JPH01212609A - Suspension device - Google Patents

Abstract

PURPOSE:To always control the attitude of a car body to a proper state by calculating the deviation quantity between the detected value of the ground clearance and a standard value and comparing the calculation value of the deviation quantity and a standard value and correcting the contents of control for an oil feed/discharge means for a ground clearance adjusting body according to the result of the comparison. CONSTITUTION:In a controller 11 which receives each detection signal supplied from a number of ground clearance sensors 10a-10d, steering angle sensor 12, and a car speed sensor 13, a means 16 calculation-sets an aimed oil feed/ discharge quantity and controls a number of oil feed/discharge means 7a-7d for a ground clearance adjusting body according to the above-described set value. In this case, a means 52 calculates the ground clearance difference between a standard ground clearance value memorized in the first memory 51 and a detected value. Further, a means 53 integration-calculates the ground clearance deviation quantity, and a means 55 compares the integration- calculation value and a standard value memorized in the second memory 54. Then, according to the result of the comparison in the means 55, a CPU 55 corrects the contents of control for each oil feed/discharge means 7a-7d.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a suspension device for preventing tilting of a vehicle body due to rolling that occurs when a vehicle turns.

(Prior Art) Various electronically controlled suspension devices have been proposed in the past for automatically suppressing rolling, etc. that occur when a car turns, and thereby stabilizing the attitude of the car body. An example of such an electronically controlled suspension device is a steering angle sensor,
A system that captures detection signals from brake sensors, accelerator sensors, etc., and switches and sets the damping force of the suspension device installed on each wheel in multiple stages based on the detection signals to suppress changes in the posture of the vehicle ( (hereinafter referred to as the first conventional example) is known.

In addition, as another suspension device, the patent application Sho A-'T7
t4: This suspension device, which is shown in +o publication (hereinafter referred to as the second conventional example), has a vehicle speed sensor,
The lateral acceleration generated in the vehicle body is estimated from the detection signal of the steering angle sensor, and based on this estimated lateral acceleration, oil is supplied to and discharged from the suspension cylinder (vehicle height adjustment body). The difference between the estimated value and the actually required supply/displacement amount caused by differences in weather, etc. is adjusted using the detection results of the vehicle height sensor, and the posture of the vehicle body is corrected. That is, on the condition that the detection result of the vehicle height sensor continues to be different from the reference value for a predetermined period of time or more, the supply and displacement amounts are adjusted and the attitude of the vehicle body is corrected.

(Problem II to be Solved by the Invention) However, the conventional electronically controlled suspension described above has the following problems.

First, in the first conventional example described above, the damping force of the suspension device provided on each wheel is changed and set in stages to suppress changes in the attitude of the car body, and the damping force is set in stages to suppress changes in the attitude of the car body. As a result, rolling could not be reliably suppressed.

In addition, in the second conventional example, if the correction request state does not continue for a certain period of time, the vehicle height sensor does not perform a severe attitude correction based on the detection result of the vehicle height sensor. However, if the vehicle body temporarily falls within the reference value, the posture correction is not performed, and the vehicle body cannot be corrected to an appropriate posture.

The present invention has been made in view of the above circumstances, and it is possible to appropriately correct the unstable posture of the vehicle body caused by estimated value control without being affected by instantaneous changes in vehicle height, etc., and to improve comfort. An object of the present invention is to provide a suspension device that can provide a comfortable ride.

(Means for Solving Problems 7a8) In order to achieve the above object, the present invention estimates and sets a target supply/displacement amount using logical calculation means based on the detection output of a sensor installed in a vehicle, and In a suspension system, the vehicle height can be adjusted by controlling the supply and discharge means according to the vehicle height and controlling the supply and discharge of pressurized fluid to the vehicle height adjustment body provided for each wheel of the vehicle. deviation amount calculating means for calculating a vehicle height deviation amount by calculating a difference between the determined vehicle height reference value and detection data indicating a displacement of the vehicle height at a predetermined timing;

an integration calculation means for integrating the vehicle height deviation amount to obtain a deviation amount IIi calculation value; a means for comparing the deviation amount integration value with a preset integration reference value; controlling the supply/discharge means based on a target supply/discharge amount;
The apparatus is characterized by further comprising a control means for correcting the content of control for the supply/discharge means based on the processing result of the comparison means.

