JP3163757B2 - Suspension control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suspension control device for predictively controlling an actuator inserted between a wheel to be controlled and a vehicle body based on road surface information detected at a position ahead of the wheel to be controlled.

[0002]

2. Description of the Related Art As a conventional suspension control device, there is one disclosed in Japanese Patent Application Laid-Open No. 60-35618 previously proposed by the present applicant. This conventional example includes a vehicle speed detecting means for detecting a vehicle speed, an acceleration detecting means for detecting an acceleration applied to a front wheel, a vibrating means for applying a vibrating force to a rear wheel, the vehicle speed detecting means and the acceleration detecting means. Control means for controlling the vibrating means based on the output signal of, after acceleration corresponding to the vehicle speed when acceleration is applied to the front wheels, corresponding to the acceleration applied to the front wheels A configuration is provided in which an exciting force acting in the same direction is applied to the rear wheels to prevent vibration input from the road surface to the rear wheels.

[0003]

However, in the above-mentioned conventional suspension control device, the excitation force on the wheel to be controlled (rear wheel) is determined based on only the motion information of the front wheel ahead of the wheel to be controlled. Because it is determined, the excitation force applied to the rear wheel by the excitation means is too much or too small for the absorption of input from the road surface of the rear wheel,
Even if the vehicle speed detection value is constant, even if the excitation force generation timing is shifted due to the road surface conditions, or if the front wheel motion information includes noise due to the body motion such as rolls due to cross wind, these conditions Irrespective of the above, there is an unsolved problem that the excitation force on the rear wheel is controlled, and the vehicle body may be excited by the reaction of the excitation force on the rear wheel.

Accordingly, the present invention has been made in view of the above-mentioned unresolved problems of the prior art, and evaluates whether or not the control force of the control target wheel on the actuator is appropriate to change the control gain. Accordingly, it is an object of the present invention to provide a suspension control device capable of optimizing a control force and performing good preview control.

[0005]

In order to achieve the above object, a suspension control device according to the present invention is provided between a wheel to be controlled and a vehicle body as shown in FIG. An actuator, a driving unit for driving and controlling the actuator, a vehicle speed detecting unit for detecting a vehicle speed, a front road surface information detecting unit for detecting road surface information ahead of the control target wheel, and a vertical movement of the vehicle body at each control target wheel position. First vertical acceleration detecting means for detecting acceleration; second vertical acceleration detecting means for detecting vertical acceleration of the vehicle body at the position of the front road surface information detecting means; and road surface information of the front road surface information detecting means corresponding to the front road surface. Based on the delay road surface information delayed by a delay time based on the vehicle speed detection value of the vehicle speed detection unit until the control target wheel reaches the road surface detected by the information detection unit. And a preview control unit for forming a preview control command value for the driving unit, and an acceleration detection value of the first vertical acceleration detection unit and an acceleration detection value of the second vertical acceleration detection unit are delayed by the delay time. Gain correction means for comparing a control gain in the preview control means by comparing the detected acceleration value with a delay acceleration detection value.

[0006]

In the suspension control apparatus according to the present invention, the first vertical acceleration detecting means detects the vertical acceleration of the vehicle body at the wheel position to be controlled, and the second vertical acceleration detecting means detects the vehicle vertical acceleration at the position of the front road surface information detecting means. The vertical acceleration of the vehicle body is detected, and the vertical acceleration of the two vehicle bodies is compared by comparing means to determine whether or not the control of the actuator by the preview control means is proper. The control gain is increased, and when inappropriate, the control gain is reduced to suppress the vibration of the vehicle body due to the reaction of the control force.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 is a schematic diagram showing the first embodiment of the present invention. In the drawing, reference numeral 10 denotes a vehicle body side member, 11FL to 11RR denote front left to rear right wheels, and 12 denotes an active suspension.

