JPS629447B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a shock absorber control device, and more particularly to a shock absorber control device for controlling a shock absorber so that an automobile can perform stable cornering.

As an example of a shock absorber control device for a vehicle in which the damping force is adjusted in response to an electric signal, the publication No. 56-147107 is known.

By the way, when a vehicle is running in general, when operating a steering operating device such as a steering wheel, the turning angular velocity at the time when the operation of the steering operating device starts, that is, when turning is started, and the turning angular velocity when the operation starts, that is, when the steering operating device starts turning, and after the operation starts, when operating a steering operating device such as a steering wheel, the turning angular velocity is It was found that there is a speed difference between the restoring angular velocity and the restoring angular velocity when restoring to the neutral position. Specifically, when the vehicle enters a curved road, it starts steering at a relatively slow turning angular speed, but when it exits the curved road, the steering system automatically restores itself, resulting in a relatively fast restoring angular speed. Restore with .

However, in the conventional shock absorber control device as described above, the rotational angular velocity of the steering device is simply taken into consideration both at the start of operation and in the case of restoration, so the shock absorber should normally be made stronger at the time of restoration. Although this is not desirable in terms of driving feeling, it becomes strong (hard), and the driving feeling is likely to be impaired.

The present invention has been made in view of the above points,
The main purpose is to improve the driving feeling by making the direction of rotation of the steering device one of the elements of shock absorber control.

Furthermore, the present invention focuses on the fact that the shock absorber frequently switches between strong and weak states due to frequent operations of the steering system, etc., which tends to impede the driving feeling, and the present invention provides a predetermined setting for the strong (hard) state. The purpose is to further improve the driving feeling by continuing the test for a certain period of time.

FIG. 1 shows the configuration of an embodiment of a shock absorber control device according to the present invention.

In the figure, 1 is a microcomputer which is an example of a control means, that is, an arithmetic control circuit, 2 is a vehicle speed sensor that generates a pulse signal proportional to the vehicle speed, and 3 is a signal generation means, which controls the movement angular velocity of the steering wheel (steering device). A steering sensor generates a proportional pulse signal, 4 and 5 are input buffers, and 6 to 9 are shock absorbers provided corresponding to each of the four wheels of the automobile, whose damping force is adjusted in response to an electric signal. Reference numerals 10 to 13 respectively represent drive circuits for driving the corresponding shock absorbers 6 to 9 based on control signals from the microcomputer 1, and 14 represents a key switch.

The vehicle speed sensor 2 is composed of a photoelectric conversion method, an electromagnetic pickup method, or a contact method, etc., and is installed in a transmission (not shown) to generate a pulse signal synchronized with the rotation of the gear.The vehicle speed and the number of pulse signals are determined based on the frequency of the pulse signal. You can know more about the distance traveled.

The steering sensor 3 is constructed using a photoelectric conversion method, an electromagnetic pickup method, or a contact method, and is disposed on a steering shaft (not shown) and generates a pulse signal proportional to the angular velocity of movement of the steering wheel. FIG. 2 shows the relationship between the steering sensor 3, which uses a photoelectric conversion method, and the steering shaft 15, which is linked to the steering operation.The steering sensors 3 are fixedly arranged with a predetermined phase difference from each other. It has two sensors 3-1 and 3-2, and also includes a rotating body 16 that rotates as the steering shaft 15 rotates.
Light emitted from light sources (not shown) disposed at opposite positions of sensors 1 and 3-2 is received by and blocked by the sensors 3-1 and 3-2 by the rotation of the rotating body 16. Therefore, when the rotating body 16 rotates clockwise, the output waveforms of the sensors 3-1 and 3-2 are as shown in FIG. 3A, while when the rotating body 16 rotates counterclockwise, the output waveforms are as shown in FIG. As shown in FIG. 3B, the rotation direction of the steering shaft 15 can be determined from the output waveforms of the sensors 3-1 and 3-2, as is clear from these two output waveforms.

Furthermore, the angular velocity of movement (operation speed) can be determined from the frequency of the output waveform, and the angle of movement (operation position) can be determined from the number of pulses.

By the way, the center of the steering wheel is required to know whether to turn the steering wheel or to turn it back. It is difficult to set this steering center accurately due to variations in the parts that make up the steering wheel, variations in assembly, etc.

Therefore, when the car is going straight, the angle of movement of the steering wheel is small, so if the angle of movement of the steering wheel is continuously smaller than a certain value for a certain distance traveled, the car is considered to be going straight, and the steering position at that time is is determined as a temporary center. The following equation is used to find the true center.

