JPS60203513A - Level-controlling method - Google Patents

Abstract

PURPOSE:To perform stable control over plural desired values, by constituting a both up and down commands so as to be corrected in a way of outputting a stop command with a stop level and finding a deviation between a mean value and the stop level at a time when the car level mean value is out of a control starting dead zone. CONSTITUTION:When each signal out of car level sensors FR-RL is inputted into a central processing unit 20 via filters FL1-FL4 and an A/D converter 10, a mean car level is calculated according to a control program, and when it is below a dead zone LL at the side of a control starting rise, a car level upping signal is outputted, controlling each of car-level valves 60-2-60-4 via driver 50. And, simultaneously with arrival at a control stopping level L, a car level change is stopped. Next, after the elapse of the given period of time, a deviation between the present point mean car level and the desired value is found whereby the stopping level L is corrected so as to make the deviation zero. With this constitution, even if there are plural desired values, stable level control is attainable.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a vehicle height adjustment control method for outputting a control signal to a drive means for vertically driving a suspension to control the vehicle height to a target value.

[Background of the invention]

In conventional vehicle height adjustment control of this type, there are multiple vehicle height adjustment target values, and in some cases, the adjustment area is divided, and vehicle height adjustment control is performed in the target area with a dead band for each target value. I was going. The purpose of providing the dead zone here is to reduce the frequency of vehicle height adjustment.

In this type of vehicle height adjustment control, when the number of target values is about two, the dead zone can be set wide and the vehicle height adjustment control can be performed in a stable state. However, as the number of target values increases, individual targets Therefore, as the vehicle height adjustment speed becomes faster (for example, 10 mm/sec or more), the vehicle height adjustment control operation becomes unstable and hunting is likely to occur. There was a drawback.

In addition, in conventional vehicle height adjustment control, vehicle height detection
An optical or magnetic vehicle height detector that outputs a signal is used, and the vehicle height is not continuously detected, but the control content is to maintain the vehicle height within a preset target range. Therefore, it was not possible to adjust the vehicle height (change the target value) in response to the driver's request.

[Purpose of the invention]

An object of the present invention is to provide a vehicle height adjustment control method that can stably perform vehicle height adjustment control even if there are a plurality of vehicle height adjustment target values.

[Summary of the invention]

The present invention provides an adjustment stop dead band defined by a rise stop level and a fall stop level within an adjustment start dead band defined by a rise adjustment start level and a fall adjustment level with respect to a vehicle height target value, and When the average value of the vehicle height within a certain period of time (vehicle height average value) during high adjustment is within the adjustment start dead band, a control signal for raising or lowering the suspension is output to the suspension drive means, and the vehicle height average value When the vehicle height reaches the rising stop level or the falling stopping level, the output of the control signal is stopped, and after a predetermined period of time has elapsed since the control signal output stopped, the current average vehicle height is compared with the target value, and the deviation is calculated. The present invention is characterized in that the rising stop level or the falling stopping level is corrected and set in a direction closer to the target value by the same amount.

[Embodiments of the invention]

Embodiments of the present invention will be described based on the drawings. FIG. 1 shows the configuration of a vehicle height adjustment control device to which the present invention is applied, and in the same figure, a filter FL is shown.

~FL4 are analog vehicle height sensors FR, FL, RR, and R that have linear characteristics to detect the height position of the suspension installed on each wheel, that is, the vehicle height.
The detection outputs of L are taken in, noise components are removed from these detection outputs, and the signals are used for A/D conversion. A/
The D converter 10 has a built-in multiplexer (not shown), which selectively receives the detection outputs of the vehicle height sensors FR, FL, RR, and RL and converts them into digital signals. 20 is a central processing unit (hereinafter referred to as CPU)
, read-only memory (hereinafter referred to as ROM) that stores fixed data and control programs, and random access memory (hereinafter referred to as RAM) that is a storage element for temporarily writing and reading data. This is a storage unit consisting of, etc.

Furthermore, 40 is an input/output interface circuit (hereinafter referred to as Ilo).
It is written as ), 50 is a vehicle height adjustment valve 60-1 to vertically drive the suspension attached to each wheel.
This is a driver that outputs a drive signal to 60-4. In the figure, only the vehicle height adjustment valve 60-1 attached to the front light (FR) side is shown, and the others are omitted for convenience.

In the above configuration, the CPU 20 receives the digital signal from the A/D converter 0 and stores it in the ROM in the storage unit 30.
Performs various arithmetic processing based on the control program stored in the Ilo 40? A control signal for driving the vehicle height adjustment valves 60-1 to 60-4 is outputted to the driver 50 via the control signal.

Next, FIG. 2 shows the contents of the vehicle height adjustment control routine executed by the CPU 20. In the figure, when the program is started, the average value of the vehicle height is calculated in step 100. In other words, the average value of the vehicle height within a certain period of time, specifically the detection output of a specific vehicle height sensor, is converted into a digital value for the A/D conversion converter l at a certain sampling period, which is about 20 values. Find the average value xk of the data.

