JPH0370617A - Active type suspension - Google Patents

Abstract

PURPOSE:To prevent the occurrence of rolling during straight running by a method wherein based on vertical accelerated detected on the left and right wheel sides of a car body. the roll angular velocity of the car body is computed, and based on the roll angular velocity, command values by means of which roll movement is suppressed is computed respectively for left and right wheel. CONSTITUTION:A fluid pressure cylinder A is located classified by each wheel between members on the car body side and on the wheel side, and the working pressure thereof is individually controlled by each pressure control valve B according to a given command value. In this case acceleration in the vertical direction of the car body both on the right wheel side and the left wheel side is detected by a means C. Based on detected vertical acceleration, the roll angular velocity of the car body is computed by a means D. Based on the computed roll angular velocity, the command value outputted to each pressure control valve B is computed respectively for left and right wheels by a menas D so that roll movement of the car body is suppressed. This constitution prevents the occurrence of rolling to the car body due to irregularity of a road surface during straight running, and stabilizes orientation of a vehicle.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an active suspension, and particularly relates to a fluid pressure cylinder disposed between a vehicle body side member and a wheel side member, and a fluid pressure cylinder disposed between a vehicle body side member and a wheel side member. The present invention relates to an active suspension that includes a pressure control valve that controls the operating pressure of a vehicle according to a command value, and that changes the command value according to the roll motion of a vehicle.

[Conventional technology]

As a conventional active suspension for a vehicle, for example, one disclosed in Japanese Patent Application Laid-Open No. 1-95924, which has been proposed by the applicant of the present invention, is known.

This conventional active suspension includes a fluid pressure cylinder interposed between the vehicle body and each wheel, and a pressure control valve that controls the operating pressure of the fluid pressure cylinder according to a command value.
Vertical speed and lateral acceleration of the vehicle body.

A method is disclosed in which a command value for vibration damping in each direction is calculated by multiplying each longitudinal acceleration by a control gain, and the command value is output to a pressure control valve.

[Problem to be solved by the invention]

However, such conventional active suspensions mainly perform roll control based on the magnitude of lateral acceleration generated in the vehicle body in order to prevent changes in attitude when the vehicle turns. When a vehicle rolls due to an uneven road surface while traveling straight, almost no lateral acceleration is detected, so there has been an unresolved problem that roll control cannot be performed accurately.

The present invention has been made by focusing on these unsolved problems of the conventional technology, and even when the vehicle rolls due to an uneven road surface while driving straight, it can accurately suppress this roll and stabilize the vehicle posture. The problem we are trying to solve is to improve the

(Means for Solving the Problems) In order to solve the above problems, as shown in FIG. 1, the present invention includes a fluid pressure cylinder interposed between a vehicle body side member and a wheel side member for each wheel, A pressure control valve that individually controls the operating pressure of each fluid pressure cylinder according to a command value, a vertical acceleration detection means that detects the vertical acceleration of the vehicle body on the right wheel side and the left wheel side, and this vertical acceleration detection means roll angular velocity calculation means for calculating the roll angular velocity of the vehicle body based on each detected value, and command value calculation means for calculating the command value for suppressing the roll movement for each left and right wheel based on the calculation value of the roll angular velocity calculation means. ing.

[Effect]

In the present invention, it is assumed that while the vehicle is traveling straight at a constant speed, the vehicle passes through an uneven part of the road surface and an external force in the vertical direction is applied to the vehicle, causing the vehicle body to attempt to roll. At this time,
The vertical acceleration detection means detects each vertical acceleration occurring on the right wheel side and the left wheel side of the vehicle body, and based on each vertical acceleration, the roll angular velocity calculation means calculates the roll angular velocity corresponding to the roll motion of the vehicle body. Based on the value, a command value calculating means calculates a command value for suppressing the roll motion, and applies this command value to each pressure control valve. Therefore, the operating force of the hydraulic cylinders of the left and right wheels damps the roll motion of the vehicle body, and when the vehicle is traveling with almost no lateral acceleration, rolling that tends to occur due to road surface irregularities, etc. is accurately suppressed.

〔Example〕

(First Embodiment) Hereinafter, a first embodiment of the present invention will be described based on FIGS. 2 to 6. The active suspension of this embodiment performs roll control, pitch control, and bounce control of the vehicle body.

