JPS60131308A - Level-control device for car - Google Patents

Abstract

PURPOSE:To improve a function of stabilization for a traveling attitude of a car body, by detecting a surface gradient through each signal out of a level sensor and a tilt sensor, while controlling each of level-control mechanism so as to cause them to become a stable attitude to a road surface. CONSTITUTION:When car levels 1-4, a sidewise tilt 5, a lengthwise tilt 6, a steering turning angle 7, a car speed 8 and a setting car level 9 are all inputted into a central processing unit 10, this CPU10 processes the steering turning angle 7 in accordance with the prescribed program and judges of whether car tilt control is necessary or not. If judging 'necessary', it determines a level-control value in each of level-control mechanisms 14-17 with these tilt angles 5 and 6, car levels 1-4, the steering turning angle absolute value 7 and the car speed 8 through operation of a surface tilt angle and a ground tilt angle by the prescribed program, thus the CPU10 outputs a regulating signal to each of these level-control mechanisms 14-17. With this constitution, a car body can be kept in its stable attitude even when a road surface is inclined.

Description

[Detailed Description of the Invention] E-Industrial Application Field] The present invention relates to a vehicle height control device, and particularly to a vehicle height control device capable of controlling the inclination of a vehicle body in response to vehicle running conditions and road surface conditions. .

[Prior Art] Conventionally, the height of the vehicle has been adjusted according to changes in the number of passengers and cargo on the vehicle, or the running condition of the vehicle, so that the vehicle body has always been stable. There is a vehicle height 11IJIIl device that controls the vehicle's posture. .

In this type of vehicle height control device, each wheel usually has
It is equipped with a vehicle height sensor and a vehicle height adjustment mechanism, and the vehicle height is adjusted based on signals from each vehicle height sensor and from the front.

The height of the vehicle relative to the road surface can be adjusted to a predetermined value, and the unbalance of the vehicle height for each wheel can be resolved. On the contrary, a problem may arise in that the slope of the vehicle increases. In other words, as mentioned above, conventional vehicle height control devices simply control the vehicle from the road surface, so even if the road surface is tilted, the vehicle body is also controlled to tilt, resulting in vehicle height control This means that the vehicle body may be controlled to lean more than a vehicle without the device.

[Object of the invention]゛.

Therefore, it is an object of the present invention to provide a vehicle height control device that is equipped with an inclination sensor for detecting the inclination of the vehicle body so that the vehicle body always maintains a stable posture even when the road surface is inclined. The purpose is

[Configuration of the Invention] The configuration of the present invention to achieve the above object is as illustrated in FIG. , multiple vehicle height sensors that detect the vehicle height; and a tilt sensor that detects the vehicle's tilt;
The height of each vehicle is adjusted so that the slope of the road surface on which the vehicle is located is detected based on the detection signals from each of the above-mentioned sensors The gist of the present invention is a vehicle height control device characterized by comprising a control circuit (2) which outputs a control signal for each adjustment mechanism 1 and controls the inclination of the vehicle.

[Example] The present invention will be described below by giving an example and referring to the drawings.

FIG. 2 is a block diagram showing the overall configuration of the vehicle IL#A control device of this embodiment. In the figure, 1 to 4 are vehicle height sensors that detect the height of the vehicle, and 5 is the vehicle height sensor that detects the left-right tilt of the vehicle body.
6 is a tilt sensor that detects the tilt of the vehicle body in the front and rear directions, respectively;
7 is a steering angle sensor that detects the rotation angle of the steering wheel, 8 is a vehicle speed sensor that detects the running speed of the vehicle, and 9 is a steering angle sensor that detects the rotation angle of the steering wheel;
is a control switch used to set middle and high.

10 consists of a CPU 11, a ROM 12, a RAM 13, an r10 circuit (not shown), etc., and receives signals from the above-mentioned sensors and control switch 9, and adjusts the vehicle height according to the running condition of the vehicle and the road surface condition according to a predetermined control program. The i control circuit executes control and outputs control signals to the vehicle height adjustment mechanisms 14 to 17 provided at each wheel.

