JPH0331010A - Device for controlling height of vehicle - Google Patents

Abstract

PURPOSE:To control height of a vehicle always optimally and stably by moving a body of the vehicle and independently with respect to each of front and rear running wheels by means of plural vertical driving devices, and by compensating a controlled variable or the like through moving the body of the vehicle forcedly to a required position. CONSTITUTION:A body of a vehicle is moved vertically with respect to each of right and left pairs of front and rear running wheels A1 and A2 by using plural vertical driving devices B. The height of the vehicle body moved vertically is sensed by means of plural vehicle height sensing means C. At the same time, according to these sensed signals, the respective vertical driving devices B are driven and controlled by means of a drive control means D. On the other hand, when a learning condition is satisfied, the respective vertical driving devices B are driven forcedly by means of a forced driving means E so as to move the body of the vehicle up to a required position. Then, the sensed valued values of the respective vehicle height sensing means C at the above- mentioned required position are read by using plural reading means F. Next, the height of the vehicle or the drive controlled variable is compensated by means of a compensating means G on the basis of the respective read values.

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 order to solve this problem, it is conceivable to move the vehicle up and down independently at four positions at the front and rear of the vehicle, but in this case it is necessary to provide vehicle height sensors at the four positions. However, each vehicle height sensor has detection variations due to manufacturing, deterioration, etc., and installation variations of each vehicle height sensor, so the vehicle height at the four positions is different and the vehicle body is optimally controlled in a horizontal state. There is a problem that it cannot be done.

The present invention has been made in view of the above-mentioned circumstances, and even if installation variations or deterioration occur in the vehicle height sensor, the vehicle body can be moved up and down optimally, and one side of the vehicle can be moved up and down relative to the other side. The purpose of the present invention is to provide a vehicle height control device that can control the vehicle height.

<Means for Solving the Problems> For this reason, the present invention, as shown in FIG. A plurality of vertical movement devices B that move the vehicle body up and down with respect to A2, and vehicle height detection means C that is provided correspondingly near each vertical movement device B and detects the height of the vehicle body,
a drive control means for driving and controlling a vertical movement device B corresponding to each vehicle height detection means C based on the vehicle height detected by each vehicle height detection means C; a forced driving means E for driving each of the vertical movement devices B to move the vertical movement device B; a reading means F for reading the detected values of the respective vehicle speed detecting means C at the predetermined positions; A correction means G is provided for correcting the vehicle height detected by the vehicle speed detection means C or the control amount of the drive control means when the drive control means is in operation.

<Function> Each vertical movement device is independently driven and controlled based on the detection signal of each vehicle speed detection means to tilt the vehicle body forward and backward as well as to the side, and the vehicle speed detection means at a predetermined position By making corrections based on the detected values, it is possible to perform optimal vehicle height control even if mounting variations or deterioration occur in the vehicle speed detection means.

<Example> An example of the present invention will be described below based on FIGS. 2 to 4.

In FIG. 2, a piston rod 2A of a hydraulic cylinder 2 is swingably attached to an axle housing near each traveling axis l of the vehicle, and a main body of the hydraulic cylinder 2 is attached to a vehicle body (not shown).

The main body of the hydraulic cylinder 2 is defined by a diaphragm 2B, and has a hydraulic chamber 2C and a gas chamber 2D filled with an inert gas for a damper. Said hydraulic chamber 2
An oil supply passage 3 and an oil discharge passage 4 are connected to C. The oil supply passage 3 is provided with an upward movement solenoid valve 5, and the oil discharge passage 4 is provided with a downward movement solenoid valve 6.

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 as a vehicle speed detection means, and a swing lever 7A of the vehicle height sensor 7 is provided.
is attached to a member on the running wheel 1 side so as to be able to swing freely. In each vehicle height sensor, a swing lever swings as the vehicle body moves up and down, 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 10. 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's meant to be controlled.

Here, the control device 8 constitutes a drive control means, a forced drive means, a reading means, and a correction means.

Next, the operation will be explained according to the flowchart shown in FIG. This routine is executed every 10m5ec.

