JPH10315733A - Electronically controlled suspension device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve riding feelings and driving stability by recognizing a road surface state from the output of vehicle sensors. SOLUTION: The estimated value of road surface height where a vehicle actually travels taking account of the motion of an axle is computed by a road surface computing part 210 using acceleration signals detected by a vertical acceleration sensor 111 and an axle vertical acceleration sensor 112. A low frequency component, a high frequency component and a width are obtained by a low frequency computing part 220, a high frequency computing part 230 and a road surface with computing part 240 from the obtained road surface. A road surface frequency ratio is obtained by a road surface frequency ratio computing part from the output of the computing parts 220, 230, and a damper position computing part 260 computes the appropriate position of a damper from the computed result of the computing parts 230, 240, 250.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical acceleration sensor mounted on a vehicle and an axle vertical acceleration sensor, which detects the state of the road surface and determines the frequency and magnitude of the road surface irregularities. By appropriately adjusting the damping force of the variable damper of the wheels according to the result, the vehicle body motion can be minimized, the road surface contact force of the wheels can be improved, and the riding feeling and steering stability of the vehicle can be improved. The present invention relates to an electronically controlled suspension system for a vehicle.

[0002]

2. Description of the Related Art In general, a vehicle is provided with a suspension device for connecting an axle to a vehicle body so that when the vehicle runs, vibrations and impacts received from the road surface by the axle are not transmitted directly to the vehicle body. This prevents damage to the vehicle body and the things on board, and improves riding comfort and steering stability.

Further, the suspension system transmits the braking force of each drive wheel to the vehicle body when braking the vehicle, and maintains the drive wheel at an accurate position with respect to the vehicle body by overcoming the centrifugal force generated during turning. Designed for In addition, the suspension
In order to reduce the impact received from the road surface, it is necessary to not only need a flexible connection in the vertical direction, but also to overcome the driving force generated by the drive wheels, braking force, and centrifugal force when turning. Requires strong bonding in the horizontal direction.

[0004] Such a suspension system is used for the traveling speed of a vehicle,
In addition to varying the damping force of the variable damper in accordance with braking and acceleration / deceleration, even at a constant traveling speed, the damping force of the variable damper is adjusted in response to road surface conditions. The damping force of the damper is adjusted by driving a stepping motor as an actuator.
That is, the variable damper includes a control rod, and by driving the actuator to rotate the control rod, the flow path of the damper oil is changed,
The damping force is made variable.

As shown in FIG. 7, each component of a conventional electronically controlled suspension system for a vehicle is mounted at a corresponding position on the vehicle.
In this electronically controlled suspension, the controller 7 includes a vertical acceleration sensor 1 for detecting the vertical acceleration of the vehicle, a vehicle speed sensor 2 for detecting the vehicle speed, a brake switch 3 for detecting the braking of the vehicle, and a throttle of the engine. A detection signal of a TPS (Throttle Position Sensor) 4 for detecting an opening angle, a mode conversion switch 5 for converting the control mode, and a steering angle sensor 6 for detecting a steering angular velocity of the vehicle is input to the vehicle. By driving the electronic actuator 8 arranged at the upper end of the damper in accordance with the result of this judgment, and changing the size of the damper oil flow path by rotating the control rod, four The damping force of the damper is simultaneously adjusted appropriately to the hard mode, the medium mode or the soft mode.

[0006] In such a conventional electronically controlled suspension device, the actuator is driven by six individual logics according to the running condition of the vehicle. In the first anti-bounce (ANTI-BOUNCE) control, the vehicle speed is equal to or higher than V1 kph, and the magnitude of the vertical acceleration of the vehicle at the console box position is detected when a vehicle speed is equal to or higher than V1 kph by detecting a situation such as a bump or running on a rough road. When the value is equal to or more than G1g, the actuator is switched to the medium, and when t1 seconds elapse after the condition is released, the actuator returns to the original state.

In the second anti-shake (ANTI-SHAKE) control, the vehicle speed is set to V2 kp in order to reduce the movement of the vehicle when the vehicle is stopped, when passengers get on and off and when cargo is loaded and unloaded.
h, it is switched to hardware and the vehicle speed is V2
If the pressure is maintained at 1 kph or more and maintained for t2 seconds or more, the state is switched to the original state.

