JPH082231A - Suspension control device - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a suspension control device capable of quickly responding to front-back, left-right, and lateral accelerations acting on a vehicle during traveling to obtain good ride comfort and maneuverability. [Structure] If the lateral acceleration change rate is positive, the expansion side of the shock absorber on the right side of the vehicle body is set to the hardware characteristic, and the contraction side of the shock absorber on the left side of the vehicle body is set to the hardware characteristic (steps S6 and S7), and the lateral acceleration change is set. If the ratio is negative, the shrink side of the shock absorber on the right side of the vehicle body is set to the hard characteristic, and the stretch side of the shock absorber on the left side of the vehicle body is set to the hard characteristic (steps S8 and S7). When the vehicle turns left and a rightward force acts on the vehicle body and begins to roll, the rightward leaning force is surely suppressed to prevent leaning of the vehicle body, and when the returning force begins to act on the vehicle body, Since this return force is gradually absorbed, it is possible to prevent a sudden return of the vehicle body and obtain good riding comfort and steering stability.

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 used in a vehicle.

[0002]

2. Description of the Related Art As an example of a conventional suspension control device, there is a suspension control device disclosed in Japanese Unexamined Patent Publication No. 5-330325. This suspension controller
The structure is roughly as shown in FIG. In the figure, a spring 3 and a damping force reversal type hydraulic shock absorber are provided between a vehicle body 1 (on a spring) and four wheels (only one is shown in the drawing) 2 constituting a vehicle (under a spring). 4 and 4 are interposed in parallel and support the vehicle body 1. A vertical acceleration sensor 5 that detects a sprung acceleration α (vertical acceleration) of the vehicle body 1 is mounted on the vehicle body 1.

The damping force reversal type hydraulic shock absorber 4 adjusts the damping force (damping coefficient) as shown in FIG. 3 by adjusting the passage area of the oil liquid by the operation of the actuator 6. A controller 7 is connected to the vertical acceleration sensor 5 and the actuator 6. The vertical acceleration signal of the vertical acceleration sensor 5 is supplied to the controller 7, and the controller 7 outputs an actuator opening signal to the actuator 6 to drive a movable body (not shown) provided in the oil liquid passage portion of the damping force reversing hydraulic shock absorber 4. By positioning, the damping coefficient is changed so that a desired damping force can be obtained. In addition,
The damping force reversing hydraulic shock absorber 4 and the spring 3 are provided in four pieces corresponding to the four wheels 2, but only one of them is shown for convenience.

In this suspension control device, the vertical acceleration signal is integrated to obtain the vertical absolute speed, the actuator opening signal is determined based on this vertical absolute speed, and the damping coefficient corresponding to the actuator opening signal is obtained to obtain the ride. It is designed to improve comfort and drivability.

[0005]

By the way, in the suspension control device, when lateral acceleration in the front-rear, left-right direction acts on the vehicle body 1 at the time of roll or squat,
Respond quickly to this and provide ride comfort and handling stability (stability)
Is desired. In contrast,
In the above-mentioned conventional technique, the suspension is controlled based on the vertical acceleration of the vehicle body 1, so that the control is delayed and the above-mentioned demand cannot be met.

The present invention has been made in view of the above circumstances, and a suspension control device capable of quickly responding to the lateral acceleration in the front, rear, left, and right acting on the vehicle during traveling to obtain a good ride comfort and maneuverability. The purpose is to provide.

[0007]

According to the first aspect of the present invention,
It is installed between the vehicle body and each wheel side, and when the extension side damping force is set to the hard characteristic, the contraction side damping force becomes the soft characteristic, and when the extension side damping force is set to the soft characteristic, the contraction side damping force is set to the soft side. In a suspension control device having a damping force reversing hydraulic shock absorber capable of controlling the damping force to have a hard characteristic, an acceleration detecting means for detecting acceleration in at least one of the front-rear direction and the left-right direction which acts on the vehicle body during traveling. When the absolute value of the detected value of the acceleration detecting means is in the increasing direction, the extension side of the damping force reversing type hydraulic shock absorber on the acceleration direction side has a hard characteristic, and the extension side of the damping force reversing type hydraulic shock absorber on the other direction side When the compression side is set to the hard characteristic and the absolute value of the detection value of the acceleration detection means is in the decreasing direction, the compression side of the acceleration direction side hydraulic shock absorber is set to the hard characteristic and the damping direction in the other direction is reversed. Type hydraulic pressure The extension-side vessel, characterized in that a control means for setting the hard characteristic.