In this embodiment, a hydropneumatic suspension is used as the vehicle height adjustment mechanism.The vehicle height adjustment mechanisms 114R14 to 17 provided on each wheel are each equipped with a hydropneumatic suspension, as shown in FIG. Suspension 21 to 24 and normally closed solenoid valve 25
Consisting of 28 to 28 pieces. Each normally closed solenoid valve 25 or 2
8 is driven by a control signal from the control circuit 10, and communicates the oil supply pipe 29 or oil drain pipe 30 with the vehicle height adjustment cylinder of the hydraulic suspension 21 to 2'4. The vehicle height at each wheel is adjusted by adjusting the oil pressure in the vehicle height adjustment cylinder. A hydraulic pump 33 for pumping up oil stored in a reservoir 32 is connected to the oil supply pipe 29 via a regulating valve 31 that adjusts the oil pressure, and a normally open 1ill valve 34 connects the oil supply pipe 2'9. An accumulator 35 is connected to prevent oil pressure pulsation, and the oil pressure in the oil supply pipe 29 is adjusted to a predetermined pressure. In addition, the oil in the oil drain pipe 30 and the oil that has become necessary after the oil pressure has been adjusted with the regulating valve 31 are returned to the reservoir 32 again.
It is designed to be stored internally.

Each of the vehicle height adjustment mechanisms 14 to 17 configured in this way
When each normally-closed solenoid valve 25 to 28 is energized to the position where it connects with the oil supply pipe 29 by a control signal from the control circuit 10, each hydropneumatic suspension 21 is activated.
When the vehicle height adjusting cylinders 25 to 24 are filled with oil and the vehicle height is raised against the load of the vehicle body, the normally closed solenoid valves 25 to 28 are biased to the position where they are connected to the oil drain pipe 30, etc. Then, oil is drained from inside the cylinder and the vehicle height is lowered.

Vehicle height sensors 1 to 4 are provided in hydropneumatic suspensions 21 to 24 provided on each wheel, respectively, as shown in FIG. 3, and generate signals that change stepwise or continuously in accordance with the vehicle height. Known types such as photoelectric type and inductance type are used.

As mentioned above, the inclination sensors 5 and 6 are used to detect the inclination of the vehicle body in the left-right direction and the inclination in the longitudinal direction, respectively. Just check to see if it is tilted.

In other words, as shown in FIG. 4, for example, as shown in FIG.
A conductor ball 43 is arranged in parallel on a flat plate 42 by a holding member (not shown), and is provided with a conductor ball 43 that moves while making point contact with the resistor 40 and the conductor 41, and a voltage is applied to the resistor 40. Voltage of conductor 41 when applying Vo and lc
By measuring this, the tilt of the vehicle body can be detected.

Further, as the steering angle sensor 7, a conventionally known potentiometer type sensor may be used, and as the vehicle speed sensor 8, an electromagnetic pickup type sensor using a reed switch and magnets 1 to 1 may be used.

Next, the operation of the vehicle height &lJH device of this embodiment will be explained along with the flowchart representing the control program shown in FIGS. 5 and 6.

This control program is executed at predetermined regular intervals. First, step 101 shown in FIG.
The signal from the steering angle sensor 7 is read in, and the rotation angle θ of the steering wheel is measured.

In the following step 102, the difference Δθ between the rotation angle θ measured in the step 101 and the rotation angle θ' measured in the previous process, that is, a certain period ago, is calculated, and in the next step 103, this eight A comparison judgment is performed between the absolute value 1Δθ1 of 〇 and a preset rotation angle θ1.

Here, Δθ represents the amount of change in the rotation angle of the steering wheel within a certain period, and when this absolute value 1Δθ1 is large, it indicates that the steering wheel has been turned significantly, and represents a transition period of the curve.

In the following explanation, assuming that IΔθ1≧θ1, rNOJ is determined in step 103, and the process moves to the next step 104. In step 104, the timer T1 is reset and set to start time counting, and the process moves to the subsequent step 105.

In step 105, it is determined whether the value of a flag F1 indicating meandering operation, which will be described later, is [0], and Fl-1
In this case, it is determined to be 1'NOJ in this step 105 and the process of this routine is directly terminated.On the other hand, in the case of F1-0, it is determined to be "YES" in this step 1.5, and the process moves to step 106. do.

In step 106, a process is executed to determine whether or not the direction of rotation of the steering wheel has been changed based on the sign of Δθ calculated in steps 1 and 2 above. In other words, the flag 1:2 indicates the direction of rotation of the previous steering ring.
and the sign si of Δθ indicating the current direction of steering rotation.
It is determined whether or not gn (Δθ) match.

