JP3792891B2 - Damping force adjustable shock absorber controller - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an actuator control device that changes a damping force of a shock absorber.
[0002]
[Prior art]
Conventionally, anti-roll control for changing a shock absorber (shock absorber) capable of changing damping force based on the detected or estimated lateral G in order to suppress the roll of the vehicle body is known. In the control, while the lateral G exceeds a predetermined value, the actuator is driven to increase the damping force of the shock absorber, and the roll of the vehicle body is reduced.
[0003]
[Problems to be solved by the invention]
However, in the above conventional example, when the lateral G increases during the turn, the damping force maintains a large value according to the lateral G regardless of the road surface condition. In some cases, there is a problem that shock from the wheels is transmitted to the inside of the vehicle and lowers the ride comfort. To detect the road surface condition, it is necessary to perform control using image recognition or the like, which complicates the device. Therefore, there is a problem that the manufacturing cost is greatly increased.
[0004]
Further, even if the lateral G increases during the turn and exceeds the threshold and then rolls in the opposite direction due to a decrease in the lateral G by turning back the handle, etc. The force is maintained as it is, and there is a problem that the damping force is not switched in spite of the roll in the opposite direction.
[0005]
Accordingly, the present invention has been made in view of the above-described problems, and an object of the present invention is to suppress rolls and improve the riding comfort while having a simple configuration without complicating the apparatus.
[0006]
[Means for Solving the Problems]
The first invention provides an actuator for driving a shock absorber capable of adjusting a damping force, a lateral G detection means for estimating a change amount of the lateral G in accordance with a driving state of the vehicle, and a detection value of the lateral G detection means. A damping force adjusting type shock absorber control device comprising an anti-roll control means for driving the actuator to change the damping force based thereon,
The lateral G detection means includes a steering angle detection means for detecting a steering angle of the steering, the vehicle speed detecting means for detecting a vehicle speed, line low-pass filter processing on the steering angle and the detected low-pass filter for calculating a low-pass signal A processing means; a steering angular speed equivalent value calculating means for calculating a steering angular speed equivalent value by taking a difference between the steering angle and the low-pass signal; and a lateral G variation estimation value is calculated from the steering angular speed equivalent value and the vehicle speed. A lateral G change amount estimating means, wherein the anti-roll control means is adapted to turn in the turning direction according to the lateral G change amount estimated value while the lateral G change amount estimated value exceeds a predetermined threshold value. Increase the damping force of the corresponding shock absorber.
[0007]
In a second aspect based on the first aspect, the threshold value increases according to the vehicle speed when the vehicle speed reaches a predetermined high vehicle speed range.
[0008]
In a third aspect based on the first aspect, the lateral G variation estimation means increases the lateral G variation estimation value as the steering angular velocity equivalent value or the vehicle speed increases.
[0009]
【The invention's effect】
Therefore, in the first invention, the steering angle speed equivalent value obtained by performing the low-pass filter process on the steering angle gradually approaches the steering angle detection value while causing a predetermined phase delay with respect to the steering angle. Increases temporarily when the steering angle changes, and then decreases according to the time constant of the low-pass filter. While the value corresponding to the lateral G change amount exceeds a predetermined threshold value, By changing the damping force of the shock absorber to a value corresponding to the lateral G variation equivalent value, at the initial stage of steering, the damping force is quickly increased to suppress excessive rolls, and then the roll is stabilized. After the time, the rudder angle and the rudder angular velocity equivalent value match and the lateral G change amount equivalent value decreases, so the anti-roll control is finished, and the damping force returns to the reference position, for example, soft. The damping force returns to the reference position. When turning, even if there are road joints or steps, it is possible to absorb shocks smoothly, and the damping force is fixed according to the lateral G as in the conventional example, and can follow changes in the road surface. It is possible to reliably prevent the loss of the roll, and it is possible to improve the operability and the ride comfort by combining the suppression of the roll at the beginning of the turn and the absorption of the shock due to the change of the road surface condition during the turn. When the steering is slightly returned to the inside, it is possible to smoothly shift to the roll angle corresponding to the reduced lateral G, and the behavior of the roll change can be changed according to the driving intention. In addition to being able to improve drivability compared to the example, the lateral G change amount estimated value uses a value obtained by subjecting the steering angle to low-pass filter processing, so that noise such as steering shake is reliably removed. Excess Response can be avoided, control accuracy can be improved, and low-pass filter processing can be performed to calculate the steering angle and low-pass signal. An increase in manufacturing cost can be suppressed.
[0010]
Further, in the second invention, when the vehicle speed becomes a predetermined high vehicle speed range, the threshold value increases according to the vehicle speed. Therefore, frequent anti-roll control can be suppressed during highway turning, and the highway It is possible to prevent the ride comfort from deteriorating during high-speed turning such as.
