JPH0316283B2 - - Google Patents

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a vehicle height adjustment device for a vehicle.

(Prior Art) Normally, in a vehicle, if cargo or passengers are unevenly distributed, the amount of load on the front, rear, left, and right sides of the vehicle body is not equalized, causing the vehicle to tilt, which is undesirable. For example, if the load on the rear increases, the optical axis of the headlights will shift upwards during night driving, causing annoyance to oncoming vehicles.

Therefore, as a measure to correct the inclination of the vehicle body and maintain a constant vehicle height when the load fluctuates, for example, a vehicle height sensor that detects changes in the strut lengths of the front and rear wheels is installed, so that each vehicle height value matches the target vehicle height value. It is known that the strut lengths of the front and rear wheels are controlled by air pressure or the like.

[Problem to be Solved by the Invention] However, in the case of the conventional vehicle height adjustment device that takes such measures, it is difficult to adjust the area where the vehicle height changes greatly and the area where the vehicle height changes little among the front, rear, left and right sides of the vehicle body. However, the speed of adjustment of the vehicle height was different for each vehicle, and there was a problem in that the vehicle body shook significantly during the adjustment, giving the occupants a sense of discomfort.

That is, different loads are applied to the actuators that adjust the vehicle height in the front, rear, left, and right directions, and the magnitude of the load corresponds to the amount of variation in the vehicle height at that location.

For this reason, the vehicle height adjustment is delayed in areas with a large load compared to areas with a small load, resulting in the vehicle body shaking significantly.

(Object of the Invention) Therefore, an object of the present invention is to provide a vehicle height adjustment device that can first adjust the vehicle height at a location where the change in vehicle height is greatest, and then adjust the vehicle height at other locations. purpose.

(Structure of the Invention) In order to achieve the above object, the present invention, as shown in the basic conceptual diagram in FIG. A plurality of vehicle height detection means a, a reference vehicle height setting means b for setting a reference vehicle height value of the vehicle body, a convergence zone setting means c for setting a convergence zone of a predetermined width with respect to the reference vehicle height value, and a plurality of vehicle height detection means a for setting a reference vehicle height value of the vehicle body; On the other hand, if even one of the vehicle height values detected by the dead zone setting means d which sets a dead zone wider than the convergence zone width and the plurality of vehicle height detecting means a exceeds the dead zone, vehicle height adjustment is required. When the vehicle height is in a fluctuating state, a determining means e for determining a vehicle height fluctuation state, compares all vehicle height values detected by the plurality of vehicle height detecting means a with a reference vehicle height value, and determines from the reference vehicle height value. a selection means f for selecting the vehicle height value with the largest deviation; and a capture zone setting means g for setting a capture zone of a predetermined width that includes the vehicle height value selected by the selection means f.
and a control input determining means h for comparing each vehicle height value detected by the plurality of vehicle height detecting means a with a capture zone and determining a vehicle height value included in the capture zone as a control input; control value calculation means i for calculating a vehicle height control value for directing the vehicle height value determined by the control input determination means h into the convergence zone set by the convergence zone setting means c; and a plurality of vehicle height operating means j provided on the front, rear, left and right sides of the vehicle body for individually manipulating the vehicle height to be controlled.

(Function) In the present invention, when all vehicle height values exceed the dead zone, the following vehicle height adjustment is performed. That is, a capture zone including the vehicle height value farthest from the reference vehicle height value is set, and the vehicle height value captured in this capture zone is used as a control input to manipulate the vehicle height to be controlled.

Therefore, if only one vehicle height value deviates significantly and none of the other vehicle height values are captured, the vehicle height adjustment for one vehicle height value is performed first, and then, If another vehicle height value is captured, this captured vehicle height value will also be
Vehicle height adjustment is performed in the same manner, and as a result, vehicle height adjustment is performed in descending order of vehicle height change.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

In FIGS. 2 and 3, reference numeral 11 denotes a car body, and a front right tire 12 and a front left tire 13 are provided on the lower front side of the car body 11, which are attached to the right and left sides of a front axle (not shown). A rear right tire 14 and a rear left tire 15 are provided on the lower rear side of the vehicle body 11, which are attached to the right and left sides of a rear axle (not shown).

Between the front axle and the vehicle body 11 near the interior side of the front right tire 12, and the front left tire 1
A front right actuator 16 and a front left actuator 17 are interposed between the front axle and the vehicle body 11 near the inside of the vehicle interior of No. 3, respectively,
A rear right actuator 18 and a rear left actuator are located between the rear axle of the rear right tire 14 near the inside of the vehicle interior and the vehicle body 11, and between the rear axle of the rear left tire 15 near the interior of the vehicle interior and the vehicle body 11. An actuator 19 is interposed.