In Fig. 2, 10 is a suspension arm on the vehicle body side, IIFL to IIRR are front left to rear right wheels,
Reference numeral 12 indicates an active suspension.

The active suspension 12 includes a vehicle body side member 10 and a wheel 1.
A hydraulic cylinder 18FL- as a fluid pressure cylinder interposed between each wheel side member 14 of 1FL to IIRR.
18RR, and pressure control valves 20FL to 20RR that adjust the operating pressures of the hydraulic cylinders 18FL to 18RR, respectively.
It has a hydraulic power source 22 of this hydraulic system and an accumulator 24,24 for accumulating pressure inserted between this hydraulic power source 22 and the pressure control valves 20FL to 2ORR, and a lateral Acceleration sensor 261 Front and rear acceleration sensor 27. Vertical acceleration sensor 28PL~28R
R and the pressure control valve 20FL based on the detection signal of each sensor.
Controller 30 that individually controls the output pressure of ~20RR
It has In addition, hydraulic cylinders 18FL to 18R
Each of the pressure chambers R, which will be described later, is connected via a throttle valve 32 to an accumulator 34 for vibration absorption. Furthermore, each spring mass of the hydraulic cylinders 18FL to 18RR,
A coil spring 36 having a relatively low spring constant and supporting the static load of the vehicle body is disposed between the unsprung portions.

Each of the hydraulic cylinders 18FL to 18RR has a cylinder tube 18a, and this cylinder tube 18a includes:
A lower pressure chamber is formed separated by the piston 18c. The lower end of the cylinder tube 18a is attached to the wheel side member 14, and the piston rod 18b
The upper end of is attached to the vehicle body side member IO. Also,
Each of the pressure chambers is connected to the pressure control valve 2 via a hydraulic pipe 38.
It is connected to the output ports from 0FL to 20RH.

Further, each of the pressure control valves 20FL to 20RR is a conventional three-bottom proportional electromagnetic pressure reducing valve (3-bottom proportional solenoid) having a cylindrical valve housing and a proportional solenoid integrally provided therein.
For example, see Japanese Patent Laid-Open No. 64-74111). By adjusting the command value S, which is the current value supplied to the excitation 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 boat from the hydraulic source 22 is controlled. It is possible to control the hydraulic oil supplied to the hydraulic cylinders 18FL to 18RR via the output ports, and the hydraulic oil returned from the hydraulic cylinders 18FL to 18RR to the hydraulic source 22 via the output boat and the return boat.

Here, the command value S (:S FL
-SR-) and the control pressure P output from the output port of the pressure control valve 20FL (~20RR) is as shown in FIG. In other words, when the minimum command value is 5818 considering noise, the lowest control pressure P□A is obtained, and when the command value S is increased from this state, the control pressure P increases linearly in proportion to the command (I!S). Maximum command value S 14
When using AX, is the highest profit corresponding to the set line pressure? III
Pressure P becomes MAX.

On the other hand, a lateral acceleration sensor 26 and a longitudinal acceleration sensor 27 are installed at predetermined positions ahead of the center of gravity of the vehicle, and these sensors 26 and 27 measure the lateral acceleration 2 in the lateral (vehicle width) direction acting on the vehicle body. Detects longitudinal acceleration in the longitudinal direction,
A lateral acceleration signal gv and a longitudinal acceleration signal gx, which are positive and negative analog voltage values corresponding to the acceleration and the direction of its action, are output to the controller 30, respectively. Further, the vertical acceleration sensors 28FL to 2 are located at the vehicle body position approximately directly above the front left to rear right wheels 11FL to 11RR.
8RR are each equipped with these sensors 28FL
~28RR is a vertical acceleration signal g2FL that detects the vertical acceleration of the vehicle body that occurs at each wheel position, and has a value corresponding to the vertical acceleration and a positive/negative analog voltage value (positive for downward acceleration) according to the direction in which it occurs. -g 2RR are output to the controller 30 respectively.

Furthermore, as shown in FIG. 4, the controller 30 includes an A/D converter 70 that converts the input analog lateral acceleration detection signal gv+longitudinal acceleration detection signal gx into a digital quantity.
A, 70B, and the analog vertical acceleration signal g
2FL-g A/ to convert z, I, l into digital quantities
D converters 71A to 71D, a microcomputer 72 for arithmetic processing, and D/A converters 73A to 73D that individually convert digital control signals SC output from the microcomputer 72 into analog quantities; It has drive circuits 74A to 74D that individually output command values SFL'=SFR corresponding to analog control signals SC to the pressure control valves 20FL to 20RR.