If it is determined in step 106 that F2-8i90 (Δθ), vehicle tilt control shown in step 200, which will be described later, is executed;
If it is determined that ign (Δθ), proceed to step 1.
Moving on to 07.

In step 107, in order to set the flag F2 to a value indicating the current direction of rotation of the steering wheel, the sign
(Δ0) is set to 7 lag F2.

In the following step 108, the value of the timer T2 is measured, and in the next step 109, the timer T2 is reset and set to 1~, and timekeeping starts. This is to measure the elapsed time from when the rotational direction of the steering wheel is changed this time.

In the next step 109, the timer T2 is set as described above, and in the following step 110, the timer T2 is set as described above.
The value of timer T2 measured at and the preset time t
A comparison judgment with 2 is executed.

Here, if T2>t2, in this step 110, FY
ESJ is determined, and the process moves to step 2O0, which will be described later, to vehicle inclination ll1JIII. On the other hand, if T2≦t2, it is determined "No" in this step 110, and the process proceeds to step 11.
1, and the value of the flag F1 is set to [1].

The processing in steps 106 to 110 above determines whether or not the vehicle is driving in a meandering manner! , :It's the first one.1. When the series of processes from step 106 to step 110 is executed and the process moves to step 111, the flag F1 is set to "1", indicating that the vehicle is not meandering, and the °C vehicle inclination control is not performed. This is what we are doing.

Next, IΔθ1 × β1, and in step 103 rYE
If it is determined to be sJ, the process moves to step 112, and it is determined whether the value of the flag "1" is "0" or not. In other words, it is determined whether or not the vehicle is driving in a meandering direction. If F1=1 here, in step 112, r
If NOJ is determined, the process moves to step 113.

In step 113, the value of the timer T1 whose time measurement was started in step 1.4 is read, and in the next step 114, the value of the timer T1 is preset! [Time (1 will be compared and determined.

In the case of T1≦t1, in this step 114, rN
It is determined that OJ is OJ, and the processing of this routine is ended as it is. On the other hand, if Tl > t 1, rY is determined in this step 114.
When EsJ is determined, the value of the flag "1" is set to rOJ in step 115, and the vehicle inclination 1IillIII shown in step 200 is executed.

The processing in steps 113 to 115 is performed when the steering wheel becomes stable after the vehicle starts meandering and the flag F1 is set to [1]. By looking at the value of 1, the stabilization time is measured, and after confirming that the meandering run has definitely ended, the vehicle is about to move to the vehicle inclination 1bIJII1.

On the other hand, if the rotation of the steering wheel is small or not rotated at all and the value of flag F1 is "0", a series of processes of step 1o1, step 102, step 103, and step 112 are executed. The vehicle tilt control shown in step 2°0 is then executed.

Next, the skewer/double inclination control in step 200 is executed according to a control program as shown in FIG. 6, which controls the height, inclination, etc. of the vehicle in accordance with the running condition of the vehicle and the road surface condition.

As shown in FIG. 6, when the vehicle tilt control is started, step 201 is first executed, and the vehicle body tilts hα1 and β1 detected by the tilt sensors 5 and 6 are measured. still,
The vehicle body tilt angle α1 is the vehicle body tilt angle in the left and right direction, and the vehicle body tilt angle β
1 indicates the inclination of the vehicle body in the longitudinal direction.

Next, in step 202, signals from the vehicle height sensors 1 to 4 are received, and vehicle heights h1 to h4 at each wheel are measured. Vehicle heights h1 to h4 indicate the vehicle heights at the right front wheel, left front wheel, right rear wheel, and left rear wheel, respectively.

In the following step 203, the above-mentioned step 101
The absolute value of the steering rotation angle θ measured at 1θ1
is compared with a preset rotation angle θ2, and when 1θ1<β2, it is determined that rYEsJ, and the series of processes from step 204 to step 210 is performed, whereas when 1θ1≧02, [ No” is determined, and [Steps 211 to 216 and Step 2
09, a series of processes of step 210 will be performed.

Here, whereas the process executed in step 103 described above was a comparison judgment of the rotation angle Δθ of the steering wheel within a predetermined period of time, the process executed in this step 203 is a determination of the absolute rotation angle of the steering wheel within a predetermined time. In other words, it compares and determines the rotation angle θ in the left and right directions when the vehicle is traveling straight, and determines whether the vehicle is traveling straight or traveling around a curve. and step 2
If rYEsJ is determined in step 03, vehicle height adjustment is performed when the vehicle is traveling straight, and if it is determined to be NO4, vehicle height adjustment is performed when the vehicle is traveling on a curve.