The active suspension 12 is a vehicle-side member.
10 and each wheel side member 14 of the wheels 11FL to 11RR
Hydraulic cylinder 1 as each interposed actuator
8FL-18RR and these hydraulic cylinders 18FL-18RR
Pressure control valves 20FL to 20RR for individually adjusting the operating pressure;
A hydraulic oil of a predetermined pressure is supplied to these pressure control valves 20FL to 20RR.
The pressure is supplied through the supply pipe 21S and the pressure control valve
Return oil from 20FL-20RR through return pipe 21R
Pressure source 22 for collecting and recovering the pressure, this hydraulic source 22 and pressure control
Inserted in the supply pressure side pipe 21S between the valves 20FL to 20RR
Detects accumulators 24F and 24R for accumulator and vehicle speed
Speed sensor 26 which outputs a pulse signal corresponding to the
And arranged in parallel with the front wheel side hydraulic cylinders 18FL and 18FR
And the relative displacement between the front wheels 11FL and 11FR and the vehicle body
Stroke sensors 27FL and 27FR to be detected and front wheel 1
Top and bottom of the vehicle at positions corresponding to 1FL and 11RR respectively
Second vertical acceleration detection for detecting direction acceleration individually
Vertical acceleration sensors 28FL and 28FR as means
At positions corresponding to the rear wheels 11RL and 11RR, respectively.
A first up and down direction for individually detecting the up and down direction acceleration of the vehicle body
Vertical acceleration sensor 28RL as acceleration detecting means
And 28RR, the front wheel side vertical acceleration sensor 28FL and
28FR vertical acceleration detection value Z_GFLAnd Z_GFRBased on
And active for the front wheel side pressure control valves 20FL and 20FR
Control as well as the vehicle speed detection value V
Stroke detection value S of trooke sensor 27FL and 27FR
_FLAnd S _FRAnd vertical acceleration sensors 28FL-28RR
Vertical acceleration detection value Z_GFL~ Z _GRRFront wheel luck based on
To the rear wheel side pressure control valves 20RL and 20RR
And a controller 30 for performing preview control for the
You.

Each of the hydraulic cylinders 18FL to 18RR has a cylinder tube 18a.
8a, a lower pressure chamber L separated by a piston 18c having an axial through hole is formed.
A thrust corresponding to the pressure receiving area difference between the upper and lower surfaces and the internal pressure is generated.
The lower end of the cylinder tube 18a is
4 and the upper end of the piston rod 18b is attached to the vehicle body side member 10. Further, each of the pressure chambers L is connected to a pressure control valve 20FL-20RR via a hydraulic pipe 38.
Connected to the output port. Hydraulic cylinder 1
Each of the pressure chambers L of 8 FL to 18 RR is connected to an accumulator 34 for absorbing unsprung vibration through a throttle valve 32. A coil spring 36 having a relatively low spring constant and supporting the static load of the vehicle body is disposed between the upper and lower portions of each of the hydraulic cylinders 18FL to 18RR.

Each of the pressure control valves 20FL to 20RR has a well-known three-port proportional electromagnetic pressure reducing valve having a cylindrical valve housing having a spool slidably mounted therein and a proportional solenoid provided integrally therewith. (For example, Japanese Patent Application Laid-Open No. 64-7
No. 4111). Then, by adjusting the command current i (command value) supplied to the exciting coil of the proportional solenoid, the moving distance of the poppet housed in the valve housing, that is, the position of the spool is controlled, and the supply port and the output port or the output port are controlled. Hydraulic oil flowing between the hydraulic source 22 and the hydraulic cylinders 18FL to 18RR can be controlled via the port and the return port.

FIG. 3 shows the relationship between the command current i (: i _{FL to} i _RR ) applied to the exciting coil and the control pressure P output from the output port of the pressure control valve 20FL (to 20 _RR ). As described above, the minimum control pressure P _NIM is at the minimum current value i _MIN in consideration of noise. When the current value i is increased from this state, the control pressure P linearly increases in proportion to the current value i, when the current value i _MAX is the maximum control pressure P _MAX corresponding to the set line pressure of the hydraulic source 22. This figure 3
Where i _N is a neutral command current and _PCN is a neutral control pressure.

As shown in FIG. 4, each of the stroke sensors 27FL and 28FR outputs zero neutral voltage V _S when the vehicle height coincides with a predetermined target vehicle height, and when the vehicle height becomes higher than the target vehicle height, the stroke sensors 27FL and 28FR output the same. When the vehicle height is lower than the target vehicle height, the stroke detection values S _FL and S _FR are output as negative voltages according to the deviation.

As shown in FIG. 5, each of the vertical acceleration sensors 28FL to 28RL has a zero voltage when the vertical acceleration is zero, and a positive voltage corresponding to the acceleration value when the upward acceleration is detected. When the analog voltage and the downward acceleration are detected, the vehicle vertical acceleration detection values Z _{GFL to} Z _GRR which are negative analog voltages corresponding to the acceleration values are output.