[0011]
Further, in the third aspect of the invention, the estimated lateral G change amount increases as the steering angular velocity equivalent value or the vehicle speed increases, so that it can be approximated to the actually generated lateral G, and the control accuracy is improved. be able to.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
[0013]
In FIG. 1, shock absorbers 5L and 5R capable of changing the damping force are provided with actuators 4L and 4R connected to a damping force adjusting mechanism via a control rod inserted into the inner periphery of a piston rod (not shown). These actuators are composed of, for example, a step motor, and the damping force of the shock absorbers 5L and 5R is changed according to the rotational position.
[0014]
Based on the steering angle θ detected by the steering angle sensor 2 and the vehicle speed VSP detected by the vehicle speed sensor 3, the controller 1 calculates an estimated value dLG of the lateral G change applied to the vehicle, as will be described later. The actuators 4L and 4R are driven so as to change the damping force of the shock absorbers 5L and 5R according to the lateral G change amount estimated value dLG.
[0015]
FIG. 2 shows an example of the anti-roll control performed by the controller 1, and the details of the control will be described in detail below with reference to this flowchart. This flowchart is executed at a predetermined cycle, for example, every 10 msec.
[0016]
In step S1, the vehicle speed VSP and the steering angle θ are read from each sensor, and in step S2, the steering angle signal θ is subjected to low pass filter processing to remove noise from the steering angle θ as shown in FIG. In addition, a low-pass signal LPFθ whose phase is delayed with respect to the steering angle θ is calculated.
[0017]
Next, in step S3, the steering angular velocity equivalent value dθ is calculated from the difference between the low-pass signal LPFθ and the steering angle θ.
dθ = θ−LPFθ
Calculate more.
[0018]
Therefore, the value of the steering angular velocity equivalent value dθ becomes the shaded portion shown in FIG. 5A, and the phase is delayed and different from the actual steering angular velocity θv as shown in FIG. 5C. Calculated as a value. The steps S2 and S3 can be expressed as shown in FIG.
[0019]
In step S4, the lateral G change amount estimation value dLG is calculated from the steering angular velocity equivalent value dθ using the detected vehicle speed VSP as a parameter based on the map of FIG.
[0020]
In step S5, the preset threshold value εdLG is compared with the lateral G change amount estimated value dLG obtained in step S4. If the lateral G change amount estimated value dLG exceeds the threshold value εdLG, step S6 is performed. In step S9, the anti-roll control is not performed. In step S9, the damping force is set in software to be described later, and the process proceeds to step S8.
[0021]
In the anti-roll control, first, in step S6, the steering direction (or turning direction) is determined by comparing the previous value and the current value of the steering angle θ, and then in step S7, the estimated lateral G change amount is estimated. The rotational positions of the actuators 4L and 4R are determined so as to obtain a damping force according to the magnitude of the.
[0022]
For example, when the settable damping force of the shock absorbers 5L and 5R sequentially increases in three stages of software, medium, and hardware, the rotational position of the actuators 4L and 4R is assumed to be software and the lateral G change amount is estimated. When the value dLG exceeds the preset threshold value dLG1, the hardware having the highest damping force is set, while otherwise, the medium is set to medium. However, the threshold value dLG1> εdLG is set. This damping force is set for each actuator 4L, 4R. Actually, it is set individually for the turning inner ring side (extension hard) and the outer ring side (compression side hard).
[0023]
In step S8, the actuators 4L and 4R are driven so that the damping force determined in step S7 or step S9 is obtained.
[0024]
When steady turning is performed by the above control, the relationship among the steering angle θ, the lateral G change amount estimated value dLG, the lateral G, and the actuator position (damping force) is as shown in FIG.
[0025]
As the steering angle θ increases, the lateral G change amount estimated value dLG also increases. At time t0, the lateral G change amount estimated value dLG exceeds the threshold value εdLG, anti-roll control is started, and the actuator position is soft. After setting to 1 indicating medium, the actuator position is set to 2 and set to hard indicating the maximum damping force.
[0026]
Thereafter, the lateral G change amount estimation value dLG is the difference between the steering angle θ and the low-pass signal LPFθ. Therefore, when the peak value is exceeded, the lateral G change amount estimation value dLG decreases according to the time constant of the low-pass filter. The value dLG ≦ dLG1 is satisfied, and the damping force is reduced from hard to medium. Further, at time t2, the lateral G change amount estimated value dLG ≦ εdLG is satisfied, and the anti-roll control is finished, and the damping force set in step S9. Return to the reference position = soft.
[0027]
That is, at the beginning of steering, the damping force is quickly increased to suppress an excessive roll, and after the time t1 when the roll is stabilized, the damping force can be gradually reduced. The roll control is completed, and the damping force returns to the software that is the reference position.
[0028]
On the other hand, in the conventional control, as shown in the lowermost stage of FIG. 6, the damping force is maximized by increasing the lateral G, and the maximum damping force is maintained corresponding to the continuation of the lateral G during turning. .
