JPH01106718A - Vehicle suspension system - Google Patents

Abstract

PURPOSE:To enhance the follow-up ability of control by obtaining variations per unit time in data of vehicle operation such as a vehicle speed and the like, and by selecting one of control contents stored in memory in accordance with the result of the variations so as to allow a detected position of a suspension apparatus to coincide with the selected control content. CONSTITUTION:A computing means (d) computes variations (b) and manipulated values in accordance with signals from means for detecting manipulated conditions such as a vehicle speed, a steering angle, a braking degree, an acceleration and the like. With the result of the computation, a selecting means (f) selects one of various kinds of data stored in a memory means (e). Meanwhile, a second detecting means (c) detects an telescopic position of a suspension apparatus which is inputted to a control means (h) for controlling the suspension apparatus (a) so as to allow a signal from the second detecting means (c) to coincide with the control content selected by the selecting means (f). Thus, it is possible to estimate a variation in attitude in accordance with a running condition of the vehicle, thereby it is possible to enhance the follow-up ability of control.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a suspension control device used in a vehicle such as an automobile, and more particularly relates to a suspension control device for use in a vehicle such as an automobile. The present invention relates to a control device for a vehicle suspension that can maintain the posture of a vehicle in an appropriate state even when centrifugal force or the like changes.

"Prior Art and its Problems" When a vehicle is started by stepping on the accelerator, an inertial force acts backwards on the vehicle. the result,
The rear wheel suspension unit contracts and the front wheel suspension unit expands, causing the so-called sifting phenomenon in which the front of the vehicle body lifts up. When the vehicle reaches a desired speed and the accelerator is released to a certain extent, a so-called "rollback" occurs.

Furthermore, when a braking force acts on a running vehicle, inertial force acts forward on the vehicle. As a result, the front wheel suspension unit contracts, the rear wheel suspension unit expands, and a so-called north dive phenomenon occurs in which the front portion of the vehicle body sinks. Then, when the vehicle comes to a stop, rolling back occurs.

The larger the amount of change in acceleration or damping, the more rapidly these drift phenomena, north dive phenomena, or swingback appear.

Generally, when a vehicle corners, centrifugal force accompanying the rotation acts on the vehicle in a direction outward from the center of rotation. As a result, the outer suspension unit contracts and the inner suspension unit extends,
The vehicle body tilts and rolls occur. In this case, the resultant force of centrifugal force and gravity acts on the car body, but since the car body is tilted, the resultant acceleration acts on the passengers in a direction that is significantly deviated from the direction perpendicular to the car floor, making the ride uncomfortable. .

Conventionally, the following attempts have been made to solve this problem. One of them uses a height sensor to detect the inclination of the vehicle body, and feeds the result back to the controller, which controls each suspension unit to return the vehicle body to a horizontal position.

In this type of control, if the acceleration acting on the car body suddenly changes and the car body suddenly tilts significantly, the control speed cannot follow the speed of the change in the attitude of the car body, and the inclination of the car body cannot be adequately controlled. cannot be suppressed.

Furthermore, the following methods have been attempted as control methods when a vehicle performs cornering. In other words, in order to make the floor of the vehicle perpendicular to the direction of the resultant acceleration acting on the car body, an accelerometer detects the acceleration acting on the car body, then calculates the direction of the resultant acceleration, and calculates the direction of the resultant acceleration. Each suspension unit is controlled so that the floor of the vehicle is vertical. In this case as well, changes in the posture actually occurring in the vehicle body are detected and fed back to the controller to control each suspension unit.

Specifically, this suspension unit control is to adjust the amount of expansion and contraction of the suspension unit by supplying or discharging the hydraulic oil in the unit, and it takes a certain amount of time for each suspension unit to reach the desired amount of expansion and contraction. However, since this time delay occurs, there is a drawback that the control cannot sufficiently follow changes in posture that actually occur.

``Means for Solving the Problems'' ``The present invention has been made to solve the above problems, by preventing delays in the operation of each suspension unit,
The purpose is to obtain a vehicle suspension control device that can immediately respond to changes in attitude during cornering, sudden starts, and sudden braking, and in order to achieve this objective, the functional block diagram shown in FIG. In a vehicle suspension control device that adjusts the vehicle height by adjusting the amount of hydraulic oil in the suspension unit (a), the vehicle speed, steering, brake,
a first detection means (b) for detecting the operation state of various vehicle operations such as an accelerator that may cause a change in the attitude of the vehicle body; and a second detection means (c) for detecting the expansion/contraction position of the suspension unit. , a calculation means (d) for performing various calculations on the amount of change in vehicle speed per unit time, the amount of operation of the steering, brake, accelerator, etc., based on the detection data of the first detection means, and corresponding to the calculation results of this calculation means. storage means (e) in which various control contents of the suspension unit are stored in advance as storage data;
and a selection means for selecting one of the stored data stored in the storage means based on the calculation result of the calculation means, and a selection means for holding the storage data selected by the selection means; When the data is retained, a control means (g) for controlling the expansion/contraction position of the suspension unit to match the control content of the retained stored data based on the detection data of the second surface detection means;
I am trying to prepare for this.

