (Δx _FL ,
Δx _FR , Δx _RL , Δx _RR ) signals are obtained.

On the other hand, in B3, as shown in the following equation (3),
Using the transfer function Gu _(S) from each sprung vertical acceleration to the sprung-unsprung relative velocity, the vertical acceleration G (G _FL , G _FR , G _RL , G _{RR )} detected by each vertical G sensor 1. ) Signal from the sprung-unsprung relative velocity (Δx
−Δx ₀ ) [(Δx−Δx ₀ ) _FL , (Δx−Δx
₀ ) _FR , (Δx−Δx ₀ ) _RL , (Δx−Δx ₀ ) _RR ] signal is obtained. Gu _(S) =-ms / (cs + k) (3) where m is a sprung mass, c is a damping coefficient of the suspension, and k is a spring constant of the suspension. Next, the shock absorber S in the control unit 4 is used.
The details of the damping force characteristic control operation of A will be described with reference to the flowchart of FIG. The basic control is performed for each of the shock absorbers SA _FL , SA _FR , SA _RL , and SA _RR .

In step 101, the sprung vertical speed Δx
Is determined to be a positive value. If YES, the flow proceeds to step 102 to control each shock absorber SA to the extension-side hard region HS. If NO, the flow proceeds to step 103.

In step 103, the sprung vertical speed Δx
Is determined to be a negative value. If YES, the routine proceeds to step 104, where each shock absorber SA is controlled to the pressure-side hard area SH, and if NO, the routine proceeds to step 105.

Step 105 is a processing step when NO is determined in steps 101 and 103, that is, when the value of the sprung vertical speed Δx is 0,
At this time, each shock absorber SA is
To control.

Next, the operation of the damping force characteristic control will be described with reference to the time chart of FIG. When the sprung vertical speed Δx based on the sprung vertical speed Δx and the sprung-unsprung relative speed (Δx−Δx ₀ ) changes as shown in this figure, as shown in the figure, as shown in the figure, Is 0, the shock absorber SA is controlled to the soft region SS.

When the value of the sprung vertical velocity Δx becomes a positive value, 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 extension-side damping force characteristic (target The damping force characteristic position P _T ) is changed in proportion to the sprung vertical speed Δx based on the following equation (4). P _T = α · Δx · K · δ (4) where α is a constant on the extension side, and K is a relative speed between sprung and unsprung. A gain variably set according to (Δx−Δx ₀ ),
δ is a control gain variably set in accordance with a change in the load on the vehicle, and the details of the control for variably setting the control gain δ will be described later.

When the value of the sprung vertical velocity Δx becomes a negative value, the compression-side hard region SH is controlled to fix the expansion-side damping force characteristic to the soft characteristic while the compression-side damping force characteristic (target damping force) The characteristic position P _C ) is calculated based on the following equation (5).
It changes in proportion to the sprung vertical speed Δx. P _C = β · Δx · K · δ (5) where β is a pressure-side constant.

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

In the time chart of FIG.
Is a state in which the sprung vertical speed Δx based on the sprung vertical speed Δx and the sprung-unsprung relative speed (Δx−Δx ₀ ) is reversed from a negative value (downward) to a positive value (upward). At this time, since the relative speed (Δx−Δx ₀ ) is still a negative value (the stroke of the shock absorber SA is on the pressure stroke side), at this time, the relative speed (Δx−Δx ₀ ) is determined based on the direction of the sprung vertical speed Δx. The shock absorber SA is controlled in the extension-side hard region HS. Therefore, in this region, the pressure stroke side, which is the stroke of the shock absorber SA at that time, has a soft characteristic.

In region b, the sprung vertical velocity Δx remains a positive value (upward), and the sprung-unsprung relative velocity (Δx−Δx ₀ ) changes from a negative value to a positive value (shock absorber). In this case, the shock absorber SA is controlled to the extension-side hard region HS based on the direction of the sprung vertical speed Δx, and the shock absorber is switched to the extension-side hard region HS. Is also an extension stroke. Therefore, in this region, the extension stroke which is the stroke of the shock absorber SA at that time has a hardware characteristic proportional to the value of the sprung vertical speed Δx.

