JP4716071B2 - Suspension control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a suspension control device used in a vehicle.
[0002]
[Prior art]
As an example of a conventional suspension control device, there is a device disclosed in Japanese Patent Application Laid-Open No. 2001-12530. This suspension control device is provided with a damping force adjusting hydraulic shock absorber, and a damping characteristic variable means including a proportional solenoid is provided in the piston and piston rod of the shock absorber. As the energizing current to the proportional solenoid is increased, the shock absorber is soft on the expansion side and soft on the contraction side (H / S), soft on both the expansion side and the contraction side (S / S), and is soft on the expansion side and the contraction side. Hard (S / H) damping force can be generated, and it has stretch / shrink reversal characteristics. The suspension control device can perform semi-active suspension control based on the so-called skyhook theory because the shock absorber has expansion / contraction reversal characteristics.
[0003]
In the suspension control device having the above-described configuration, for example, when roll motion occurs during turning of the vehicle, the damping characteristic variable means is switched and controlled so as to generate damping force in accordance with the motion in the roll direction. For example, at the start of right steering (right turn), the shock absorber on the right wheel, which is the turning inner wheel, is the expansion side hardware (H / S), and the shock absorber on the left wheel, which is the turning outer wheel, is the compression side hard (S / H). After the above, when the steering wheel is returned, the left wheel side shock absorber becomes the expansion side hard (H / S) and the right wheel side shock absorber becomes the contraction side hard (S / H) during left steering. To control.
[0004]
[Problems to be solved by the invention]
By the way, in the above-described prior art, for example, in order to suppress the roll at the start of the right steering (right turn), the shock absorber on the right wheel side which is the turning inner wheel is the extension side hard (H / S), turning outer wheel. When the left wheel side shock absorber is controlled to be contraction side hard (S / H) and then the steering is switched (left steering is performed), the roll direction changes, and the left wheel side shock absorber extends to the expansion side hard. (H / S), control is performed so that the shock absorber on the right wheel side becomes the contraction side hardware (S / H). In this way, while switching from the right steering to the left steering, a position where the expansion side and the contraction side are both soft (S / S) is once taken. And by performing soft (S / S) control on both the expansion side and the contraction side, the roll motion is promoted and the behavior is increased.
Moreover, in order to reduce the behavior of the vehicle, there is a case where control is performed so as to be on the contraction side, but in this case, unevenness (high frequency) on the road surface is easily picked up, and riding comfort is deteriorated.
[0005]
The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a suspension control device capable of suppressing the behavior of the vehicle body and improving the riding comfort.
[0006]
[Means for Solving the Problems]
The invention according to claim 1 is provided between the vehicle body and the axle at four positions on the front, rear, left and right sides of the vehicle, and the damping characteristic has a mode of expansion soft and contraction hard, extension soft and contraction soft, expansion hard and contraction soft. A characteristic inversion type shock absorber, a vehicle body behavior detecting means for detecting the roll of the vehicle body, and a control means for controlling the damping characteristics on the expansion side and the contraction side in accordance with the behavior signal detected by the vehicle body behavior detection means, , wherein the control means, wherein during detecting the vehicle behavior detecting means roll, for the four points all the attenuation characteristic inverted shock absorbers, the roll control to the elongation damping characteristics hard and shrinkage soft mode It is characterized by performing.
According to a second aspect of the invention, in the configuration of claim 1, wherein the roll control, the line Ukoto until the time the vehicle from the time when the vehicle behavior detection means detects the roll is returned to the horizontal state Features. Here, the period from the time when the vehicle body behavior detecting means detects the roll to the time when the vehicle body is returned to the horizontal state means, for example, from the start of the roll to the end of the roll. Note that the end of the roll includes during the rollback.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is an invention belonging to an invention group including a plurality of inventions described below. Hereinafter, the first to fourth embodiments will be described as embodiments of the invention group. The first embodiment corresponds to the invention described in the scope of claims of the present applicant.
First , a suspension control apparatus according to a first embodiment of the present invention will be described with reference to FIGS. In FIG. 1, a spring 3 and a damping characteristic are provided between a vehicle body 1 (sprung) and four (only one is shown) wheels 2 (unsprung) constituting an automobile (vehicle). Four adjustable damping characteristic inversion type shock absorbers (hereinafter referred to as shock absorbers) 4 are interposed in parallel, and these support the vehicle body 1.