(Function) The present invention is configured as described in E, and integrates the amount of change in vehicle height, and compares the am value with a reference value. Even if the vehicle height changes from time to time, the attitude can be appropriately corrected without being directly affected by the change.

(Example) Below, one example of the present invention will be described in detail based on the drawings.

To explain the configuration of the suspension device IT in FIG. 3, the front wheels, the rear wheels, the wheels 2a, 2b, 2c,
2d are hydraulic cylinders 3a and 3b as vehicle height adjusting bodies attached to a vehicle body (not shown).

The wheels 2a, 2b, 2c, 2d are fixed relative to the vehicle body by supplying and discharging oil to the hydraulic cylinders 3a, 3b, 3c, 3d. The vehicle height increases and decreases as the vehicle moves. Although this embodiment uses an example in which the pressure fluid is an oil liquid, the present invention is not limited to this, and may be other liquids, or may be gas depending on the vehicle load. You can.

Each hydraulic cylinder 3a, 3b, 3c, 3d has an accumulator 5a, 5b which is a spring element of the suspension device.
, 5c, and 5d are connected, and oil liquid is accumulated therein.

Further, the hydraulic cylinders 3a, 3b, :lc, 3d are connected to the hydraulic power source 6 via oil supply/discharge means 7a, 7b, 7c, 7d. The oil supply and drainage means 7a, 7b, 7c, 7d are the fourth
As shown in the figure, a pair of 2-point 2-position electromagnetic switching valves 8.
9 are combined in parallel, and by alternately switching and opening the electromagnetic switching valves 8.9, oil can be supplied from the hydraulic source 6 to the hydraulic cylinders 3a, 3b, 3c, and 3d, or the hydraulic cylinders 3a, 3b.

Drain oil from 3c and 3d.

In addition, 10a, 10b, 10c, and lOd in FIG. 3 are vehicle height sensors, and hydraulic cylinders 3a and 3b, respectively.

3c, :ld and its lots 4a, 4b, 4c, 4d
The vehicle height data is obtained by detecting the amount of expansion/contraction change of the rods 4a, 4b, 4c, and 4d.

Next, the hydraulic power source 6 and oil supply/drainage means 7a, 7b, 7
The controller 11 that controls the controllers c and 7d will be explained.

The controller 11 includes a steering angle sensor 12 that detects a steering angle from the rotation angle of a steering link shaft (not shown);
Vehicle speed sensor 13 that detects vehicle speed and the vehicle height sensor l
Detection signals of Oa, 10b, 10c, and 10d are input.

Here, the control means of the controller 11 is shown in FIG. 1a.

This will be explained with reference to FIG. 1b.

The controller 11 includes a CPU 50 that reads and executes a control program stored in a memory (not shown), and the CPU 50 has a timer function. When the steering angle and vehicle speed detection signals are input to the controller 11, the lateral acceleration estimating means 14 estimates the lateral acceleration expected to occur in the vehicle body. This estimation is based on the fact that, as can be seen from the experimental results shown in Figure 6 (a) and (b), lateral acceleration is proportional to the steering angle in the low range of 0.6 G or less, and is proportional to the square of the vehicle speed. It is based on this.

In addition, since a proportional relationship (see Figure 6 (c)) exists between the lateral acceleration generated on the vehicle body and the roll angle, calculation means 1
5, the roll angle is calculated based on the lateral acceleration. Furthermore, once the roll angle is calculated, the amount of change in the length of each hydraulic cylinder 3a, 3b, 3c, and 3d due to the roll angle is also calculated.

Next, the hydraulic cylinder 3a calculated in this way
, : The logical calculation means 16 determines the amount of oil to be supplied and discharged to each hydraulic cylinder 3a, 3b, 3c, and 3d (target oil supply and discharge amount) so as to suppress changes in the lengths of Ib, 3c, and 3d, and The oil supply/discharge means 7a, 7b, 7c, 7d connected to the hydraulic cylinders 3a, 3b, 3c, 3d are appropriately controlled based on this target oil supply/discharge amount. In addition, the target oil supply and drainage amount at this time is
Hydraulic cylinders 3a, :lb, 3c generated when the vehicle rotates
, 3d may be set to 0, or,
The amount of oil supplied and discharged may be set to be large so as to cause a reverse roll.