The controller 30 includes, as shown in FIG.
Stroke sensor 27FL, stroke detected value S _FL outputted from 27FR, S _FR and the vertical acceleration sensor 28FL
Body vertical acceleration detection value Z _GFL output from ~ 28FR ~
A / D converters 43a to 43 which convert Z _GRR into digital values
43f, the vehicle speed detection value V of the vehicle speed sensor 26 and each A / D
A microcomputer 44 to which A / D conversion outputs of the converters 43a to 43f are input, and control force command values U _{FL to} U _RR output from the microcomputer 44 are supplied via D / A converters 45FL to 45RR. It is, and a composed driving circuit 46FL~46FR them in the driving current i _FL through i floating type constant-voltage circuit, for example into a _FR to the pressure control valve 20FL～20RR.

Here, the microcomputer 44 has a small number.
At least the input side interface circuit 44a and the output side
Interface circuit 44b, arithmetic processing unit 44c, and storage device
44d. For the input interface circuit 44a
Are the changes in the detected vehicle speed V and the A / D converters 43a to 43f.
Is input to the output-side interface circuit 44b.
Are pressure command values P for each of the pressure control valves 20FL to 20RR.
_FL~ P_RRAre output to the D / A converters 45FL to 45RR.
The arithmetic processing unit 44c executes the processing of FIG.
And a predetermined sampling time T_S(For example, 20 msec)
For each case, the vehicle speed detection value V and the stroke detection value S_FL,S_FRas well as
Vehicle vertical acceleration detection value Z_GFL~ Z_GRRAnd the front wheel side
Body vertical acceleration detection value Z_GFL,Z_GFRThe band pass
Active control force U for front wheels_FLAnd U_FRIs calculated
And a delay between the front and rear wheels based on the vehicle speed detection value V.
Time τ_RAnd the stroke detection value S_FL,S_FRAnd delay
Time τ_RAnd a shift register formed in the storage device 44d.
Area while shifting it sequentially, and delay time τ_RTo
For the shift, the sampling time T_SSubtract
The new delay time τ_RUpdate as the front wheel side
Vertical acceleration detection value Z _GiFilter (i = FL, FR)
Vertical acceleration detection value Z representing low frequency component extracted by processing
_Gi'And the vertical acceleration detection value Z on the rear wheel side_Gj(J = RL, R
R) Upper and lower representing low frequency components extracted by filtering
Acceleration detection value Z_Gj'And control gain K_pUpdate
And the updated control gain K_pAnd delay time τ_RIs zero
Stroke detection value S_FL, S_FRAnd based on the rear wheel
Predictive control force U_RL,U_RRIs calculated and based on these
Each of the pressure control valves 20FL to 20RR is controlled.

Further, the storage device 44d stores a program necessary for the arithmetic processing of the arithmetic processing device 44c in advance, and also detects the stroke detection values S _FL, S _FR and the vertical acceleration detection value Z for each predetermined sampling time T _{S. GFL} ', Z
A shift register area for storing a predetermined number of _GFR's while sequentially shifting the _GFR 'together with the delay time τ _R is formed, and the operation results required in the operation process of the operation processing unit 44c are sequentially stored.

Next, the operation of the above embodiment will be described with reference to the flowchart of FIG. 7 showing the processing procedure of the arithmetic processing unit 44c in the microcomputer 44. That is,
The processing in FIG. 7 is performed for a predetermined sampling time T _S (for example, 20 ms).
ec) is executed as a timer interrupt process. First, in step S1, the current vehicle speed detection value V of the vehicle speed sensor 26 is read, and then the process proceeds to step S2, in which the stroke detection values S from the stroke sensors 27FL and 27FR are read. The vehicle vertical acceleration detection values Z _GFL -Z _GRR are read from the _FL , S _FR and vertical acceleration sensors 28FL-28RR, and at least the vehicle vertical acceleration detection values Z _GFL -Z _GRR are formed in the storage device 44d, for example. The data is stored while being sequentially shifted in a shift register area for storing five times.

Next, the process proceeds to step S3, where the shift
5 vertical accelerations stored in the register area
Degree detection value Z_GFL~ Z_GRRFor example, a transverser
Perform moving average processing by filter processing
Delay time τ_RThe effect of this error
Vertical acceleration detection value Z from which received high-frequency components are removed
_GFL'~ Z_LRR'.

Next, the process proceeds to step S4, where the following equation (1) is calculated based on the detected vehicle speed V to obtain the front wheel 11FL.
And the delay time τ _R required for the rear wheels 11RL and 11RR to reach the road surface on which the vehicle has passed 11FR. τ _R = (L / V) −τ _S (1) where L is the wheel base, τ _S is the response delay time of the control system, and the response delay time of the hydraulic system and the computational waste of the controller in advance. It is set as the sum of the time and the response delay time of the filter.