In the third high-speed sensitive control, when the vehicle speed is equal to or higher than V3 kph and maintained for t3 seconds or more, the medium is switched to medium in order to secure the steering stability of the vehicle when the vehicle runs at high speed. When the vehicle speed is equal to or lower than V31 kph, the vehicle is returned to the original state.

In the fourth antisquat (ANTI-SQUAT) control, the vehicle speed is less than V4 kph and the engine throttle opening angle is θ4Deg in order to minimize the vertical movement of the front part of the vehicle when starting at low speed. If it is greater, the actuator is switched to medium, and after t4 seconds have elapsed or when the vehicle speed is equal to or higher than V41 kph, the actuator is switched to medium or hard, which is the original state.

In the fifth anti-dive (ANTI-DIVE) control, in order to minimize the downward movement of the front part of the vehicle when braking from medium to high speed, the vehicle speed must be increased from V5 kph or more.
When the brake switch is turned on by braking, the mode is switched to the hard mode, and when t5 seconds elapse from the time when this condition is not satisfied, the mode is switched to the medium or the hardware.

Finally, the sixth anti-roll (ANTI-ROLL)
In the control, when the vehicle speed is higher than V6 kph and the vehicle speed is V61 in order to secure the stability of the vehicle during steering.
When kph, V62 kph, V63 kph, and V64 kph, the steering angular velocities are respectively θ61Deg / sec.
c, θ62Deg / sec, θ63Deg / sec, θ
If it is greater than 64 Deg / sec, the state is switched to hardware, and the state is returned to the original state after a lapse of t6 seconds from when this condition is canceled.

[0012]

However, in the above-mentioned electronically controlled suspension system, the damping force of the damper is adjusted by an arbitrary control table without considering the characteristics of the road surface on which the vehicle travels. The feeling was reduced, and unnecessary damping force control was frequently performed, and the movement of each wheel of the vehicle could not be accurately controlled.

[0013] Therefore, the conventional electronically controlled suspension system for a vehicle has a problem that the ride feeling and the steering stability cannot be greatly improved as compared with the manual damper system.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an actuator in which the damping force of a variable damper is appropriately adjusted in accordance with a traveling road surface. By driving the vehicle, the motion of the vehicle body during traveling on the road surface is reduced to the utmost, the grounding force of the wheels on the road surface is improved, and the riding feeling and the driving stability can be simultaneously improved. It is to provide a control suspension.

[0015]

According to an electronic control suspension system for a vehicle according to the present invention, a controller outputs a drive signal in response to an output from a vertical acceleration sensor, and a variable damper and an actuator are provided. An electronically controlled suspension system for a vehicle is provided with an axle vertical acceleration sensor 112, and the controller 200 further comprises: the vertical acceleration sensor 111 and the axle vertical acceleration sensor 1
A road surface calculation unit 210 that calculates the road surface using the acceleration signal output from the road surface 12; a low frequency calculation unit 220 that calculates the magnitude of the low frequency component of the road surface calculated by the road surface calculation unit 210; High frequency calculator 23 for calculating the magnitude of the high frequency component of the road surface calculated by calculator 210
0, the size of the low-frequency component calculated by the low-frequency calculation unit 220 and the high-frequency calculation unit 230 by the road-size calculation unit 240 that calculates the size of the road surface calculated by the road-surface calculation unit 210, respectively. Road frequency ratio calculation unit 25 that calculates the road surface frequency ratio from the ratio between the frequency and the magnitude of the high frequency component
0, the road surface frequency ratio calculated by the road surface frequency ratio calculation unit 250, the size of the high frequency component calculated by the high frequency calculation unit 230, and the size of the road surface calculated by the road surface size calculation unit 240 And a damper position calculator 260 for calculating an appropriate damper position.