The controller 11 also includes a first memory 51 that stores a vehicle height reference value in advance, and vehicle height sensors 10a and 1Ob.
, 10c, and lOd are quantized for each time and expressed in five stages of HH, H, N, L, and LL, and the vehicle height reference value read from the first memory 51 and the above It is provided with a deviation amount calculation means 52 which compares the vehicle height data with the vehicle height data and calculates the vehicle height deviation amount as shown in FIG. 8a.

Further, the controller 11 includes a summation operator stage 53 and a second
memory 54 and comparison means 55.

The integration calculation means 53 sequentially tarlts the vehicle height deviation amount obtained from time to time by the deviation amount calculation means 52 to obtain a deviation amount integration value A.

The second memory 54 stores a first . Second accumulation reference value N
A cumulative reference value consisting of n and N L is stored. 1st. The second integration reference values N o and N L are each set to two levels of large and small values as shown in FIG. 9. The data stored in the second memory 54 is stored in the CPU 5.
It is selectively read out by the G timer instruction. In other words, after the supply/discharge operation based on lateral acceleration, c p u so is
Start time measurement and use the first integrated reference value NII within time T.
as the smaller value "50", and the second! Ii calculation reference value Nt, select the larger value "50." After time T has passed, select the larger value r200J as the first integration reference value N□, and select the larger value r200J as the second integration reference value NL. The smaller value r-200 is selected and the selected data is transferred to the comparing means 55.

The comparison means 55 calculates the deviation amount I obtained by the integration calculation means 53.
The IIIH value A is compared with the integrated reference value transferred from the CPU 50, and the comparison result is sent to the CPU 5G.

When the CPU 5G takes in the comparison result, it performs the following processing in accordance with the content of the comparison result, provided that neither the supply/discharge operation nor the posture correction operation is performed.

a, when A≦NL: oil supply and drainage means 7a, 7b;

Hydraulic cylinders 3a, 3b, 3c,
Supply oil to 3d.

In the case of b, N, ≦A: oil supply and drainage means 7a, 7b.

Hydraulic cylinders 3a, :lb, by controlling 7c, 7d.
Discharge oil from 3c, 3d c, NL <A<NH: Based on this comparison result, the oil supply and discharge means 7a, 7b, 7c, and 7d are not controlled and no posture correction is performed.

The operation of the suspension device configured as above will be described below with reference to the accompanying drawings.

First, with reference to FIG. 2, we will explain the roll angle, changes in the length of the hydraulic cylinder, changes in the speed of the hydraulic cylinder, etc. when the driver operates the steering wheel when the suspension device of this embodiment is not used. .

When the driver starts steering operation to turn the vehicle to the right and increases the steering angle until it reaches the maximum turning angle, the second
As shown in figure (a), the steering angle increases and takes a constant value. Further, the vehicle body rolls a little after the start of the steering operation, and the roll angle due to the rolling is shown in FIG. 2 (0).

When the vehicle body tilts due to rolling, the right wheels 2b and 2d
The hydraulic cylinders 3b and 3d provided in the left wheels 2a and 2c extend, and the hydraulic cylinders 3a and 3c of the left wheels 2a and 2c contract, changing as shown in FIG. 2 (8). Further, the expansion and contraction speeds of the hydraulic cylinders 3a, 3b, 3c, and 3d at this time are as shown in FIG. 2(d).

In this case, depending on the speed of extension, oil is discharged from the right hydraulic cylinders lb and 3d, as shown in Figure 2 (illustration), and depending on the speed of contraction, the left hydraulic cylinder 3a
, :Ic, as shown in FIG. 2 (N), the vehicle body is stabilized by supplying oil.

The specific action will be explained.

Vehicle speed detected by vehicle speed sensor 13 and steering angle sensor 12
The steering angle detected by the controller 11 is used as a detection signal.
is input.

In the controller 11, a lateral acceleration estimating means 14 estimates the lateral acceleration occurring in the vehicle body based on this detection signal.

Then, the calculation means 15 calculates the roll angle caused by this estimated lateral acceleration, and further calculates the length of each hydraulic cylinder 3a, 3b, 3c, 3d provided on each wheel based on this calculated roll angle. Changes are calculated.