Next, the process proceeds to step S5, where
Stroke detection value S read in step S2_FL,S_FR,
Front wheel side vertical acceleration detection value Z calculated in step S3
_GFL′ _,Z_GFR'And the delay calculated in step S4 above
Time τ_RAre formed as a set in the storage device 44d.
At the beginning of the register area,
The stored stroke detection value S_FL,S_FR, Front wheel side car
Body vertical acceleration detection value Z_{GF L}′_,Z_GFR'And delay time τ
_RAre sequentially shifted. At this time, the delay time τ_Rabout
Is the delay time τ of each shift position when shifting_RFrom
Sampling time T _SIs the new delay time
τ_RAnd then store it.

Next, the process proceeds to step S6, where the oldest delay time τ stored in the shift register area is stored.
_The detected value Z _Gf ′ of the vehicle vertical acceleration on the front wheel when _R becomes zero.
(F = FL, FR) are read out, and the read-out front-wheel-side vehicle body vertical acceleration detection value Z _Gr 'and the current rear-wheel-side vehicle body vertical acceleration detection value Z _Gr ' (r = RL, FR) calculated in step S3 are read out.
RR) is substantially zero. At this time, when Z _Gf ′ = Z _Gr ′ ≒ 0, it is determined that the vehicle body does not swing, and the process proceeds to step S7 to set the preview control gain K _p to a preset set value, for example, “1”. Then, the process proceeds to step S12 to be described later. If the front wheel side vehicle body vertical acceleration Z _Gf ′ or the rear wheel side vertical acceleration Z _Gr ′ is not substantially zero, the process proceeds to step S8.

In step S8, the front wheel side vehicle body vertical
Speed Z_Gf'And the rear wheel side vertical acceleration Z _Gr'Is the same sign
It is determined whether or not. At this time, both have different signs, that is, the front wheel side.
Body vertical acceleration detection value Z_Gf′ Is positive, body up and down on the rear wheel side
Acceleration detection value Z_Gr′ Is negative or vice versa,
The control force applied to the wheels is excessive to absorb the input from the road surface
It is determined that the current
Look control gain K_pFrom the preset value β
The new value is used as the new preview control gain K._pFrom later
The process moves to step S12.

On the other hand, when the result of the determination in step S8 is that the detected value of the vertical acceleration Z _Gf 'of the front wheel body and the current detected value Z _Gr ' of the vertical acceleration of the rear wheel calculated in step S3 are the same, In step S10, it is determined whether or not the absolute value | Z _Gr '| of the detected value of the vertical acceleration of the rear wheel is equal to or less than the absolute value | Z _Gf ' | of the detected value of the vertical acceleration of the front wheel. . Here, when | Z _Gf '|> | Z _Gr ' |, the timing at which the control force is applied to the rear wheels is different from the timing of the input from the road surface, or the motion information of the front wheels is different from the input from the road surface. rolls, it is determined that it contained noise components such as pitch, the value obtained by subtracting a predetermined value β proceeds to step S9 from the current preview control gain K _p as a new preview control gain K _p Set, |
If Z _Gf ′ | ≧ | Z _Gr ′ |, it is determined that the vibration isolating effect is exerted by the control force applied to the rear wheel, and the process proceeds to step S11 to exhibit a greater vibration isolating effect. shifts from the set as a new preview control gain K _p to step S12 to a value obtained by adding a predetermined value α set in advance in the preview control gain K _p to.

In step S12, the vehicle body vertical acceleration detection values Z _GFL and Z _GFR read in step S2 are integrated by performing a band-pass filter process for passing through a sprung resonance frequency region. The speeds Z _VFL and Z _VFR are calculated, and based on these,
The front wheel-side active control forces U _FL and U _FR for the front wheel-side pressure control valves 20 _FL and 20 _FR are calculated according to the equations (2) and (3), and the oldest, ie, oldest, stored in the shift register area in step S2. The front-wheel-side stroke detection values S _{FL and} S _{FR for} which the delay time τ _R has become zero are read out, and based on these and the preview control gain K _p set in step S8 or step S10, the following (4) and (5) ), Predictive control forces U _RL and U _RR for rear wheel side pressure control valves 20 _RL and 20 _RR are calculated and read out, and read out oldest stroke detection values S _FL, S _FR and front wheel vertical acceleration detection value Z _GFL ′. _, Z _GFR ′ and the delay time τ _{R corresponding} thereto are erased from the shift register area.