[0029]
Therefore, according to the present invention, in the initial stage of cornering after, for returning to the soft damping force is the reference position, in turning, it is possible to absorb shock even if there are such seams and steps of the road surface, the As in the conventional example, it is possible to reliably prevent the damping force from being fixed in accordance with the lateral G and unable to follow the change in the road surface, and by suppressing the roll in the initial turning and the change in the road surface state during the turning. It is possible to improve the handling and ride comfort by making shock absorption compatible.
[0030]
In addition, during the steady turn shown in FIG. 6, when the steering is slightly returned after time t2, the damping force is returned to soft at time t2, so that the roll angle corresponding to the reduced lateral G is smoothly turned to the roll angle. Therefore, the behavior of the roll change can be changed according to the driving intention, and the drivability can be improved as compared with the conventional example.
[0031]
Further, when the steering is increased during steady turning, as shown in FIG. 7, the anti-roll control by the first steering is completed at time t2, so that the lateral G change amount estimation accompanying the increase is estimated. After the damping force increases from the time t3 due to the increase of the value dLG, the damping force can be returned to the soft again after the time t4 when the roll change becomes stable. However, the road surface followability during turning can be improved.
[0032]
In addition, since the lateral G change amount estimation value dLG uses a low-pass signal LPFθ obtained by subjecting the steering angle θ to low-pass filter processing, it is possible to reliably remove noise such as steering shake and avoid an excessive response. The accuracy of anti-roll control can be improved.
[0033]
In addition, according to the present invention, low-pass filter processing is performed to calculate the difference between the steering angle θ and the low-pass signal LPFθ, so that the apparatus is not complicated and an increase in manufacturing cost can be suppressed. .
[0034]
In the above embodiment, the threshold value εdLG for starting the anti-roll control is a fixed value. However, as shown in FIG. 8, in the high vehicle speed range where the vehicle speed VSP exceeds the predetermined value V1, the vehicle speed VSP The threshold value εdLG may be increased according to the increase, so that frequent anti-roll control can be suppressed during highway turning, and the ride comfort is deteriorated during high-speed turning on a highway. Can be prevented.
[0035]
Further, the threshold value εdLG may be changed by the driver. In this case, the anti-roll control timing can be adjusted according to the driver's preference.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of an anti-roll control device according to an embodiment of the present invention.
FIG. 2 is a flowchart illustrating an example of anti-roll control performed by a controller.
FIG. 3 is a conceptual diagram of low-pass filter processing.
FIG. 4 is a map of a steering angular velocity equivalent value dθ and a lateral G change amount estimation value dLG;
5A and 5B are graphs showing changes in signals with respect to a change in steering angle θ, where FIG. 5A is a steering angle θ and a low-pass filter signal, FIG. 5B is a lateral G change amount estimation value dLG, and FIG. The relationship between the angular velocity equivalent value dθ, the steering angular velocity, and time is shown.
FIG. 6 is a graph showing the relationship between each signal and damping force during steady turning and time, and the relationship between steering angle θ, lateral G variation estimated value dLG, lateral G, damping force, and damping force by conventional control and time. Indicates.
FIG. 7 is a graph showing the relationship between each signal, control output, and time when the steering angle θ is increased during steady turning, and the steering angle θ, lateral G variation estimation value dLG, lateral G, damping force, and conventional The relationship between damping force by control and time is shown.
FIG. 8 is a map showing a relationship between a threshold value εdLG of a lateral G change amount estimated value dLG and a vehicle speed VSP.
[Explanation of symbols]
1 Controller 2 Steering angle sensor 3 Vehicle speed sensor 4L, 4R Actuator 5L, 5R Shock absorber

Claims (3)

An actuator that drives a shock absorber with adjustable damping force;
Lateral G detection means for estimating the amount of change in lateral G according to the driving state of the vehicle;
In a damping force adjusting type shock absorber control device comprising anti-roll control means for driving the actuator and changing damping force based on a detection value of the lateral G detection means,
The lateral G detection means includes
Steering angle detection means for detecting the steering angle of the steering;
Vehicle speed detection means for detecting the vehicle speed;
What line low-pass filtering of the steering angle obtained by the detection, and a low-pass filter processing means for calculating a low-pass signal,
Rudder angular velocity equivalent value calculating means for calculating a steering angular velocity equivalent value by taking the difference between the steering angle and the low pass signal ;
A lateral G variation estimation means for calculating a lateral G variation estimation value from the steering angular velocity equivalent value and the vehicle speed;
The anti-roll control means increases the damping force of the shock absorber corresponding to the turning direction according to the lateral G variation estimation value while the lateral G variation estimation value exceeds a predetermined threshold value. A damping force control type shock absorber control device.   2. The damping force adjusting type shock absorber control device according to claim 1, wherein the threshold value increases according to a vehicle speed when the vehicle speed falls within a predetermined high vehicle speed range.   2. The control of a damping force adjustable shock absorber according to claim 1, wherein the lateral G variation estimation means increases the lateral G variation estimation value as the steering angular velocity equivalent value or the vehicle speed increases. apparatus.

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