JPS63137008A - Posture control device for vehicle - Google Patents

Abstract

PURPOSE:To improve the steering property and the riding feeling, by detecting the inclination of a vehicle, and operating a reversible pump to feed the operating solution to jacks mounted at wheels in the direction to negate the inclination, in a captioned device to prevent the posture variation owing to the variation of the organization of passangers or the like. CONSTITUTION:A control unit 30 computes the lateral acceleration depending on the input detecting signals of a steering angle sensor 52 and a car speed sensor 54. Then it computes the rotation angle of a hydraulic pump 28 to move the operating oil between the left side and the right side hydraulic jacks 16 and 18 in the oil amount to compensate the sinking amount of the car body by the lateral acceleration. And, depending on the resultant rotation angle, the solenoid of a solenoid valve 46 is converted to the side either the 46a or 46b side, the hydraulic pump 28 is rotated in a direction to move the operating oil between the both hydraulic jacks 16 and 18, and the inclination is negated. In such a composition, both the steering property and the riding feeling are improved.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides a vehicle attitude control device that prevents changes in the attitude of the vehicle body due to changes in the occupant composition when the vehicle starts, advances, stops, turns, or is stopped. Must be related to.

[Prior Art] Rolling of the vehicle body when turning, sudden braking, and forward and backward tilting of the vehicle body when starting suddenly not only make the vehicle uncomfortable to ride, but also have a negative effect on maneuverability. Therefore, various methods and devices have been proposed to prevent such changes in the posture of the vehicle body. Among them, a device described in Japanese Patent Application Laid-Open No. 54-159921 utilizes steering oil pressure generated in the steering system of a vehicle equipped with so-called vehicle speed-sensitive power steering to control the roll of the vehicle body. An arrangement is shown in which the left or right suspension is extended or retracted to compensate. Also, US Patent No. 2,9
27,801 also shows a mechanism that controls the attitude of the car body by supplying and discharging steering pressure oil to and from a jet provided in the suspension part, but this one
The structure is such that the steering oil circuit is switched to the suspension oil circuit only when the vehicle is stopped, and attitude control is performed only when the vehicle is stopped.

[Problems to be Solved by the Invention] The above-mentioned conventional techniques have a drawback in that the above-mentioned roll control device cannot be used unless the vehicle is equipped with power steering.

Furthermore, in addition to the above-mentioned jacking method, a method often used to prevent changes in the posture of the vehicle body is to stiffen the suspension characteristics, but this method is not compatible with improving riding comfort.

The present invention provides a device that can achieve both high steering performance and ride comfort by preventing changes in the posture of the vehicle body when the vehicle is running or stopped.

[Means for Solving the Problems] The present invention, which has been made to solve the above-mentioned problems, is based on a vehicle wheel WFL, as shown in FIG.
, WFR, WRL, WRR hydraulic jack J
FL, JFR, JRL.

Fluid paths PFR, PRR, and PLF connect the JRR and the hydraulic chambers of the hydraulic jacks on the left and right or front and rear of the vehicle.

PRT, and reversible pumps MFR, MRR, which are connected to 5Ω in each liquid path.
MLF, MRT, and a pump that controls the reversible pump so as to move hydraulic fluid between the left and right or front and rear hydraulic pressure chambers in a direction to cancel the tilting when the left and right or front and rear tilting of the vehicle body 8D is detected. The gist of the present invention is a vehicle attitude control device characterized by comprising a control means PC.

Here, the liquid passages connecting the hydraulic pressure chambers may include, for example, only liquid passages PFR and PRR connecting the left and right sides, or only liquid passages PLF and PRT connecting the front and rear sides.

Note that by using a positive displacement pump as the reversible pump, vehicle body tilt compensation control can be performed more simply and accurately.

[Action The fact that the vehicle body 8D is tilted left and right or front and rear can be detected by conventionally known techniques such as a suspension control device, a brake control device, etc. The pump control means PC of the present invention may utilize signals from such a device, or may be provided with a mechanism for independently detecting tilting of the vehicle body.