"Operation" According to the present invention, after comparing the calculation result of the calculation means with various stored data in which control contents are stored in advance, one of the stored data corresponding to the calculation result is selected. . Further, after holding the selected storage data, the expansion and contraction positions of these suspension units are controlled based on the output signal of the second detection means for detecting the expansion and contraction positions of the suspension units. control to match the .

In other words, by appropriately selecting and retaining one of various types of storage data in which control details are stored in advance,
The system predicts a change in the posture of the vehicle that will occur later based on the current driving conditions of the vehicle, and controls the suspension unit in order to suppress the change in posture or change the posture to a desired one.

"Embodiment" Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 to 9.

According to this embodiment, each suspension unit of the vehicle is configured such that when the vehicle is cornering, the floor surface of the vehicle is maintained at an angle perpendicular to or close to the direction of the resultant acceleration acting on the vehicle. controlled.

FIG. 1 shows the arrangement of the suspension unit and each sensor. That is, suspension unit 1
a, 1 b and 2 a, 2 b are front wheels FR and P
It is attached to the axles of rear wheels RR and RL, and supports the right front, left front, right rear, and left rear of the vehicle body S, respectively. The heights of the right front part, left front part fr, and fQ of the vehicle body are determined by height sensors (second detection means) 3a, 3b.
respectively, and also the right rear of the vehicle body,
The left rear portion is measured by height sensors (second detection means) 5a and 5b, respectively.

Furthermore, the rotation angle of the steering wheel 6 is detected by a steering sensor (first detection means) 7.

As shown in Fig. 2, the height sensor in this embodiment divides the height positions of each of the molecules r, IQ, rr, and rQ of the vehicle body into seven regions, and sets the middle position ( N
) to the highest position (HH) and lowest position (LL) 7
A height detection signal consisting of a logic signal is output across stages.

Further, the speed sensor 35 is configured to detect the speed of the vehicle and output a signal corresponding to the speed.

Next, the configuration of the suspension control device according to this embodiment will be explained with reference to FIG.

In addition, suspension units 1a, lb, 2
Since all the suspension units 1a and 2b have the same configuration, only the suspension unit 1a is specifically illustrated, and illustrations of the other units are omitted.

The symbol IO is the suspension body. This suspension body 10 has an outer shell 2 having a cylindrical structure.
The rod 12 is inserted into the outer shell 11 so as to be relatively movable, and the piston 13 is attached to the tip of the rod 12. Divided into 14A and 14B, both oil chambers 14A and 14B are connected to the communication passage 13 provided in the piston 13.
It communicates via A.

On the other hand, a pressure oil passage 16 is formed in the center of the rod 12 in the axial direction of the rod 12. Then, by sending or discharging pressure oil into the oil chamber 14A and moving the piston 13 up and down, the amount of expansion and contraction of the suspension unit 1a is adjusted, and the right front part f of the vehicle body S is adjusted.
The height of r is adjusted. moreover,
The lower end of the outer shell 11 is connected to the axle via a knuckle 15, and the upper end of the rod 12 is fixed to the frame 17 via a mount rubber 18 provided on the frame 17. It is now possible to do so.

The pressure oil flow path 16 has a branch! 9 is connected,
This branch 19 is provided with a switching valve 21, and is further connected to traction accumulators 22A and 22B via damping force valves 20A and 20B, respectively, so as to be selectively connected to the hydraulic system. .

Further, the flow path I6 is connected to the hydraulic unit 2 through a pipe 23.
It is connected to the discharge side boat 24a and the return side boat 24b of No. 4, and the flow path toward each boat is provided with flow control valves 25A, 25B and switching valves 26A and 26B.

The hydraulic unit 24 includes a pump 27, a motor 2
8, a reservoir 29, and a relief valve 30.

Furthermore, a check valve 31 is provided between the discharge side pump 24a and the switching valve 26A.
An arcuumulator 32 is provided at a branch provided between the switching valve 26A and the switching valve 26A. This arcuumulator 32 is of a gas-filled type similar to the above-mentioned arcuumulator, and a pressure switch (first detection means) 33 is actuated by a change in its internal pressure.

The hydraulic piping 23 to each of the suspension units 1a-1b and the suspension units 2a and 2b has the same configuration and is connected to the hydraulic unit 24 in parallel.

And a suspension unit la having the above configuration.

1b, 2a, and 2b, pressurized oil is supplied to each suspension unit by operating the oil supply side switching valve 26A and connecting the suspension tank main body 10 to the discharge side boat of the hydraulic unit and soto 24. is extended to raise the position of each corresponding part of the vehicle body S, and the pressure is increased by operating the return side switching valves 26B and 26A to connect the suspension body 10 to the return side boat of the hydraulic unit 24. Oil is drained from each suspension unit la, lb.

2a and 2b are contracted by the weight of the vehicle, and the corresponding parts of the vehicle body S are lowered.

Furthermore, by operating the switching valve 21, the arcuumulator 22A, which is connected to the suspension body 10,
By changing the number of 22B, the spring constant and damping force of each suspension can be adjusted.

Next, the structure of the control circuit for the subenditane system will be explained using FIG. 4.