Region c is a state in which the sprung vertical speed Δx is reversed from a positive value (upward) to a negative value (downward). At this time, the sprung-unsprung relative speed (Δx
−Δx ₀ ) is a region having a positive value (the stroke of the shock absorber SA is on the extension stroke side). At this time, the shock absorber SA sets the compression-side hard region SH based on the direction of the sprung vertical speed Δx. , And therefore
In this region, the extension stroke side, which is the stroke of the shock absorber SA at that time, has soft characteristics.

In the area d, the sprung vertical velocity Δx remains a negative value (downward), and the sprung-unsprung relative velocity (Δx-Δx ₀ ) changes from a positive value to a negative value (shock absorber). At this time, the shock absorber SA is controlled to the compression-side hard region SH based on the direction of the sprung vertical velocity Δx, and the stroke of the shock absorber is also increased. Pressure 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 sprung vertical speed Δx.

As described above, in this embodiment, the sprung vertical speed Δx and the sprung-unsprung relative speed (Δx−Δx
₀ ) and the same sign (area b, area d), the stroke side of the shock absorber SA at that time is controlled to hard characteristics,
At the time of the different sign (area a, area c), the stroke side of the shock absorber SA at that time is controlled to a soft characteristic.
The same control as the damping force characteristic control based on the skyhook control theory is performed based only on the sprung vertical speed Δx signal. And furthermore, in this embodiment,
When the stroke of the shock absorber SA switches, 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), the damping force characteristic position on the switching stroke side is the previous area. Since the switching to the hardware characteristics has already been performed at a and c, the switching from the soft characteristics to the hardware characteristics is performed without a time delay. As a result, a high control response can be obtained and the hardware characteristics can be reduced. Switching to the soft characteristic is performed without driving the pulse motor 3.
As a result, the durability of the pulse motor 3 is improved and power consumption is reduced.

Next, among the control operations of the control unit 4, the contents of the variable setting control of the control gain δ based on the change in the load on the vehicle will be described. First, a configuration of a signal processing circuit for obtaining a determination signal for determining a change state of the load capacity will be described with reference to a block diagram of FIG.

At C1, the sprung vertical acceleration at the front wheel center position is calculated from the average value of the front wheel left and right sprung vertical accelerations G _FL and G _FR detected by the front wheel left and right vertical up / down G sensors 1 _FL and 1 _FR. while seeking G _FS, the C3, rear-wheel-side left and right vertical G sensors 1 _RL, 1 on wheel left and right spring after being detected by the _RR vertical acceleration G _RL, from the average value of G _RR signal, the rear wheel side The sprung vertical acceleration _GRS at the center position is obtained.

In the following C2, the sprung vertical acceleration G _FS at the front wheel center position is converted into a sprung vertical speed Δx _FS at the front wheel center position using a phase lag compensation formula.
Using the phase lag compensation equation to convert the sprung mass vertical accelerations G _RS at the rear wheel center to the sprung mass vertical velocity [Delta] x _RS at the rear wheel center position. In other words, C1 to C4 constitute a vehicle state quantity detecting means in the claims.

The following C5 constitutes an instantaneous rotation center position calculating means according to the claims. Based on the following equation (6), a reference position Q, such as the center of gravity position of the vehicle, is set from an arbitrarily set reference position Q. The distance L to the instantaneous rotation center position E in the direction is determined (see FIG. 19). Note that when the instantaneous rotation center position E is behind the reference position Q in the vehicle, a positive value is detected, and when the instantaneous rotation center position E is in front of the vehicle, a negative value is detected.

[0045] _{L = {Δx FS (L 1} + L 2) / (Δx RS -Δx FS)} + L 1 = (L 1 · Δx RS + L 2 · Δx FS) / (Δx RS -Δx FS) ···· (6) in addition, L _1, as shown in FIG. 19, the distance from the reference position Q to the front side central position, L ₂ is the distance to the rear wheel center position from the reference position Q.