First, to explain normal vehicle height control, when the vehicle is stopped on a slope with one side raised high, the driver uses an indicator to control the control device 8, for example, in order to control the vehicle to a horizontal state. A target vehicle height signal is output so that the vehicle height of the above-mentioned example 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 to open the valves and drain the oil from the hydraulic chamber 2C of the hydraulic cylinder 2 through the oil discharge passage 6. It is discharged into the reserve tank 11. Therefore, one side of the vehicle is moved down together with the main body of the hydraulic cylinder 2, and the vehicle body is controlled to become horizontal.

At this time, the control device 8 performs feedforward control based on the detection signal from the vehicle height sensor 7 so that the actual vehicle height becomes the target vehicle height. Also, while the vehicle is running, feedforward control is performed to increase the vehicle speed.

Note that the other side of the vehicle body may be moved upward to control the vehicle body to become horizontal.

Next, a learning routine for the vehicle height sensor will be explained.

In Sl, it is determined whether the learning condition is satisfied or not, and YES is determined.
If so, the process advances to S2, and if No, the process advances to S9. Learning conditions include special conditions such as turning off the engine key when the vehicle is stopped.

In S2, all lifting electromagnetic valves 5 are opened to supply oil to the hydraulic chambers 2C of all hydraulic cylinders 2 in order to move the vehicle body upward to the uppermost position. As a result, the vehicle body moves upward and is brought to the uppermost position. At this time, all the lowering electromagnetic valves 6 may be opened in order to lower the vehicle body to the lowest position.

In S3, it is determined whether the opening time of the upward movement electromagnetic valve 5 has exceeded a predetermined time. If YES, the process advances to S4, and if NO, the process returns to S3 again.

The predetermined time is set to a value sufficient for the vehicle height to rise to the highest position (lowest position).

In S4, the voltage signals of each vehicle height sensor 7 when the vehicle body is at the highest position (lowest position) are read.

In S5, it is determined whether the voltage signal of each vehicle height sensor 7 has been sampled a predetermined number of times. If YES, the process advances to S6, and if NO, the process returns to S4.

In S6, the sampled voltage signals are averaged for each vehicle height sensor 8.

In S7, the averaged voltage ■ and the actual highest vehicle height H, A
X is substituted into the following equation to calculate the b value for each vehicle height sensor 7, and the data in the RAM is updated to the calculated value.

H=(V-b)/a H: Vehicle height a: Constant (slope) Here, as shown in FIG. The line changes from indicated to broken line. Therefore, if the b value is converted to the b'' value in response to the change, even if the output voltage of the vehicle height sensor 7 changes, the actual vehicle height can be accurately detected by the output voltage from the vehicle height sensor 7. It can be done.

In S8, the upward movement solenoid valve 5 is closed and the downward movement solenoid valve 6 is opened to move the vehicle body downward, and the learning of each vehicle height sensor 8 is completed.

In S9, voltage signals from each vehicle height sensor 7 are read.

In SIO, the current vehicle height is calculated for each running wheel 1 from the above equation based on the voltage signal and the learned b value.

In Sll, based on the calculated vehicle height, as mentioned above,
Normal control is performed by moving the vehicle body up and down for each running wheel.

Note that a horizontal sensor may be provided on the vehicle body, and the vehicle height may be controlled to move the vehicle body up and down for each running wheel based on the detection signal of each vehicle height sensor so that the vehicle body is always maintained horizontally. Further, the control amount in the control device may be corrected in response to the change in the value described above.

<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. At this time, the vehicle body is forcibly moved to a predetermined position, and the detected vehicle height or control amount of the vehicle height detecting means is corrected based on the detected value of the vehicle height detecting means at this time. Even if installation variations or deterioration occur, vehicle height control can be performed optimally.

[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,
FIG. 4 is a diagram for explaining the same effect as above. 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 with respect to the front and rear running wheels, and a plurality of vertical movement devices respectively corresponding to the vicinity of each vertical movement device. a vehicle height detection means for detecting the height of the vehicle body; a drive control means for driving and controlling a vertical movement device corresponding to each vehicle height detection means based on the vehicle height detected by each vehicle height detection means; a forced driving means for driving each of the vertical movement devices to forcibly move the vehicle body to a predetermined position when a condition is satisfied; a reading means for reading a detected value of each of the vehicle speed detecting means at the predetermined position; A vehicle height control device for a vehicle, comprising: correction means for correcting the vehicle height detected by the vehicle speed detection means or the control amount of the drive control means when the drive control means is activated based on each detected value. .