That is, the control of the suspension system is performed by a control unit (calculating means, storing means, selecting means, controlling means) 34, which is composed of a microcomputer or the like having a calculating section, a storage section, and a control section. The control unit 34 includes the height sensor 3a,
The detection signals of 3b, 5a, 5b, the detection signal of the steering sensor 7, the detection signal of the pressure switch 33, and the detection signal of the speed sensor (first detection means) 35 that detects the vehicle speed are manually input. , each suspension unit 1a, lb, 2a,
The refueling side switching valve 26A, return side switching valve 26B1, and damping force adjustment switching valve 21 for each of 2b are connected, and furthermore, the motor 28 of the hydraulic unit 24 is connected to control these. There is.

The storage section of the control unit 34 stores various types of data including three items of data regarding the amount of steering operation obtained from the steering sensor 7, that is, rotation direction, rotation angle, and rotation angular velocity, and one item of data obtained from the speed sensor 35, that is, vehicle speed. The combinations of are memorized, and the optimal expansion/contraction amount of each suspension unit (
The amount of oil that should be sent to each suspension), that is, the expansion and contraction position of each suspension so that the floor surface of the car body can be maintained in a direction perpendicular to the direction of the resultant force of centrifugal force and gravity, or in a direction as close to this as possible, is determined by the table. It is digitized and memorized.

That is, a certain set of values of steering rotation direction (10 or -), rotation angle (θ), rotation speed, and vehicle speed (V) is set as one data set. Assuming that the vehicle is running under the set of values at this moment, for example, calculate the vehicle's running speed and turning radius 0.5 seconds from now and get 0.5 seconds. Calculate the acceleration α that will later act on the vehicle body. The appropriate amount of expansion and contraction of each suspension unit to maintain the vehicle floor at an angle perpendicular or close to the direction of the combined acceleration of the acceleration α and the acceleration of gravity is divided into the seven regions shown in Figure 2. Calculate. Then, a set of logic representing each area is stored in correspondence with the data set described above. Similarly, another set of logic is determined for data sets consisting of other value combinations. In this way, the undefeated data set and the logic set are associated with each other, created into a table, and stored in the storage unit.

As shown in FIG. 8, the steering sensor 7 generates a detection signal proportional to the operating angle, with a positive signal when the steering wheel is operated to the right from the neutral point and a negative signal when the steering wheel is steered to the left. From this signal, the steering wheel operation direction and operation speed (change rate of the operation angle within unit time) are determined.
, the control unit 34 calculates the operating angle from the neutral point. In addition, the speed sensor 35
As shown in FIG. 9, the speed is converted into voltage and output. Note that these changes may be taken as changes in the number of pulses.

Next, the suspension units 1 a, l b
.

The operation of the control device 2a and 2b will be explained.

First, the inclination of the vehicle body in the case of cone ringing without suspension control will be explained with reference to FIG. 6.

A fixed load acts on each suspension unit of a vehicle traveling straight. For example, in FIG. When the cone ring starts, a rightward centrifugal force GC acts on the vehicle as shown in the figure. Then, the resultant force F of this centrifugal force GO and the gravity GM acting on the vehicle acts diagonally downward to the right. Therefore, the load acting on the suspension unit of the right wheel increases, the load acting on the suspension unit of the left wheel decreases, the right suspension contracts, the left suspension unit extends, and the vehicle has a certain roll angle. It will lean to the right. The centrifugal force GC or acceleration α acting at this time is determined by the speed of the vehicle at that moment and the radius of rotation.

Note that when a vehicle corners, maintaining the floor surface of the vehicle at an angle that is perpendicular to or close to perpendicular to the resultant acceleration acting on the vehicle (see Figures 5 and 7) improves ride comfort. Connecting has already been mentioned in the prior art.

Hereinafter, such subengitane 1 a, 1 b,
2 a.

The control of 2b will now be explained in detail.

While the vehicle is traveling straight, the control unit 34 controls all suspension units 1a, lb,
A control logic signal of "N" is held for 2a and 2b. And each height sensor 3a.

A logic signal indicating the height of each of the vehicle body parts r, f (2°rr, r4) detected by 3b, 5a, 5b is fed back to the control unit 34, and a control logic signal held in the control section , and each suspension unit la, 1b, 2a, 2b is
is controlled. During this time, the speed sensor 35
, the steering sensor 7 detects the vehicle speed and the steering angle (the steering angle is -0 because the vehicle is traveling straight).

When the steering wheel is operated to turn the vehicle, the steering sensor 7 detects the operating angle, as shown in FIG. A detection signal proportional to the magnitude of is output and input to the calculation section of the control unit 34. The calculation section uses this signal to determine the steering wheel operation direction,
Calculate the operating speed (change in operating angle per unit time) and operating angle from the neutral point. Further, the speed sensor 35 inputs a signal corresponding to the speed to the calculation section of the control unit 34, as shown in FIG. Next, the control unit 34 collates the set of data obtained in this manner, that is, data indicating the steering direction, steering angle, steering speed, and vehicle speed, with a table stored in the storage section of the control unit 34. . and,
A pre-stored set of logic corresponding to the set of data is found. As explained earlier, this logic is based on the acceleration α that is predicted to act on the vehicle 0.5 seconds from now based on the current running conditions of the vehicle, and the floor surface of the vehicle is affected by that acceleration or the resultant force of centrifugal force and gravity. This corresponds to the amount of expansion and contraction of each suspensicon at right angles to the direction of action.

The set of logic thus found, for example the suspension unit la on the right side of the vehicle.