When rYEsJ is determined in step 203, the value of flag F2 is set to "0" in step 204, and then in step 205, the horizontal inclination angle α2 of the road surface and the longitudinal inclination angle are calculated from the following equation. β2 is calculated. However, 1
, K2 is a constant.

When the road surface inclination angles α2 and β2 are calculated in step 205, the following step 206 is executed, and the inclination angles α3 and β3 of the vehicle with respect to the road surface (ground inclination angle) have the characteristics as shown in FIG. 6 formula% However, K a SK a is a constant.

In other words, in order to keep the car body horizontal regardless of the inclination of the road surface, target inclination angles α3 and β3 are set. Instead of maintaining the angles of inclination to the ground, changes in the angles of inclination αB and β3 are suppressed as the inclination of the road surface increases. This is because in order to keep the vehicle level even when the road surface is highly sloped, it is necessary to change the vehicle height of each wheel considerably, putting strain on the vehicle height adjustment mechanisms 14 to 17, and temporarily reducing the road surface slope. This setting was made with consideration given to the possibility that it could become a dangerous situation if it were to become large.

Next, in step 207, the vehicle body inclination angle α1,
Based on β1, road surface inclination angles α2, β2, and ground inclination angles α3, βB, the inclination adjustment angles Δα, Δβ are calculated from the following formula - Δα-(α2-α3)-α1 Δβ=(β2-β3)-β1 . Here (α2
-αB) or (β2-β3) indicates the target inclination angle of the vehicle, and the inclination adjustment angles Δα and Δβ are determined by taking the difference between this target inclination angle and the actual vehicle body inclination angle α1 or β1.

Then, in the next step 208, the amount of vehicle height adjustment Δ in each of the vehicle height adjustment mechanisms 14 to 17 is determined based on the inclination adjustment angles Δα and Δβ.
h1 to Δh4 are determined by the following equation 6, and the process moves to step 209. still,
K or 1□ is a constant.

In step 209, the opening time T3 of the normally closed solenoid valves 25 to 28 in each of the vehicle height adjustment mechanisms 14 to 17 is determined according to the vehicle height adjustment amounts Δh1 to Δh4 determined above.
to T6 is calculated using the following formula 6, and the process moves to the subsequent step 210.

However, K1. or K16 is a constant i.

In step 210, the amount valve time 11 determined above is
17a to T6 and each vehicle height adjustment -Δh1 to Δh
Solenoid valve control is executed to open each of the normally closed solenoid valves 25 to 28 to the oil supply side or the oil discharge side in accordance with the sign 4, and the processing of this routine is completed.

Next, increase the rotation angle θ of the steering wheel, step 203
If rNOJ is determined in step 21, first
At step 1, the vehicle speed V is measured based on the signal from the vehicle sensor 8.

In the subsequent step 212, the centrifugal force F is determined from the steering rotation angle θ and the vehicle speed V using the following formula 6, and in the subsequent step 213, the road surface inclination angles α4 and β4 in consideration of the centrifugal force F are determined. It is determined by the following formula. Furthermore, K
t'i, Klfl % K, 9, K2o are constants.

In the following step 213, similar to step 206, the ground inclination angles α and β are calculated using the following formula 6, %βd - and 2□β4, and in the next step 215, as in step 207, The inclination adjustment angles Δα and Δβ are calculated using the following formulas (%)), and in step 216, the vehicle height adjustment amount Δh is calculated as in step 208.
1 □ □ Δh4 is calculated by the following formula 6 % Δha=4qΔα+′30Δβ. Here, 2□ to o are constants. When the mid-height adjustment amounts Δh1 to Δh4 are calculated in this manner, steps 209 and switch 210 are executed to adjust the vehicle height, and the processing of this routine is completed.

Here, the road surface inclination angle α executed in step 212 above is
The calculation in step 4 is carried out taking into account the centrifugal force F, which is intended to reduce the lateral force exerted on the vehicle body and passengers when driving around curves, allowing for comfortable driving. Therefore, the actual road surface inclination angle is corrected in accordance with the centrifugal force F so that the vehicle height of the inner wheels is lower and the vehicle height of the outer wheels is higher when traveling on a curve. Correction amount K18 corresponding to the centrifugal force F set in this case
F is set so that the actual inclination angle of the vehicle body has a relationship with the ideal inclination angle corresponding to the centrifugal force F as shown in FIG.