[0008]
A vertical acceleration sensor 6 for detecting vertical acceleration (sprung acceleration) α with respect to the absolute coordinate system of the vehicle body 1 is mounted on the vehicle body 1. In addition, the vehicle body 1 is provided with a roll detection sensor 7 (vehicle body behavior detecting means) comprising a lateral acceleration sensor, which detects that the vehicle body 1 has been rolled and outputs it as a roll signal β. The sprung acceleration α detected by the vertical acceleration sensor 6 and the roll signal β from the roll detection sensor 7 are supplied to the controller 8 (control means). Although four shock absorbers 4 and four springs 3 are provided corresponding to the four wheels 2, only one of them is shown for convenience.
[0009]
The shock absorber 4 is of a side-mounted type provided with an actuator 9 (proportional solenoid) that adjusts the energization current in accordance with a control signal D from the controller 8 on the outer peripheral side. The shock absorber 4 is not limited to the horizontal type, but may be of a type in which a damping characteristic varying means including a proportional solenoid is incorporated in the piston and the piston rod. The actuator 9 adjusts the damping force generation position of the shock absorber 4 by adjusting the energization current.
As the energizing current to the actuator 9 increases, the shock absorber 4 is hard on the expansion side and soft on the contraction side (H / S), soft on both the expansion side and the contraction side (S / S), and is soft on the expansion side and soft on the contraction side. A damping force can be generated in the order of (S / H), and has an expansion / contraction reversal characteristic. The suspension control device according to the present embodiment can perform semi-active suspension control satisfactorily based on the so-called skyhook theory because the shock absorber 4 has expansion / contraction reversal characteristics.
[0010]
The controller 8 integrates the sprung acceleration α from the vertical acceleration sensor 6, energizes the actuator 9 according to the sprung absolute speed, and the shock absorber 4 provided corresponding to each wheel 2. The damping force generation position is adjusted to generate a desired damping force in each shock absorber 4 so as to ensure good riding comfort and steering stability. Further, when the roll signal β from the roll detection sensor 7 exceeds a predetermined value, the controller 8 performs roll control E (behavior control) as shown in FIG. 3 to suppress the roll of the vehicle body 1. In this roll control E, the damping force generation position is adjusted based on the roll signal β in preference to the adjustment of the damping force generation position based on the sprung acceleration α. Note that the roll control E may be performed such that the adjustment of the damping force generation position based on the sprung acceleration α is corrected based on the roll signal β.
[0011]
The roll control E is divided into a shock absorber 4 for the right side of the vehicle [right front wheel (FR), right rear wheel (RR)] and a shock absorber 4 for the left side of the vehicle [left front wheel (FL), left rear wheel (RL)]. The damping force generation position is adjusted.
The controller 8 is provided with a roll control first counter 10, and when the roll detection sensor 7 detects a roll, time measurement is started for the shock absorber 4 on the right side of the vehicle as shown in FIG. By comparing the measured value with a predetermined reference time A, time management of the roll control E can be performed. The reference time A is a time from the occurrence of the roll to the completion, and is set to about 5 seconds, for example. In addition, when it is still in the roll after this time passes, it is desirable to extend time further, and when extending in this way, the predetermined predetermined time can be made into short time.
[0012]
Here, the calculation processing contents of the controller 8 will be described based on the flowchart of FIG. 2 and the timing chart of FIG.
As shown in FIG. 2, when the vehicle engine is started (actuated) and the power source is connected to the controller 8, the controller 8 performs initial setting (step S1).
Thereafter, the determination is made until it is determined whether or not a predetermined control cycle has elapsed (step S2). If YES is determined in step S2, the actuator 9 is driven based on the control signal D calculated in the previous control cycle (step S3).
Subsequent to step S3, the output is made to members other than the actuator 9, such as LED (step S4).
[0013]
In the next step S5, the sprung acceleration α (detected value) is input from the vertical acceleration sensor 6, and a roll signal β is input from the roll detection sensor 7 when a roll is generated.
In subsequent step S6, the detection value of the vertical acceleration sensor 6 read in step S5 is integrated, and based on the sprung absolute speed, the damping force necessary for damping the vehicle body 1 and this damping force are required. The control signal D is obtained. In subsequent step S7, based on the roll signal β from the roll detection sensor 7 read in step S5, a damping force necessary for suppressing the roll and a control signal D necessary for generating this damping force are obtained (roll). Control E is executed), and the process returns to step S2.