First, the control logic signal "N" held in the control section of the control unit 34 is rewritten so that the logic for the left suspension units 1b and 2b becomes "H" and the logic for the left suspension units 1b and 2b becomes "L'. At this point, the vehicle body has not yet tilted, and the detection signals (logic signals) of each height sensor 3a, 3b, 5a, 5b are all "N", and are substantially different from the rewritten control logic signal. different.

Therefore, each suspension unit l a, 1 b,
2 a.

2b is started, and control is performed so that each expansion/contraction amount matches the corresponding control logic signal. That is, by operating the switching valve 26A on the oil supply side of the suspension unit 1a, 2a, the suspension body 10 is
and the discharge side boat 24 of the hydraulic unit 24 to start feeding pressure oil into the suspension units 1a, 2a, and the suspension units 1a,
2 Extend a.

On the other hand, the return opening switching valves 26B of the suspension units lb, 2b are operated to communicate the suspension main body 1O and the return side boat 24b of the hydraulic unit 24, and the return to the pressure oil unit 24 in the suspension unit is started. As a result, the suspension unit 1b,
2 b contracts due to the weight of the vehicle.

Then, after 0.5 seconds, the suspension unit Ia,
Suspension unit 2a is oiled so as to extend by an amount corresponding to the control logic signal "H", while suspension unit 1b, 2b
is drained so as to contract by an amount corresponding to the control logic signal "S". During this time, the height sensors 3 a, 3 b,
From 5a and 5b, each part of the car body molecules r, r(
A signal indicating the actual height of 1.degree.

Next, which speed sensor and steering sensor 3 should be selected first?
It is assumed that the vehicle speed and the steering angle at that moment are detected again 1, for example, 0.05 seconds after the travel data is detected by 5, and are input to the calculation section of the control unit 34.

Then, by the same procedure as described above, we further add 0
．． Find a set of logic that corresponds to the target roll angle (in this example, the roll angle at which the floor of the car body is perpendicular to the direction of the resultant force acting on the car) for the acceleration that will be acting on the car body after 5 seconds. . As a result, if the control logic signal is the same as the previous control logic signal, no rewriting is performed, and the control that is in progress is continued from the beginning, and each suspension unit 1a, 1b, 2
The height sensors 3a and 3b have determined that the amount of expansion and contraction of the height sensors 3a and 2b matches the logic signal controlled by the control section of the control unit 34.

Once confirmed by the outputs of 5a and 5b, feedback control is thereafter performed to maintain that state.

However, on the other hand, if the new set of logic selected from the table is substantially different from the control logic signals previously held in the control section of the control unit, for example, the new set of logic When the right suspension control system (1a, 2a) is "HH" and the left suspension unit (lb, 2b) is "LL", the control logic signal of the control section is immediately set to "H", "
"L" was rewritten to "HH" and "LL" respectively,
At the same time, each suspension unit 1a, l
Control of the expansion/contraction amounts of b, 2a, and 2b is started based on new control logic signals "HH" and "LL".

Further, when signals from the speed sensor 35 and the steering sensor 7 are input to the control unit 34 every 0.05 seconds, the above-described control is performed continuously.

In this way, when cornering, by comparing the constantly changing data with the data stored in the table and giving each suspension unit 1a-1b, 2a, 2b an appropriate amount of expansion and contraction, as shown in FIG. By adjusting the inclination of the vehicle body, the angle of the vehicle floor surface during cornering can be maintained in a direction substantially perpendicular to the direction of the resultant force F of centrifugal force GC and gravity GM, or in a direction as close to it as possible. .

Note that during this time, the height sensors 3a, 3b, 5
a, 5 b, each part of the car body molecules r, fLrr, r(
! When the height of each suspension unit 1a, 1b, 2a, 2b is detected and inputted to the control unit 34, the control unit 34
control so that the amount of expansion and contraction of the control unit matches the control logic signal of the control section of the control unit, and after matching, control is performed so that the matched state is maintained unless the control logic signal of the control section is rewritten. .

Furthermore, the control unit 34 activates the oil pressure source motor 28 in response to a signal from the pressure switch 33 that detects that the internal pressure of the pressure storage tank 32 has decreased from a specified value, and maintains the oil pressure of the suspension control system at an appropriate value. .

Furthermore, the suspension units 1g, 1b,
The spring constants of the suspension units 2a and 2b can be adjusted by operating the switching valve 21 and connecting the accumulators 22A and 22B to the hydraulic system as appropriate. If the control unit determines that the adjustment response speed of suspension units 1a, lb, 2a, and 2b is insufficient based on the speed at which the actual amount of expansion and contraction changes, suspension units 1a-1b, 2a, and 2b
The switching valve 2 is set so that the damping characteristics and spring constant of
1 to maintain safety.

That is, the connection between, for example, 22B of the accumulators 22A and 22B and the hydraulic system is cut off.

Then, the oil will only flow into the accumulator 22A, so the response speed for adjusting the suspension unit will become faster. If the response speed is too fast, increase the number of connected accumulators.

Next, a second embodiment of the present invention will be described with reference to FIGS. 1O to 14.

In this embodiment, each suspension unit is designed to maintain the vehicle body horizontally against the tendency to change when a force that causes a sudden change in posture, that is, acceleration or deceleration, acts on the vehicle. It controls the

In other words, even if there is a sudden change in acceleration or braking force that cannot be followed by conventional simple feedback control, or if the steering is suddenly operated, each suspension system is adjusted so that the vehicle body remains horizontal. control the jin unit.