According to the second aspect of the present invention, when the damping force on the extension side is set between the vehicle body and each wheel side so that the damping force on the extension side is set to the hard characteristic, the damping force on the contraction side becomes the soft characteristic and the damping force on the extension side is set. In a suspension control device that has a damping force reversing hydraulic shock absorber that can be controlled so that the damping force on the contraction side has a hard characteristic when the force is set to a soft characteristic, the acceleration in one direction to the left or right or front and rear increases. An acceleration change rate detecting means for detecting the time as plus and the minus when the acceleration in one direction decreases is provided, and when the detected value of the acceleration change rate detecting means is plus, the damping force reversing hydraulic buffer on the one direction side is provided. Set the expansion side of the device to the hard characteristic and the damping direction of the other direction to the damping force reversing type.If the compression side of the hydraulic shock absorber is set to the hard characteristic, and the detection value of the acceleration change rate detection means is negative, the damping force of the one direction is the reversing type. Hydraulic buffer The compression-side as a hard characteristic of, characterized in that the extension-side in the other direction side of the damping force inversion type hydraulic shock absorber provided with a control means for setting the hard characteristic.

The invention according to claim 3 is the invention according to claim 1 or 2.
In the configuration described above, the control means has means for setting the value of the damping force on the hard side of the damping force reversing hydraulic shock absorber to a large value in accordance with the magnitude of the rate of change in acceleration detected by the acceleration detecting means. It is characterized by

The invention according to claim 4 is the invention according to claims 1 to 3.
In any one of the configurations above, the control means includes means for setting the characteristic of the damping force reversing hydraulic shock absorber with a delay with respect to the detection result of the acceleration detection means.

According to a fifth aspect of the present invention, in the configuration according to the third aspect, the control means attenuates when the rate of change in acceleration detected by the acceleration change rate detecting means exceeds a preset limit value. The value of the damping force on the hard side of the force reversal type hydraulic shock absorber is set to a value corresponding to the limit value.

[0012]

According to the structure of claim 1, when the absolute value of the detected value of the acceleration detecting means is in the increasing direction, the damping force reversing hydraulic shock absorber on the acceleration direction side has the extension side hard characteristic and the damping on the other side. The force reversal type hydraulic shock absorber is set to the shrink side hard characteristic,
When the absolute value of the detection value of the acceleration detecting means is in the decreasing direction, the damping force reversing hydraulic shock absorber on the acceleration direction side is set to the contraction side hard characteristic, and the damping force reversing type hydraulic shock absorber on the other side is set to the extension side hard characteristic. To be done.

According to the second aspect of the present invention, the acceleration change rate detecting means detects the increase in the left / right or front / rear acceleration in one direction as plus and the decrease in the one direction acceleration as minus. If the value is positive, the damping force reversing hydraulic shock absorber on one side is set to the extension side hard characteristic, and the damping force reversing type hydraulic shock absorber on the other direction side is set to the contraction side hard characteristic, and the acceleration change rate detection means detects it. When the value is negative, the damping force reversal type hydraulic shock absorber on one side is set to the contraction side hard characteristic, and the damping force reversal type hydraulic shock absorber on the other side is set to the extension side hard characteristic.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A suspension controller according to a first embodiment of the present invention will be described below with reference to FIGS. In FIG. 1, between a vehicle body 1 (sprung) and four wheels (only one is shown in the figure) 2 (unsprung) constituting a vehicle,
A spring 3 and a damping force reversal type hydraulic shock absorber 4 are interposed in parallel and support the vehicle body 1. A vertical acceleration sensor 5 that detects a sprung acceleration α (vertical acceleration) of the vehicle body 1 is mounted on the vehicle body 1. Also, in the vehicle,
A lateral acceleration sensor 8 is attached. The lateral acceleration sensor 8 detects lateral acceleration (hereinafter, simply referred to as lateral acceleration) acting on the vehicle body 1 in the lateral direction of the vehicle.

A damping force reversal type hydraulic shock absorber (hereinafter, referred to as a shock absorber) 4 is disclosed in, for example, Japanese Patent Laid-Open No. 5-272570, and an actuator 6 and the actuator 6 are driven to displace the shock absorber 4. Has a movable body (not shown) that adjusts the passage area (damping coefficient) of the passage that connects the upper and lower chambers defined by the piston inside the actuator 6 It is configured to adjust the damping force. in this case,
When the value of the actuator opening signal is within a predetermined range (the right part of FIG. 3), the contraction damping coefficient is soft (low value) and constant, and the extension damping coefficient varies from soft to hard according to the value of the actuator opening signal. Changes to (higher value). on the other hand,
When the value of the actuator opening signal is in a range different from the above (left part of FIG. 3), the expansion side damping coefficient is soft (low value) and constant, and the contraction side damping coefficient depends on the value of the actuator opening signal. It is designed to change from soft to hard (high value).