The vehicle body 11 near the vehicle interior side of each actuator 16, 17, 18, 19 has a front right vehicle height measurement point A, a front left vehicle height measurement point B, a rear right vehicle height measurement point C,
This is the rear left vehicle height measurement point D, and each of the vehicle height measurement points A, B, C, and D includes a front right vehicle height sensor 20, a front left vehicle height sensor 21, and a rear right vehicle height sensor 2.
2. A rear left vehicle height sensor 23 is attached.
Each of these vehicle height sensors 20 to 23 functions as a plurality of vehicle height detection means.

The front right vehicle height sensor 20 detects the vehicle height Ha at the front right vehicle height measurement point A, and issues a vehicle height value signal Sa indicating this vehicle height Ha. The front left vehicle height sensor 21 detects the vehicle height Hb at the front left vehicle height measurement point B, and issues a vehicle height value signal Sb indicating this vehicle height Hb. Rear right vehicle height sensor 2
2 detects the vehicle height Hc at the rear right vehicle height measurement point C and issues a vehicle height value Sc that indicates this vehicle height Hc. The rear left vehicle height sensor 23 detects the vehicle height Hd at the rear left vehicle height measurement point D, and issues a vehicle height value signal Sd indicating this vehicle height Hd.

26 is a vehicle speed sensor that detects the vehicle speed V, and this vehicle speed sensor 26 receives a vehicle speed signal that displays the vehicle speed V.
Emit Sv.

An air compressor 28 is attached to the rear of the vehicle body 11, and a predetermined amount of the compressed air discharged from the air compressor 28 is supplied to a dryer 29, where it is dried. Compressed air exceeding the fixed amount is discharged from the discharge valve 30. A predetermined amount of compressed air out of the compressed air dried in the dryer 29 is stored in the air tank 32 via the check valve 31, and then passed through the air supply valve 33 and supplied to the flow path 34. Compressed air in excess of the predetermined amount that has not been stored is directly supplied to the flow path 34. Channel 3
The compressed air supplied to
respectively, the front right actuator 16, the front left actuator 17, and the rear right actuator 1.
8, supplied to the rear left actuator 19.

On the other hand, 42 is a control device having a microcomputer 43 and a drive circuit 44, and the microcomputer 43 executes a program to be described later based on vehicle height value signals Sa, Sb, Sc, Sd and vehicle speed signal Sv, and controls the vehicle height. The value is calculated and a drive signal N corresponding to the result of the calculation is output to the drive circuit 44. The drive circuit 44 sends vehicle height adjustment signals Ka, Kb, Kc, and Kc to the front right valve 36, front left valve 37, rear right valve 38, and rear left valve 39, respectively, based on the drive signal N.
Kd, and also outputs an exhaust amount adjustment signal K ₁ and an air supply amount adjustment signal K ₂ to the exhaust valve 30 and the air supply valve 33, respectively. the actuator 16,
17, 18, 19, the valves 30, 33, 3
6, 37, 38, and 39 constitute a vehicle height operating means 46 as a whole.

Next, the effect will be explained.

FIG. 4 is a flowchart of the vehicle height adjustment program executed by the microcomputer 43.
This program has an initial program routine (initial setting P ₁ ) that is executed only when the microcomputer 43 is started, and also has the following subroutines that are repeatedly executed at every predetermined control cycle. That is, a plurality of vehicle height sensors 20
Subroutine _P2 for vehicle height sensor input that reads each vehicle height value signal Sa, Sb, Sc, and Sd from ~24, Subroutine _P3 for determining the start of vehicle height adjustment, and Subroutine _P4 for determining the end of vehicle height adjustment. and a subroutine _P5 for outputting a drive signal N to operate the actuators 16 to 19 during the vehicle height adjustment period. Of these subroutines _P2 to _P5 , the details of _P3 are shown in Figure 5, and the details of _P4 are shown in Figure 6.
The details of _P5 are shown in FIG.

In FIG. 5, the vehicle height adjustment start determination is made when all vehicle height values Sa to Sd are outside the OK zone ΔH ₁ (step 102), and the vehicle height adjustment is outside the OK zone ΔH ₁
The start is determined when the deviation continues for a period exceeding a predetermined time T _D (step 104). The above-mentioned OK zone ΔH ₁ corresponds to a dead zone, and smoothness of control is ensured by not performing adjustment unless an error exceeding this zone occurs. Furthermore, the above-mentioned time T _D is provided to prevent a temporary or instantaneous vehicle height fluctuation from becoming a vehicle height fluctuation state to be controlled.