[0025] _{U FL = U N -K a ·} Z VFL ............ (2) U FR = U N -K a · Z VFR ............ (3) U RL = U N + K p · S FL ... _{......... (4) U RR = U} N + K p · S FR ............ (5) where, U _N is required control force to maintain the vehicle height to the target vehicle height, K _a is the active control gain, K _p is a preview control gain.

Next, the process proceeds to step S13, in which each of the pressure control valves 20FL-20RR calculated in step S11 is calculated.
Control forces U _{FL to} U _RR as pressure command values for D /
After outputting to the A converters 45FL to 45RR, the timer interrupt processing is terminated and the processing returns to the predetermined main program. In the processing of FIG. 7, the processing of steps S3, S6 to S11 corresponds to the gain correction means, and the processing of steps S5, S12, S
The process 13 corresponds to the preview control means. Therefore, if it is assumed that the vehicle is traveling straight ahead at a constant speed on a flat good road while maintaining the target vehicle height, in this state, the vehicle is maintaining the target vehicle height on a flat good road. Since the body-side member 10 does not swing, each stroke sensor 27
FL, stroke detected value S _FL of 27FR, acceleration detection value of S _FR and the vertical acceleration sensor 28FL~28FR Z _GFL ~
Z _GRR is substantially zero, and these are the A / D converters 43.
The digital values are converted into digital values by a to 43f and input to the microcomputer 44.

For this reason, the microcomputer 44
When the process of FIG. 7 is executed, the stroke detection values S _FL and S _FR and the vertical acceleration detection values Z _{GFL to} Z _GRR continue to be substantially zero while the vehicle is traveling on a flat good road. , The vertical acceleration detection value Z calculated in step S3
_{Since GFL} 'to Z _GRR ' also remain substantially zero, all the stroke detection values S _{FL and} S _FR and the vertical acceleration detection values Z _GFL ' _and Z _GFR ' stored in the shift register area are stored.
Is also substantially zero. As a result, the front wheel vertical acceleration detection values Z _GFL ′ and Z _GFR ′ before the delay time τ _R when the front wheels 11FL and 11FR pass through the road surface on which the current rear wheels 11RL and 11RR pass at step S6 in the process of FIG. And the detected vertical acceleration values Z _GRL ′ and Z _GRR ′ of the current rear wheels 11 RL and 11 RR are substantially equal to zero. Therefore, the process proceeds to step S 8, and the preview control gain K _p is set to “1”. The process proceeds to step S11 to calculate the control forces U _{FL to} U _RR .
In this case, the (2) to (5) of the second term on the right side by is substantially zero, the control force U _FL ~U _RR neutral pressure control force U _N next corresponding only to the target vehicle height H _T , These as the pressure command value through the output side interface circuit 44b and the D / A
Drive circuits 46FL to 46RR via converters 45FL to 45RR
Is output to

Therefore, control is performed by the driving circuits 46FL to 46RR.
Force U_FL~ U_RRCommand current i corresponding to _FL~ I_RRIs converted to
The pressure is supplied to each of the pressure control valves 20FL to 20RR. This result
As a result, the target vehicle height is maintained from the pressure control valves 20FL to 20RR.
Required neutral pressure P_CNAre each hydraulic cylinder 18FL-18
RR, and the hydraulic cylinders 18FL-18RR
Target stroke between body side member 10 and wheel side member 14
Generates thrust to maintain vehicle height.

When the front left and right wheels 11FL and 11FR are simultaneously traveling on a so-called ramp step road having a step where the road surface rises stepwise while the vehicle is traveling at a constant speed on the good road, Front wheel 1 by stepping
1FL and 11FR are bound, whereby the stroke detection value of the stroke sensor 27FL and 27FR S _FL and S
_{As FR} rapidly decreases from zero in the negative direction, an upward acceleration is generated in the vehicle body-side member 10, and this is detected by the vertical acceleration sensors 28FL and 28FR of the front left and right wheels.

For this reason, for each sampling time T _S at which the processing of FIG. 7 is executed by the microcomputer 44, the front-wheel-side vehicle vertical corrugation speed detection values Z _{GFL and} Z _GFR read in step _S 2 are read for the front wheels. since increased according to the vehicle increases speed by riding step, the front-wheel side control force U _FL calculated in step _S12, the U _FR will be decreased from the neutral pressure control force U _N, driving circuit 46FL accordingly And the command currents i _{FL and} i _FR output from _FR 46 and FR 46 decrease,
This pressure control valve 20FL, the control pressure P _C is output from 20FR and lower than the neutral pressure P _CN, the hydraulic cylinder 1
The thrust of the 8FL and 18FR is reduced, and the stroke of the front wheel side is reduced by exhibiting the skyhook damper function, so that the swing of the vehicle body side member 10 due to the front wheels 11FL and 11FR riding on the convex portion can be suppressed. On the other hand, on the rear wheel side, the front wheel vertical acceleration detection values Z _GFL ′ _, Z _GFR ′ _{, for} which the delay time τ _R has become zero at the time of riding over the front wheel step, remain zero, so that the rear wheel hydraulic cylinder 18 RL, 18
In the RR, a control state for generating a thrust for maintaining the target vehicle height is continued.