A controller 9 is connected to the vertical acceleration sensor 5, the lateral acceleration sensor 8 and the actuator 6. The controller 9 is provided with a differentiating circuit 10 and an amplifier 11 that function when the lateral acceleration control mode described later is selected (FIG. 2). The differentiating circuit 10 differentiates the lateral acceleration from the lateral acceleration sensor 8 to obtain the lateral acceleration change rate, and the amplifier 1
1, the gain K is applied to the lateral acceleration change rate. The controller 9 selects one of the semi-active basic control mode and the lateral acceleration control mode according to the magnitudes of the vertical acceleration signal from the vertical acceleration sensor 5 and the lateral acceleration signal from the lateral acceleration sensor 8, and selects the mode. The desired damping force can be obtained by the shock absorber 4 by executing the arithmetic processing based on the selected mode.

The shock absorber 4 and the spring 3 are composed of four wheels 2
4 are provided for each of the above, but only one of them is shown for convenience.

The semi-active basic control mode is selected when the value of lateral acceleration is small and the vehicle is traveling straight. By being selected, the vertical acceleration signal is first integrated to obtain the absolute vertical speed. Then, the actuator opening signal is obtained based on the vertical absolute speed, and the damping coefficient corresponding to the actuator opening signal is obtained to improve the riding comfort and drivability.

The lateral acceleration control mode has the control contents shown in the flowchart of FIG. In this lateral acceleration control mode, the controller 9 determines the direction of acceleration as follows. That is, when the lateral acceleration in the right direction with respect to the traveling direction of the vehicle increases (the lateral acceleration change rate increases), the value is positive, and when the lateral acceleration decreases in the same direction (the lateral acceleration change rate decreases), the value is negative. And For example, when the vehicle starts turning the steering wheel so as to make a left turn at the point A on the road 12 as shown in FIG. 5, starts the steering wheel returning at the point B, and finishes the steering wheel returning at the point C, the points A to At the point B, a centripetal force (leftward with respect to the traveling direction of the vehicle) acts on the vehicle body 1, and the lateral acceleration sensor 8 detects a lateral acceleration (vehicle leftward direction) corresponding to the centripetal force. At the points A and B, the lateral acceleration gradually increases in the left direction of the vehicle, that is, the lateral acceleration decreases in the right direction of the vehicle, and the lateral acceleration change rate becomes negative (-) as shown in Table 1. . Similarly, at points B to C, the lateral acceleration increases to the right of the vehicle, contrary to the case of points A to B described above, and the lateral acceleration change rate is set to plus (+) as shown in Table 1. It will be.

[0020]

[Table 1]

The direction of acceleration when the vehicle turns right as shown in FIG. 6 as opposed to FIG. 5 will be described. When turning the steering wheel to turn right at the point D, starting the returning of the steering wheel at the point E, and ending the returning of the steering wheel at the point F, at the points D to E, the car body 1 has a centripetal force (right side of the vehicle). Direction) acts, and the lateral acceleration sensor 8 detects the acceleration (vehicle rightward direction) corresponding to the centripetal force. At this time, the lateral acceleration gradually increases to the right of the vehicle, that is, the lateral acceleration increases to the right of the vehicle, and as shown in Table 2, a negative (+)
Will be. Similarly, at points E to F,
Contrary to the case of the points D to E described above, the lateral acceleration decreases to the right of the vehicle and becomes positive (-) as shown in Table 2.

[0022]

[Table 2]

In the flow chart of FIG. 4, when it is determined that the lateral acceleration signal is input from the lateral acceleration sensor 8 or the lateral acceleration signal exceeds a predetermined value, it is determined that the vehicle is turning. Set (Step S
1), input and output signals (step S2). Next, the differentiating circuit 10 differentiates the lateral acceleration to obtain the lateral acceleration change rate (step S3). Then, the amplifier 11 multiplies the lateral acceleration change rate by the gain K to obtain the calculated damping coefficient (step S4). Then, it is determined whether or not the lateral acceleration change rate is positive (step S5). If YES is determined in this step S5 (the lateral acceleration change rate is positive), the actuator 4 on the right side of the vehicle body 1 corresponding to the acceleration direction is controlled to extend the shock absorber 4 on the right side of the vehicle body 1 (attenuation on the extension side). In a state where the coefficient becomes a large value and thus a large damping force is obtained in the extension direction), the actuator 6 on the left side of the vehicle body 1 is controlled to set the shock absorber 4 on the left side of the vehicle body 1 to shrink and set to hard (steps S6 and S7). ). YES in step S5
When it is determined that the lateral acceleration change rate is positive, for example, as shown in FIG. 5 and Table 1, in the case of points B to C at the time of turning left, or as shown in FIG. It may be point D or point E at the time of turning.