In the above formula (6), the molecule (Δx _RS
In order to prevent the value of L from diverging due to the value of -Δx _FS ) being zero, a process of setting a limit is performed. That is, when the value of the numerator (Δx _RS −Δx _FS ) is less than the positive limit value Δxmp and is equal to or greater than 0 (0 ≦ (Δx _RS −Δx _FS ) <Δx)
When a mp) is a value of the numerator (Δx _RS -Δx _FS) and the positive side limit value Derutaxmp, The molecular ([Delta] x _RS - [delta
When the value of (x _FS ) exceeds the minus limit value Δx mm and is less than 0 (Δx mm <(Δx _RS −Δx _FS ) <0), the value of the numerator (Δx _RS −Δx _FS ) is changed to the minus limit value Δx mm.
Is performed.

That is, FIG. 20 shows the fluctuation state (b) of the sprung vertical speed Δx _FS at the front wheel side center position and the sprung vertical speed Δx _{RS at} the rear wheel side center position while the vehicle is running, and the state of the vehicle at that time. 6 is a time chart showing, in an enlarged manner, a variation state (a) of a distance L from a reference position Q to an instantaneous rotation center position E in the vehicle longitudinal direction.

The following C6 constitutes a moving average value calculating means according to the present invention. In this embodiment, by passing through a second-order low-pass filter LPF (0.1 Hz),
A moving average value L ₀ of a distance L from the reference position Q to the instantaneous rotation center E is obtained. FIG. 21 is a time chart showing a variation state of the distance L from the reference position Q to the instantaneous rotation center position E. FIG. 22 is a time chart showing a variation state of the moving average value L ₀ of the distance L. is there. That is, in the time chart of FIG. 22, the time zone (I) is a moving average value when the vehicle is driven by a single driver and the luggage in the luggage compartment is zero and the vehicle is in the minimum load state. L ₀ fluctuating state, while time zone
(II) shows the state of fluctuation of the moving average L ₀ when traveling with a large amount of luggage loaded in the trunk room, and there is a clearly distinguishable difference in the level of the moving average L ₀ depending on the load. You can see it is happening. This is a phenomenon that occurs when the luggage is loaded in the trunk room because the ratio of the load acting on the rear wheel side to the front wheel side increases, and the same phenomenon occurs when a person gets on the rear seat side.

Therefore, a load capacity judgment threshold value (reference value in claims) Sg is set at an intermediate position between the two levels, and the moving average value L ₀ is compared with the load capacity judgment threshold value Sg. It is possible to detect a variation state of the loading amount in the vehicle. That is, the part that performs the above-described operation constitutes a loaded amount change determination unit in the claims.

Next, the contents of the control for variably setting the control gain δ due to the change in the load amount will be described. (A) When the loading capacity is minimum When the vehicle is driven by a single driver and has the minimum loading capacity in which the luggage in the trunk room is 0, as shown in the time chart of FIG. , The moving average value L ₀ of the distance L from the reference position Q to the instantaneous rotation center position E is equal to or less than the above-mentioned loading amount determination threshold value Sg. In this case, the target damping force characteristic positions P _T ,
The formula for obtaining the P _C (4), the control gain δ in (5),
In which a state in which the basic gain δ is set to _M, Thus, at the time of loading of the minimum, the damping force characteristic control for optimal based on skyhook control theory is carried out, and ride comfort and steering stability of the vehicle Can be secured.

(B) When the loading capacity is increased When traveling starts with a large amount of luggage loaded in the luggage compartment from the above-described minimum loading capacity state, as shown in the time chart of FIG. Q
Moving average value L ₀ of distance L from to instantaneous rotation center position E
Is higher than the threshold value Sg, and at this time, the target damping force characteristic position P
_T, the equation (4) for obtaining the P _C, control gain δ in (5)
Is variably set to a correction gain δ _H higher than the basic gain δ _M , whereby the target damping force characteristic position P _T ,
P _C is the state they were set to increase. Therefore, it is possible to prevent the deterioration of the riding comfort and the steering stability of the vehicle due to the increase in the load amount by using the high damping force characteristic which is automatically variably set.

As described above, the loading state determining apparatus of this embodiment has the following effects. Without providing a separate vehicle height sensor, it is possible to detect a change in the loading state of the vehicle from two sprung vertical speed signals obtained from the sprung vertical acceleration signals detected by the respective vertical G sensors 1 in the vehicle longitudinal direction. Thus, the cost can be reduced.