In this way, when the pump control means PC detects, for example, the longitudinal tilting of the vehicle body BD, the pump control means PC is installed in the liquid passages PLF and PRT connecting the hydraulic pressure chambers of the front and rear wheels JFL and JRL and JFR and JRR. The reversible pumps MLF and MRT are rotated forward or backward to move the hydraulic fluid in a direction that cancels out the longitudinal tilting of the vehicle body BD. For example, if it is detected that the front of the vehicle body BD sinks (nose dive) during sudden braking, pumps MLF and MRT are driven to adjust the hydraulic jacks for the rear wheels JRL and JRR, and then the hydraulic jacks for the front wheels JFL and JFR. Move the hydraulic fluid to. As a result, the distance between the front of the vehicle body BD and the front wheels WFL, WFR is expanded, and the distance between the vehicle body BD and the rear wheels WRL, WRR is reduced, so the above-mentioned nose dive is prevented and the attitude of the vehicle body BD is is kept constant.

In the case of a rearward tilt of the vehicle body BD during a sudden start, the hydraulic pumps MLF and MRT are simply rotated in the opposite direction to the above example; has the other pair of pumps MFR and MRR.
All you have to do is reverse or forward. As mentioned above, the liquid path and reversible pump are located on the left and right (PLF, MLF and PPT, MR
T) only or before and after (PFR, MFR and PRR, MRR
), but in this case, the tilting of the vehicle body that can be handled is naturally limited to rolling or pitching (tilting forward and backward).

Here, the reversible pumps MFR, MRR, MLF.

When the MRT is a positive displacement pump, the pump control means P
Since C can calculate the amount of movement of hydraulic fluid from side to side or front to back based on the amount of operation (rotation amount) of each pump or the output time of the drive signal to each pump, it is easy to control to keep the posture of the vehicle body BD constant. You will be able to do this.

[Example] An example in which the present invention is implemented as a roll prevention device for a vehicle will be described below. FIG. 2 is a configuration diagram mainly showing the front wheel side portion of the configuration of this embodiment. This device consists of left and right hydraulic jacks 16.18 provided between the left and right front wheel suspension springs 10°12 and the vehicle body 14, a hydraulic pipe 24 connecting between the hydraulic chambers 20.22 of each hydraulic jack 16.18, and A gear pump 26 provided in the middle of the hydraulic pipe 24, a hydraulic motor 28 that drives the gear pump 26,
It consists of a pump control device 30 that controls the hydraulic motor 28 and the like.

Since the structures of the left and right hydraulic jacks 16, 18 are the same, the vicinity of the jack 18 on the right front wheel side will be explained in more detail with reference to FIG. The suspension spring 12 is provided between a spring seat 34 provided on the suspension arm 32 and a flange fixed to the cylinder 36 of the upper hydraulic jack 18, and buffers the vertical movement of the wheel 38 connected to the suspension arm 32. do. A shock absorber 40 is also provided between the vehicle body 14 and the suspension arm 32 in parallel with the spring 12, and damps the vertical vibration of the wheel.

The hydraulic jack 18 includes the cylinder 36, a piston 42 fixed to the vehicle body 14, the hydraulic chamber 22 formed between the two, an oil seal 44, and the like.

Returning to FIG. 2, the hydraulic motor 28 that drives the gear pump 26 is connected to a hydraulic power source 48 via a 3-position, 4-port solenoid valve 46. This solenoid valve 4
6 is two solenoids 46a, No. 1 and No. 2,
46b, each solenoid 46
a and 46b are controlled by the pump control device 30. Further, the hydraulic motor 28 is equipped with a rotation angle sensor 50, and the motor rotation angle detected by this is inputted to the pump control device 30. Pump control device Effi
In addition to this, signals from a steering angle sensor 52 of the steering wheel and a vehicle speed sensor 54 are also input to the sensor 30 .

As shown in the block diagram of FIG. 4, the pump control device 30 is mainly composed of a microcomputer CPU 30a, and a ROM 30b in which programs, data, etc. are written, and calculation results, etc. are written and read out. RAM30C.

A backup RAM 30d for holding data while the ignition switch is turned off, inputs signals from each of the sensors 50, 52, and 54;
1. It includes an input/output section (Ilo) 30e that outputs a control current to the No. 2 solenoids 46a and 46b, a pass line 30f that connects them, and the like.

Next, the processing performed in the pump control device 30 will be explained with reference to the flowchart shown in FIG. When the process shown in FIG. 5 is started, first in step 100 both solenoids 46a and 46b of the solenoid valve 46 are turned off. As a result, the solenoid valve 46 is in the center position shown in FIG. 2, the pressure oil from the hydraulic source 48 is not transmitted to the hydraulic motor 28, and the gear pump 26 is in a stopped state.

As a result, the left and right hydraulic chambers 20 and 22 are placed in a blocked state.