In other words, as in the case of the relationship between the ground inclination angle and the road surface inclination angle in Fig. 7, the inclination angle of the vehicle body is always in a one-to-one relationship with the ideal inclination angle according to the centrifugal force F. This is because, if set, the vehicle height adjustment mechanisms 14 to 17 will be strained and may be dangerous due to changes in the unevenness or slope of the road surface.

As explained above, in the vehicle height control device of this embodiment, the meandering driving of the vehicle is detected using the steering angle sensor, and the vehicle tilt Mtllll is detected only when the vehicle is not meandering.
As a result, if the steering wheel is rotated to the right and then immediately turned to the left, the vehicle height adjustment mechanism may be controlled to tilt the vehicle according to the right rotation of the steering wheel. Erroneous "III till" due to response delay can be eliminated. When the vehicle tilt control is started, the slope of the road surface is calculated based on the signals from the slope sensor and the vehicle height sensor, and when the vehicle is traveling straight, it is controlled so that the vehicle body is level without being affected by the slope angle of the road surface. When traveling on a curve, the vehicle body is controlled in consideration of the angle of inclination of the road surface so that the vehicle tilts according to the centrifugal force. Therefore, the vehicle body can maintain a stable posture at all times without being affected by the running condition of the vehicle or the road surface condition, and the occupants can also enjoy a comfortable ride.

Although this embodiment has been explained using a hydropneumatic suspension, the above-mentioned vehicle height control can also be used if the suspension has a mechanism that can independently detect and adjust the height of each wheel, such as an air suspension. can be done.

Further, each of the above-mentioned sensors uses only typical types, and other sensors may be used as long as the necessary signals can be obtained.

Furthermore, in this embodiment, a steering angle sensor is used to detect meandering driving of the vehicle, and a vehicle speed sensor is used to increase the centrifugal force when driving around a curve, but the above-mentioned pendulum type sensor is used as an inclination sensor. When used, it is possible to detect not only the direction of gravity but also meandering operation and centrifugal force.
Vehicle height control can be performed using only an inclination sensor and a vehicle height sensor. However, in this case, the detection speed of meandering operation and centrifugal force is considered to be inferior to the case where a steering angle sensor or the like is used, so it is preferable to take this into account when controlling.

[Effects of the Invention] As detailed above, in the vehicle height control device of the present invention,
Equipped with an inclination angle sensor and a vehicle height sensor, it detects the inclination of the road surface and controls the vehicle body so that it always maintains a stable posture without being affected by the inclination of the road surface. Therefore, even if the road surface is inclined, stable running can be achieved without the vehicle body leaning accordingly, and the occupant can also maintain a stable posture, making the vehicle comfortable to ride.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of the present invention, FIGS. 2 to 8 show an embodiment of the present invention, FIG. 2 is a 10-block diagram showing the overall structure of this embodiment, and FIG. Figure 4 is a schematic system diagram showing the vehicle height adjustment mechanism, Figure 4 is a schematic diagram showing the inclination sensor, Figures 5 and 6 are flowcharts showing the control program, Figure 7 is the road surface inclination angle and ground inclination angle. 1 shows the relationship with
FIG. 8 is a diagram showing the relationship between the ideal inclination angle and the vehicle body inclination angle when traveling on a curve. 1.2.3.4, ■...Vehicle height sensor 5.6, ■...Inclination sensor 10, IV...Control circuit 14.15.16.17, ■...Vehicle height adjustment mechanism substitute Patent attorney Tsutomu Tateru and 1 other person

Claims (1)

[Claims] A vehicle height control device equipped with a plurality of vehicle height adjustment mechanisms that adjust the vehicle height according to a control signal, including a plurality of vehicle height sensors that detect the vehicle height, and a tilt sensor that detects the tilt of the vehicle. Based on the detection signals from each of the above sensors, the inclination of the road surface on which the vehicle is located is detected, and a control signal is output to each of the above vehicle height adjustment mechanisms so that the vehicle maintains a stable body posture with respect to the road surface. and the inclination of the vehicle is 1Iil]1
A vehicle height control device characterized in that it is equipped with an IiIJ1m circuit that performs 11 functions.