If it is determined to be NO (the lateral acceleration change rate is negative) in step S5, the actuator 6 on the right side of the vehicle body 1 corresponding to the acceleration direction is controlled to shrink the shock absorber 4 on the right side of the vehicle body 1 and to By controlling the actuator 6 on the left side of the vehicle body 1, the shock absorber 4 on the left side of the vehicle body 1 is extended and set to hard (steps S8, S7). Step S5
As a case where it is determined to be NO (the lateral acceleration change rate is negative), for example, as shown in FIG. 5 and Table 1, in the case of a point A or a point B when turning left, or in FIG. 6 and Table 2.
As shown in, there may be a point E or a point F when turning right.

In steps S6, S7 and S8, specifically, the damping force of the shock absorber 4 is set as follows. An example of this setting will be described with reference to FIG. 3 showing the movable body position-damping coefficient characteristic. For example, if the lateral acceleration change rate is M (M> 0),
As described above, the shock absorber 4 on the right side of the vehicle body 1 is extended and hard, and the shock absorber 4 on the left side of the vehicle body 1 is contracted and hard. However, if the calculated damping coefficient obtained in step S3 is M ₁ , while the movable member of the damper 4 is the arithmetic damping coefficient M ₁ is moved to a position alpha ₁ obtained, the movable member of the vehicle body 1 left damper 4 is shrinkage M ₁ so as to obtain a hard state
Is set to a position α ₂ corresponding to M ₂ (M ₂ <0) whose absolute value is equal to.

If the lateral acceleration change rate N (N>M> 0) is satisfied, the shock absorber 4 on the right side of the vehicle body 1 is extended and hard, and the shock absorber 4 on the left side of the vehicle body 1 is reduced and hard as described above. If the calculated damping coefficient obtained in step S3 is N ₁ , the movable body of the shock absorber 4 on the right side of the vehicle body ₁ is moved to the position β ₁ obtained by the calculated damping coefficient N ₁ , while the buffer on the left side of the vehicle body 1 is moved. The movable body of the container 4 is set at a position β ₂ corresponding to N ₂ (N ₂ <0) whose absolute value is equivalent to N ₁ so that a contracted hard state can be obtained.

The operation of the suspension control device configured as described above will be described.

Before point A in FIG. 5, after point C, or in FIG.
When the vehicle is traveling straight ahead such as before the point D and after the point F, the controller 9 performs the control based on the above-mentioned semi-active control mode. Then, for example, as shown in FIG. 5, when a left turn is started by operating the steering wheel at a point A, the right side of the vehicle sinks as shown in (B) on the left side of FIG. 5 due to the centrifugal force acting as a reaction of the centripetal force (right side). Force will start to act on the vehicle body 1. At this time, the controller 9 which has received the lateral acceleration signal from the lateral acceleration sensor 8 obtains the direction and magnitude of the lateral acceleration change rate. As described above, at the points A to B, the lateral acceleration change rate is determined to be negative. It will be. Based on the result of this determination, the shock absorber 4 on the right side of the vehicle body 1 is set to shrink hard and the shock absorber 4 on the left side of the vehicle body 1 is set to extended hard. Therefore, at the points A to B, both the right and left shock absorbers 4 of the vehicle body 1 exert great restraining force against the roll of the vehicle body 1 to the right, and the vehicle body 1 sinks to the right side. Surely prevent.

After the point B at which the handle is returned,
A returning force acts on the vehicle body 1 from the state shown in FIG. 5B to the state shown in FIG. 5C. On this occasion,
The controller 9 which receives the lateral acceleration signal from the lateral acceleration sensor 8 obtains the direction and magnitude of the lateral acceleration change rate.
As described above, at the points B to C, the lateral acceleration change rate is determined to be positive. Based on this determination result, the shock absorber 4 on the right side of the vehicle body 1 is set to be extended hard, and the shock absorber 4 on the left side of the vehicle body 1 is set to be contracted hard. Therefore, the shock absorbers 4 on the right side and the left side of the vehicle body 1 gradually absorb the return force acting on the vehicle body 1, and it is possible to prevent the vehicle body 1 from suddenly returning at the points B to C.