True center = {(A x previous true center) + B x temporary center)} / (A + B) Here, A>B, for example, A = 15/16, B =
It will be 1/16. Note that the initial value of the previous true center in the above equation may correspond to the steering position at the time of key-on.

The structure of each of the shock absorbers 6 to 9 is as schematically shown in cross-section in FIG. 4, for example.

In FIG. 4, a coil 21 electrically connected to the drive circuit 10, 11, 12 or 13 is provided on the upper part of the upper movable part 20, and a connecting rod 22 is connected to the connecting rod 22 by the magnetic force generated when the coil 21 is energized. The ring-shaped core 2 is moved upward and held together with the ring-shaped core 2.
3 are provided.

When the coil 21 is de-energized, the flow control valve 24 at the tip of the connecting rod 22 and the piston rod 2
The piston 26 provided at the tip of the piston 5 is maintained in the state shown in the figure, so that oil can flow relatively smoothly between the first oil chamber 40 and the second oil chamber 50. In other words, the damping force of the shock absorber 6, 7, 8 or 9 is maintained at a normal level, ie at a low level. That is, the shock absorber 6,
7, 8 or 9 are maintained as weak dampers, ie, soft.

On the other hand, the coil 21 is connected to the drive circuits 10, 11,
When energized by 12 or 13, the core 23
receives an upward force due to the generated magnetic force, and this core 2
3, the connecting rod 22 moves upward, and the flow rate control valve 24 closes the passage 28 that communicates the first oil chamber 40 and the valve chamber 27.
The flow resistance with the oil chamber 50 becomes high, and therefore the damping force of the shock absorber 6, 7, 8 or 9 becomes high. While the coil 21 is energized, the flow control valve 24 continues to block the passage 28 and the shock absorber 6, 7, 8 or 9
The damping force is kept high, that is, a strong damper is maintained.

Next, the processing operation of this embodiment configured as described above will be explained.

When the key switch 14 is turned on, the microcomputer 1 starts processing as schematically illustrated in FIG.

First, execute initialization step 101,
Performs initial settings for subsequent processing execution.

Next, a vehicle speed calculation step 102 is executed to calculate the vehicle speed VF based on the signal from the vehicle speed sensor 2. For example, in this vehicle speed calculation process, if the vehicle speed sensor 2 generates four pulses per wheel rotation, the distance traveled by the car in one wheel rotation is calculated from the time when the 1st pulse is input to the (+4)th pulse input. The vehicle speed VF is calculated by dividing by the time up to that point.

Next, a steering movement angle determining step 103 is executed to calculate the movement angle from the steering position, and it is determined whether the movement angle is larger than _θ1 .

Here, the reference angle _θ1 has a relationship with the vehicle speed VF as shown in, for example, FIG. 6 or FIG. 7.

If NO, that is, if there is little change in the steering wheel, the mileage count is incremented in the next step 104. As a result, it is determined in the next step 105 whether the count has reached M.
When the mileage count reaches M, that is, if the steering angle of movement is smaller than _θ1 for the distance M, the steering center is corrected in step 106, and the counter is reset in step 107. Clear and prepare for the next mileage count.

When it is determined in step 103 that the moving angle exceeds _θ1 , the distance traveled is cleared in step 108, and processing is performed so that center correction is not performed.

Therefore, when the steering is stable, the path including steps 103, 104, 105, and 106 is executed to perform steering center correction, and when the steering is moving, the center correction is not performed and the steering angular velocity is calculated. Step 1
09 is executed to calculate the steering angular velocity ω based on the signal from the steering sensor 3. Therefore, in determining the steering angular velocity ω,
Sensors 3-1, 3-2 with phase shifts as described above
Steering shaft 1 based on each signal from
Check the direction of rotation of steering shaft 1.
The steering angular velocity ω is calculated as a normal angular velocity only when the steering wheel 5 is continuously rotating to the right or continuously rotating to the left. In other cases, the steering angular velocity is calculated as a normal angular velocity. When the steering angle is slightly changed in the vehicle, or when the steering shaft rotates frequently in the left and right directions when driving on rough roads,
Processing that does not calculate the steering angular velocity ω is performed.
Here, the steering angular velocity ω is, for example, the movement angle θ ₁
The time is measured and calculated.