In the program shown in FIG. 5, two flag states are finally set. Vehicle height adjustment consists of a downward adjustment that lowers the actual vehicle height when the actual vehicle height is higher than the standard vehicle height, and an upward adjustment that raises the actual vehicle height when the actual vehicle height is lower than the standard vehicle height. It can be divided into two parts. That is, when a downward adjustment is required, the downward flag is turned ON and the upward flag is turned OFF. Also, if upward adjustment is required, turn on the upward flag and turn on the downward flag.
Turn off. Alternatively, if all the actual vehicle heights are within the OK zone _ΔH1 , no adjustment is required, so both flags are turned OFF. These two flags are referenced in the subroutine programs shown in FIGS. here,
Step 102 of the program shown in Figure 5 above consists of the OK zone ΔH ₁ corresponding to the dead zone zone and each vehicle height value.
Compares Ha to Hd, and if even one of Ha to Hd deviates from within ΔH ₁ , it functions as a judgment means to determine a vehicle height fluctuation state that requires vehicle height adjustment, and also corresponds to a dead zone. The OK zone ΔH ₁ is set in a vehicle height region of a predetermined width above and below with respect to the target vehicle height position (m) as a reference vehicle height value. Therefore, the step 102 also functions as a reference vehicle height setting means and a dead zone setting means.

Next, the vehicle height adjustment completion determination program will be explained with reference to FIG. This program determines that if either of the two flags set in the program of FIG. 5 is ON, the vehicle height is being adjusted to either rise or fall (step 111).
Then, when all the vehicle height values Ha to Hd fall within the predetermined control end zone (ΔHe), it is determined that the vehicle height adjustment has ended (vehicle height 112), and both flags are turned OFF ( Step 113).

Here, the control end zone ΔHe is a zone set with a predetermined width above and below the reference vehicle height (m), and corresponds to a convergence zone. Therefore, step 112 functions as a convergence zone setting means and a determining means.

Next, a subroutine program for actuator output will be explained with reference to FIG. This program is roughly divided into an upward adjustment processing section 120 and a downward adjustment processing section 140. Which process to perform is determined based on the state of the rising and falling flags (steps 121 and 141). Each processing section selects the vehicle height value with the largest deviation from the standard vehicle height,
Steps 122 and 142 are provided as selection means for setting the vehicle height value as the selected vehicle height value H. In addition, each processing section determines the acquisition zone (in the rise adjustment processing section) based on the selected vehicle height value H and the operation permission zone _ΔH2 .
Steps 123 and 14 serve as capture zone setting means to set H _LOW and H _HIGH in the descending adjustment processing section.
It has 3. Then, each processing unit processes each vehicle height value Ha
~ When Hd is something that is captured in the capture zone, for example, when adjusting the elevation, a vehicle height value lower than H _LOW is captured as the adjustment target, and the captured vehicle height value is used as the control input to adjust the vehicle height. I do. For example, among the four measured vehicle heights Ha to Hd, if only Ha is lower than H _LOW and the other Hb to Hd exceed H _LOW , only Ha is captured and the vehicle height is adjusted to increase this Ha. I do. To specifically explain the rising vehicle height adjustment as an example, steps 124 and 12
7, 130, 133, and Ha~Hd, respectively.
Compare H _LOW and determine the captured vehicle height. If captured, steps 125, 128, 131,
At step 134, a control value for executing the upward vehicle height adjustment for the captured vehicle height is calculated, and if the captured vehicle height is not captured, steps 126, 129, 132,
At step 135, control value calculation for that vehicle height is stopped. In other words, vehicle height adjustment is stopped. Therefore,
Steps 124, 127, 130, 133 above
(Steps 144 and 1 for the descending adjustment processing section)
47, 150, 153) function as control input determining means, and also perform the steps 125, 12 described above.
8, 131, 134 (steps 145, 148, 151, 154 for the descending adjustment processing section)
functions as a control value calculation means.

Here, the flow of vehicle height adjustment in this example is as follows:
This will be explained with reference to FIGS. 8 and 9. FIG. 8 is a timing chart for explaining the operation, and FIG. 9 is a diagram schematically showing changes in vehicle height when the load on the left rear of the vehicle increases. The broken line shows the vehicle height state before adjustment, and the dashed line shows the vehicle height state after adjustment.
In Fig. 8, each vehicle height Ha to Hd in the initial state is
Since the load on the left rear part of the vehicle body is large, Hd<
The relationship is Hc<Hb<Ha. Now Hd and Hc are OK
Assume that it is outside the zone ΔH ₁ . In this case, the vehicle height is fluctuating and requires vehicle height adjustment.
Actual vehicle height adjustment is not started unless this state continues for a predetermined period of time _TD . this is,
This is because it is preferable in terms of control feeling not to adjust the vehicle height in response to temporary or instantaneous changes in vehicle height. OK even after time T _D has passed.
If it is out of zone ΔH ₁ , control starts. First, among all the vehicle height values, select the one that is farthest from the target vehicle height position m (Hd), and select this value.
Set the capture zone by adding _ΔH2 to Hd. Then, the vehicle height within the acquisition zone is determined as the control target. At the start of control, only Hd is in the capture zone, so only the vehicle height adjustment for this Hd is performed. The vehicle height unit operation for performing vehicle height adjustment is indicated by a black circle (●) in the diagram. As Hd gradually increases after several control cycles, the other values Ha to Hc also slightly increase. The other Ha to Hc do not have vehicle height adjusted, so the amount of change is smaller than Hd, which does have vehicle height adjusted. Therefore, after several control cycles, the difference between Ha~Hd becomes
Any of the other Ha~Hc will enter the capture zone. The newly captured vehicle height value (for example, Hc) is added as a vehicle height adjustment target, and
Turn on the vehicle height unit operation.