As described above, at the points A to B, the vehicle body 1 is prevented from sinking to the right side, and at the points B to C, the rapid return of the vehicle body 1 is suppressed, so that the vehicle body 1 is restrained from the right side. It is possible to obtain a good riding comfort when turning and to secure stable steering stability.

Further, for example, as shown in FIG. 6, when a right turn is started by operating the steering wheel at a point D, a centrifugal force exerts a force such that the left side of the vehicle sinks as shown in (E) on the left side of FIG. Will start. At this time, the controller 9 which receives the lateral acceleration signal from the lateral acceleration sensor 8 obtains the direction and the magnitude of the lateral acceleration change rate. As described above, at the points D to E, the lateral acceleration change rate is determined to be positive. It will be. Based on this determination result, the shock absorber 4 on the right side of the vehicle body 1 is set to be extended hard, and the shock absorber 4 on the left side of the vehicle body 1 is set to be contracted hard. Therefore, at the points D to E, both the right and left shock absorbers 4 of the vehicle body 1 exert a great suppressing force against the roll of the vehicle body 1 to the left, and the vehicle body 1 sinks to the left side. Surely prevent.

After the point E where the handle is returned,
Due to the centrifugal force, a returning force acts on the vehicle body 1 from the state shown in (E) on the left side of FIG. 6 to the state shown in (F) in FIG. At this time, the controller 9 which has received the lateral acceleration signal from the lateral acceleration sensor 8 obtains the direction and magnitude of the lateral acceleration change rate. As described above, at the points E to F, the lateral acceleration change rate is determined to be negative. It will be. Based on the result of this determination, the shock absorber 4 on the right side of the vehicle body 1 is set to shrink hard and the shock absorber 4 on the left side of the vehicle body 1 is set to extended hard. Therefore, the shock absorbers 4 on the right side and the left side of the vehicle body 1 gradually absorb the return force acting on the vehicle body 1, and the sudden return of the vehicle body 1 at the points E to F is suppressed.

As described above, at the points D to E, the vehicle body 1 is prevented from sinking to the left side, and at the points E to F, the rapid return of the vehicle body 1 is suppressed so that the vehicle body 1 is restrained from the right side. It is possible to obtain a good riding comfort when turning and to secure stable steering stability.

In the above embodiment, the damping force on the hardware side may be increased according to the magnitude of the lateral acceleration change rate. By controlling in this way, the leaning of the vehicle body 1 can be suppressed more quickly, and by extension, the riding comfort and steering stability can be improved.

In the above embodiment, the case where the control is performed based on the acceleration change rate is taken as an example, but instead of this, the control may be performed based on the increase or decrease tendency of the absolute value of the acceleration and the acceleration direction. Good. That is, when the absolute value of the detected value of the lateral acceleration sensor 8 is in the increasing direction, the buffer 4 on the acceleration direction side is set to be extended hard and the buffer 4 on the other side is set to be contracted hard to detect the detected value of the lateral acceleration sensor 8. When the absolute value of is in the decreasing direction, the shock absorber 4 on the acceleration side is controlled to be contracted and the shock absorber 4 on the other side is set to be expanded.

For example, when the vehicle turns left as shown in FIG. 5, as shown in Table 1, the absolute value of the acceleration is at the point A.
Or point B increases, point B or point C decreases,
In addition, the acceleration direction when turning left is the left direction as described above. On the other hand, when the vehicle turns right as shown in FIG. 6, the absolute value of acceleration increases at points D to E, decreases at points E to F, and the acceleration direction changes as shown in Table 2. To the right.

Therefore, by performing the above-described control, at the time of turning left as shown in FIG. 5, at the points A and B, as in the case of the control based on the acceleration change rate, the shock absorber 4 on the right side of the vehicle body 1 is performed. Is set to be contracted hard, and the shock absorber 4 on the left side of the vehicle body 1 is set to be extended hard to prevent the vehicle body 1 from sinking to the right side. Point B to Point C in FIG. 5, Point D to Point E, Point E to Point F in FIG.
Also, in the above, the shock absorber 4 on the same side as that selected in the case of the control based on the acceleration change rate described above is selected, and the expansion or contraction hardware is set equally, and the control based on the acceleration change rate described above is performed. As in the case of (3), good ride comfort and steering stability can be obtained.