Of these, the microcomputer 72 includes at least an interface circuit 76, an arithmetic processing unit 78, a RAM, and a RAM.
The interface circuit 76 includes an I10 board and the like. Further, the arithmetic processing unit 78 outputs the detection signals gy+gx+ and g2FL~ via the interface circuit 76.
g 2R11 is read in sequence, and based on these, calculations and other processing described below are performed. The storage device 80 stores in advance predetermined programs, fixed data, etc. necessary for the execution of processing by the arithmetic processing device 78, and also
The processing results can be stored.

Next, the operation of the above embodiment will be explained.

When the ignition switch of the vehicle is turned on, the controller 30 is activated and executes the timer interrupt process shown in FIG. 5 at predetermined time intervals (for example, every 20 m5ec) while a predetermined main program is being executed.

The process shown in FIG. 5 will be explained. First, in the step of the figure, the arithmetic processing unit 78 of the microcomputer 72 outputs each acceleration detection signal gy+gx+g ZFL """
g z** are read in sequence and the process moves to step ■. In this step ■, lateral acceleration GY + longitudinal acceleration GXI vertical acceleration GZFL is calculated from the detection signal read in step
After calculating %GZRR and temporarily storing each calculated value in a predetermined storage area, the process moves to step (2).

In step ■, the vertical acceleration GZ calculated in step ■
Integral calculation is performed on FL''-G2R1 to calculate the vertical speed VZFL''V2RR of the vehicle body.

Next, the process moves to step ■, and among the calculated values of the vertical speeds VZFL to vZRII in step ■, the left and right vertical speeds V2FL and VZFII on the front side of the vehicle are used to calculate the absolute value of the roll angular speed ψ, 1ψl = l GZ□ -G
Determine from the calculation of ZFL l.

Next, the process moves to step (2), where the information is stored in the storage device 80 in advance. With reference to the memory table corresponding to FIG. 6, the correction gain is set according to the roll angular velocity 1ψ1.

According to this memory table, when the roll angular velocity is 1ψ1-0, the correction gain is K.

-〇, and the gain also changes in proportion to 1φ1.

Next, the process proceeds to step (2), where the vertical direction control gain, which is set to a fixed value in advance, is 2, and K2= is calculated to be 2+, and is changed in accordance with the roll angular velocity ψ.

After correcting the vertical control gain by 2 in order to attenuate the roll motion in this way, steps ■ to ■ are performed, and the normal Calculate the command value.

First, in step (2), in order to obtain the command value S2FL for bounce control and roll control, the vertical direction control gain set in step (2) is used, 52FL = V2FL ' K2.52F
l ”' ”ZFR′Kz −, 52RL =V21
The calculation of 2 is performed on L'Kz 5SZRII =Vz,l,l- for each wheel.

Next, in step (2), a command value Sx for anti-pitch (anti-pitch, anti-scut) control for acceleration/deceleration driving is calculated by calculating SX=Gx'Kx. Here, the longitudinal acceleration Gx is the calculated value in step (2), and the 2 longitudinal direction control gain Kx is a value set to a predetermined value in advance.

Next, the process moves to step (2), and a command value Sv for anti-roll control is calculated using 5V=G, K7.

Here, Gv is the calculated value in step (2), and K7 is a preset lateral control gain.

Next, the process moves to step [phase], and the total value SF of each command value is calculated.
L”””SRR, 5FL=S2FL +Sx +Sv
+SN, 5FR=SZFR+SX 10Sv +SN
, 5llL=S211L+SX +Sv +SN ,
5RR=S2RR+Sx +Sy+SN is calculated for each wheel (however, the command value SX+Sv has a reverse phase for the front and rear, right and left, and is added with the side where the vehicle body sinks as a positive value), and the process moves to step (2). Here, Ss is a command value for maintaining the vehicle height, but is not necessarily limited to the neutral command value SN.

In step (3), control signals SC corresponding to the command values S FL''' S III calculated in step [phase] are individually output.
3A to 73D are converted into analog quantities, and outputted as command values SFL to SIR from drive circuits 74A to 74D to excitation coils of pressure control valves 20FL to 20RR, respectively. As a result, the control pressure P of the pressure control valve becomes equal to the command value SFL.
~5lll individually controlled.