Further, in an electronic control suspension system for a vehicle according to the invention of claim 2, wherein the road surface calculation unit 210, a vehicle body vertical acceleration a _s ^h, the axle vertical accelerations a _u ^h, the vehicle body vertical acceleration a _s ^h The vertical displacement of the vehicle body obtained by integrating
_{When u} (t) and controller coefficients are c1, c2, and c3,

[0017]

[Equation 11]

Thus, the present invention is characterized in that the traveling road surface r (t) is calculated.

Furthermore, in the vehicle electronic control suspension according to the third aspect of the present invention, the low frequency calculation unit 220
A low-frequency bandpass filter 221 that passes a low-frequency component of the road surface corresponding to the vehicle body resonance frequency from the road surface calculated by the road surface calculation unit 210; and a low-frequency component of the road surface that is passed by the low-frequency bandpass filter 221. And a time-domain power calculation unit 222 for calculating the time-domain power value.

Further, in the electronic control suspension apparatus for a vehicle according to the invention of claim 4, the low frequency calculating section 220 includes:

[0021]

(Equation 12)

[0022]

(Equation 13)

[0023]

[Equation 14]

Thus, the magnitude of the low frequency component on the road surface on which the vehicle travels is calculated.

Further, in the electronically-controlled suspension system for a vehicle according to the fifth aspect of the present invention, the high frequency calculating section 230
A high-frequency band-pass filter 231 for passing a high-frequency component of the road surface corresponding to the vehicle body resonance frequency from the road surface calculated by the road-surface calculation unit 210; and a high-frequency component of the road surface passed by the high-frequency band-pass filter 231. And a time-domain power calculator 232 for calculating the time-domain power value.

Further, in the electronically controlled suspension system for a vehicle according to the invention of claim 6, the high frequency calculation unit 230

[0027]

(Equation 15)

[0028]

(Equation 16)

[0029]

[Equation 17]

Accordingly, the magnitude of the high frequency component on the road surface on which the vehicle travels is calculated.

Furthermore, in the electronically controlled suspension system for a vehicle according to the present invention, the road surface size calculating section 240
Is

[0032]

(Equation 18)

[0033]

[Equation 19]

Thus, the size of the road surface on which the vehicle travels is calculated.

Further, in the vehicle electronic control suspension according to the invention of claim 8, the road surface frequency ratio calculating section 250

[0036]

(Equation 20)

Thus, the frequency component ratio of the road surface on which the vehicle travels is calculated.

Further, in the vehicle electronic control suspension according to the ninth aspect of the present invention, the damper position calculating section 260
Increases the damping force of the damper if the road surface frequency ratio obtained by the road surface frequency ratio calculation unit 250 and the road surface size obtained by the road surface size calculation unit 240 are equal to or larger than a predetermined value. The damping force of the damper is reduced when the value is equal to or less than the predetermined value.

In the electronic control suspension apparatus for a vehicle according to the tenth aspect of the present invention, the damper position calculating section 260 determines the magnitude of the high frequency component of the road surface obtained by the high frequency calculating section 230 in advance. If the value is equal to or more than the value, the axle resonates to be sensed to increase the damping force of the damper so as to suppress the axle resonance. It is characterized by the following.

[0040]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described.
The following is a description based on FIGS. 1 to 6.

FIG. 1 is a block diagram showing an electric configuration of an electronically controlled suspension system for a vehicle according to an embodiment of the present invention.
The electronically controlled suspension includes a vertical acceleration sensor 111 for detecting vertical and horizontal acceleration of the vehicle, an axle vertical acceleration sensor 112 for detecting vertical acceleration of the axle,
A vehicle speed sensor 113 for detecting the speed of the vehicle, a brake switch 114 for detecting the vehicle speed during braking, a TPS 115 for detecting the throttle opening angle of the engine, and a mode selection switch 116 for converting the control mode.
A controller 200 for receiving an input of the detection and switching signals output from the sensors and switches 111 to 116 and outputting an actuator drive signal for appropriately adjusting the damping force of the variable damper of each wheel; It is constituted by a variable damper for each wheel and an actuator 300 driven by a drive signal output from 200.

The variable damper and actuator 30
Numeral 0 is constituted by a continuously variable damper and a multi-stage control electronic actuator. By driving an electronic actuator arranged at the upper end of the damper to rotate the control rod of the damper, the size of the damper oil flow path is increased. To adjust the damping force of the four-wheel damper.

