JPS6181808A - Vehicle height control method - Google Patents

Abstract

PURPOSE:To improve vehicle height control speed and accuracy in a vehicle height control method of a pneumatic control type, by detecting a difference between a time average vehicle height and a target vehicle height, and shortening a control time according to whether the difference is positive or negative. CONSTITUTION:When a vehicle height is detected by a sensor 1 and applied to a controller 2A, an operating unit 11 computes a time average vehicle height Ha every vehicle height operating time, and calculates a difference DELTAs between the time average vehicle height Ha and a target vehicle height St. Then, the operating unit 11 determines a control time DELTAt corresponding to the difference DELTAs in a control map, and detects whether the difference DELTAs is positive or negative. If DELTAs is positive, a suction valve 3 and an exhaust valve 4 are opened to reduce an air pressure in a suspension to thereby lower the vehicle height. If DELTAs is negative, the suction valve 3 and a compressor 7 are operated to increase the vehicle height. At this time, the control map is divided into a lowering and a lifting control map, and a lifting control time is increased. Thus, vehicle height control accuracy and speed may be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for adjusting vehicle height A to a target vehicle height by supplying and discharging air pressure to and from a suspension.

[Prior art]

As a vehicle height adjustment device using conventional suspension, the 9th
There are things shown in the figure. This means that the processor compares and calculates the current vehicle height detected by the vehicle height sensor 1 and the next target vehicle height stored in advance in the memory of the controller 2, and based on the result of this calculation, if the current vehicle height is higher than the target vehicle height. To do this, both the intake valve 3 and the exhaust pulp 4 are opened to remove the air inside the suspension 5 and lower the vehicle height. Conversely, if the current vehicle height is lower than the target vehicle height, the exhaust pulp 4 and open the air supply valve 3. At the same time, the motor 6Vc drives the compressor 7 to supply air to the suspension 5 and raise the vehicle height. When the target vehicle height is reached,
The controller stops the operation of the compressor 7 and valves 3 and 4 to maintain the target vehicle height.

In addition, when adjusting the vehicle height while the vehicle is running, it is necessary to set a certain time t (vehicle height calculation time λ) in which the vehicle height always changes,
During this time, the vehicle height fluctuation signal shown in FIG. 10 is integrated, and the above-mentioned vehicle height adjustment is performed based on the integrated output.

[Problem that the invention seeks to solve]

However, if the vehicle height fluctuation signal is not a simple vertical vibration shown in FIG. 10, but a vehicle height fluctuation signal accompanied by undulating vertical vibration as shown in FIG. changes significantly, and cannot be used as a substantial vehicle height signal, and the vehicle height cannot be determined based on this. In order to prevent this, a more sufficient time, for example 2t, is required as the determination time. However, if this time t is extended, the stopping operations of the compressor 7 and the air intake valve 3 as well as the stopping operations of the air intake valve 3 and the exhaust pulp 4 will inevitably be delayed, even though the vehicle height has reached near the target value. Despite this, the vehicle height adjustment continues and ends up exceeding the target value (overshoot). By the way, if a certain number of insensitive areas are provided above and below the target vehicle height, the pinching operation will be repeated. Furthermore, in such a vehicle height adjustment system, the vehicle height is affected by the weight and force of the vehicle, so although the vehicle height can be lowered quickly, it takes time to raise the vehicle height.

In other words, the vehicle height adjustment speed becomes unbalanced and the accuracy of adjustment decreases. .

Unexploded E! It was done by focusing on the problems of conventional methods that make A stupid fc
Because of the stuttering, adjust the compressor, air intake valve, or exhaust pulp control time 'f, 1I71 according to the difference between the current hourly average vehicle height and the target vehicle height, thereby adjusting the vehicle height. The purpose is to perform this with high precision and speed.

[Means for solving problems]

The present invention includes a first step of determining the current time average vehicle height based on the vehicle height sensor output, a second step of determining the difference Δs between the time average vehicle height and a preset target vehicle height, and an electronic controller. a third step of determining the control time Δt corresponding to the difference Δs using a control map stored in the memory of the controller; and a fourth step of determining whether the difference Δs is positive or negative.
step, and the control time Δt based on this determination result.
and a fifth step of selectively operating the compressor, the air supply valve, and the exhaust pulp.

[Effect]

According to the present invention, the current vehicle height data input from the vehicle height sensor is stored in the memory in the -H controller, and the vehicle height data is time-averaged within a certain period of time to obtain an average vehicle height value. The difference Δst between the vehicle height and the target vehicle height is calculated by the processor, and the control time Δt proportional to this difference Δ3 is determined from the control map. On the other hand, the above difference d
Determine whether the S force is higher or lower than the S target level, and use the above '! During the BU clause time Δt, the compressor, air supply valve, and exhaust pulp are operated to adjust the vehicle height in a direction that constantly reduces the N control time Δt, thereby speeding up the vehicle height adjustment. .