Next, the overall operation will be explained.

It is now assumed that a vehicle is traveling straight at a constant speed on a flat, smooth road. In this state, roll, dive,
Since no rocking such as scut or bounce occurs, the lateral acceleration sensor 265 and the longitudinal acceleration sensor 27. Detection signals gv + gx r of vertical acceleration sensors 28FL to 28RR
Both gzvL-gz** are zero, and the lateral acceleration G71
Longitudinal acceleration GK, vertical acceleration G 2 F L = G
Both z** become zero (Steps ■ and ■ in Figure 5).

Therefore, the vertical speed ■2FL-V2IllIll=0,
Roll angular velocity φ=0. and correction gain KG-〇, the command value SFL calculated in the process shown in FIG.
``'5jllll=neutral value SN, pressure control valve 20F
L to 20RR output neutral pressure PN (see FIG. 3) to the pressure chambers of the hydraulic cylinders 18FL to 18RH. As a result, the hydraulic cylinders 18FL to 8RR are at neutral pressure PM.
The vehicle body is maintained in a flat position at a predetermined vehicle height by generating a force corresponding to the vehicle height.

In this straight-ahead state, when the wheels 11FL to IIRR pass through an uneven road surface, that is, an uneven road, a relatively low frequency vibration input corresponding to the sprung mass resonance frequency range is transmitted to the pressure chamber via the wheel side member 14. Suppose that it is input. In this case, pressure changes in the hydraulic cylinders 18FL to 18RR due to input vibrations are absorbed between the hydraulic pressure source 22 and the pressure control valves 20FL to 20RR, thereby suppressing vertical vibrations to a certain extent.

However, if the vertical vibration cannot be absorbed even by the damping control performed by the pressure control valves 20FL to 20RR, if the vehicle body is vibrated vertically and bounces, or if the left and right wheel positions are different from each other, the vertical vibration Rolling occurs in the vehicle due to the difference in vibration force, and a vertical acceleration signal g2FL-gZIIR corresponding to this bouncing and rolling occurs.
are detected from the vertical acceleration sensors 28FL to 28RR, respectively.

In such a state, the controller 30 calculates the vertical acceleration G from the vertical acceleration signal gZFL-g2R11.
ZFL ”' Calculate GZRR respectively, and calculate the vertical acceleration GZF
L~G2. Vertical speed of the vehicle body v2FL~■ based on l and l
2. Find l and I, respectively. Furthermore, roll angular velocity 1ψ1
After calculating the correction gain KG proportional to this 1ψ1 and correcting the vertical direction control gain by 2 by this correction gain KG, the command value S ZFL that generates the damping force proportional to the vertical speed V2FL = V2RII is determined. -Sz
Find m3 (Steps ■ to ■ in Figure 5). In other words, the command value 52FL""821+11 is the sum of the command value components that dampen the bounce and roll caused by road surface irregularities.

Then, a command value s for attenuating bounce and rolling
zrt "" s z+tm is added to the command value S8, and the control signal S is added in response to the sum value SFL"" SRI+
C is output (step [phase], ■ in the figure). Therefore, the hydraulic cylinders 18FL to 18RR are set to the command value 52FL-.
The actuation force generated in response to 3ZRR becomes a damping force having a predetermined phase difference with respect to the vertical displacement of the vehicle body, and accurately damps the bounce and rolling of the vehicle body. Therefore, even when driving straight on an uneven road and no lateral acceleration occurs, by re-controlling bounce and rolling,
It is possible to maintain a flat vehicle posture. At this time, depending on the uneven state, rolling may not occur, and in that case, ψ1=0, so only the bounce described above is controlled.

In this way, the active suspension 12 of this embodiment is
Unlike the case of the conventional example described above, even if the vehicle body is vibrated vertically due to an uneven road surface while traveling straight at a constant speed, and rolling occurs in state B where no lateral acceleration Gv is generated (for example, a state not turning). , has the advantage of accurately suppressing the rolling. Moreover, in this embodiment, the roll angular velocity 1
Since the value of 6 is changed in the correction gain in proportion to the size of φ1, a damping force corresponding to the roll angular velocity can be obtained.
There is also the advantage that ride comfort does not deteriorate in a region where the roll angular velocity is relatively small compared to a case where the roll angular velocity is kept high all the time.