Next, a second embodiment of the present invention will be described with reference to FIGS.
Based on the above, description will be made with reference to the first embodiment. In the first embodiment, the case where the lateral acceleration sensor 8 is provided to detect the lateral acceleration is taken as an example. However, instead of the lateral acceleration sensor 8, in the second embodiment, steering as shown in FIGS. 7 and 8 is performed. A sensor 20, a vehicle speed sensor 21, and an estimated lateral acceleration calculation circuit 22 are provided. The estimated lateral acceleration calculation circuit 22 is
A vehicle speed square value calculation circuit 23 that squares the vehicle speed value of the vehicle speed sensor 21, an arithmetic circuit 24 that calculates the following equation (1) with respect to data from the vehicle speed square value calculation circuit 23 and the steering sensor 20, and an arithmetic circuit 24. And a storage circuit 25 that obtains the estimated lateral acceleration based on the data from and outputs the estimated lateral acceleration data. In the second embodiment, the equation (1) is calculated (step S11) to obtain the estimated lateral acceleration (step S12), and the direction and magnitude of the lateral acceleration change rate are obtained based on the result. ing.

G = θ × V ² (1) where G: estimated lateral acceleration θ: steering wheel angle (value of steering sensor) V: vehicle speed (value of vehicle speed sensor)

In the suspension controller thus constructed, the estimated lateral acceleration G of the equation (1) can be used instead of the step S3 of FIG. 4, whereby the same control as in the first embodiment can be performed. By selecting the shock absorber 4 and setting the expansion or contraction hard, good riding comfort and steering stability can be obtained.

Next, a third embodiment of the present invention will be described based on FIG. 9 and with reference to FIG.

In the first embodiment, the lateral acceleration sensor 8 for detecting the lateral acceleration in the left-right direction is provided, and based on the detection result, good ride comfort and steering stability for the roll during turning are secured. As an example, in the third embodiment, a longitudinal sensor (not shown) that detects lateral acceleration in the vehicle longitudinal direction is provided in place of the lateral acceleration sensor 8, and the longitudinal acceleration change rate is calculated from the longitudinal acceleration detected by the longitudinal sensor. Seeking
The longitudinal acceleration change rate is used in place of the lateral acceleration change rate of the first embodiment, and the magnitude and extension side of the damping coefficient of the shock absorber 4 on the front side and the rear side of the vehicle body 1 and selective setting of the expansion side and the contraction hardware are performed. I am configuring. The controller of this third embodiment is shown in FIG.
The control is performed as shown in. That is, the lateral acceleration (FIG. 4) used in the first embodiment is replaced with the longitudinal acceleration, and the vehicle body right side and left side actuators (FIG. 4) used in the first embodiment are replaced with vehicle body front side and rear side actuators. The other parts are configured in the same manner as in FIG.

In the suspension control device of the third embodiment, as shown in FIG. 9, the left and right directions in the control of the first embodiment are replaced by the front and rear directions, and a force for tilting the vehicle body in the front and rear directions begins to act. In this case, the front and rear shock absorbers 4 are selected and the hard side is set so as to gradually absorb the force, and when the vehicle body starts to return to its original state,
The front and rear shock absorbers 4 are selected and the hard side is set so that the force in the return direction is gradually absorbed. Therefore, it is possible to suppress a sudden inclination behavior of the vehicle body 1 at the time of starting and accelerating the vehicle and at the time of stopping the vehicle, and it is possible to secure good riding comfort and steering stability.

Next, a suspension controller according to a fourth embodiment of the present invention will be described with reference to FIGS. 10 and 11.
In the fourth embodiment, a low-pass filter 30 is provided in the latter stage of the amplifier 11 as compared with the first embodiment, and the data (calculation attenuation coefficient) obtained by multiplying the lateral acceleration change rate obtained through the amplifier 11 by the gain K is predetermined. I am trying to output it with a delay.
FIG. 11 shows the control contents of the lateral acceleration control mode in the controller 9 of the fourth embodiment, and the processing by the low-pass filter 30 is performed between step S3 and step S4 of FIG. 4 of the first embodiment. Do (step S31)
With this configuration, the operation of the damping coefficient inversion type hydraulic shock absorber based on the lateral acceleration change rate is delayed for a certain period of time.

In the fourth embodiment, the damping coefficient inversion type hydraulic shock absorber is controlled based on the lateral acceleration change rate after a certain time delay from the detection by the lateral acceleration sensor 8.
As compared with the embodiment, the fluctuation can be suppressed more gently, the steering stability is further increased, and a good riding comfort can be maintained.