Next, in step 110, the steering angle MA of the steering wheel and the vehicle speed V are read from the steering angle sensor 52 and the vehicle speed sensor 54, respectively. Then, in step 120, the lateral acceleration G applied to the vehicle body is calculated using the following equation.

Here, Kh is a so-called stability factor, and is a value used to express steering characteristics such as understeer and oversteer of a vehicle.If the turning radius of a car at very low speed is RO1 and the turning radius at each vehicle speed is R, then It is defined by the formula (2). Further, in equation (1), Ω represents the wheel base, and NG represents the total gear ratio in the steering system.

The reason why the lateral acceleration G is calculated as in formula (1) is as follows. First, the lateral acceleration G is calculated from the speed V and the turning radius R as shown in formula % formula % (3).On the other hand, Since the turning radius RO at very low speed is determined by the formula, the above formulas (2>, (3)).

Equation (1) is derived from (4).

After calculating the lateral acceleration G as described above, step 1
At step 30, the required rotation angle θO of the hydraulic pump 28 is calculated.

Here, the required rotation angle θO is the movement of hydraulic fluid between the left and right jacks 16.18 in the amount necessary to compensate for the amount of sinking of the vehicle body on the outside of the roll, based on the lateral acceleration G of the vehicle calculated above. This is the required rotation angle of the gear pump 26 to perform this. θO is determined by the formula. Here, W is the vehicle weight, r is the loam arm (distance between the center of gravity of the vehicle and the roll center), A is the effective cross-sectional area of each hydraulic jack 16.18, k is the wheel rate due to only the spring of each suspension, T is the tread (distance between the left and right wheels), and q is the discharge amount per unit rotation angle of the gear pump 26.

In the next step 140, the calculated required rotation angle θO is
If it is O, there is no need to operate the pump 26, so no processing is performed and the process returns to immediately after the start.

θ0=il! When =O, it is further determined in step 150 whether the value is positive. This is to determine whether to move the hydraulic oil from right to left or from left to right depending on the roll direction. If θO>Q, step 16
0, the N091 solenoid 46a is turned on, and the solenoid valve 46 is placed in the upper position in FIG.

As a result, the hydraulic pump 28 and the gear motor 26 are rotationally driven in one direction, and hydraulic oil is moved from the hydraulic chamber 22 of the right wheel hydraulic jack 18 to the hydraulic chamber 20 of the left wheel hydraulic jack 16. Then, in step 170, the hydraulic pump 2
The rotation angle θ is input from the rotation angle sensor 50 of No. 8, and in step 180, the detected rotation angle θ is determined as the calculated required rotation angle θO
Determine whether it becomes equal to . Here, if θ=θO, the roll is in a corrected state, so the return is made immediately after the start, and if No at step 100, 1. N.

Both of the two-lenoids 46a and 46b are turned off.

If θ≠θO, then in step 190 it is determined whether θ exceeds the required value θO. If it exceeds, No in step 200, 1 solenoid 46a is turned off.
Step 1 by turning on F, No, 2 solenoid 46b
Returning to step 10, correction processing is then performed to restore the excess amount.

This is because when the No. 2 solenoid 46b is turned ON, the solenoid valve 46 is placed in the lower position shown in FIG. 2, and the hydraulic motor 28 and gear pump 26 are rotated in the opposite direction.

If it is determined in step 190 that θ>θO, that is, θ<θO, and the rotation angle θ of the hydraulic motor 28 has not yet reached the required value θO, the process returns to step 110. Repeat the above process.

If it is determined in step 150 that θO is negative, the process proceeds to step 210, and from then on until step 250, the process is the same as above, except that the movement direction of the hydraulic fluid is from the left hydraulic chamber 20 to the right hydraulic chamber 22. Processing for role correction is performed. That is, the hydraulic fluid is moved from the left hydraulic chamber 20 to the right hydraulic chamber 22 in step 210, and in step 220
The rotation angle θ of the hydraulic motor is read, and step 2
At step 30, it is determined whether or not it is equal to the required rotation angle θO, and at step 240, it is determined whether or not it exceeds the required rotation angle θO (because θ is an angle in this case, the inequality sign is opposite to that at step 190). .> is determined, and in step 250, processing is performed for moving in the opposite direction when the required value is exceeded.

In the above explanation, the front wheel side left and right hydraulic jacks 16.
Although the explanation has been given only regarding 18, it is of course possible to provide similar left and right hydraulic jacks on the rear wheel side and perform the same processing as above.