In addition, relatively high frequency vibration input corresponding to the unsprung resonance frequency range due to small irregularities on the road surface is applied to the hydraulic cylinder 18F.
When transmitted to the pressure chambers L to 18RH, the pressure fluctuations due to this vibration input are transmitted to the fixed throttle 32 and the accumulator 34.
This prevents deterioration of riding comfort.

Furthermore, if the vehicle accelerates or decelerates while traveling straight at a constant speed on a good road, this will generate longitudinal acceleration, and the vehicle body will attempt to perform pitch movements such as nose dive or scut at a pitch angle that corresponds to the inertial force. At this time, the longitudinal acceleration generated is detected by the longitudinal acceleration sensor 27, and the detection signal gx
is supplied to the controller 30. Therefore, the controller 30 adjusts the longitudinal acceleration GX corresponding to this acceleration/deceleration state.
is calculated, and a command value S proportional to the absolute value of this acceleration GX is calculated.
Calculate x and set command value SFL to resist pitch motion for each wheel.
A control command is given by ""5Fllll (steps ■, ■, ■, [phase], ■ in FIG. 5).

In other words, the hydraulic cylinder 18FL on the sinking side of the vehicle body.

For 1BPR (or 18RL, 18RR), its command value SFL, 5F11 (or 5IIL, 5RI
), the working pressure increases, and the hydraulic cylinders 18RL, 18RR (or 18
FL, 1 BPR), the command value is 5ift,
The reduction in 511 m (or S FL + S yu) reduces the operating pressure. Therefore, on the side where the car body sinks, a force is generated to resist the sinking, and on the side where the car body rises, it does not encourage the lifting.
An anti-pitch moment is generated in the vehicle body in advance, and nose dive, where the front of the vehicle sinks, and scut, where the rear of the vehicle sinks, are reliably suppressed, ensuring high vehicle stability and maneuverability.

Furthermore, when the vehicle shifts from the constant-speed straight running state on a good road to a turning state by steering, the vehicle body experiences acceleration in the lateral (vehicle width) direction according to the turning state, and the inertia force causes the outer wheels of the vehicle to A sinking roll is about to occur. At this time, the controller 30 calculates the lateral acceleration G from the lateral acceleration detection signal gv of the lateral acceleration sensor 26, and calculates the total command value SFL""31111 including the commands (Ii!S, , ) corresponding to the anti-roll moment. The pressure is controlled based on the command values S, , -SI (step in FIG. 5).

■, ■~0). As a result, as in the case of pitch control, the operating pressure of the hydraulic cylinders 18FL, 18RL (or 18FR, 18RR) on the outer wheel side is increased, and conversely, the operating pressure of the hydraulic cylinders 18FR, 18RR (18FL) on the inner wheel side is increased.

18RL) is lowered, an anti-roll moment is generated in the car body in advance to resist roll, preventing the car body from sinking on the outer wheel side and lifting up on the inner wheel side.
A flat body posture is maintained.

In addition, in the case of driving in which two or more vehicle movements among bounce, pitch, and roll occur simultaneously, command values for suppressing each attitude change are calculated individually, and the same suppression control as described above is performed simultaneously.

As described above, in the first embodiment, the vertical acceleration sensor 28FL,
28PR, the A/D converters 71A and 71B and the processing of step (2) in FIG. ■〜■, [phase].

(2) Processing and D/A converters 73A to 73D, drive circuit 7
4A to 74D constitute command value calculation means.

(Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIGS. 7 and 8. Here, the same reference numerals are used for the same components as in the first embodiment.

In the second embodiment, the correction gain KG in the first embodiment described above is changed according to the value of the vehicle speed ■, and as shown in FIG. 7, a vehicle speed sensor 82 is newly added. The detection signal V of this vehicle speed sensor 82 is transmitted to the controller 3.
I am trying to have it input to 0. The vehicle speed sensor 82 has a structure that magnetically or optically detects the rotation speed of the output shaft of the transmission, and outputs a vehicle speed signal V consisting of a pulse signal according to the engine rotation speed.