As a means for converting the sprung vertical acceleration to the sprung vertical velocity, a phase lag compensation formula is used to prevent signal drift based on extra low-frequency signal input such as during braking. Thus, it is possible to prevent the controllability of the damping force characteristic of the shock absorber SA from deteriorating and to secure the riding comfort of the vehicle.

The switching from the soft characteristic to the hardware characteristic is performed without time delay, whereby a high control response is obtained, and the switching from the hardware characteristic to the soft characteristic is performed without driving the actuator. This makes it possible to improve the durability of the actuator and save power consumption.

(Second Embodiment) Next, a second embodiment of the present invention will be described. In the description of this embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. Only different points will be described.

That is, this embodiment differs from the first embodiment in the means for judging a change in the load capacity. Hereinafter, a judgment signal for judging the change state of the load capacity will be described. The configuration of the signal processing circuit for obtaining the signal will be described with reference to the block diagram of FIG.

First, D1 to D4 in FIG. 23 constitute the vehicle state quantity detecting means described in the claims, and are the same as C1 to C4 in FIG. 18 in the first embodiment, and therefore description thereof is omitted. .

At D5, as shown in FIG. 24A, both the positive and negative peak values V _FP and V _FM of the sprung vertical velocity Δx _{FS at} the front wheel side center position are obtained, and the positive and negative peak values V _{FP are obtained.} while seeking V _FM of variation _{V FV (= V FP -V FM} ), the D6, as shown in (b) of FIG. 24, the rear wheel on the side central positions of the spring vertical velocity [Delta] x _RS positive and negative both Peak value V _RP ,
With obtaining the V _RM, obtaining the positive and negative peak values V _RP, V _RM of variation _{V RV (= V RP -V RM} ). That is, D5 and D
6 constitutes a peak value change amount calculating means in the claims.

At D7, an operation is performed to obtain a comparison value V _D (= V _FV −V _RV ) between the front wheel side change amount V _FV and the rear wheel side change amount V _RV . That is, the D7 constitutes a comparison value calculation means in the claims.

The following D8 constitutes a moving average value calculating means according to the claims. In this embodiment, by passing through a second-order low-pass filter LPF (0.1 Hz),
As shown in FIG. 25, the moving average value Cj of the comparison values V _D
Ask for. The moving average value Cj is used as a load amount change determination signal, and the moving average value Cj constitutes a moving average value calculating means in the claims.

That is, in the time chart of FIG.
During time period (I), the driver of the vehicle is one driver, and
While the moving average Cj when the vehicle is traveling with the minimum load capacity of zero in the trunk room is shown, the time zone (II) shows a state in which a large amount of luggage is loaded in the trunk room. This shows the fluctuation state of the moving average value Cj when the vehicle runs, and it can be seen that there is a clearly distinguishable difference in the level of the moving average value Cj depending on the loaded amount, as in the first embodiment. This is a phenomenon that occurs when the luggage is loaded in the trunk room because the ratio of the load acting on the rear wheel side to the front wheel side increases, and the same phenomenon occurs when a person gets on the rear seat side.

Therefore, as in the first embodiment, a load amount determination threshold value (reference value in claims) Sj is set at an intermediate position between the two levels, and the moving average value Cj is used to determine the load amount. By comparing the value with the value Sj, it is possible to detect a change in the load capacity of the vehicle, and a portion for performing this operation constitutes a load capacity change determining means according to the claims.

Then, the switching control of the control gain δ is performed based on the load amount determination threshold value Sj, whereby
Deterioration of ride comfort and steering stability of the vehicle due to an increase in the load capacity can be prevented by a high damping force characteristic that is automatically variably set. As described above, also in the second embodiment, the same effects as those of the first embodiment can be obtained.

Although the embodiment of the present invention has been described above, the specific configuration is not limited to this embodiment, and even if there is a design change within the scope of the present invention, it is included in the present invention. It is.

For example, in the embodiment, the case where the sprung vertical velocity signal is used as the vehicle state quantity detected by the vehicle state quantity detecting means has been described. A relative speed signal, a sprung unsprung relative acceleration, or the like can also be used.

In the embodiment, the change in the load capacity is always determined. However, each time the door and / or the trunk of the vehicle is opened, the load capacity determination is reset, and thereafter, the load travels by the vehicle running. You may make it start quantity determination.