In this embodiment, the same reference numerals are used for parts common to those in the first embodiment, and the description thereof will be omitted.

FIG. 1θ shows the arrangement of the suspension unit and each sensor according to this embodiment.

Suspension units 1a, Ib and 2a,
2b supports wheels PR, PL, RR, and RL, respectively, and their heights are determined by the height sensors 3a and 2b described above.
3 b.

5a and 5b, respectively. These height sensors output logic signals as height detection signals over seven stages, similar to the height sensor in the first embodiment (see FIG. 2).

In this embodiment, in addition to the steering sensor 7 and speed sensor 35 adopted in the first embodiment, a throttle position sensor (first detection means) 3 that detects the amount of accelerator operation, that is, the throttle position of the engine, is used.
7, a brake sensor (
(first detection means) 36.

The configurations of the suspension units 1a, 1b, 2a, 2b and the hydraulic unit 24 used in this embodiment are the same as those in the first embodiment, so their explanation will be omitted.

FIG. 11 shows a block diagram of the control system in this embodiment.

A control unit (computing means, storage means, selection means, control means) indicated by reference numeral 50 in FIG. 11 is similar to the control unit 34 in the first embodiment, and the control unit 50 includes height sensors 3a, 3b.
, 5a, 5b, steering sensor 7, pressure switch 33, speed sensor 35, brake sensor 37
and a detection signal from the slot position sensor 37 are input. The output of the control unit 50 is connected to the refueling side switching valve 26A1, the return opening switching valve 26B, the spring constant and damping force adjustment switching valve 21, and the motor 28.
a, 1b, 2a, and 2b are controlled as appropriate.

The control unit 50 in this embodiment includes a calculation section, a storage section, and a control section like the control unit 34 in the first embodiment.

As in the case of the first embodiment, the storage section stores various combinations of data obtained directly from each sensor or data obtained as a result of calculating data from each sensor in a calculation section, and the data corresponding to each combination. A logic set for each suspension unit is stored, and a time period during which the logic set is retained in the control unit by rewriting is stored in advance.

In the normal state, the control unit controls all the suspension units la, 1b, 2a, 2
The height sensor 3a holds the control logic signal "N" for the height sensor 3a.

3 b, 5 a, 5 b to each part r of the vehicle body S,
A detection signal indicating the height of r(1, rr, r(l) is input, and feedback control is performed so that all suspensions are maintained at the amount of expansion and contraction corresponding to the control logic signal "N". ing.

The calculation section includes a speed sensor 35, a brake sensor 36,
Signals from the throttle position sensor 37 and steering sensor 35 are input, and various calculations are performed when the brake pedal, accelerator, or steering wheel is operated. For example, when the accelerator is operated, the throttle movement direction, throttle opening degree, and throttle opening/closing speed are calculated based on the signal from the throttle position sensor 37.

Then, for example, the amount of change in acceleration acting on the vehicle after 0.5 seconds is predicted, and whether or not the amount of change is less than a predetermined value is determined. It is determined whether the change layer is within a range that can be followed.

Similarly, when the brake pedal is operated, the direction of brake operation (increasing or decreasing direction), brake pressure, and amount of change in brake pressure per unit time are calculated based on the signal from the brake sensor 36, and the steering When the accelerator is operated, the operation direction, operation angle, and operation speed are calculated from the signal from the steering sensor 7, and the same calculations and judgments as when the accelerator is operated are performed.

Various combinations of the various data described above are stored in advance in the storage unit. In other words, each suspension unit determined for each combination of data according to the following procedure is stored in this storage section! a, l b, 2 a,
The set of logic for 2b and the retention time of that logic are stored.

For example, assume a set of data on vehicle speed, throttle movement direction, throttle opening degree, and throttle opening/closing speed. Under these set conditions, for example, the amount of change in acceleration acting on the vehicle after 0.5 seconds is calculated. Then, the state of change in the load acting on each suspension based on the change in acceleration, that is, the amount of increase or decrease in load per unit time and the duration of the increase or decrease are calculated.

Then, in response to such an increase or decrease in load, the supply or discharge of oil to the suspension takes place continuously for the duration in equilibrium, resulting in suspension units 1a, 1b.

The amount of expansion and contraction of 2a and 2b does not change, logic 1N"
The logic for controlling the supply and discharge of oil to the suspension units 1a, 1b, 2a, 2b so that the suspension units 1a, 1b, 2a, 2b are maintained in a state corresponding to , 2 b
required for.

The logic set and duration obtained in this manner are stored in the storage unit as a table in correspondence with the data set described above.

Next, with reference to FIGS. 12(A) to 12(C), a description will be given of control for suppressing the drift phenomenon and the swinging back when the vehicle starts. Diagram (a) in FIG. 12(A) shows an example of a change in the output of the throttle position sensor 37 when the vehicle starts.
The diagram (b) in FIG. 12(B) shows the corresponding change in the output of the speed sensor 35. Time L1
Since the vehicle is stopped at , the signal from the speed sensor 35 indicates that the vehicle speed is zero. At this time, the accelerator is suddenly stepped on, and the output of the throttle position sensor 37 changes rapidly, as shown by the portion indicated by point A in diagram (a). Based on the signals from the speed sensor 35 and throttle position sensor 37 at this time, the calculation section of the control unit 50 calculates the throttle movement direction, throttle opening degree, and throttle opening/closing speed, and also calculates the change in acceleration after 0.5 seconds. The amount is calculated and it is determined whether it is larger than a predetermined value. For example, if the accelerator pedal is depressed slowly and it is determined that the amount of change in acceleration is smaller than a predetermined value, the normal feedback control described above is performed.