On the other hand, the controller 30 performs the same process as shown in FIG. 5 described above, but in a step corresponding to the step in FIG. In the step, a process for determining the vehicle speed V is added, and in a step corresponding to step (2), the correction gain K is calculated according to the roll angular velocity 1ψ1 and the vehicle speed V with reference to the storage table corresponding to FIG.

Set. In other words, the vehicle speed ■ is used as a parameter, and as the vehicle speed V increases, the change rate of the correction gain for a change in roll angular velocity 1φ1 increases.This data is stored in advance in the storage device 80 in the form of a table. .

The other configurations are the same as the first embodiment.

Therefore, according to the second embodiment, in addition to obtaining the same effects as the first embodiment, roll control due to uneven road surfaces when traveling straight is finely controlled according to the vehicle speed V, and more reliable attitude control is achieved. There are some advantages. In other words, even when traveling straight on the same uneven road, normally the higher the vehicle speed V, the greater the roll momentum accompanying vertical vibration. By changing this, the damping force against road surface irregularities can be finely adjusted, and the above-mentioned advantages can be obtained.

(Modification) Next, a modification will be described with reference to FIG. 9 and FIG. 1O. Here, the same reference numerals are used for the same components as in the first embodiment.

In this modification, 2 is added to the correction gain KG in the first embodiment, that is, the vertical direction control gain, and the roll angular acceleration ψ
It is designed to change depending on the situation. For this purpose, the microcomputer 72 of the controller 30 executes the process shown in FIG. 9 as a timer interrupt, and the other configurations are the same as in the first embodiment.

To explain the process of FIG. 9, first, in the step of the same figure, the arithmetic processing unit 7 of the microcomputer 72 receives each acceleration detection signal gv, gx.

Read g 2FL - g z** sequentially, step ■
to move to. In this step ■, lateral acceleration G'? + Longitudinal acceleration GX.

Vertical acceleration G2. L-G2. After calculating lR and temporarily storing each calculated value, the process moves to step (2).

In step ■, the vertical acceleration G Z at step ■
Among the calculated values of FL - Gz, I*, the absolute value of the roll angular acceleration ψ is calculated using the left and right vertical acceleration of the front side of the vehicle (JZFL, GZFW), 1ψl = l GZFII
Obtained from the calculation of GZFL. Next, the process moves to step (2), where the information is stored in the storage device 80 in advance. With reference to the memory table corresponding to FIG. 10, a correction gain KG corresponding to the roll angular acceleration ψl is set. According to this storage table, when the roll angular acceleration 1ψ1=O, the correction gain Ka=O, and the gain KG also changes in proportion to 1ψ.

Next, the process moves to step (3), where a command value 5GFL to S GII for suppressing the rolling motion of the vehicle due to road surface irregularities is set.
R, 5GFL = Gzyt ・Ka, 5GF
R=G2FR゛Krr+5GRL=Gz
Rt ° Ka, 5GRR=GZRR・K,
Each is calculated by the following calculations. Here, GZFL ””'G
ZRR is the calculated value in step (2), and KG is the value set in step (2).

Command value 5GFL to suppress roll movement in this way
After determining the 5GRR, steps ① to ② are performed to calculate normal command values for damping vibrations in the vertical, longitudinal, and lateral directions of the vehicle.

First, in step (2), the vertical acceleration calculated in step (2) is G2FL-G2. Integral calculation is performed on lR to calculate the vertical speed V2FL~VZIII+ of the vehicle body. Step■
Now, the command values S2FL to SZ for bounce control are
To find RR, use 2 for the vertical direction control gain, which is preset, and calculate 5ZFL = V2FL - KzSZ
FR=V2FR-Kz, 52RL=V2RL-
KzS211R=V21111' K2 is calculated for each wheel.

Next, in step (2), a command value Sx for anti-pitch (anti-dive, anti-scut) control for acceleration/deceleration driving is calculated by calculating S x =G x KX. Here, the longitudinal acceleration GX is the calculated value in step (2), and the 2 longitudinal direction control gain Kx is a value set in advance to a predetermined value.

Next, the process moves to step (2), and a command value S7 for anti-roll control is calculated using Sy=Gy'Kv. Here, Gy is the calculated value in step ■, and Ky
is a preset lateral control gain.