The configuration of various sensors and switches in the electronically controlled suspension system shown in FIG. 1 is mounted on a vehicle as shown in FIG.

FIG. 3 is a block diagram showing the electrical configuration of the controller 200. The controller 200 includes the vertical acceleration sensor 111 and the axle vertical acceleration sensor 112.
A road surface calculation unit 210 that calculates a road surface using the acceleration signal detected in the above, a low frequency calculation unit 220 that calculates the magnitude of the low frequency component of the road surface from the road surface calculated by the road surface calculation unit 210, A high frequency calculator 230 that calculates the magnitude of the high frequency component of the road surface from the road surface calculated by the road surface calculation unit 210, and a road surface size calculation that calculates the size of the road surface from the road surface calculated by the road surface calculation unit 210 Part 240
And the low frequency calculation unit 220 and the high frequency calculation unit 2
30, a road surface frequency ratio calculation unit 250 for calculating a road surface frequency ratio from the ratio between the magnitude of the low frequency component and the magnitude of the high frequency component, respectively, and the road surface frequency ratio calculation unit 2
The road surface frequency ratio calculated at 50 and the high frequency calculation unit 2
A damper position calculator 260 calculates a current appropriate damper position from the size of the high-frequency component calculated at 30 and the road surface size calculated at the road surface size calculator 240.

FIG. 4 is a block diagram showing a specific configuration of the low frequency calculation section 220. This low frequency calculator 2
20 is based on the road surface calculated by the road surface calculation unit 210,
A low-frequency band-pass filter 221 for passing a low-frequency component of the road surface corresponding to the vehicle body resonance frequency; and a time-domain power calculation for calculating a time-domain power value of the low-frequency component of the road surface passed by the low-frequency band-pass filter 221. And a part 222.

FIG. 5 is a block diagram showing a specific configuration of the high frequency calculator 230. This high frequency calculator 2
30 is based on the road surface calculated by the road surface calculation unit 210,
A high-frequency band-pass filter 231 for passing a high-frequency component of a road surface corresponding to the vehicle body resonance frequency; and a time-domain power calculation for calculating a time-domain power value of the high-frequency component of the road surface passed by the high-frequency band-pass filter 231. 232.

In the electronically controlled suspension system constructed as described above, the rolling of the vehicle body is controlled by the resonance control operation in the resonance region of the vehicle body, and the riding feeling is reduced by reducing the damping force of the damper in the riding feeling region. At the improved axle resonance frequency, the axle resonance is prevented by increasing the damping force, thereby ensuring the steering stability of the vehicle. The details of the riding feeling control logic as described above will be further described.

The road surface calculation unit 210 uses the acceleration detected from the vertical acceleration sensor 111 mounted on the upper end of the damper of the vehicle body and the axle vertical acceleration sensor 112 arranged on the lower axle arm to actually drive the vehicle. Calculate the road surface to do. The road surface is a physical quantity corresponding to the road surface height, and is an estimated value obtained as described below because the absolute road surface height cannot be directly measured.

First, the acceleration detected by the vertical acceleration sensor 111 and the axle vertical acceleration sensor 112 is passed through a high-frequency band-pass filter, and the vehicle vertical acceleration a
_s ^h and axle vertical acceleration a _u ^h are obtained. At this time, the high-frequency band-pass filter equation is as follows.

[0050]

(Equation 21)

[0051]

(Equation 22)

Next, the above formula 1, a vehicle body vertical acceleration a _s ^h a filtered through Equation 2, axle vertical acceleration a
_u ^h, and the vehicle body acceleration signal is integrated twice to calculate the vertical displacement d _u axle.

That is, the above equation (1) shows that the high frequency band integrator for removing the unnecessary low frequency range from the vertical acceleration detected by the vertical acceleration sensor 111 and obtaining the vehicle speed and the vehicle displacement is used. Represents the filter equation, where S is the Laplace operator, ζ ₁ and ω ₁ are constants used to determine the coefficients of the filter used for integration, and ζ ₁ is the damping coefficient of the integrator And 0 <ζ ₁ <1
Ω ₁ is a frequency different from the vehicle characteristics and is smaller than the frequency of the signal to be integrated, for example, ω ₁ <6.