However, if it is determined that the amount of change in acceleration is larger than a predetermined value, the data of the vehicle speed, throttle movement direction, throttle opening, and throttle opening/closing speed at that time is compared with a table stored in the storage section of the control unit 50. and a corresponding logic set, for example logic (L) for suspension unit la, 1b, suspension unit 2a.

Logic (H) and duration T1 are selected for 2b.

, and the control logic signal "N" for each suspension unit that was previously held in the control section is rewritten by the newly selected logic.

In this state, the height sensors 3a', 3b, and 5a.

Since the logic signal 5b is substantially different from the control logic signal held in the control section, it starts a control operation for each suspension unit. That is,
The control section of the control unit 50 opens the oil drain side switching valves 26B of the suspension units 1a and 1b and switches the suspension unit main body 11 to the pressure oil unit 2.
The suspension main body 11 is communicated with the return side boat 24b of the pressure oil unit 24 by opening the oil supply side switching valve 26A of the suspension units 2a and 2b. As a result, the load acting on the front wheel suspension units Ia and lb starts to decrease, and at the same time, the front wheel suspension units Ia and lb.

The oil starts to be discharged from the rear wheel suspension units 2a and 2b, and the load acting on the rear wheel suspension units 2a and 2b starts to increase, and at the same time, oil starts to be supplied to the suspension units, so that changes in the attitude of the vehicle are suppressed. Ru.

Then, for a predetermined duration T+, each suspension unit la responds to an increase or decrease in load.

When the refueling and draining of lb, 2a, 2b is continued and the duration T, has elapsed, all the control logic signals of the control section become "
At this point, the amount of change in acceleration acting on the vehicle is small, so normal feedback control is resumed.

Note that during this duration T, for example, 0.0
Assuming that signals from the speed sensor 35 and the throttle position sensor 37 are input every 5 seconds, the logic corresponding to the change in acceleration predicted to occur after 0.5 seconds is selected according to the procedure described above. If the newly selected logic is the same as the control logic signal held in the control section, the logic is not rewritten and the control that was previously in progress is continued.

However, if the newly selected logic is different,
The newly selected logic, for example the logic “L” for front wheel suspension units 1a, 1b.
L”, rear wheel suspension unit 2 a, 2 b
The control logic signals "L" and "H" previously held in the control unit are rewritten so that the logic becomes "HH" for the new control logic signal, and control is started according to the new control logic signal. The control continues for a new duration T.

In this way, even after the control logic signal of the degree control unit is rewritten and control using the control logic signal is started, the control logic signal may be rewritten as necessary in response to subsequent changes in vehicle running conditions, etc. It is supposed to be done. Regarding this point, the same applies to each case described below, and a redundant explanation will be omitted for each case thereafter.

In the middle period of the acceleration operation, normal feedback control is performed because the acceleration does not change to the extent that it exceeds a predetermined value. In the latter stage of the acceleration operation, when the accelerator is released at time t, the output of the throttle position sensor 37 rapidly decreases as indicated by arrow B in diagram (a). If it is determined that the resulting acceleration change is larger than a predetermined value, the same process as before is performed, and for example, (H) for the front wheel suspension units 1a, 1b, the rear wheel (L) and duration T are selected as the logic for the suspension units 2 a and 2 b, and based on these logics, the control logic signal of the control section of the control unit 50 is rewritten.

Here, since the logic signals output from each height sensor are substantially different from the control logic signals, the oil supply side switching valves 26A of the front wheel suspension units (la, Ib) are opened to switch the suspension units (la, 1b) from the pressure oil unit (24). The suspension units 2a, 2b are communicated with the return boat 24b of the pressure oil unit 24 by opening the drain oil side switching valves 26B of the rear wheel suspension units 2a, 2b.

Therefore, as the load on the front wheel suspension begins to increase, oil supply to the front suspension units 1a, 1b begins, and as the load on the rear wheel suspension begins to decrease, the same suspension units 2a,
Oil draining from 2b is started, and the oil supply and oil draining are continued for a predetermined duration T, thereby suppressing swinging back.

After the duration T has elapsed, all the control logic signals of the control section are rewritten to "N" again, and feedback control is restarted. Diagrams (c) and (d) in FIG. 12(C) show the above-mentioned control state. Note that if the accelerator is returned slowly at time t and the change in acceleration is smaller than a predetermined value, feedback control will be performed, unlike the control described above. Also, time t,
If the output of the throttle position sensor 37 suddenly changes as shown by the dotted line in diagram (a) and the change in acceleration exceeds a predetermined value, the same control as described above is performed.

With reference to FIGS. 13(A) to 13(C), a description will be given of control for suppressing the dive phenomenon and the swinging back when a braking force is applied to the vehicle. The diagram (ao) in FIG. 13(A) shows an example of the output of the brake sensor 36 when a braking force is applied to the vehicle, and the diagram (ao) in FIG.
The diagram (bo) in B) shows the corresponding output of the speed sensor 35.