Next, the process moves to step [phase], and the total value SF of each command value is calculated.
L ~ SRR, S FL = S ZFL + S + S
Y+5GFL+SN, S□=SZFe+S x + S
v + S G□+S, 4.5IIL=SZRL +
SX +Sv +5GllL +SN, S**= 5
2RR+ SX + SY + 5GRR+ 38 is calculated for each wheel (However, the command values S, SV are reversed in phase front and rear, left and right, and the side where the vehicle body sinks is added as a positive value), then proceed to step ①. . Here, SH is a command value for maintaining the vehicle height, but is not necessarily limited to the neutral command value Ss.

In this step ■, the calculated value SFL~ of step [phase]
Control signals SC corresponding to 5ll11 are output individually.

Each of the control signals SC is converted into an analog quantity by D/A converters 73A to 73D, and is converted into an analog quantity by D/A converters 73A to 73D.
is output as a command value SFL""SRI+ to the excitation coils of the pressure control valves 20FL to 20RR, respectively. Thereby, the control pressure P of the pressure control valve is individually controlled according to the command values SFL to SRR.

Next, the overall operation will be explained.

It is now assumed that a vehicle is traveling straight at a constant speed on a flat, smooth road. In this state, roll, dive,
Hydraulic cylinders 18FL to 18R1 do not cause rocking such as scut or bounce. As in the first embodiment, a force corresponding to the neutral pressure Ps is generated to maintain the vehicle body in a flat posture at a predetermined vehicle height.

Assume that the wheels 11FL to IIRR pass through an uneven road surface, that is, an uneven road while the vehicle is in this straight-ahead state. With this, the pressure control valves 20FL to 201? If the vertical vibration cannot be absorbed even with R's damping control, if the vehicle body is vibrated vertically and bounces, or if the left and right wheel positions are different from each other, it may be due to the difference in the vertical excitation force. When rolling occurs in the vehicle, the vertical acceleration signal g2FL-gZRR corresponding to this bouncing and rolling is detected by the vertical acceleration sensor 2.
Detected from 8FL to 28RR, respectively.

In such a state, the controller 30 converts the vertical acceleration GZ from the vertical acceleration signals gzrt, ~gZRR.
FL "GZRR is calculated respectively, and the vertical acceleration CyZFL
~G2. L, I based vehicle body vertical speed vzyt-V2
Find each RR and calculate the upper and lower level of achievement VZFL ””VZFI
Command value S ZFL − that generates a damping force proportional to R
Find S ZIIR (Steps in Figure 9, ■, ■, ■
). Along with this, the controller 30 determines the absolute value of the roll angular acceleration ψ caused by the difference between the front vertical acceleration GZFL and Gzy* representing the left and right sides of the vehicle, and calculates the absolute value of the roll angular acceleration ψ caused by the difference between the front vertical acceleration GZFL and Gzy* representing the left and right sides of the vehicle,
A correction gain corresponding to 1 is set, and a command value S GFL - S GRR for suppressing such roll motion is determined for each wheel (steps 1 to 2 in the same figure).

Then, command values 5ZFL-3z, +, l and 5arL-3GRI for attenuating and suppressing bounce and rolling are provided.
is added together with the command value SN, and the sum value syt~5R
A control signal SC is output in response to phase 11 (step [phase], ■ in the figure). For this reason, the hydraulic cylinders 18FL~1
The actuation force generated by 8RR in response to the command value SZFL-SZRR becomes a damping force having a predetermined phase difference with respect to the vertical displacement of the vehicle body, and accurately damps the bounce of the vehicle body. At the same time, the operating force generated by the hydraulic cylinders 18FL to 18RR in response to the command value 5GFL-3c*++ decreases on the lifting side of the vehicle body, that is, weakens the operating force, and On the sinking side, the working pressure increases, that is, the working force is strengthened to resist sinking, and as a result, a moment is exerted that suppresses rolling. Therefore, even when driving straight on an uneven road and no longitudinal acceleration occurs, the bounce occurs.

By re-controlling rolling, it is possible to maintain a nearly flat vehicle posture.

Other effects are the same as in the first embodiment.

In the above modification, the vertical acceleration sensors 28FL and 28PR
, A/D converters 71B, 71D and the steps in FIG.
The processing of step (2) constitutes the vertical acceleration detection means, the processing of step (2) in the figure corresponds to the roll momentum calculation means, the processing of steps (2), (2), [phase], (2) and the D/A converter 73A to
73D and drive circuits 74A to 74D constitute command value calculation means.