〔Example〕

FIG. 1 specifically shows the contents of two electronic controllers implementing the vehicle height adjustment method of the present invention, and the same components as those shown in FIG. 9 are given the same reference numerals. In the figure, 11 is a processor as a processing calculation unit, and 12 is a computer memory (12) for storing control programs for controlling the intake valve 3, exhaust pulp 4, and compressor 7.
RO, M l, 13 is an input processing section, 14 is an output processing section,
A random access memory (RA tVf) that stores 16-point operation results, etc., and stores addresses, data, etc.
They are connected through paths. It is a 16-port power supply section.

However, in addition to the control program, the ROM stores a control map as shown in FIG. 2, which was obtained through actual vehicle tests. This map is a proportional characteristic of the difference Δs between the current time average vehicle height and the target vehicle height versus the control time Δt, and the difference Δ
The characteristic is set such that the control time Δt is shortened each time s is shortened.

Next, a vehicle height adjustment method using the electronic controller 2AVc will be explained with reference to the flowchart of FIG. 3 while referring to the explanatory diagram of FIG. 4.

First, ■ set the target value St of the vehicle height to be adjusted, and then ■
All judgments are made as to whether the vehicle is running or not. If it is determined that the vehicle is running, (1) the vehicle height is detected by the vehicle height sensor 1; Next, the vehicle height calculation time TK as shown in FIG.
Determine the current hourly average vehicle height Haf from the vehicle height fluctuation in 2,
(2) Calculate and calculate the difference Δε between this time-average vehicle height Hα and the target vehicle height St. Next, ■ From the control map, the difference Δs
Determine the control time Δt corresponding to t/c, and further determine the difference Δ
It is determined whether s is positive or negative, and if it is positive, it is determined that the vehicle height is higher than the target value, and the air intake valve 3 in FIG.
Open both exhaust pulps 4 and check the air pressure of suspension 5? Lower the vehicle height? ■ Conversely, if the value is negative, it is determined that the vehicle height is lower than the target value, and air intake valve 3 and compressor 7 are
operate together to supply air to the suspension system 5,
Raise the vehicle height. (2) In this way, when the difference Δs becomes zero, (2) all of the above-mentioned pulps 3.4 and the compressor are stopped, the vehicle height is maintained, and the vehicle height adjustment is completed.

If the difference is not zero, repeat the steps from step ■ onwards.

The intake valve 3, the exhaust pulp 4, and the motor 6 for the exhaust valve 7 are controlled with high accuracy and speed by any opening degree or rotation amount by the duty pulse output by the controller.

Further, as described above, the time-average vehicle height after the vehicle height adjustment is completed is calculated, and if the calculated specific time-average vehicle height is within the set dead range of the target vehicle height, the adjustment is finally completed. If it is not in the dead area, the adjustment operation will be performed again for the time Δt relative to Δs.

In this way, the control time Δt can be reduced by the amount by which the difference Δs with respect to the target value is reduced by the vehicle height adjustment, and by controlling so that both Δs and Δt converge to zero, The vehicle height can be adjusted with good responsiveness without prolonging the vehicle height calculation time t.

By the way, regarding the supply and exhaust for the suspension/yellow 15, if the control time is constant for both supply and exhaust, the vehicle height can be lowered quickly due to the weight of the vehicle, but it takes time to raise the vehicle height, and the vehicle height adjustment speed becomes unbalanced. Become.

Therefore, in consideration of the influence of the vehicle weight when raising and lowering the vehicle height, a grinding map as shown in FIG. 5 is used. That is, when raising the vehicle height, the characteristic line Kl is used to increase the control time Δt for the difference Δs to control the vehicle height increase. When the vehicle height is lowered, the characteristic line is used to quickly lower the vehicle height using the full weight of the vehicle, and the vehicle height can be adjusted to be just the right amount for both raising and lowering.

Furthermore, as described above, the responsiveness of the vehicle height adjustment operation based on the control time determined by the current time-average vehicle height and the target vehicle height varies greatly depending on the internal pressure of the pneumatic system. In other words, even if the control time is constant, the controlled amount varies depending on the internal pressure.

Therefore, as shown in FIG. 6, an internal pressure sensor 8 is provided in the vehicle height adjustment device, and a fluctuating internal pressure signal is input to the controller 2 to determine the current time average internal pressure 6XW. Then, the vehicle height is adjusted using the control map shown in FIG. 7, in which the immediate control time Δt for the difference Δs determined as described above is determined for each magnitude of the time-average internal pressure. In addition, in Fig. 7, p
,,p2...Pn are different time average internal pressures, P,<Pi
<...Pn.