When a braking force is applied to a vehicle traveling at a certain speed by suddenly stepping on the brake pedal (not shown) at time t, °, the area indicated by the zero point in the diagram (ao) The output of the brake sensor 36 changes rapidly.

Then, the brake operating direction, brake fluid pressure, and amount of change in brake fluid pressure per unit time are calculated by the calculation section of the control unit 50 at this time, and the amount of change in acceleration expected after 0.5 seconds is calculated based on the predetermined amount of change in acceleration. Determine whether it is greater than or equal to the value. If the amount of change in acceleration is equal to or greater than a predetermined value, a logic set corresponding to the combination of data in this case is stored from the storage section of the control unit 50, such as logic for front wheel suspension units 1a and 1b. 'H', rear wheel suspension unit 2
a.

2b is selected as the logic "L" and the duration time TI", and the control logic signal "N" held in the control section of the control unit 50 is changed to the newly selected logics "H" and "L". ”.Here, the control logic signal and the height sensors 3a, 3b,
5a and 5b are substantially different from each other, control of each suspension unit is started, and as the load acting on the front wheel suspensions 1a and 1b begins to increase, refueling is started, and the rear wheel suspension 2 a
, 2. At the same time as the load on b starts to decrease, oil draining starts, and this oil supply and draining continues for a predetermined duration T1°, thereby suppressing the dive phenomenon. When time T I' elapses, all control logic signals are automatically rewritten to "N",
Feedback control is started again. And time t,
At 1, the brake pedal is returned and the brake sensor 3
When the output of 6 suddenly decreases as indicated by point D in the diagram (ao), the front wheel suspension unit 1
Logic "L" for a, lb, logic "H" for rear wheel suspension units 2a, 2b, and duration T% are selected, and the same control as described above is performed to suppress back-swinging. That will happen.

Further, the diagrams (C') and (d') in FIG. 13(C) show the above control state. If the operation of the brake pedal is gentle and the amount of change in acceleration does not exceed a predetermined value, the control logic signal is not rewritten and feedback control is continued, tl''.

It will be easily understood that if the amount of change in acceleration exceeds the predetermined value even at times other than t and l, the above-described control will be performed.

With reference to FIGS. 14(A) to 14(C), a description will be given of control for suppressing rolling when the steering wheel is suddenly operated while the vehicle is traveling. In other words, the line diagram (a” in FIG. 14(A) and FIG. 14(B)
), (b”) are when the vehicle is traveling at a constant speed,
Time 1. This shows that the steering wheel suddenly started rotating in one direction at time t, and started rotating in the opposite direction at time t.

Then, at time t, the calculation section of the control unit 50 calculates the steering direction, rotation angle, and rotation angle based on the signal from the steering sensor 7.
Based on these and the signal from the speed sensor 35, 0.
If it is determined that the amount of change in acceleration after 5 seconds is larger than a predetermined value, a predetermined logic is applied, for example logic "H" for the right suspension units 1a and 2a, and logic "H" for the left suspension units lb and 2b. The logic ``shi'' and the duration T,'' are selected from the storage section of the control unit 50, and the control logic signal in the control section is rewritten to control each suspension unit 1a, 1b, 2a, 2b. Start.

After the control is continued for the time TI'', the control logic signal is rewritten to "N" and the feedback control is resumed.At the time t!'', the control logic signal is rewritten to "N" and the feedback control is resumed. Logic “L” for left suspension unit l b, 2 b, logic “H” for duration T1 is selected and controlled accordingly.

In addition, the line diagrams (C") and (d") in Fig. 14 (C)
shows the control status.

In the vehicle suspension control device described in the above embodiment, based on the detection data output from the steering sensor 71, pressure switch 33, speed sensor 35, brake sensor 36, and throttle position sensor 37, In order to predict the attitude change of the vehicle S that will occur in 0.5 seconds (0.5 seconds later), and to suppress the attitude change or change it to a desired attitude, each suspension unit la, lb, 2a, 2b is immediately activated.
control started.

This eliminates the delay in the operation of suspension units 1a, 1b, 2a, and 2b, which is the case with conventional control devices that perform control using only feedback. , posture control in the case of sudden braking, etc. can be performed effectively, and ride comfort can be significantly improved.

In the above explanation, we have divided into cases where a sudden acceleration force is applied to the vehicle, a case where a sudden braking force is applied, and a case where a sudden steering operation is performed. It will be understood that it is of course possible to control the situation. For example, this may occur when the brake pedal is suddenly depressed and the steering wheel is operated rapidly. In this case, the speed sensor,
The calculation section of the control unit performs various calculations based on inputs from the brake sensor and the steering sensor. In addition, the memory section stores various combinations of vehicle speed, brake operation direction, brake pressure, rate of change in brake pressure, steering operation direction, operation angle, operation angular velocity, etc., and the corresponding logic for each suspension unit. becomes. In this case, unlike the previous three cases, the logic for the four suspension units may all be different from each other.

"Effects of the Invention" As explained in detail above, the vehicle suspension control device of the present invention can predict changes in the vehicle's attitude that will occur later based on the vehicle's current running conditions. In order to suppress the attitude change or change the attitude to a desired one, control of each suspension unit is immediately started. Therefore, the attitude control when the vehicle is cornering or when suddenly starting or braking can be effectively performed, and the riding comfort is greatly improved.