In other words, while actively adjusting the vehicle height for vehicle height values that enter the capture zone, only passive vehicle height adjustments are performed for vehicle height values that do not enter the capture zone, and the difference between the two is gradually reduced. When all vehicle height values are finally within the convergence zone, the control is terminated.

In this way, in this embodiment, among the vehicle heights on the front, rear, left, and right sides of the vehicle body, the vehicle height that deviates the most from the target vehicle height position m is actively adjusted, and the vehicle height that deviates the most is determined based on the vehicle height. A zone is set, and for other vehicle height values, the vehicle height is actively adjusted only for vehicle height values that enter the capture zone. Therefore, the acquisition zone gradually changes in the direction of controlling its vehicle height (up or down), and with this change, one or several other vehicle heights are actively It can be added as a high adjustment target. Therefore, the vehicle height adjustment time can be controlled according to the difference of each vehicle height from the reference vehicle height, and as a result, each vehicle height can be smoothly kept within the target convergence zone.

(Effect) According to the present invention, since it is configured as described above,
You can first adjust the vehicle height in areas where the change in vehicle height is the greatest, and then adjust the vehicle height in other areas.
It is possible to smoothly correct the inclination of the vehicle front, rear, left and right without causing the vehicle to shake unintentionally.

[Brief explanation of the drawing]

FIG. 1 is a conceptual configuration diagram of the present invention, FIGS. 2 to 8 are diagrams showing an embodiment of a vehicle height adjustment device according to the present invention, FIG. 2 is an overall configuration diagram thereof, and FIG. Fig. 4 is a flowchart showing the main routine of vehicle height adjustment, Fig. 5 is a flowchart showing the subroutine of step _P3 of the main routine, and Fig. 6 is a flowchart showing the subroutine of step _P4 of the main routine.
7 is a flow diagram showing the subroutine of step _P5 of the main routine, FIG. 8 is a timing chart to explain its operation, and FIG. 9 is a diagram to explain its operation. It is a schematic diagram showing a high state. 11...Vehicle body, 20,21,22,23...Vehicle height sensor, 46...Vehicle height operation means, A, B, C, D...Vehicle height measurement point, HA, Hb, Hc, Hd...Vehicle height, Sa, Sb ，
Sc, Sd...Vehicle height value signal, ΔH ₁ ...Vehicle height adjustment unnecessary zone (dead zone), m...Target vehicle height position (reference vehicle height), ΔHe...Control end zone (convergence zone),
ΔH ₂ ...Operation permission zone (capture zone).

Claims (1)

[Scope of Claims] 1 a) A plurality of vehicle height detection means provided on the front, rear, left, and right sides of the vehicle body to independently detect vehicle height values for each of the front, rear, left, and right sides, and b) a reference vehicle height for setting a reference vehicle height value of the vehicle body. c) a convergence zone setting means for setting a convergence zone of a predetermined width with respect to the reference vehicle height value, and d) dead zone setting means for setting a dead zone zone wider than the width of the convergence zone with respect to the reference vehicle height value. and e) determination means for determining a vehicle height fluctuation state that requires vehicle height adjustment when even one of the vehicle height values detected by the plurality of vehicle height detection means exceeds the dead zone; and f) vehicle height fluctuation. g) selection means for comparing all the vehicle height values detected by the plurality of vehicle height detection means with a reference vehicle height value and selecting the vehicle height value having the largest deviation from the reference vehicle height value when the vehicle is in the state; capture zone setting means for setting a capture zone of a predetermined width that includes the vehicle height value selected in; h) comparing each vehicle height value detected by the plurality of vehicle height detection means with the capture zone; i) a control input determining means for determining a vehicle height value included in the control input as a control input; i) a vehicle height control value for directing the vehicle height value determined by the control input determining means into a convergence zone set by the convergence zone setting means; j) a plurality of vehicle height operating means provided on the front, rear, left and right sides of the vehicle body for individually operating the vehicle height of the object to be controlled according to the calculation results of the control value computing means; A vehicle height adjustment device featuring: