JPH0332912A - Car height controller of vehicle - Google Patents

Abstract

PURPOSE:To control the height of a vehicle at will and just enough by making a car body vertically move independently from each pair of front and rear wheels on the right and left sides and also prohibiting feedback control when the weighted mean value of the height of the vehicle deviates from the objective height. CONSTITUTION:A plurality of devices B for vertically moving a car body in relation to each pair of front and rear wheels A1 and A2 on the right and left sides and a plurality of means C for detecting the height of the car body in relation to each of the devices B are provided respectively. With weighing of the value resulted from the last detection of the height of the car body by each means C made be larger than that of this time, weighted mean is operated by a means D. The objective height of the car body is set by means E. In addition, in order to keep the actual height of the car body at objective value when weighted mean value deviates from the objective value by specified quantity, feedback control against each vertically moving device B is done by a means F based on the detected value of car height. On the other hand, the feedback control mentioned above is prohibited by a means G until weighted mean value reaches the specified value of the objective car height.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a vehicle height control device that variably controls the vehicle height of a vehicle.

<Prior Art> Conventional examples of vehicle height control devices include the following. In other words, the vehicle height is controlled by moving the vehicle body up and down relative to the running wheels using a hydraulic system, so that it swings in the longitudinal direction of the vehicle, and the system maintains the vehicle body in a horizontal state or feeds it to a low vehicle height during high-speed driving. I am using forward control.

<Problems to be Solved by the Invention> However, in such conventional vehicle height control devices, the vehicle height is controlled by vertically moving the vehicle body so as to rock in the longitudinal direction of the vehicle. When driving or stopping with the sides of the vehicle raised,
There is a problem in that the vehicle cannot be controlled to be in a horizontal state.

In addition, a vehicle height sensor is provided to detect the height of the vehicle body relative to the running wheels, and the detected value of the vehicle height sensor is
5ec) and sampled multiple times (for example, 4ec).
In order to prevent noise, the average value of the sampled values is used as the actual detected vehicle height, and the vehicle height is controlled by feedforward control so that the vehicle body reaches the target vehicle height based on the detected vehicle height. There is something. However, since the vehicle body is constantly moving up and down while the vehicle is running, the output of the vehicle height sensor also oscillates as shown in FIG. 6, so that the average value also oscillates. Therefore, for example, if vehicle height control is performed using feedback control to maintain the vehicle height at a fixed position, feedback control will be performed frequently in response to the vibration of the average value, and this will cause the vehicle body to frequently move up and down. There is a problem with this.

In order to solve this problem, the output of the vehicle height sensor or the average value may be weighted averaged by increasing the weighting of the previous data, and feedback control may be performed based on this weighted average value and the target vehicle height. Conceivable. However, as shown in Figure 6, the weighted average value has a slow response to changes in the actual vehicle height, so when the target vehicle height is changed, the actual vehicle height changes as shown in Figure 6. However, since the vehicle height continues to be raised until the weighted average value reaches the target vehicle height, there is a problem that excessive feedback control is performed and the vehicle body moves up and down significantly.

The present invention was made in view of the above circumstances, and an object of the present invention is to provide a vehicle height control device that can move one side of a vehicle up and down relative to the other side, and can optimally control the vehicle height. do.

Means for Solving the Problems> Therefore, as shown in FIG.
A plurality of vertical movement devices B are provided at at least two positions in the vehicle width direction at the rear and move the vehicle body up and down with respect to the front and rear running wheels A, , A, respectively, and each vertical movement device B corresponds to the vicinity thereof. A vehicle height detection means C is provided to detect the height of the vehicle body, and the vehicle height detected by these vehicle height detection means C or data corresponding thereto is calculated from the previous detection value or the weighting of the data. a weighted average value calculating means for calculating a weighted average value larger than the value of the target vehicle height, a target vehicle height setting means E for setting a target vehicle height, and a target vehicle height setting means E for setting a target vehicle height; feedback control means F that starts feedback control when the target vehicle height deviates from the target vehicle height by a predetermined amount and feedback-controls the vertical motion device based on the detected vehicle height or data; Feedback control prohibition means G for prohibiting the operation of the feedback control means F until the weighted average value reaches the predetermined target vehicle height or for a time corresponding thereto when the vehicle height is switched to high. I made it.

<Function> Then, each vertical movement device is independently drive-controlled based on the detection signal of each vehicle height detection means to tilt the vehicle forward and backward as well as to the side. When the vehicle height or the weighted average value of data corresponding thereto deviates from the target vehicle height by a predetermined amount, feedback control is performed to suppress vertical movement of the vehicle body due to feedback control. Furthermore, when the target vehicle height is switched, feedback control is prohibited until the weighted average value reaches the target vehicle height or for a corresponding period of time to suppress excessive feedback control and suppress vertical movement of the vehicle body. did.

<Example> An example of the present invention will be described below based on FIGS. 2 to 5.

In FIG. 2, the piston rod 2A of the extraction cylinder 2 is attached to the axle housing near each running wheel l of the vehicle so as to be able to swing freely, and the main body of the hydraulic cylinder 2 is attached to the vehicle body (not shown). There is. The main body of the hydraulic cylinder 2 is formed with a hydraulic chamber 2C and a gas chamber 2D filled with an inert gas or the like for a damper, the bottoms of which are formed by a diaphragm 2B. An oil supply passage 3 and an oil discharge passage 4 are connected to the hydraulic chamber 2C. The oil supply passage 3
An upward movement solenoid valve 5 is interposed in the oil discharge passage 4, and a downward movement solenoid valve 6 is interposed in the oil discharge passage 4. Here, the hydraulic cylinder 2, the upward movement electromagnetic valve 5, and the downward movement electromagnetic valve 6 constitute a vertical movement device.

Further, the vehicle body is provided with a potentiometer-type vehicle height sensor 7 as a vehicle height detection means, and a swing lever 7A of the vehicle height sensor 7 is provided.
is attached to a member of one example of a running wheel so as to be able to swing freely. In each vehicle height sensor, a swing lever swings in accordance with the vertical movement of the vehicle body, and outputs a signal corresponding to the position of the vehicle body to a control device 8 comprising a microcomputer or the like.

Oil is supplied to the oil supply passage 3 from a high pressure tank 9,
Pressurized oil is supplied to the high pressure tank 9 by a hydraulic pump IO. The oil discharged from the oil discharge passage 4 is introduced into a reserve tank 11, and is supplied from the reserve tank 11 to the hydraulic pump 10.

The control device 8 receives a target vehicle height signal from a manual potentiometer (not shown) that continuously indicates the height of the vehicle body for each running wheel 1. The control device 8 independently drives the upward movement solenoid valve 5 and the downward movement solenoid valve 6 for each running wheel 1 based on the detection signal of the vehicle height sensor so that the vehicle height is as instructed by the indicator. It is meant to be controlled.

Here, the control device 8 constitutes a weighted average value calculation means, a feedback control means, and a feedback control prohibition means.

Next, the operation will be explained according to the flowchart shown in FIG.

This routine is executed every 10m5ec.

In Sl, the detection signals of each vehicle height sensor 7 are read.

In S2, 30m5ec before, 20s+sec before and 10s
The vehicle heights read sec ago and this time are averaged for each vehicle height sensor to calculate 1/4 moving average vehicle height H+ (hereinafter referred to as moving average vehicle height H). This moving average vehicle height Hl
is determined in order to prevent the influence of noise even if noise enters the signal from the vehicle height sensor 7.

In S3, the moving average vehicle height Hl calculated this time and the moving average vehicle height Hlo calculated in the previous routine are weighted averaged using the following formula to calculate a reference vehicle height H14 as a weighted average value.

H=*a = (63Ht. 10H,)/64S4,
Set the current target vehicle height Hsat.

This target vehicle height Hsat is set by a signal from the indicator. Further, the target vehicle height H□ is set by a signal from the indicator. In addition, the target vehicle height H5
tit may be set based on the detection signal of the vehicle speed sensor so that the vehicle height becomes lower as the vehicle speed increases.

In S5, it is determined whether or not the vehicle height is currently being controlled by changing the target vehicle height Hsat, and if YES, the process advances to S6 and No.
When , proceed to Sll.

At Sl, the maximum value (peak fluctuation value) HIF and minimum value (bottom fluctuation value) H4 of the moving average vehicle height Hl are detected. Here, since the vehicle body vibrates up and down while the vehicle is running, the moving average vehicle height H8 also fluctuates in substantially the same way as the output change of the vehicle height sensor 7.

In S7, the detected maximum value HIF and minimum value H4 are averaged, and the peak average vehicle height HIA□(=(HIP+H+
m) / 2).

In S8, it is determined whether the calculated peak average vehicle height H+Ava has reached the target vehicle height Hsat. If YES, the process proceeds to S9; if NO, the process proceeds to 310.

In S9, the vehicle height control is ended by closing the upward movement solenoid valve 5 and the downward movement solenoid valve 6.

In S10, the vehicle height control is continued. In Sll, it is determined whether the target vehicle height Hsat has been changed, and YE
If S, the process proceeds to 512; if NO, the process proceeds to S13.

In S12, the vehicle height control is started by feedforward control.

In step 313, it is determined whether the vehicle height is being controlled by feedback control. If YES, the process proceeds to S17; if NO, the process proceeds to S14.

In step 314, it is determined whether a predetermined time has elapsed since the end of the vehicle height control by the feedforward control, and YES is determined.
If so, the process advances to S15, and if NO, the routine is ended. The predetermined time is set to the time required for the reference vehicle height H□ to approximately reach the target vehicle height Hsat, as shown in FIG. During this time, the control amount is maintained at the control amount at the end of the vehicle height control by feedforward control, and the vehicle height is controlled by feedforward control.

In S15, the reference vehicle height Hstd is the target vehicle height Hl. .

It is determined whether or not it has deviated from a predetermined amount (dead zone).If YES, the process advances to S16, and if NO, the routine is ended.