[0031] Then, the rear wheel side, sequentially from the time the delay time tau _R has passed the front wheels 11FL and 11FR are calculated in step S5 in Fig. 7 when passing over the step, the delay time tau _R
The front-wheel-side stroke detection values S _{FL and} S _FR at the time when the front left and right wheels 11FL and 11FR pass through the step are read out just before, that is, based on these, the rear wheel-side control force U is determined in step S12.
_{RL and} U _RR are calculated and output to the pressure control valves 20RL and 20RR as rear wheel side pressure command values. As a result, the front wheel 1
1FL and 11FR are delay time τ _R from the start of step riding
Min delayed rear wheels 11RL, rear-wheel side control force from the time the 11RR rides on the step U _RL, by U _RR is decreased from the neutral pressure control force U _N, command current i _RL output from the drive circuit 46RL and 46RR There was lower than the neutral current i _N, whereby the control pressure P _C which is output from the pressure control valve 20RL and 20RR is lowered from neutral pressure P _CN, thrust of the hydraulic cylinders 18RL and 18RR are lowered, the rear left wheel side By reducing the stroke, it is possible to suppress the transmission of the vibration input due to the rear left and right wheels 11RL and 11RR running over the step to the vehicle body side member 10.

At this time, in the process of FIG.
Rear wheel vertical acceleration sensor 2 when RL and 11RR pass over a step
Vertical acceleration detection value Z of 8RL and 28RR_GRLAnd Z
_GRRVertical acceleration detection value Z obtained by filtering_GRL′
And Z_GRR'And when the front wheels 11FL and 11FR
Vertical acceleration detection value Z_GFLAnd Z_GFRFilter
Vertical acceleration detection value Z_GFL'And Z_GFR′ And
Since the value becomes larger than zero, the steps from step S6
Proceeding to S8, the front wheel side vertical acceleration detection value Z _GRL′
And Z_GRR'And the rear wheel side vertical acceleration detection value Z_GFL'And Z
_GFR′, And when both signs are the same, that is,
Detection of vertical acceleration on the front wheel side because the vehicle is riding on a step
Value Z_GFL'And Z_GFR′ Is a positive value,
Direction acceleration detection value Z_GRL'And Z_GRR′ Is also a positive value
The rear wheel side control calculated in step S12.
Force U_RL,U_RRIs judged to be in an appropriate state, and the
From step S8 to step S10.
Vertical acceleration detection value Z_GRL'And Z_GRR′
Corresponding front wheel vertical acceleration detection value Z_GFL'as well as
Z_{GF R}′, It is calculated in step S12.
Rear wheel side control force U_RLAnd U_RRVibration isolation effect
Is determined to be in operation, and the process proceeds to step S11.
And the preview control gain K_pIs increased by a predetermined value α. This
Accordingly, the rear-wheel-side control force calculated in step S12
U_RLAnd U_RRIs more neutral pressure control force U_NIs reduced from
Although the dynamic insulation effect can be further enhanced,
K_p, The preview control gain K
_pIs too large, and the vertical acceleration detection value on the front wheel side is
Z_GFL'And Z_GFR′ And the vertical acceleration detection value on the rear wheel side
Z_GRL'And Z_GRR′ Generates different excitation force
When the state is reached, the process proceeds from step S8 to step S9.
Therefore, the preview control gain K_pIs reduced by a predetermined value β.
You. After all, the preview control gain K_pMaximizes vibration isolation
It will be set to a value that can be demonstrated.