[0014]
When the roll detection sensor 7 detects a roll and the roll signal β is input to the controller 8 in step S5, the controller 8 determines that the right side of the vehicle (right front wheel (FR), FR), in step S7 and step S3 of the next control cycle. The right rear wheel (RR)] shock absorber 4 and the left side [left front wheel (FL), left rear wheel (RL)] shock absorber 4 damping force (damping characteristics) are all extended side hard And shrink side software (H / S)] (roll control E is performed). In FIG. 3, only the damping force of the shock absorber 4 of the right front wheel (FR) and the left front wheel (FL) of the shock absorber 4 on the right side of the vehicle and the shock absorber 4 on the left side of the vehicle is displayed, and the left front wheel (FL), The display of the damping force of the left rear wheel (RL) shock absorber 4 is omitted.
[0015]
The specific content of the roll control E will be described by taking as an example a case where the right steering is performed to make a right turn and a leftward roll is generated.
When the right steering is performed, the vehicle body 1 rolls in the left direction, the roll detection sensor 7 detects that the vehicle body 1 has been rolled, and a roll signal β is output. With the roll detection by the roll detection sensor 7, the controller 8 starts the roll control E and causes the roll control first counter 10 to start measuring time.
In the roll control E, the controller 8 controls the shock absorber 4 of the vehicle right side [right front wheel (FR), right rear wheel (RR)] corresponding to the turning inner wheel side and the vehicle left side [left front wheel (FL) corresponding to the turning outer wheel side. , Left rear wheel (RL)], the damping characteristics of the shock absorber 4 are all adjusted to be expansion-side hard [extension-side hard and contraction-side soft (H / S)].
When the measurement time of the roll control first counter 10 reaches a predetermined reference time A, the roll control E is stopped, and the suspension control by the sprung acceleration α of the vertical acceleration sensor 6 is performed.
[0016]
As described above, when rolls are generated, the damping characteristics of the shock absorber 4 on the right side of the vehicle corresponding to the turning inner wheel side and the shock absorber 4 on the left side of the vehicle corresponding to the turning outer wheel side are both extended side hard [extension side hard And shrink side software (H / S)]. For this reason, compared with the prior art which passes the position which becomes soft (S / S) on both the expansion side and the contraction side, the promotion of the roll motion is suppressed, and the roll is suppressed correspondingly.
[0017]
At this time, since it is set to the contraction side software, it is possible to follow the unevenness (high frequency) of the road surface and to ensure a good riding comfort. That is, in the prior art, when a roll is generated due to turning, the shock absorber on the outside of the turning is made hard on the contraction side to suppress the roll, and for this reason, it may occur that it is pushed up with respect to the road surface protrusion (unevenness). On the other hand, in the first embodiment, it is possible to ensure a good riding comfort without causing a push-up caused by the conventional technology.
[0018]
Furthermore, when performing turn-back steering (returning the steering wheel), the shock absorbers 4 on the inside and outside of the turn have already been made hard on the extension side, so that the stability of the vehicle can be ensured.
Further, during the roll control E for suppressing the roll, the shock absorber 4 on the right side of the vehicle [right front wheel (FR), right rear wheel (RR)], the left side of the vehicle [left front wheel (FL), left rear wheel (RL)] The damping force (damping characteristics) of the shock absorber 4 is controlled so as to be hard on the extension side (roll control E is performed). As described above, since any shock absorber 4 becomes hard on the extension side when the roll is suppressed, the control load can be reduced as compared with the case where the shock absorber 4 is individually driven.
[0019]
In the above embodiment, when the measurement time of the roll control first counter 10 reaches the predetermined reference time A, the roll control E is stopped. Instead, the roll detection sensor 7 (vehicle body behavior detection) is stopped. The roll control E may be performed between the time when the means) detects the roll (behavior) and the time when the vehicle body 1 is returned to the horizontal state. In this case, the time until the time point indicating that the vehicle body 1 has been returned to the horizontal state refers to the time from the start of roll (behavior) to the end of roll. Note that the end of the roll includes during the rollback.
Further, the roll detection sensor 7 may be a lateral acceleration sensor, and roll control may be performed while this output is equal to or greater than a predetermined value.
[0020]
The above-described embodiment is particularly effective for a reversible shock absorber in which a piston portion is provided with an expansion side contraction side damping force adjustment valve. This is because if the compression force adjustment valve on the contraction side is provided in the piston portion, if the compression force on the contraction side is increased, the upper chamber of the piston in the cylinder becomes negative pressure, so the upper limit of the compression force on the contraction side is limited. The Therefore, the piston portion provided with the damping force adjusting valve cannot increase the damping force on the contraction side, so that the effect of suppressing the roll cannot be exerted much even if S / H is performed during the roll. Therefore, applying the present invention and preventing S / S when the direction of the roll is changed results in suppression of the behavior of the vehicle.