In addition, since the responsiveness of raising and lowering the vehicle height differs depending on the vehicle weight, in order to adjust the vehicle height to the desired height, the control time is divided into raising and lowering the vehicle height. Each internal pressure pL, + '2 (L +...Pnα and P, b, P
, b . . . can be determined for each Pnb. In this case, the control map shown in FIG. 8 will be used. In addition, in the control maps shown in FIGS. 5 and 7, is the suspension 5 of a type in which air pressure is injected to lower the vehicle height against a spring? When used, Kj and P, a, P, eL...p
It becomes a lower operating characteristic line, K, and Plb.

P, b...Pnb becomes the upward operating characteristic line.

In the embodiment shown in Fig. 6, after adjusting the vehicle height, the time-average vehicle height and average pressure are calculated again, and if they are within the dead range, the adjustment work is finally completed, and if they are not within the dead range, the time-average height and pressure are calculated again. The difference Δs from the vehicle height is determined, the adjustment is performed for a time corresponding to ds and P, and this operation is repeated until the average vehicle height falls within the insensitive region.

〔Effect of the invention〕

According to the present invention, the current hourly average vehicle height is determined, and the compressor and air supply/exhaust pulp control time f! : By adjusting the vehicle height, the vehicle height adjustment work can be performed with high responsiveness and high precision, and the vehicle height being adjusted can be controlled to open neatly to the target vehicle height, and to control hunting inside and outside the dead zone of the vehicle height sensor. It can be prevented.

Further, by selecting the control time for raising and lowering the vehicle height separately in consideration of the vehicle weight, the raising and lowering can be controlled as necessary and sufficiently. In addition, the accuracy of vehicle height adjustment is further improved by changing the control time of the supply and discharge pulp, etc. according to the magnitude of the difference Δs between the current time-averaged vehicle height and the target vehicle height and the internal pressure conditions of the control fluid (air pressure) system. I will do it.

[Brief explanation of the drawing]

Fig. 1 is a block connection diagram of the electronic controller used to carry out the method of the present invention, Fig. 2 is a control map of the difference between the μ control time and the target vehicle height, and Fig. M3 is a control flowchart of the vehicle height adjustment method. Fig. 4 is an explanatory diagram of the vehicle height adjustment method, Fig. 5 is a control map of another embodiment, Fig. 6 is an explanatory diagram showing another embodiment of the vehicle height adjustment device, and Fig. 7 is an explanatory diagram of this embodiment. Control map, 8th
The figures show still another control map, Fig. 9 is an explanatory diagram of a conventional vehicle height adjustment device, Fig. 10 shows a simple vibration waveform of the vehicle, and Fig. 11 shows a waveform of undulation vibration of the vehicle. 1...Vehicle height sensor, 2,2A...Controller, 3
... Air supply pulp, 4... Exhaust pulp, 6... Suspension 1.6... Motor, 7... Co/breather, 8... Internal pressure sensor, 11... Arithmetic processing unit, 12・
...ROM, 13...RAM0 Patent Issuer Kayaba Kogyo Co., Ltd. Agent
Patent Attorney Izumi Amano Figure 6 Figure 7 Figure 8 Figure 9 Figure 1o Figure 11 Procedural amendment (voluntarily submitted) 1988 Patent Application No. 188712 2. Name of the invention Car High adjustment method 3, relationship with the case of the person making the amendment Patent applicant name 4, agent 5, subject of amendment (1) Drawing (1)!Submit Drawing I prepared in ink.

Claims (4)

[Claims] (1) An electronically controlled vehicle height system that controls the compressor, air intake valve, or exhaust valve to expand and contract the suspension in a direction that corrects the error between the current vehicle height detected by the vehicle height sensor and the preset target vehicle height. In the adjustment device, a first step of determining the current time average vehicle height based on the vehicle height sensor output, a second step of determining the difference Δs between this time average vehicle height and the target vehicle height, and an electronic controller. The above difference Δs is determined by the control map stored in the memory in advance.
a third step of determining the control time Δt corresponding to Δs; a fourth step of determining whether the Δs is positive or negative; and based on the result of this determination, the compressor, intake valve, and exhaust valve are The fifth element is selectively activated.
A vehicle height adjustment method comprising the steps of: (2) A patent claim in which the difference Δs characteristic between the control time Δt and the current time-average vehicle height and the target in a control map stored in advance in the memory of the electronic controller is set according to the difference in the lifting and lowering conditions of the vehicle body. The vehicle height adjustment method described in item 1. (3) Set the control time Δt versus the difference Δs characteristic between the current time average vehicle height and the target vehicle height in the control map previously stored in the memory of the electronic controller, taking into account the magnitude of the control air pressure. A vehicle height adjustment method according to claim 1. (4) The control time Δt versus the difference Δs between the current time average vehicle height and the target vehicle height in the control map stored in advance in the memory of the electronic controller is determined according to the vehicle body elevation conditions and the control air pressure. A vehicle height adjustment method according to claim 1, wherein the vehicle height adjustment method is set as follows.