By the way, in the above modification, the vehicle speed V is detected in the same manner as in the second embodiment described above, and the correction gain is set to 6.
may be changed not only according to the roll angular acceleration φ but also according to changes in the vehicle speed V.

Further, the roll momentum calculating means of the modified example is not limited to the one configured to calculate the roll angular acceleration, but may be configured to calculate the roll angle from the vertical acceleration, for example.

Note that the vertical acceleration detecting means of the present invention is not limited to determining the vertical acceleration based on the vertical acceleration sensor on the front left side of the vehicle, as described in each of the above embodiments. The detection signal of the acceleration sensor may be used, or the right and left side average values obtained by averaging the detection signals of the front and rear vertical acceleration sensors on the left and right sides of the vehicle, respectively, may be used.

Further, the fluid pressure cylinder of the present invention is not limited to the case where a hydraulic cylinder is applied as in each of the above embodiments, but may be configured to use, for example, a pneumatic cylinder.

Furthermore, in each of the above embodiments, the controller is equipped with a microcomputer, which includes, for example, an integrator that integrates the vertical acceleration detection signals gZFL to gZRR, and a difference calculator that calculates the difference between the vertical velocity signals VZFR+VZ□. an absolute value circuit that calculates the absolute value of the difference, a function generator that generates a correction gain signal according to the difference signal 1ψ1, an adder that adds 2 to the correction gain signal KG and the fixed gain signal, and a correction circuit. The gain is changed in proportion to the controlled gain signal KZ' and each vertical acceleration signal g FL
-g It may be configured with an analog electronic circuit including a variable gain amplifier that amplifies the RR.

〔Effect of the invention〕

As explained above, the present invention calculates the roll angular velocity of the vehicle body based on the vertical acceleration detected at the left wheel side and the right wheel side of the vehicle body, and calculates the command value for suppressing the roll motion for the left and right wheels based on the roll angular velocity. Accordingly, the operating pressure of each fluid pressure cylinder is controlled. For this reason, even if the right and left wheels of the vehicle are vibrated up and down by different forces when the vehicle passes through an uneven road surface in a state where no lateral acceleration is occurring while traveling straight at a constant speed, causing rolling of the vehicle, the conventional technology Unlike this, rolling can be accurately suppressed, and the stability of the vehicle posture and maneuverability can be improved.

[Brief explanation of drawings]

Fig. 1 is a diagram corresponding to the claims of the present invention, Fig. 2 is a schematic configuration diagram showing a first embodiment of the invention, and Fig. 3 is a graph showing the relationship between the command value for the pressure control valve and the output control pressure. , FIG. 4 is a block diagram showing an example of a controller, FIG. 5 is a schematic flowchart showing an example of a processing procedure executed in the controller, and FIG. 6 shows the relationship between roll angular velocity and correction gain in the first embodiment. Graph, FIG. 7 is a partial block diagram showing the configuration of the second embodiment of the present invention, FIG.
The figure is a graph showing the relationship between the roll angular velocity and the correction gain using the vehicle speed as a parameter in the second embodiment, FIG. 9 is a schematic flowchart showing an example of the processing procedure executed in the modified example, and FIG. 10 is a graph in the modified example. It is a graph showing the relationship between roll angular acceleration and correction gain. In the figure, 10 is a vehicle body side member, 12 is an active suspension, 14 is a wheel side member, and 18FL to 18R1'l are front left to
Rear right hydraulic cylinder, 20FL to 20RR are front left to rear right pressure control valves, 28FL to 28RR are vertical acceleration sensors, 3
0 is a controller, 71A to 71D are A/D converters, 7
3A to 73D are D/A converters, and 74A to 74D are drive circuits.

Claims (1)

[Claims] (1) A fluid pressure cylinder interposed between the vehicle body side member and the wheel side member for each wheel, a pressure control valve that individually controls the operating pressure of each fluid pressure cylinder according to a command value, and the vehicle body vertical acceleration detection means for detecting the vertical acceleration of the right wheel side and left wheel side; roll angular velocity calculation means for calculating the roll angular velocity of the vehicle body based on each detection value of the vertical acceleration detection means; and the roll angular velocity calculation means. an active suspension comprising: command value calculation means for calculating the command value for suppressing roll motion separately for left and right wheels based on the calculated value of .