The above equation (2) is a high-frequency band-pass filter equation for determining an axle speed and an axle displacement by removing unnecessary low-frequency areas from the axle vertical acceleration detected by the axle vertical acceleration sensor 112. And ω ₂
Is smaller than the frequency of the signal to be integrated, eg, ω ₂ <
Selected as 6. Ζ ₂ is an attenuation rate, and 0 <ζ ₂
<Choose 1.

[0055] Then, the vehicle body vertical acceleration a _s ^h and axle vertical accelerations a _u ^h, which is the filtered, and a vertical displacement d _u axle, calculates the road surface r (t) through the equation 3.

[0056]

(Equation 23)

[0057] That is, the coefficient set when the controller designed for high frequency range of the vehicle body vertical acceleration a _s ^h determined by the formula 1 c
1 and the axle vertical acceleration a calculated by the above equation (2).
by adding a value of the coefficient c2 by multiplying that was set during the controller design _u ^h, and the vehicle body vertical acceleration a _s twice integrating the calculated vehicle body vertical displacement d _u (t), vehicle body motion and The road surface r (t) is calculated in consideration of the axle motion.

In this way, the road surface calculation section 210 estimates and calculates the road surface on which the vehicle actually travels.

Next, the low frequency calculator 220 calculates a time domain power value of a low frequency component corresponding to the vehicle body resonance frequency from the road surface calculated by the road surface calculator 210.

The low-frequency band-pass filter 221 passes a signal having a frequency equal to or lower than the frequency set by the low-frequency band-pass filter expression shown in the following Expression 4, and removes a signal having a frequency equal to or higher than the set frequency.

[0061]

(Equation 24)

Then, the time domain power calculator 222
Calculates the power of the signal input to the time-domain power calculator 222 through Equations 5 and 6, which are nonlinear filter equations for calculating the time-domain power.

[0063]

(Equation 25)

[0064]

(Equation 26)

In equation (4), ζ ₃ is the attenuation coefficient of the integrator, which is selected to be 0 <ζ ₃ <1, and ω ₃ is larger than the frequency of the signal to be integrated, for example, ω ₃ > 18. . Equations (5) and (6) show that the absolute value of the output signal of the pre-stage circuit is taken and filtered to obtain an average value that reflects the past calculation result on the calculation result of the output signal. , T ₁ are constants corresponding to the time to be averaged.

Similarly, the high frequency calculation unit 230 calculates a time-domain power value of a high frequency component corresponding to the axle resonance frequency from the road surface calculated by the road surface calculation unit 210. That is, the high-frequency calculation unit 230 calculates the time-domain power in the time-domain power calculation unit 232 from the signal that has passed through the high-frequency band-pass filter 231, thereby obtaining the high-frequency component corresponding to the axle resonance range. Calculate time domain power.

The high-frequency band-pass filter 231 passes only the axle resonance band signal through the following high-frequency band-pass filter system, and removes the vehicle body resonance band signal and the like, which are signals of lower frequency components.

[0068]

[Equation 27]

The time-domain power calculation unit 232 calculates the time-domain power value of the axle resonance range through the following equations (8) and (9).

[0070]

[Equation 28]

[0071]

(Equation 29)

In equation (7), ζ ₄ is the attenuation coefficient of the integrator, which is selected as 0 <ζ ₄ <1, and ω ₄ is smaller than the frequency of the signal to be integrated, for example, ω ₄ <24. . Equations (8) and (9) indicate that an average value that reflects the past calculation result in the calculation result of the output signal is obtained by filtering only the absolute value of the output signal of the preceding circuit. , T ₂ are constants corresponding to the time to be averaged.

As described above, the high frequency calculator 230
Calculates the magnitude of the high frequency component, which means the magnitude of the resonance of the axle, from the power value h of the high frequency component corresponding to the axle resonance range.

Then, the road surface size calculation unit 240 calculates the time domain power value of the road surface calculated by the road surface calculation unit 210 using the following Expressions 10 and 11.