Next, the calculated hydraulic cylinders 3a, 3b, 3c,
Based on the length change of 3d, and the hydraulic cylinders 3a, 3b,
3c, according to desired data such as the amount of oil that should be supplied and discharged to make the length change of ld zero, or the amount of oil that should be supplied and discharged to make the vehicle body into a reverse rolling state. A logical operator stage 16 establishes a target supply/displacement amount in order to stabilize the attitude of the vehicle body.

Then, based on the determined target supply and discharge amount, the oil supply and discharge means 7
a, 7b, 7c, and 7d are controlled, and after a predetermined time has elapsed from the start of the steering operation, as shown in FIG. 2 ([1)], each hydraulic cylinder 3a, 3b, 3c, and 3d is adjusted to the optimal length This stabilizes the posture of the vehicle. At this time, the oil supply/drainage means 7a, 7b, 7c, and 7d are ideally controlled by controlling the opening operation of the electromagnetic switching valve 8.9 in a pulsed manner at predetermined time intervals, as shown in FIG. I am trying to approximate the curve.

When performing such processing, cpus.

acquires vehicle height data from the vehicle height sensors 10a, 10b, 10c, and lOd at minute intervals, and performs the following correction processing for the above-mentioned processing content, using the flowchart in FIG. This will be explained below. First, vehicle height sensors 10a, lOb, and 10c.

10d or when the vehicle height data is detected, the deviation amount calculation means 52
The vehicle height data is taken in via CPUSO and the deviation amount is obtained as shown in FIG. 8a (Step Sl).

Then, the integration calculation means 53 sequentially adds the deviation amounts to obtain the deviation amount integrated value A (step S2).

In this case, the processes of steps SL and S2 are similarly carried out every hour by repeating the following processes every hour.

As a result, even if the vehicle body changes temporarily, the deviation amount integrated value A obtained in step S2 becomes data that is less affected by temporary changes.

It is determined whether the supply/discharge operation is being executed based on the lateral acceleration estimated at this stage (step S3).

Here, if it is being executed, cpuso is the oil supply and drainage means 7a,
7b, 7c, and 7d to prohibit the correction supply/discharge operation (step S4), and reset the correction operation counter used to cause the correction supply/discharge operation to be performed continuously for a certain period of time (step S5). .

When it is determined that rNOJ is determined in step S3, it is determined whether or not a supply/discharge operation for posture correction is being executed (step S
6) If it is being executed, it is determined to be rYEsJ and the correction operation counter is incremented (step S7).

Then, it is determined whether the correction operation counter has reached the set value N (step S8), and if it is determined that rYEsJ is determined, the supply/ejection operation for attitude correction is prohibited (step S9), and the correction operation counter reset
(Step 5tO).

In step S6, if it is determined that rNOJ, the deviation amount integrated value A obtained in step S2 becomes the first U calculation reference value N,
It is determined whether the above is the case (step 5ti).

If the deviation amount vi calculated value A is equal to or less than the first integrated reference value N, the oil supply and discharge means 7a, 7b, 7c, and 7d are controlled to drain the oil from the hydraulic cylinders 3a, 3b, 3c, and 3d. (step 512), and resets the deviation amount integrated value A (step 515).

In step Sll, the deviation amount integrated value A is set to the first integrated reference value N.
, then the determination is "NO", and it is then determined whether the deviation amount integrated value A is smaller than the second integrated reference value NL (step 513). If the deviation amount integrated value A is equal to or less than the second integrated reference value NL, the oil supply and drainage means 7a, 7b, 7c, and 7d are selectively controlled and the corresponding hydraulic cylinders 3a, :lb, 3c, and 3d are An instruction to supply oil to the engine is output (step 514), and the deviation amount integrated value A is reset (step 515).

In addition, as in steps Sll and S13, the vehicle height sensor 1
An integrated value is calculated based on the detection data of 0a, 10b, loc, and lOd, and this is calculated as the first. Second integration reference value NH1N
Since the vehicle is compared with L, the unstable posture of the vehicle body caused by estimated value control can be appropriately corrected and stabilized even if the vehicle body fluctuates over time, without being affected by this. Can be converted into

As a result, a comfortable ride can be provided.