Through these processes, when the driver operates the steering wheel to turn, the corresponding lateral acceleration G is calculated, and the hydraulic jacks of the left and right wheels are raised and lowered to compensate for the roll of the vehicle body caused by this lateral acceleration G. In order to
This has a useful effect on improving passenger comfort and ensuring vehicle operability.

As described above, in this embodiment, only the roll during turning is canceled without changing the suspension characteristics themselves, so even if you are driving on a rough road, you can drive with the suspension characteristics softened. Riding comfort can also be improved from this aspect. In addition, in the above embodiment, since the hydraulic oil is transferred between the left and right hydraulic chambers 20 and 22, the hydraulic oil is injected only into the jack on the right or left sunken wheel side. This has the advantage that the movement (pumping amount) of the pump can be halved, and the driving power of this system can be reduced accordingly.

In the above embodiment, since a positive displacement pump such as the gear pump 26 is used to transfer the hydraulic oil between the left and right hydraulic chambers 20 and 22, the amount of oil transfer vJ can be simply calculated from the rotation angle of the motor 28. In addition to being able to accurately correct the roll,
The pump 26 itself serves as a valve, and by stopping the pump 26, the left and right hydraulic chambers 20, 22 are completely shut off. By using the hydraulic motor 28 to drive the gear pump 28, it is possible to ensure that the pump 26 stops, but even if this is replaced with an electric motor with a brake mechanism, the effect will be the same.

Although the above description has been about correcting the roll of the vehicle when turning, the application of the present invention is not limited thereto, and by adding vehicle height sensors for the left and right wheels to the above configuration, the roll when turning and when the vehicle is stopped can be corrected. be able to. In addition to this, it is also possible to easily correct the tilting of the vehicle body in the front and rear, instead of the left and right tilting. That is, as in the above embodiment, the left and right hydraulic chambers 20.
Rather than providing a passage between the front and rear hydraulic chambers, correcting the longitudinal inclination during a sudden start or sudden stop is possible by creating a passage between the front and rear hydraulic chambers and using vehicle height sensors on the front and rear wheels or acceleration sensors on the vehicle body.
This can be easily done by slightly modifying the above embodiment. Furthermore, it is a completely similar technique to provide passages both between the left and right hydraulic chambers and between the front and rear hydraulic chambers, and to control the movement of hydraulic fluid between the two according to the situation.

[Effects of the Invention] The attitude control device according to the present invention allows the vehicle to turn, start,
Changes in posture due to braking, changes in occupant distribution, etc. can be easily corrected with less power by moving hydraulic fluid between the front and rear or left and right hydraulic chambers. Since this can be done independently of the suspension characteristics, it has the advantage of being able to be done without changing the riding comfort. In addition, by making the pump installed in the passage between the left and right hydraulic pressure chambers a positive displacement type, the calculation and control of the pump drive to compensate for the amount of tilting of the vehicle body is simplified, and the valves for both hydraulic pressure spaces are omitted. It will also have the effect of being able to do it.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram illustrating the outline of the present invention, Fig. 2 is a system configuration diagram of an attitude control device that is an embodiment of the present invention, and Fig. 3 is a configuration showing a portion near the right wheel of the embodiment. figure,
FIG. 4 is a block diagram of the pump control device, and FIG. 5 is a flowchart of processing performed in the pump control device. JFL, JFR, JRL, JRR...Hydraulic jack PFR, PRR, PLF, PRT...Liquid path MFR, MRR, MLF, MRT...Reversible pump PC...Pump control means 14...Vehicle body 16 .18...Hydraulic jack 20.22...Hydraulic chamber 24...Passage 26...Gear pump 28...Hydraulic motor 30...Pump control device 46...Solenoid valve

Claims (1)

[Scope of Claims] 1. A hydraulic jack provided on the wheels of a vehicle, and a fluid path connecting the hydraulic chambers of each of the hydraulic jacks on the left and right or front and rear of the vehicle, and a fluid path provided in each of the fluid paths. a reversible pump that controls the reversible pump so as to move hydraulic fluid between the left and right or front and rear hydraulic pressure chambers in a direction that negates the tilting when the left and right or front and rear tilting of the vehicle body is detected; A vehicle attitude control device comprising: a control means. 2. The vehicle attitude control device according to claim 1, wherein the reversible pump is a positive displacement pump.