Further, the change rate of the vehicle speed is obtained from the vehicle speed signal detected by the vehicle speed sensor, and when the change rate of the vehicle speed exceeds a predetermined threshold value, the determination of the load amount may be stopped. Good.

[0068] Further, in the embodiment, although to perform a variable setting of the control gain in one step, as shown in FIG. 26, it may be made to stepwise slowly varying with the hold time T _H. Further, in the embodiment, the control gain is variably set in two stages of the basic gain and the correction gain, but may be variably set in a plurality of stages.

In the embodiment, the variable setting of the control gain is performed for all the shock absorbers on the front wheel side and the rear wheel side. However, only one of the front wheel side and the rear wheel side is used, or both are set. Even in the case of performing this, the value may be made different variable characteristics between the front wheel side and the rear wheel side.

In the embodiment, the control is performed in the soft area SS only when the sprung vertical speed signal is 0.
By providing a predetermined dead zone centered at the center of the dead zone and maintaining the damping force characteristic in the soft region SS while the sprung vertical speed is changing within the range of the dead zone, control hunting can be prevented.

Further, in the second embodiment, the comparison value calculating means is provided by subtracting the rear wheel side variation V _RV from the front wheel side variation V _FV (= V _FV −V _RV ). V
_{Although D} is obtained, the ratio of the front wheel side change amount V _{FV to} the rear wheel side change amount V _RV (= V _FV / V _RV ) may be obtained and used as a comparison value.

[0072]

As described above, the first aspect of the present invention is as follows.
In the loading state determination device described above, as described above, a pair of vehicle state amount detection means provided at a predetermined distance at least in the front-rear direction of the vehicle and detecting the state amount of the vehicle, respectively, An instantaneous rotation center position calculating means for calculating a distance from a reference position to an instantaneous rotation center position of the vehicle body from two vehicle state quantities obtained by a pair of vehicle state amount detecting means; Moving average value calculating means for calculating a moving average value of a distance from the reference position to the instantaneous rotation center position of the vehicle body, and comparing the moving average value obtained by the moving average value calculating means with a predetermined reference value. And a load amount change determining means for determining the change state of the load amount of the vehicle, without providing a vehicle height sensor separately, two positions in the vehicle longitudinal direction detected by the vehicle state amount detecting means Vehicle shape Effect that it is possible to detect the change of the loading state of the vehicle from the amount. Further, in the loading state judging device according to the second aspect of the present invention, as described above, a pair of vehicle states provided at a predetermined distance at least in the front-rear direction of the vehicle and each detecting a state amount of the vehicle. From the quantity detection means and the respective vehicle state quantities obtained by the pair of respective vehicle state quantity detection means, both positive and negative peak values of the vehicle state quantity at each detection position are obtained, and the change amount of both the positive and negative peak values at each detection position Respectively, a comparison value calculation means for obtaining a comparison value of both peak value change amounts at both detection positions obtained by the peak value change calculation means, and a comparison value calculation means for obtaining the comparison value obtained by the comparison value calculation means. Moving average value calculating means for obtaining a moving average value of both peak value change amount comparison values at both detection positions, and comparing the moving average value of the comparison value obtained by the moving average value calculating means with a predetermined reference value. By And a load amount change judging means for judging a change in the load amount between the two, similarly to the above-mentioned claim 1, without providing a vehicle height sensor separately at two places in the vehicle longitudinal direction. The effect is obtained that a change in the loading state of the vehicle can be detected from the vehicle state quantity.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a claim showing a loading state determination device of the present invention.

FIG. 2 is a configuration explanatory view showing a loading state determination device according to the first embodiment of the present invention.

FIG. 3 is a system block diagram illustrating a loading state determination device according to the first embodiment;

FIG. 4 is a sectional view showing a shock absorber applied to the first 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 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 is a block diagram showing a signal processing circuit for obtaining a sprung vertical speed and a sprung-unsprung relative speed in the device of the first embodiment.

FIG. 15 is a diagram showing a gain characteristic (a) and a phase characteristic (b) of a sprung vertical velocity signal obtained by the signal processing circuit in the first embodiment device.

FIG. 16 is a flowchart showing the details of the damping force characteristic control operation of the control unit in the first embodiment.

FIG. 17 is a time chart showing the content of the damping force characteristic control operation of the control unit in the first embodiment.