Next, a fifth embodiment of the present invention will be described based on FIG. 12 and with reference to FIG. The fifth embodiment is the fourth embodiment.
In contrast to the embodiment having the low-pass filter 30 and the controller 9 having the step S31, the low-pass filter 30 and the processing steps of the low-pass filter 30 are omitted, and the steps S3 and S31 are replaced. It is different from the fourth embodiment in that it is configured to perform steps S41 to S45 of FIG. In FIG. 12, in step S41, the data obtained by subtracting the previous lateral acceleration from the current lateral acceleration is set as the lateral acceleration change rate, and in the subsequent step S42, it is determined whether the lateral acceleration change rate is smaller than a preset limit value. judge. If YES in step S42, that is, if the lateral acceleration change rate is smaller than the limit value, the previous lateral acceleration + lateral acceleration change rate is updated as the previous lateral acceleration, and the process proceeds to step S4.

If NO in step S42, that is, if the lateral acceleration change rate is equal to or greater than the limit value, the previous lateral acceleration + limit value is updated as the previous lateral acceleration (step S44),
The lateral acceleration change rate is used as the limit value (step S45), and the process proceeds to step S4.

In the fifth embodiment, when the lateral acceleration change rate is equal to or greater than the limit value, the damping coefficient is obtained using the limit value as the lateral acceleration change rate to control the shock absorber 4, so that an excessive damping force is exerted. You can suppress things.

In the above embodiment, the case where the shock absorber 4 is configured to increase or decrease the damping force by adjusting the damping coefficient is taken as an example. However, a pressure control valve is provided and the pressure control valve A device configured to directly control the damping force by operation may be used.

In the above embodiment, an example for controlling the roll at the time of turning is shown. However, a longitudinal acceleration sensor for detecting longitudinal acceleration is provided, and the rate of change in acceleration is calculated based on the detection result. Alternatively, the front and rear shock absorbers 4 may be controlled to effectively suppress the dive when starting and the squat when braking.

Further, in each of the above-described embodiments, an example in which the lateral acceleration control mode and the semi-active control mode are switched and controlled is shown, but instead of this, both mode controls are performed simultaneously, and both modes are controlled. The resulting control signals may be added together to control the actuator.

[0052]

When the absolute value of the detected value of the acceleration detecting means is in the increasing direction, the damping force reversing type hydraulic shock absorber in the acceleration direction has the extension side hardware characteristic and the other direction. When the damping force reversal type hydraulic shock absorber on the side is set to the contraction side hard characteristic and the absolute value of the detected value of the acceleration detecting means is in the decreasing direction, the damping force reversal type hydraulic shock absorber on the acceleration side is the contraction side hard characteristic. When the damping force reversing hydraulic shock absorber on the other direction is set to the extension side hard characteristic and the force in one of the front, rear, left and right directions acts on the vehicle body and the vehicle body begins to lean, the force in the leaning direction is ensured. When the return force begins to act on the vehicle body by restraining the vehicle body to prevent the vehicle body from leaning, this return force is gradually absorbed. Stability can be obtained.

According to the second aspect of the invention, when the absolute value of the detected value of the vehicle body side acceleration detecting means is in the increasing direction, the damping force reversing hydraulic shock absorber on the acceleration direction side has the contraction side hardware characteristic and the other side. When the damping force reversal type hydraulic shock absorber is set to the extension side hard characteristic and the absolute value of the detection value of the vehicle body side acceleration detecting means is in the decreasing direction, the damping force reversal type hydraulic shock absorber on the acceleration side is the extension side hard characteristic. Characteristics, the damping force reversing hydraulic shock absorber on the other side is set to the contraction side hard characteristic, and when the vehicle body begins to lean due to a force in any of the front, rear, left, and right directions, the force in the leaning direction is ensured. To prevent the car body from tilting,
In addition, when the return force starts to act on the vehicle body, the return force is gradually absorbed, so that it is possible to prevent a sudden return of the vehicle body and obtain good riding comfort and steering stability.

According to the third aspect of the invention, the value of the damping force on the hard side of the damping force reversal type hydraulic shock absorber is set to a large value in accordance with the magnitude of the rate of change in acceleration detected by the acceleration detecting means. Therefore, it is possible to speed up the tilt adjustment of the vehicle body.

According to the structure described in claim 4, since the characteristic of the damping force reversing hydraulic shock absorber is set with a delay in the detection result of the acceleration detecting means, it is possible to suppress the fluctuation gently, and It is possible to increase steering stability and maintain a good riding comfort.