However, when traveling on a flat, good road, crosswind
For example, it leans down to the right as viewed from behind
When a roll occurs, the vertical acceleration due to this roll
The component is the vertical direction of the vertical acceleration sensor 28FL-28RR
Acceleration detection value Z_GFL~ Z_GRRIncluded on the upper left and lower
Direction acceleration detection value Z_GFL,Z_GRLIs a positive value and conversely
Vertical acceleration detection value Z_GFR,Z_GRRIs a negative value.
When this roll occurs, data is read from the shift register area.
Vertical wheel acceleration detection value Z on the front wheel side_GFL'as well as
Z_GFR′ Is almost zero when driving on a flat road.
Since the state is maintained, it is determined in step S8 that the sign is different.
Or the same sign, the rear wheel side in step S10.
Absolute value of the vertical acceleration detection value | Z_GRL'| And | Z
_GRR'| Is the absolute value of the vertical acceleration detection value on the front wheel side | Z
_GFL'| And | Z_GFR'||
However, the process proceeds to step S9, and the preview control gain K_pIs reduced
Will be reduced. During this time, data is read from the shift register area
Stroke detection value S_FLAnd S_FRAlso maintain a state of almost zero
Therefore, the rear wheel-side control force U calculated in step S12_RLPassing
And U_RRIs the neutral pressure control force U_NTo maintain the state. like this
And the preview control gain K _pOf the decrease is repeated
, The stroke detection value S generated when the roll occurs_FLAnd S
_FRDelay time τ for reading the change in_RForeseeing at the time
Control gain K_pApproaches zero, and the stroke detection value S
_FLAnd S_FRBased on the rear wheel side hydraulic cylinders 18RL and 1
To ensure that the 8RR is not activated unnecessarily
It is possible to secure a good ride comfort.

[0034] Thus, even in a state close to a preview control gain K _p is zero, then the return to the straight running state without change in posture to the vehicle body, a front wheel side of the absolute value of the vertical acceleration detection value | Z _GFL '| and | Z _GFR ' | and the absolute value of the vertical acceleration detection value on the rear wheel side | Z _GRL '| and | Z _GRR '
Returns to a substantially zero state, the process shifts from step S6 to step S7, and the preview control gain _Kp becomes “1”.
Therefore, when the vehicle subsequently passes over the road surface irregularities, accurate preview control can be executed.

Further, depending on road surface conditions and changes in vehicle speed,
When preview control timing of the rear wheel is deviated with respect to the road surface passing timing of the rear wheels 11RL and 11RR, by the transition from step S10 to step S9, since the preview control gain K _p is reduced, Preview Control Unnecessary excitation force acting on the vehicle body-side member 10 due to the timing deviation can be reliably prevented.

On the other hand, when either one of the front wheels 11FL and 11FR, for example, only the front left wheel 11FL rides on the transient convex portion, the preview control is performed only on the left wheel hydraulic cylinders 18FL and 18RL. Control for maintaining the neutral pressure is performed for the right wheel side hydraulic cylinders 18FR and 18RR that do not cause a crossover. Also, front wheels 11FL, 11
When the FR falls into the temporary recess, the control can be performed in the reverse manner to suppress the vehicle's swing, and the continuous uneven road surface such as irregular road surface is not limited to the temporary uneven surface. Even when the vehicle is running, the preview control of the rear wheels can be performed according to the behavior of the front wheels.

As described above, according to the above embodiment, the detected value of the vertical acceleration of the vehicle body when the front wheels pass over the uneven road surface is compared with the detected value of the vertical acceleration of the vehicle body when the corresponding rear wheels pass over the uneven road surface. Therefore, the preview control gain _Kp is changed, so that the optimal preview control is performed without being affected by a disturbance due to a shift in control timing, generation of an excessive control force, and a change in posture such as a roll and a pitch of the vehicle body. Since the low frequency component extracted by the filtering process is used as the detected value of the vehicle body vertical acceleration, it is affected by the error of the delay time τ _R calculated based on the detected vehicle speed V. Without this, accurate preview control can be performed.

In the above embodiment, the case where the preview control force of the rear wheels is calculated based on the front wheel side stroke detection values S _FL and S _FR has been described. However, the present invention is not limited to this. Front wheel motion information such as differential values of the detected values S _FL and S _FR , front wheel vertical acceleration detected values Z _{GFL and} Z _GFR or their integrated values can be applied. In the above embodiment, the microcomputer 44
In the above, the case where the moving average is performed by the transversal filter processing in step S3 has been described. However, the present invention is not limited to this, and low-frequency components may be extracted by performing low-pass filter processing.
Instead of the filter processing in step 4, hardware processing may be performed using an analog filter.

Further, in the above embodiment, the preview control
Gain K_pΑ and β were applied as predetermined values to increase or decrease
The case has been described, but the present invention is not limited to this.
You may make it set. Furthermore, in the above embodiment,
In this case, the microcomputer 44 detects the stroke.
Outgoing S_FL, S_FRThe delay time τ_RWith shift register
Area while shifting sequentially to the delay time τ_RIs zero
Stroke detection value S_FL, S_FRForeseeing control force based on
Is described, but the stroke detection is performed in advance.
Outgoing S_FL,S _FRCorresponding to step S10 based on the
Calculation to calculate the predictive control force, which is referred to as the delay time τ_RWhen
Both are stored while shifting sequentially to the shift register area,
The control gain K is added to the preview control force at which the delay time becomes zero._pSquared
Calculate the control force U_RL, U_RRMay be calculated.
No.