[0021]
In the above embodiment, as shown in FIG. 3, at the start of the roll control E, the damping characteristics of the shock absorbers 4 on the turning inner wheel side and the turning outer wheel side are both extended side hard [extension side hard and contraction side soft (H / S)], but instead, it may be configured as shown in FIG. 4 (second embodiment). That is, in the second embodiment (FIG. 4), the controller 8 is provided with the roll control second counter 11, and when the roll detection sensor 7 detects the roll, the shock absorber on the left side of the vehicle as shown in FIG. 4 is started, and time measurement of the roll control E can be performed by comparing the measured value with a predetermined reference time B.
[0022]
In the second embodiment (FIG. 4), the roll control second counter 11 is used for the damping characteristic of the shock absorber 4 on the left side of the vehicle (left front wheel (FL), left rear wheel (RL)) corresponding to the turning outer wheel side. Until the measurement time reaches the reference time B (initially), it is referred to as contraction-side hard [stretch-side soft and contraction-side hard (S / H)]. The reference time B is a time from when the roll is generated until it becomes a steady roll, for example, set to about 2 seconds. If the roll is still increasing after this time has elapsed (the lateral acceleration change rate is equal to or greater than a predetermined value), it is desirable to further extend the time. In this case, the predetermined time is shortened to a short time. Can be. After the measurement time of the roll control second counter 11 reaches the reference time B, the roll control second counter 11 is adjusted so as to become the expansion side hard [extension side hard and contraction side soft (H / S)]. In FIG. 4, the display of the damping force of the shock absorber 4 for the left front wheel (FL) and the left rear wheel (RL) is omitted as in FIG.
[0023]
In this second embodiment, the outer shock absorber passes through the extension soft and contraction software (S / S), but immediately switches to the extension hard and contraction software (H / S) without maintaining this value. Therefore, the posture change during turning can be effectively suppressed.
Instead of the reference time B, the lateral acceleration change rate may be a predetermined value or more, and the reference time A may be a time when the lateral acceleration is a predetermined value or more.
[0024]
Further, as shown in FIG. 5, when the roll control E is finished, the damping characteristics of only the shock absorber 4 on the left side of the vehicle (left front wheel (FL), left rear wheel (RL)) corresponding to the turning outer wheel side are shown. Further, it may be adjusted so as to be extended-side hard [elongated-side hard and contracted-side soft (H / S)] (third embodiment).
In this case, when the vehicle runs on the S-hour curve that immediately turns to the opposite side after the end of the roll control E, the shock absorber FL does not keep the value of the extension soft and contraction software (S / S), and the extension hard and Since the contraction software (H / S) is used, the posture change can be effectively suppressed.
[0025]
Next, a fourth embodiment will be described with reference to FIGS. In this embodiment, the parts shown in FIG. 1 and FIG. 2 of the above embodiment are the same, so the same parts are denoted by the same reference numerals and description thereof is omitted.
The characteristic of the damping force characteristic reversal type shock absorber 4 of the present embodiment is the characteristic shown in FIG. 6, and the damping force (M / M) has a position to generate. The (M / M) position may be the same (H / H) as the hard characteristics. Further, an (M / M) position may be provided on the higher current side.
[0026]
Next, control will be described. Each step in FIG. 2 is the same as that described above, and only the content of the roll control in S7 is different, and this point will be described with reference to FIG.
When the roll signal β is received from the roll detection sensor 7, roll control is started. Each roll control is continued for a predetermined time, that is, during the roll (about 5 seconds). If the roll is being continued after the predetermined time, this counter counts again and continues the roll control. During this roll control, both the outside and inside of the turn are fixed to the expansion medium and the contraction medium (M / M).
[0027]
As a result of this control, during the roll, the shock absorber is not stretched and contracted (S / S) so that a stable posture can be maintained.
As another modified example, as shown in FIG. 8, conventional roll control may be performed at the initial stage of the roll, and fixed to an expansion medium and a contraction medium (M / M) a predetermined time after the start of the roll. .
Further, when the vehicle speed is equal to or higher than a predetermined value, the medium may be fixed to the expansion medium and the contraction medium (M / M) regardless of the posture change such as the roll.