FIG. 18 is a block diagram illustrating a signal processing circuit for obtaining a moving average value as a load amount determination signal in the first embodiment.

FIG. 19 is an explanatory diagram for deriving an equation for calculating a distance from the reference position to the instantaneous rotation center position of the vehicle in the first embodiment.

FIG. 20 is a time chart (b) showing the state of fluctuation of the sprung vertical speed at the front wheel side center position and the rear wheel side center position in the first embodiment device, and the fluctuation of the distance from the reference position to the instantaneous rotation center position at that time. It is a time chart (a) which shows a state.

FIG. 21 is a time chart showing a variation state of a distance from a reference position to an instantaneous rotation center position in the first embodiment.

FIG. 22 is a time chart showing a state of change of a moving average value of a distance from a reference position to an instantaneous rotation center position due to a change in a load amount in the apparatus of the first embodiment, and a control gain switching control operation state for the change;

FIG. 23 is a block diagram showing a signal processing circuit for obtaining a moving average value as a load amount determination signal in the device of the second embodiment.

FIG. 24 is a time chart showing the fluctuation state of the sprung vertical velocity and the positive and negative peak values thereof at the front wheel side center position (a) and the rear wheel side center position (b) in the device of the second embodiment.

FIG. 25 is a time chart showing a change state of a moving average value of a change amount of both positive and negative peak values due to a change in a load amount in the apparatus of the second embodiment, and a control gain switching control operation state for the change;

FIG. 26 is a time chart showing another example of the variable characteristic of the control gain.

[Explanation of symbols]

a ₁ vehicle state quantity detecting means a ₂ vehicle state quantity detecting means b instantaneous rotation center position calculating means c moving average value calculating means d loading amount change determining means e peak value changing amount calculating means f comparison value calculating means g moving average value calculating Means h Load amount change judgment means

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B60G 17/015 B60G 17/00 G01G 19/12

Claims (6)

(57) [Claims] 1. A pair of vehicle state quantity detection means provided at a predetermined distance at least in the front-rear direction of the vehicle and detecting a state quantity of the vehicle, respectively. Instantaneous rotation center position calculating means for calculating the distance from the reference position to the instantaneous rotation center position of the vehicle body from the two obtained vehicle state quantities; and instantaneous rotation of the vehicle body from the reference position obtained by the instantaneous rotation center position calculation means. Moving average value calculating means for obtaining a moving average value of the distance to the center position; and comparing the moving average value obtained by the moving average value calculating means with a predetermined reference value to determine a change in the load capacity of the vehicle. And a loading amount change determining means. 2. A pair of vehicle state quantity detecting means provided at a predetermined distance at least in the front-rear direction of the vehicle and detecting state quantities of the vehicle, respectively, and the pair of vehicle state quantity detecting means. A peak value change amount calculating means for obtaining both positive and negative peak values of the vehicle state amount at each detection position and obtaining an amount of change of both the positive and negative peak values at each detection position from each vehicle state amount obtained in Comparison value calculation means for obtaining a comparison value of both peak value change amounts at both detection positions obtained by the quantity calculation means, and a moving average of both peak value change amount comparison values at both detection positions obtained by the comparison value calculation means A moving average value calculating means for obtaining a value, and a load capacity change determining means for determining a load capacity change state of the vehicle by comparing a moving average value of the comparison value obtained by the moving average value calculating means with a predetermined reference value. When, the loading state determination apparatus characterized by comprising a. 3. The loading state judging device according to claim 1, wherein said vehicle state quantity detecting means comprises a sprung vertical speed detecting means for detecting a sprung vertical speed of the vehicle. . 4. The loading state judging device according to claim 1, wherein the vehicle state quantity detecting means comprises a sprung vertical acceleration detecting means for detecting a sprung vertical acceleration of the vehicle. . 5. The loading state determination according to claim 1, wherein the vehicle state quantity detecting means comprises a relative speed detecting means for detecting a relative speed between a sprung and unsprung state of the vehicle. apparatus. 6. The loading state determination according to claim 1, wherein the vehicle state quantity detecting means comprises a relative acceleration detecting means for detecting a sprung unsprung relative acceleration of the vehicle. apparatus.