In addition, in steps Sll and S13 of the above processing, based on the estimated lateral acceleration,
After time T, the first. Second integration reference value N Il, N
L is changed as shown in FIG. Then, the correction supply and discharge operation is frequently performed until one hour T after the end of the supply and discharge operation based on the estimated lateral acceleration, and after the time T, the frequent correction supply and discharge operation is suppressed. In this way, time is passed and the first and second
Because the integration reference values No. and NL are changed and set,
Abnormal postures that occur when there is an error in lateral acceleration estimation can be quickly corrected. Also, if you perform frequent correction supply/discharge operations,
Vibrations caused by the undulations of the road surface are easily transmitted to the vehicle body, deteriorating the ride comfort, but in conditions where the lateral acceleration generated in the vehicle body does not change, such as when driving straight or turning in a steady circle, corrective supply and discharge should be carried out as much as possible as described above. This prevents the ride from becoming uncomfortable by not performing any operations.

In addition, in this embodiment, the first. Second integration reference value N o,
Is the frequency of the supply/discharge operation changed by changing the setting of N/L?Alternatively, after the supply/discharge operation based on the lateral acceleration, calculation is made as shown in Figure 8b up to time T, and Figure 8a after time T. The frequency of the correction supply/discharge operation can also be changed by changing the calculation method or by changing the calculation method.

(Effects of the Invention) As described above, the present invention integrates the amount of change in vehicle height and compares the integrated value with a reference value.

Even if temporary changes in vehicle height occur, the unstable posture of the vehicle body caused by estimated value control can be appropriately corrected without being directly affected by this, and in turn, it is possible to provide a comfortable ride. It has this effect.

[Brief explanation of the drawing]

FIGS. 1a and 1b are a block diagram showing a controller of a suspension device according to an embodiment of the present invention, a schematic diagram showing its functions, and FIGS. ) is a diagram showing temporal changes in the steering angle, roll angle, length and speed of the hydraulic cylinder when the vehicle is rotated to the right when the device of the present invention is not used, and FIG.
FIG. 3 shows the structure of a suspension device according to an embodiment of the present invention. A plan view showing. Fig. 4 is a diagram showing the configuration of the supply/discharge means provided in the suspension device of Fig. 3, and Fig. 5 shows the operating state when the solenoid valve is pulse-driven in order to approximate the target oil amount. Figure 6 (a) is a diagram showing the experimental results showing the relationship between steering angle and lateral acceleration, Figure 6 (0) is a diagram showing the experimental results showing the relationship between vehicle speed and lateral acceleration, Figure 6 (c) is a diagram showing the relationship between lateral acceleration and roll angle, FIG. 7 is a flowchart showing the operation of the controller shown in FIG. 1a, and FIGS. 8a and MAB are the deviation amounts of the controller shown in FIG. 1a, respectively. FIG. 9, a diagram showing an example of calculation by the calculation means, is a schematic diagram showing data stored in the second memory of the controller shown in FIG. 1a. 7a, 7b, 7c, 7d - "Oil supply and drainage means 10a, 10
b, loc, lOd---Vehicle height sensor 11...Controller 50...CPU 5I...First memory 52...Deviation amount calculation means 53-...Integration calculation means 54...Second memory of

Claims (1)

[Claims] A target supply/displacement amount is estimated and set by a logical calculation means based on the detection output of a sensor installed in the vehicle, and the supply/displacement means is controlled according to the set value, so that each wheel of the vehicle is In a suspension system that allows vehicle height to be adjusted by supplying and discharging pressurized fluid to and from a vehicle height adjustment body, this system detects the vehicle height reference value set in advance and the displacement of the vehicle height corresponding to the vehicle height. a deviation amount calculating means for calculating a vehicle height deviation amount by calculating a difference between the data and the vehicle height deviation amount at a predetermined timing; an integration calculation means for integrating the vehicle height deviation amount to obtain a deviation amount integrated value; means for comparing a set integration reference value; and controlling the supply/discharge means based on the target supply/discharge amount determined by the logical operation means, and controlling the supply/discharge means based on the processing result of the comparison means. A suspension device comprising: a control means for correcting the control content for the suspension device;