[Brief explanation of the drawing]

1 to 9 are diagrams showing a first embodiment of the present invention, in which FIG. 1 is a perspective view showing the arrangement of the sensor, and FIG. 2 shows the types of logic signals output from the height sensor. Explanatory diagram, Figure 3 is a hydraulic system diagram for operating the suspension unit, Figure 4 is a block diagram of the control system, Figure 5 is an explanatory diagram of the direction of acceleration applied to the vehicle body, and Figure 6 is when suspension control is not performed. 7 is a front view of the vehicle body whose roll has been corrected by suspension control; FIG. 8 is an output characteristic diagram of the steering sensor;
Figure 9 is the output characteristic diagram of the speed sensor, Figures 10 to 1
5 is a diagram showing a second embodiment of the present invention, FIG. 10 is a perspective view showing the arrangement of sensors (throttle position sensor/brake sensor), FIG. 11 is a block diagram of the control system, and FIG. 12 (A) to FIG. 12(C) are diagrams showing anti-slip control, in which FIG. 12(A) is a diagram showing the output of the accelerator sensor, and FIG. 12(B) is a diagram showing the output of the speed sensor. FIG. 12(C) is a diagram showing control signals of the control unit based on the outputs of the accelerator sensor and speed sensor, and FIGS. 13(A) to 13(C) are diagrams showing anti-spout control. Diagram (A)
13(B) is a diagram showing the output of the brake sensor, FIG. 13(C) is a diagram showing the control signal of the control unit based on the output of the brake sensor and the speed sensor, Figure 14 (A) - 14th
Figure (C) is a diagram showing anti-roll control, and shows the 14th
Figure (A) is a diagram showing the output of the steering sensor, No. 14.
Figure (B) is a diagram showing the output of the speed sensor, Figure 14 (
C) is a diagram showing control signals of the control unit based on the output of the steering sensor, and FIG. 15 is a functional block diagram showing the configuration of the present invention. la, 1b, 2a, 2b...Suspension unit, 3a, 3b...Height sensor (second detection means), 5a, 5b...Height sensor (second detection means) detection means), 7... Steering sensor (
(first detection means), 33... pressure switch (first detection means), 35... speed sensor (first detection means), 36... brake sensor (first detection means), 37... Throttle position sensor (first detection means), 34...
Control unit (computation means, storage means, selection means, control means), 50... Control unit (computation means, storage means, selection means, control means).

Claims (7)

[Claims] (1) In a vehicle suspension control device that adjusts the vehicle height to a desired height by supplying and discharging hydraulic fluid in the suspension unit, the vehicle speed and the posture of the vehicle body such as steering, brakes, and accelerators are controlled. a first detection means for detecting operating states of various vehicle operations that may cause changes; a second detection means for detecting an expansion/contraction position of the suspension unit; and a unit based on the detection data of the first detection means. A calculating means for various calculations of the amount of change in vehicle speed per hour and the amount of operation of the steering, brake, accelerator, etc., and various control contents of the suspension unit corresponding to the calculation results of this calculating means are stored in advance as storage data. a selection means for selecting one of the stored data stored in the storage means based on the calculation result of the calculation means; a storage means for holding the storage data selected by the selection means; If the data is retained,
and a control means for controlling the expansion/contraction position of the suspension unit to match the control contents of the stored stored data based on the detection data of the second detection means. Control device. (2) The first detection means includes a speed sensor that detects the vehicle speed and a steering sensor that detects the amount of steering operation, and the control content stored in the storage means acts on the vehicle when the vehicle is cornering. 2. The vehicle suspension control device according to claim 1, wherein the amount of expansion and contraction of the suspension unit is such that the floor surface of the vehicle is positioned substantially perpendicular to the direction of the resultant acceleration. (3) The calculation means receives the output signals of the speed sensor and the steering sensor, calculates the vehicle speed, the steering direction, the steering angle, and the steering speed, and the amount of expansion and contraction of the suspension unit stored as the control content is: the calculated vehicle speed, steering operation direction,
Claims 1 and 2 are characterized in that the acceleration is determined based on the magnitude of acceleration that will act on the vehicle under the same conditions as the operating angle and operating speed after a certain period of time. Vehicle suspension control device. (4) The storage means stores a retention time corresponding to each of the control contents, and when the control means retains one of the control contents, the retention time corresponding to the retained control contents is stored in the storage means. 2. The vehicle suspension control device according to claim 1, wherein said control content is maintained for a limited period of time, and said suspension unit is controlled based on said control content. (5) The first detection means includes a speed sensor that detects vehicle speed and a sensor that detects the amount of operation of at least one of steering, brake, and accelerator, and the calculation means includes an output of the sensor. An amount of change in acceleration acting on the vehicle that occurs after a predetermined period of time is calculated, and if the calculated amount of change exceeds a predetermined value, the rewriting means rewrites the control content held in the control means. A control device for a vehicle suspension according to claim 1. (6) The vehicle suspension control device according to claim 1, wherein the second detection means is a height sensor. (7) The output signal of the second detection means is a logic signal, and the control contents stored in the storage means are stored in logic form.
A control device for a vehicle suspension according to paragraph 1.