Next, a strong damper condition vehicle speed determination step 110 is executed, and the vehicle speed calculated in the above step 102 is determined.
It is determined whether or not the first reference vehicle speed _VL1 , for example, 20 km/h to 40 km/h, is sufficient to change the VF to strong damper control. Immediately after the key switch 14 is turned on, the vehicle speed VF is zero, so the determination result is "NO".Next, the weak damper condition vehicle speed determination step 111 is executed, and the vehicle speed VF is set as the standard for performing the weak damper control unconditionally. The second, which is the vehicle speed
It is determined whether the reference vehicle speed VL ₂ is, for example, 10 km/h. This determination result is also "YES" because the vehicle speed VF is zero, and then the weak damper control step 112 is executed and the shock absorber 6
to 9 are maintained as a weak damper, and then a timer counter clear step 113 is executed.

After the key switch 14 is turned on, the closed loop consisting of steps 102 to 107 and 111 to 113 or step 10 continues until the vehicle speed VF exceeds the second reference vehicle speed _VL2 .
One of the closed loops 2, 103, and 108 to 113 is always selected and executed, and the shock absorbers 6 to 9 are maintained as weak dampers.
During this time, center correction is also performed as the steering wheel moves.

Then, when the vehicle speed VF exceeds the second reference vehicle speed VL ₂ , the determination result of the weak damper condition vehicle speed determination step 111 becomes "NO", and then the strong damper control determination step 117 is executed, and the current strong damper control is It is determined whether or not this is being done. At this point, weak damper control is being performed as described above, so step 11
The result of the determination in step 7 is "NO", and the process returns to the vehicle speed calculation step 102. From now on, vehicle speed VF is the first reference vehicle speed.
Shock absorber 6 or 9 until VL exceeds ₁
is maintained at a weak damper.

If the vehicle speed VF exceeds the first reference vehicle speed _VL1 and there is a movement of the steering wheel, the determination result of the strong damper condition vehicle speed determination step 110 is "YES".
Then, according to the steering direction in step 114, the strong damper condition angular velocity determination step 11 is performed.
5 or 116 is executed, and when the steering angular velocity ω calculated in the steering angular velocity calculation step 109 is in the steering direction, the angular velocity K ₀ · VF + K ₁ ( K ₀ is a negative constant and K ₁ is a positive constant.
At this point, if it is determined that the steering angular velocity ω is less than the first reference angular velocity K ₀ · VF + K ₁ , that is, the steering operation by the driver is not so sudden considering the driving state of the vehicle, the strong damper condition is set. Since the determination result of the angular velocity determination step 115 is "NO", the strong damper control determination step 117 is then executed, and since the determination result is "NO", the process returns to the vehicle speed calculation step 102. In this way, when the vehicle speed VF is greater than or equal to the first reference vehicle speed VL _{1 and} in the turning direction, when the steering angular velocity ω is less than the first reference angular velocity K ₀ ·VF + K ₁ , the shock absorbers 6 to 9 are still weak dampers. will be maintained.

After that, while the vehicle is traveling at a vehicle speed higher than the first reference vehicle speed VL ₁ , the operating speed increases, such as when the vehicle enters a curve, and the steering angular velocity ω changes to the first reference angular velocity.
When K ₀ · VF + K ₁ or more, the judgment result of the strong damper condition angular velocity judgment step 115 is reversed to "YES", and then the strong damper control step 118 is executed, and the weak damper control up to that point is changed to strong damper control. , then execute the timer counter set step 119 to set the timer counter to a predetermined time value.
Set _T0 .

Here, this set time T ₀ is a fixed time or a value determined according to the vehicle speed, and when setting the value according to the vehicle speed, (a) the value is determined as the vehicle speed increases from low to high. The value T ₀ is increased, or (b) it reaches a peak value at high speeds, for example, _around 80 km/h, and decreases as the distance from around 80 km/h increases.

Thereafter, the vehicle speed VF is equal to or higher than the first reference vehicle speed VL ₁ and the steering angular velocity ω is the first reference angular velocity.
While K ₀ · VF + K ₁ or more, steps 102 to 110 and steps 114, 115, 118, 1
19 is selectively executed, and the shock absorbers 6 to 9 are maintained as strong dampers.

After that, the steering operation by the driver becomes relatively stable, and the steering angular velocity ω becomes the first reference angular velocity.
K ₀・VF+K less than ₁ or vehicle speed VF
When the vehicle decelerates to less than the first reference vehicle speed VL ₁ , after executing steps 110, 114, and 115, or after performing steps 110, 114, and 115, or performing strong damper condition vehicle speed determination step 1.
10 and weak damper condition vehicle speed determination step 11
After executing step 1, strong damper control judgment step 1
17 is executed. In this step 117, since the strong damper control is currently being performed, the judgment result is "YES", and then the angular velocity judgment step 120 is executed, and the steering angular velocity ω is set to the second reference angular velocity K ₄ (K ₄ is the above-mentioned K is a positive constant smaller than ₁ ) or less. If the steering angular velocity ω has not yet become equal to or less than the second reference angular velocity _K4 , the timer counter set step 119 is selected, and a time value is set in the timer counter.
_T0 is always set.