Further, in the above-described embodiment, a case has been described in which the road surface vibration input input to the front wheels 11FL and 11FR is detected by applying the front wheel position stroke sensors 27FL and 27FR as the front road surface information detecting means. However, the present invention is not limited to this.
A non-contact distance sensor such as an ultrasonic distance sensor and a laser distance sensor and a vertical acceleration sensor are disposed at a position forward of 1FR, and the front wheel side hydraulic cylinders 18FL and 18FR are connected to each other based on a distance detection value of the non-contact distance sensor. Foreseeing control of both the rear wheel side hydraulic cylinders 18RL and 18RR can also be performed.

In each of the above embodiments, the case where the pressure control valves 20FL to 20RR are used as the control valves has been described. However, the present invention is not limited to this, and other flow control type servo valves or the like may be used. What you get. Further, in the above-described embodiment, the case where the controller 30 is configured by the microcomputer 62 has been described. However, the present invention is not limited to this, and the controller 30 may be configured by combining electronic circuits such as a shift register and an arithmetic circuit. It goes without saying that it is good.

Further, in the above embodiment, the case where the working oil is applied as the working fluid has been described.
The invention is not limited thereto, and any working fluid may be used as long as the fluid has a low compression ratio.

[0043]

As described above, according to the suspension control apparatus of the present invention, the vertical acceleration of the vehicle at the position of the wheel to be controlled is detected by the first vertical acceleration detecting means, and the vertical acceleration at the position of the wheel to be controlled is detected. The road surface information is detected by the front road surface information detecting means, and the vertical acceleration of the vehicle body at the position of the front road surface information detecting means is detected by the second vertical acceleration detecting means. The detected vertical acceleration value of the vehicle body is delayed by a delay time until the wheel to be controlled passes the detected road surface, and the detected value is set to the first delay value.
The control gain is changed by comparing with the vertical acceleration of the vehicle at the wheel position to be controlled detected by the vertical acceleration detection means of By being included
The effect that the effect of improving the riding comfort can be sufficiently exhibited while reliably preventing the control force generated by the preview control from acting on the vehicle body as the exciting force is obtained.

[Brief description of the drawings]

FIG. 1 is a basic configuration diagram showing a schematic configuration of the present invention.

FIG. 2 is a schematic configuration diagram showing one embodiment of the present invention.

FIG. 3 is a characteristic diagram showing a relationship between a control current and a command current of a pressure control valve.

FIG. 4 is a characteristic diagram illustrating output characteristics of a stroke sensor.

FIG. 5 is a characteristic diagram illustrating output characteristics of a vertical acceleration sensor.

FIG. 6 is a block diagram illustrating an example of a controller.

FIG. 7 is a flowchart illustrating an example of a processing procedure of a microcomputer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Body member 11FL-11RR Wheel 14 Wheel member 18FL-18RR Hydraulic cylinder 20FL-20RR Pressure control valve 22 Hydraulic source 26 Vehicle speed sensor 27FL, 27FR Stroke sensor 28FL-28RR Vertical acceleration sensor 30 Controller

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B60G 17/015 B60G 23/00

Claims (1)

(57) [Claims] 1. An actuator interposed between a wheel to be controlled and a vehicle body, a driving means for driving and controlling the actuator, a vehicle speed detecting means for detecting a vehicle speed, and a method for detecting road surface information ahead of the wheel to be controlled. Forward road surface information detecting means for detecting, first vertical acceleration detecting means for detecting the vertical acceleration of the vehicle body at each wheel position to be controlled, and second vertical detecting means for detecting the vertical acceleration of the vehicle body at the front road surface information detecting means position Acceleration detection means, and delaying the road surface information of the front road surface information detection means by a delay time based on a vehicle speed detection value of the vehicle speed detection means until the controlled wheel reaches the road surface detected by the front road surface information detection means. Foreseeing control means for forming a foreseeing control command value for the driving means based on the delayed road surface information, and an acceleration detection value of the first vertical acceleration detecting means. Gain correction means for comparing the detected acceleration value of the second vertical acceleration detection means with a delayed acceleration detection value delayed by the delay time to change a control gain in the preview control means. Suspension control device.