Next, in step 102, the vehicle height average value de and the vehicle height target value xo
A determination is made as to whether it is larger or smaller than the rising side dead zone LL for starting adjustment. If it is determined in step 102 that x < LL, the process moves to step 104, and in step 104, the corresponding vehicle height adjustment valve (any one of 60-1 to 60-4) is set in the direction in which the suspension rises. A control signal for driving is sent from the CPU 20 to the driver 5 via 11040.
Output to 0. F processed simultaneously in step 104
LAGI'''-FLAG3 is a software flag process and does not involve a control output. It is necessary to continue the rise until it reaches x) after the judgment starts to rise, and to maintain that the previous adjustment was an upward adjustment after the adjustment is completed. This is necessary in the same way as adjustment.In step 106, a determination is made as to whether it is larger than or equal to the rising stop level L. If it is determined to be x) L, the process moves to step 108, where the rising stop is performed and The process moves to step 118. If it is determined that x < L in step 106, the process returns to step 100. Even if it is determined that x)'LL in step 102, the process returns to step 10 in the flag processing of step 13o.
Jump to 6x) The rising signal continues to be output until it becomes L.

On the other hand, if it is determined in step 102 that x) LL, the process moves to step 110, and in step 110 it is determined whether the vehicle height average value i and the descending side dead zone HH for starting adjustment of the vehicle height target value xo are larger or smaller. x ) HH in step 110
If it is determined that
It is output to the driver 50 via 1040. In step 114, a determination is made regarding the level H for stopping the descent.
If it is determined that x<H, the process moves to step 116,
The descent is stopped and the process moves to step 118. If x ) H is determined in step 114, step 1
Return to 00. Even if it is determined in step 110 that x<HH, the process jumps to step 114 through flag processing in step 132, and the falling signal continues to be output until x<1 (in step 116).

After the vehicle height adjustment is completed, the process moves to step 118 and the F
Set LAG1'i and proceed to step 120, and as shown in Figure 3 (in the case of upward adjustment) and Figure 4 (in the case of downward adjustment), the time is calculated from the time when the stop level is reached (1 = 11). It is determined whether T has elapsed. This time T is set to, for example, 1 second, which is sufficient time for the vehicle height to stabilize from the point in time (1=11) when the output of the control signal outputted by the CPU 20 is stopped in step 108 or 116.

If the determination in step 120 is "NO4", the process returns to step 100, and the flag processing in step 128 causes the flow to jump to step 120, where the elapsed determination of the time T is repeated.If the determination in step 120 is "YES", the process returns to step 100 12
2, FLAG2 is determined to determine whether the previous adjustment was an increase or decrease. When the adjustment is upward (FLAG2 is set), the process moves to step 124, and when the adjustment is downward (FLAG2 is reset), the process moves to step 134. In step 124, the current vehicle height average value i and target value X are determined. Deviation Δ from
x ("Xo x+) ', rise stop level Lk
Correct and set L+ (=L+ΔX), step 1
Move to 26. On the other hand, in step 134, the deviation Δx (=★
2 Request, descending stop level H'1H1 (=H-△X
) and then proceed to step 126. In step 126, FLAGl necessary for correction of the dead zone for stopping
and returns to step 100.

In the process described above, the vehicle height average value is controlled to converge to the target value.

In this embodiment, for convenience, only the case where there is one target value is described, but the same applies even if there are a plurality of target values.

Also, vehicle height adjustment is performed for each suspension individually, but this point will be omitted since the explanation would be complicated.

As explained above, in this embodiment, two dead zones for stopping are provided for the vehicle weight target value, one for stopping the full rise and the other for stopping the descent. Since the width of the dead zone in the high adjustment direction is narrowed, the vehicle height can be adjusted to an optimal position near the target value.

Furthermore, hunting is less likely to occur even if the vehicle height adjustment speed is set quickly, and the vehicle height adjustment control operation can be stabilized.

Furthermore, since the target value can be easily changed, it becomes possible to continuously change the vehicle height according to the driver's request.

〔Effect of the invention〕

According to the present invention, vehicle height adjustment control can be stably performed for a plurality of vehicle height adjustment target values.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of a vehicle height adjustment control device to which the present invention is applied, and FIG. 2 is the content of a vehicle height adjustment control routine executed by the vehicle height adjustment control device shown in FIG. Figures 3 and 4 show the control state when adjusting the vehicle height, Figure 3 shows the case where the vehicle height is adjusted upward relative to the target value, and Figure 4 shows the case where the vehicle height is adjusted to the target value. The cases in which the values are adjusted in the downward direction are shown respectively. FLI-FL4...Filter, lO...A/D
Converter, 20...CPU, 30...Storage unit, 40.
... Ilo, 50... Driver, 60-1 to 60-4
...Vehicle height adjustment valve. Agent Tatsuyuki Unuma (and 1 other person) Figure 3 Figure 4

Claims (1)

[Claims] (1) In a vehicle height adjustment control method in which a control signal is output to a drive means that drives the suspension in the entire vertical direction to control the vehicle height to a value close to a target value, the vehicle height is adjusted at an upward adjustment start level and a downward adjustment start level relative to the target value. An adjustment stop dead zone defined by a rise stop level and a fall stop level is provided within the specified adjustment start dead band, and the average value of the vehicle height within a certain period of time (vehicle height average value) is adjusted when adjusting the vehicle height. When it is outside the starting dead band, the control signal tJfl for raising or lowering the suspension is output by the hand drive means, and the output of the control signal is stopped when the average vehicle height reaches the raising stop level or the lowering stopping level. At the same time, after a predetermined period of time has elapsed since the control signal output was stopped, the vehicle height average value at the present time is compared with the target value, and the above-mentioned ascent stop level or descending stop level is corrected in the direction closer to the target value by the difference. A vehicle height adjustment control method characterized by setting.