[0075]

[Equation 30]

[0076]

(Equation 31)

Therefore, the road surface size calculation unit 240
Calculates the average height of the road surface on which the vehicle travels from the time-domain power value le.

As described above, when the magnitude of the low frequency component, the magnitude of the high frequency component, and the magnitude of the road surface of each road surface are calculated, the road surface frequency ratio calculating section 250 calculates the road surface ratio on which the vehicle travels. Then, the ratio of the resonance frequency component of the vehicle body to the axle resonance frequency range component is calculated. That is, the ratio of the road surface frequency is defined by the ratio of the vehicle body resonance frequency component to the axle resonance frequency region component of the road surface, and as shown in the following Expression 12,
The road surface frequency ratio w is calculated by dividing the low frequency size rl of the road surface by the high frequency size h of the road surface.

[0079]

(Equation 32)

Next, the damper position calculator 260 calculates the road surface frequency ratio obtained by the road surface frequency ratio calculator 250, the magnitude of the high frequency component of the road surface obtained by the high frequency calculator 230,
From the road surface size calculated by the road surface size calculation unit 240, the current appropriate damper position is calculated. At this time,
The position of the damper according to the road surface frequency ratio and the road surface size is
As shown in FIG.

That is, as shown in FIG. 6 and the following equations (13) and (14), the damper position calculation unit 260 calculates the road surface frequency ratio obtained by the road surface frequency ratio calculation unit 250 and the road surface size calculation unit 240. The obtained road surface size is w2
If R2 or more, the state of the damper is converted to a hard state with high damping force, and if it is between w2 and w1 and between R2 and R1, respectively, it is converted to a medium with intermediate damping force,
If w1 and R1 or less, it is converted to software with low damping force.

[0082]

[Equation 33]

[0083]

(Equation 34)

When the high frequency magnitude R of the road surface obtained by the high frequency calculation unit 230 is equal to or greater than r1, the current state of the damper is converted to a hard state having a high damping force, and r1 If less, the current state of the damper is converted to a soft state with low damping force.

If R <r1 → hard else → soft More specifically, if the high frequency magnitude of the road surface is equal to or greater than the set value, it is sensed that the axle resonates and the damping force is increased to increase the axle resonance. , The steering stability of the vehicle is ensured, and when the value is equal to or less than the set value, the damping force is reduced, thereby ensuring the riding feeling of the vehicle.

[0086]

As described above, the present invention recognizes a running road surface based on the outputs of the vertical acceleration sensor mounted on the upper end of the damper and the axle vertical acceleration sensor mounted on the axle, and provides the road surface frequency ratio. The optimal damping force is selected by a damper control map based on the size of the road surface and the size of the high frequency of the road surface, so that the vehicle body motion can be minimized, and the riding feeling and the steering stability can be improved at the same time.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an electric configuration of an electronically controlled suspension device for a vehicle according to an embodiment of the present invention.

FIG. 2 is a diagram showing a state in which the electronically controlled suspension device shown in FIG. 1 is mounted on a vehicle.

FIG. 3 is a block diagram showing a specific configuration of a controller in the electronically controlled suspension device shown in FIG.

FIG. 4 is a block diagram showing a specific configuration of a low-frequency calculator in the electronically controlled suspension shown in FIG. 1;

FIG. 5 is a block diagram showing a specific configuration of a high frequency calculation unit in the electronically controlled suspension device shown in FIG.

FIG. 6 is a diagram illustrating a damper control map based on a road surface frequency ratio and a road surface size according to the present invention.

FIG. 7 illustrates a typical prior art electronically controlled suspension mounted on a vehicle.