In S16, vehicle height control is started using feedback control. Vehicle height control using this feedback control is performed simultaneously for all running wheels l.

In S17, similarly to S6, the maximum value HlP and minimum value HIM of the moving average vehicle height H+ are detected.

31B, similarly to S7, the detected maximum value HIF and minimum value H4 are averaged to obtain the peak average vehicle height 1 (tAv
Calculate t.

In 319, it is determined whether the calculated peak average vehicle height H1avt has reached the target vehicle height Hsat. If YES, the process proceeds to 320, and if No, the process proceeds to S21.

At 320, vehicle height control using feedback control is ended.

At 321, vehicle height control using feedback control is continued.

In this way, when the target vehicle height H1 is switched as shown in FIG. 5, vehicle height control is started by feedforward control. And the peak average vehicle height Lav
The vehicle height is controlled by feedforward control until a reaches the target vehicle height Hsat. Furthermore, as shown in FIG. 5, during a predetermined period of time until the reference vehicle height H□4 becomes the target vehicle height H3°, feedback control is prohibited and the control at the end of the feedforward control is performed. 11 and performs vehicle height control by feedforward control. As a result, the reference vehicle height H□ becomes the target vehicle height Ho due to the response delay.

However, the actual vehicle height (peak average vehicle height) approaches the target vehicle height with good responsiveness as shown in Figure 5, so even if vehicle height control is performed using feedback control, excessive vehicle height control may occur. It is possible to prevent this from occurring and suppress the vertical movement of the vehicle body.

Furthermore, when maintaining the vehicle height at the target vehicle height Hset, the reference vehicle height Hsta is changed to the target vehicle height HsaL as shown in FIG.
When the vehicle height deviates from a predetermined amount (dead zone), feedback control is started, and vehicle height control is performed by feedback control based on the peak average vehicle height HIAv and the target vehicle height HsaL. In this way, the standard vehicle height Hst+
1 deviates from the target vehicle height Hsat by a predetermined amount, feedback control is performed, so the frequency of feedback control is significantly reduced, and the frequency of vertical movement of the vehicle body due to feedback control can be significantly reduced.

In addition, since the vehicle body is moved up and down independently for each running wheel, when the vehicle is stopped on a slope with one side elevated, the driver can give commands to control the vehicle body to a horizontal state. The controller outputs a target vehicle height signal to the control device 8 so that, for example, the vehicle height on the negative side is lowered. As a result, the control device 8 outputs an on signal to the lowering solenoid valves 6 at the front and rear sides of the vehicle height to open the valves, and lowers one side of the vehicle together with the hydraulic cylinder 2 body. The vehicle body is controlled to be horizontal.

Note that the vehicle heights detected by the vehicle height sensor 7 may be weighted averaged.

<Effects of the Invention> As explained above, the present invention allows the front and rear running wheels to move up and down independently using a plurality of vertical movement devices, so that the vehicle can be moved even on slopes, etc. The vehicle body can be held in a horizontal state by moving one side up or down. In addition, feedback control is started when the vehicle height detected by the vehicle height detection means or the weighted average value of the data corresponding thereto deviates from the target vehicle height by a predetermined amount, so the frequency of feedback control is significantly reduced. Therefore, the frequency of vertical movement of the vehicle body due to this feedback control can be significantly reduced. Furthermore, when the target vehicle height is changed, feedback control is now prohibited until the weighted average value reaches the target vehicle height or for a corresponding period of time, which prevents excessive feedback control. vertical movement can be suppressed.

[Brief explanation of drawings]

Fig. 1 is a claim correspondence diagram of the present invention, Fig. 2 is a configuration diagram showing an embodiment of the present invention, Fig. 3 is a flowchart of the same as above,
4 and 5 are diagrams for explaining the same effect as above, and FIG. 6 is a diagram for explaining the conventional drawbacks. 1... Running wheel 2... Hydraulic cylinder 5...
Upward movement solenoid valve 6...Downward movement solenoid valve 7...Vehicle height sensor 8...Control device

Claims (1)

[Claims] A plurality of vertical movement devices provided in at least two positions in the vehicle width direction at the front and rear of the vehicle to move the vehicle body up and down relative to the front and rear running wheels, and each vertical movement device provided correspondingly in the vicinity of each vertical movement device. vehicle height detection means for detecting the height of the vehicle body, and the vehicle height detected by these vehicle height detection means or data corresponding thereto, with the previous detection value or data weighted higher than the current one. Weighted average value calculation means for weighted averaging; target vehicle height setting means for setting a target vehicle height;
When the actual vehicle height is to be maintained at the target vehicle height and the weighted average value of the target deviates from the target vehicle height by a predetermined amount, feedback control is started to control the vertical movement device to the detected vehicle height or the target vehicle height. feedback control means for performing feedback control based on data; and when the target vehicle height is switched to a predetermined target vehicle height, for a period of time until the weighted average value reaches the predetermined target vehicle height or a time corresponding thereto; A vehicle height control device for a vehicle, comprising: feedback control prohibition means for prohibiting operation of the feedback control means.