Then, the steering operation by the driver is sufficiently stable, and the steering angular velocity ω becomes the second reference angular velocity.
When the time value falls below _K4 , a timer counter subtraction step 121 is executed to start subtracting the timer counter to which the time value _T0 has been set.

After starting the timer counter subtraction process, while the time T ₀ has not yet elapsed, the judgment result of the T ₀ elapse judgment step 122 is "NO", so the shock absorbers 6 to 9 are still maintained as strong dampers. Ru.

And the time T ₀ after the start of timer counter subtraction processing
When the time has elapsed, the judgment result of the T ₀ progress judgment step 122 becomes "YES", and then the weak damper control step 112 is executed, and the shock absorber 6
to 9 are changed from a strong damper to a weak damper. And timer counter clear step 113
Execute and clear the timer counter.

Also in the case of steering return based on the determination in step 114, the steering angular velocity is the third reference angular velocity.
The operation is the same as in the case of the cutting direction described above, except that K ₂ VF + K ₃ is used as the criterion.

An example of the shock absorber control process has been explained in sequence above, but as is _clear from the flowchart shown in FIG. Since this is used as a parameter for changing the shock absorber from weak to strong, it is possible to prevent the shock absorber from becoming undesirably strong during so-called idle driving or driving on rough roads. In addition, when changing the shock absorbers 6 to 9 from a weak damper to a strong damper, if the vehicle speed VF is greater than the first reference vehicle speed VL ₁ and the steering angular velocity ω is in the turning direction, the first reference angular velocity K When ₀・VF+K becomes ₁ or more, make the change and then return from _the strong damper to the weak damper. The return is performed when a state in which the reference angular velocity K ₄ or less continues for a predetermined period T ₀ .

Furthermore, since the first reference angular velocity K ₀ · VF + K ₁ and the third reference angular velocity K ₂ VF + K ₃ are given as values using the vehicle speed VF as a parameter, for example, when the vehicle speed VF is large, a relatively small steering operation is performed. Even in this case, shock absorbers 6 to 9 will be changed to strong dampers, and if a relatively large steering operation is performed when the vehicle speed VF is small, shock absorbers 6 to 9 will be changed to strong dampers. Therefore, it is possible to perform shock absorber control that matches the actual cornering conditions of the automobile.

In addition, if the reference angular velocity in the turning direction and returning direction of the steering wheel is set to be higher than the return value, unnecessary strong damper control will not be performed when returning the steering wheel. It is possible to control the damper to a strong level only in certain cases.

In addition, since the damping force is maintained in a high state for a set period of time, the steering angle is changed sequentially when the steering operation is repeated alternately turning and returning during a turn, or when the curvature of a curved road is not constant. This prevents the damping force from changing frequently even when the vehicle is turned, and stable cornering can be expected.

According to the present invention, it is possible to perform shock absorber control that matches the actual cornering driving conditions of a vehicle, thereby making it possible to sufficiently improve handling stability and driving stability.

[Brief explanation of the drawing]

Fig. 1 shows the structure of an embodiment of the shock absorber control device of the present invention, Figs. 2 and 3 are explanatory diagrams of its steering sensor, Fig. 4 shows an example of the schematic structure of the shock absorber, and Fig. 5 shows the shock absorber control system. Flowcharts for explaining the process, FIGS. 6 and 7, each show a relationship between the reference angle and vehicle speed. 1...Control means, 2...Vehicle speed sensor, 3...Signal generation means, 6 to 9...Shock absorber.

Claims (1)

[Scope of Claims] 1. A shock absorber control device for a vehicle, which includes a shock absorber whose damping force is adjusted in response to an electric signal, and which controls the damping force of the shock absorber based on at least the operation of a steering operating device. a signal generation means for generating an operation signal corresponding to the operation of the steering operation device; and based on the signal from the signal generation means, the operation direction of the steering operation device departs from the neutral position or changes to the neutral position. determines whether the turning operation is to be started or restored depending on whether the vehicle approaches the vehicle, and adjusts the damping force of the shock absorber in accordance with the result of this determination;
A shock absorber control device comprising: control means for maintaining the increased damping force for a set time once the damping force is increased; 2. The shock absorber control device according to claim 1, wherein the set time is determined depending on the vehicle speed.