[Explanation of symbols]

 111 Vertical acceleration sensor 112 Axle vertical acceleration sensor 113 Vehicle speed sensor 114 Brake switch 115 TPS 116 Mode selection switch 200 Controller 210 Road surface calculation unit 220 Low frequency calculation unit 221 Low frequency bandpass filter 222 Time domain power calculation unit 230 High frequency calculation unit 231 High frequency band pass filter 232 Time domain power calculator 240 Road surface size calculator 250 Road surface frequency ratio calculator 260 Damper position calculator 300 Variable damper and actuator

Claims (10)

[Claims] An electronic suspension system for a vehicle in which a controller outputs a drive signal in response to an output from a vertical acceleration sensor to control a variable damper and an actuator. The controller 200 further includes: a road surface calculation unit 210 that calculates a road surface using acceleration signals output from the vertical acceleration sensor 111 and the axle vertical acceleration sensor 112; A low-frequency calculator 220 for calculating the magnitude of the low-frequency component of the road surface; a high-frequency calculator 230 for calculating the magnitude of the high-frequency component of the road surface calculated by the road surface calculator 210; A road surface size calculation unit 240 for calculating the size of the road surface calculated in the above, a low frequency calculation unit 220 and a high frequency calculation A road surface frequency ratio calculation unit 250 that calculates a road surface frequency ratio from the ratio of the magnitude of the low frequency component to the magnitude of the high frequency component calculated by the unit 230; and a road surface frequency calculated by the road surface frequency ratio calculation unit 250. A damper position calculator 260 for calculating an appropriate damper position from the ratio, the magnitude of the high frequency component calculated by the high frequency calculator 230 and the size of the road surface calculated by the road surface size calculator 240. An electronically controlled suspension device for a vehicle. Wherein said road surface calculation unit 210, a vehicle body vertical acceleration a _s ^h, the axle vertical accelerations a _u ^h, the vertical displacement of the vehicle body determined by integrating the vehicle body vertical acceleration a _s ^h 2 times d
_{When u} (t) and controller coefficients are c1, c2, and c3, 2. The electronically controlled suspension system for a vehicle according to claim 1, wherein the travel road surface r (t) is calculated from the following equation. 3. The low-frequency calculator 220 includes: a low-frequency band-pass filter 221 that passes a low-frequency component of a road surface corresponding to a vehicle body resonance frequency from the road surface calculated by the road surface calculator 210; Bandpass filter 221
2. The electronically controlled suspension system for a vehicle according to claim 1, further comprising a time-domain power calculation unit 222 for calculating a time-domain power value of a low-frequency component of the road surface passed by the control unit. 4. The low-frequency calculator 220 calculates: (Equation 3) (Equation 4) The electronically controlled suspension system for a vehicle according to claim 3, wherein the magnitude of the low frequency component on the road surface on which the vehicle travels is calculated from the following. 5. The high-frequency calculator 230 includes a high-frequency band-pass filter 231 that passes a high-frequency component of a road surface corresponding to a vehicle body resonance frequency from the road surface calculated by the road surface calculator 210; Band pass filter 231
2. The electronically controlled suspension system for a vehicle according to claim 1, further comprising a time-domain power calculation unit 232 that calculates a time-domain power value of a high-frequency component of the road surface passed by the control unit. 6. The high frequency calculating section 230: (Equation 6) (Equation 7) 6. The electronically controlled suspension system for a vehicle according to claim 5, wherein the magnitude of the high frequency component on the road surface on which the vehicle travels is calculated from the following. 7. The road surface size calculating section 240: (Equation 9) 2. The electronically controlled suspension system for a vehicle according to claim 1, wherein the size of the road surface on which the vehicle travels is calculated from the following. 8. The road surface frequency ratio calculation unit 250: The electronically controlled suspension system for a vehicle according to claim 1, wherein a frequency component ratio of a road surface on which the vehicle travels is calculated from the following. 9. The damper position calculator 260 determines whether the road surface frequency ratio obtained by the road surface frequency ratio calculator 250 and the road surface size obtained by the road surface size calculator 240 are equal to or greater than a predetermined value. 2. The electronically controlled suspension system according to claim 1, wherein the damping force of the damper is increased in a case where the damping force is smaller than the predetermined value. 10. The damper position calculating section 260 detects that the axle resonates when the magnitude of the high frequency component of the road surface obtained by the high frequency calculating section 230 is equal to or larger than a predetermined value. 2. The electronically controlled suspension of a vehicle according to claim 1, wherein the damping force of the damper is increased to suppress axle resonance, and the damping force of the damper is reduced when the damping force is less than the predetermined value. apparatus.