According to the fifth aspect of the invention, when the magnitude of the rate of change in acceleration detected by the acceleration change rate detecting means exceeds a preset limit value, the damping force reversing hydraulic shock absorber on the hardware side is Since the value of the damping force is set to a value corresponding to the limit value, it is possible to prevent the excessive damping force from being exerted.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a suspension control device according to a first embodiment of the present invention.

FIG. 2 is a block diagram schematically showing a part of control contents of a controller of the suspension control device.

FIG. 3 is a diagram showing a correspondence between a position of a movable body and a damping coefficient in a shock absorber of the suspension control device.

FIG. 4 is a flowchart showing the control contents of a lateral acceleration control mode in the controller of the suspension control device.

FIG. 5 is a view showing a vehicle traveling position and an operating state of the suspension control device in association with each other when turning left.

FIG. 6 is a view showing a vehicle traveling position and an operating state of the suspension control device in association with each other when the vehicle turns right.

FIG. 7 is a block diagram for explaining a second embodiment of the present invention.

FIG. 8 is a flowchart showing a part of control contents of the controller of the second embodiment.

FIG. 9 is a flow chart for explaining a third embodiment of the present invention.

FIG. 10 is a block diagram for explaining a fourth embodiment of the present invention.

FIG. 11 is a flowchart showing a part of control contents of the controller of the fourth embodiment.

FIG. 12 is a flow chart for explaining a fifth embodiment of the present invention.

FIG. 13 is a diagram schematically showing an example of a conventional suspension control device.

[Explanation of symbols]

 1 vehicle body 2 wheels 4 shock absorber (damping force reversal type hydraulic shock absorber) 6 actuator 9 controller

Claims (5)

[Claims] 1. When the damping force on the extension side is set to a hard characteristic, the damping force on the contraction side has a soft characteristic, and the damping force on the extension side is set to a soft characteristic, which is interposed between the vehicle body and each wheel side. In a suspension control device having a damping force reversing hydraulic shock absorber that can be controlled so that the damping force on the contraction side has a hard characteristic, the acceleration in at least one of the front-rear direction and the left-right direction that acts on the vehicle body during traveling is An acceleration detecting means for detecting is provided, and when the absolute value of the detected value of the acceleration detecting means is in the increasing direction, the extension side of the damping force reversing type hydraulic shock absorber on the acceleration direction side has a hard characteristic, and the damping force on the other side reverses. When the contraction side of the hydraulic shock absorber is set to the hard characteristic and the absolute value of the detection value of the acceleration detection means is in the decreasing direction, the contraction side of the damping force reversing hydraulic shock absorber on the acceleration direction side is the hard characteristic, and the other direction Damping force on the side A suspension control device comprising control means for setting the extension side of a reversing hydraulic shock absorber to a hardware characteristic. 2. When the extension side damping force is set to a hard characteristic, the contraction side damping force has a soft characteristic, and the extension side damping force is set to a soft characteristic, which is interposed between the vehicle body and each wheel side. In a suspension control device having a damping force reversing hydraulic shock absorber that can control the damping force on the contraction side to have a hard characteristic when the acceleration is increased in one direction to the left, right, front or rear, plus Is provided with an acceleration change rate detecting means for detecting a decrease in the acceleration to the negative side, and when the detected value of the acceleration change rate detecting means is positive, the extension side of the damping force reversing type hydraulic shock absorber on one side is hardened. Characteristics, if the contraction side of the damping force reversal type hydraulic shock absorber on the other side is set to the hard characteristic and the detection value of the acceleration change rate detection means is negative, the contraction side of the damping force reversal type hydraulic shock absorber on the one direction side The hard characteristics The suspension control device is provided with a control means for setting the extension side of the damping force reversing hydraulic shock absorber on the other direction to the hardware characteristic. 3. The control means sets means for setting the value of the damping force on the hard side of the damping force reversal type hydraulic shock absorber to a large value in accordance with the magnitude of the rate of change in acceleration detected by the acceleration detecting means. The suspension control device according to claim 1 or 2, further comprising: 4. The control means includes means for setting the characteristic of the damping force reversing hydraulic shock absorber with a delay with respect to the detection result of the acceleration detection means. 3. The suspension control device according to any one of 3 above. 5. The damping means on the hard side of the damping force reversal type hydraulic shock absorber when the magnitude of the rate of change in acceleration detected by the acceleration rate of change detecting means exceeds a preset limit value. The suspension control device according to claim 3, wherein the value is set to a value corresponding to the limit value.