The control in each of the above embodiments is performed when the lateral acceleration is equal to or greater than a predetermined value. If the lateral acceleration is equal to or less than the predetermined value, the conventional roll control is performed such that the inner wheel is H / S and the outer wheel is S / H May be.
[0028]
In each of the above embodiments, as a specific example of the roll control E, the case where the right steering is performed and the vehicle body 1 rolls leftward is taken as an example, but the case where the left steering is performed and the vehicle body 1 rolls rightward is also used. In the same manner as described above (when the vehicle is steered to the right and the vehicle body 1 rolls to the left), the roll control E can be performed to suppress the roll and ensure a good riding comfort. In this case (left steering) during roll control E, the left side of the vehicle corresponding to the turning inner wheel side [left front wheel (FL), left rear wheel (RL)] shock absorber 4 and the right side of the vehicle corresponding to the turning outer wheel side. The damping characteristics of the shock absorber 4 for the [right front wheel (FR) and the right rear wheel (RR)] are adjusted so that both become the expansion side hard [extension side hard and contraction side soft (H / S)].
[0029]
In each of the above embodiments, the case where the vehicle body 1 tilts in the left-right direction (one direction) of the front-rear direction and the left-right direction is an example of a roll motion, but the pitch motion (squat behavior, The present invention can also be used in the case of dive behavior. In this case, a pitch detection sensor for detecting the pitch motion is provided, and when the pitch motion is detected, the pitch control (behavior control) corresponding to the roll control E is performed, and the vehicle front [left front wheel (FL), right front wheel ( FR)] shock absorber 4 and the rear side of the vehicle corresponding to the turning outer wheel side [left rear wheel (RL), right rear wheel (RR)] shock absorber 4 damping characteristics are both extended side hard [extended side hard and Adjustment is made so that the compression side software (H / S) is obtained. By this pitch control, it is possible to suppress the pitch motion and ensure a good riding comfort in the same manner as the roll control E.
[0030]
In the above embodiment, the case where the vehicle body behavior detection means is the roll detection sensor 7 or the pitch detection sensor is taken as an example, but a vertical acceleration sensor is provided on the left and right sides of the vehicle body 1 or a vertical acceleration is provided on the front and rear sides of the vehicle body 1. A sensor may be provided, and the vertical acceleration sensor on the left and right sides of the vehicle body 1 or the vertical acceleration sensor on the front and rear side of the vehicle body 1 may be used as the vehicle body behavior detection means.
[0031]
【The invention's effect】
According to the present invention, especially when a roll is generated, the damping characteristic of any shock absorber performs roll control in which the damping characteristic is set to an expansion hard and contraction soft mode. The promotion of exercise is suppressed, and the roll is suppressed accordingly.
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing a suspension control apparatus according to a first embodiment of the present invention.
2 is a flowchart showing calculation contents of a controller of the suspension control device of FIG. 1;
FIG. 3 is a timing chart of signals during roll control of the suspension control device of FIG. 1;
FIG. 4 is a timing chart of signals during roll control in the second embodiment of the present invention.
FIG. 5 is a timing chart of each signal during roll control in the third embodiment of the present invention.
FIG. 6 shows damping force characteristics of the fourth embodiment of the present invention.
FIG. 7 is a timing chart showing the contents of roll control according to the fourth embodiment.
FIG. 8 is a timing chart showing the content of control that is fixed to the expansion medium and the contraction medium (M / M) after a predetermined time from the start of the roll in the control instead of FIG. 7;
[Explanation of symbols]
4 Shock absorber 7 Roll detection sensor 8 Controller

Claims (2)

Damping characteristic reversal type shock absorber, which is provided between the vehicle body and the axle at the front and rear left and right sides of the vehicle and has a damping characteristic that has a soft and contraction hard extension mode, a soft extension and contraction soft mode, a hard extension and a contraction soft mode,
Vehicle body behavior detecting means for detecting a roll of the vehicle body;
Control means for controlling the attenuation characteristics on the expansion side and the contraction side according to the behavior signal detected by the vehicle body behavior detection means,
Said control means, said in detecting the vehicle behavior detecting means roll, wherein said about 4 places all attenuation characteristic inverted shock absorbers, to perform a roll control to the elongation damping characteristics hard and shrinkage soft mode Suspension control device. The roll control, suspension control apparatus according to claim 1, wherein the vehicle behavior detection means and said line Ukoto between the time of detecting the roll to the point where the vehicle is returned to the horizontal state.

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