JP2001121939A - Suspension controlling device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a suspension controlling device that makes a gas spring of a semi-active suspension variable to give fully a damping function. SOLUTION: A proportional solenoid valve 5 is intervened in a hydraulic circuit that connects a hydraulic damper 3 with an accumulator 4, and a hydraulic circuit connected with at least one other accumulator 14 is branched from the hydraulic circuit connected between the proportional solenoid valve 5 and the accumulator 4 to intervene an ON-OFF valve 15 for gas spring variation with the hydraulic circuit. A controller 6A that opens fully the proportional solenoid valve 5 and opens the ON-OFF valve 15 for gas spring variation at the time of minimum damping force to control in a way that the proportional solenoid valve 5 is throttled in proportion to a vertical speed of vehicle body and the ON-OFF vale 15 for gas spring variation is closed when a damping force is needed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a plurality of legs (wheels).
The present invention relates to a suspension control device for a passenger vehicle in which a vehicle body is supported (suspended) via a hydraulic damper (suspension cylinder).

[0002]

2. Description of the Related Art In recent years, in such a suspension control device, a hydraulic active suspension or the like has been put into practical use as a system for achieving a high level of ride comfort and steering stability. There is a problem that a power source is required.

On the other hand, a semi-active suspension that controls the damping force of a hydraulic damper in real time in accordance with the vibration state of a vehicle is inferior to the active suspension in terms of steering stability, but is expected to provide a ride quality close to that of the active suspension. It is said that it does not require a power source such as a hydraulic pump and is excellent in energy consumption.

This semi-active suspension is constituted by a hydraulic circuit as shown in FIG. 7, for example.

According to this, a proportional solenoid valve 5 is interposed in the hydraulic circuit connecting a hydraulic damper (suspension cylinder) 3 connected to the rolling wheel 1 via a bell crank 2 and an accumulator 4. 5 is controlled by the controller 6 in accordance with the control method shown in Table 1 below, so that the damping force is adjusted.

[0006]

[Table 1] In Table 1 above, vb-vw: Output of vertical relative speed sensor between wheel and vehicle vb: Output of vehicle vertical speed sensor Fd: Damping force min: Minimum damping force C: Coefficient

In the figure, reference numeral 7 denotes a relief valve for preventing an excessive rise in the hydraulic pressure in the circuit, 8 denotes an automatic switching valve for driving the hydraulic pressure of the proportional solenoid valve 5, and 9 denotes a passive control (see FIG. Control), consisting of a check valve and a fixed orifice.

The control logic for achieving the above control method will be described with reference to the block diagram of the semi-active control shown in FIG.

First, a vehicle vertical speed measurement voltage from a vehicle vertical speed sensor (refer to the vehicle vertical speed sensor 12 in FIG. 1) is calculated by a calculation unit 20 as a vehicle vertical speed measured voltage physical quantity conversion coefficient.
After the speed is converted by multiplying by Gdzb, the operation unit 21 unnecessarily turns off the switch 22 when the suspension is stopped.
To avoid N-OFF operation, the bias value Cv
(A constant value, for example, 2 cm / sec) is added and branched and input to the operation unit 23 and the operation unit 24.

Next, an absolute value is obtained by the arithmetic unit 23, and the absolute damping value is multiplied by a negative target damping force coefficient Ksemi by the arithmetic unit 25 to determine a target damping force (for example, the proportional electromagnetic force shown in FIG. 9). As can be seen from the graph showing the relationship between the valve opening degree and the absolute vertical velocity of the vehicle body, the two are inversely related, so they are given in the form of a decreasing function, and in the opposite case, they are given in the form of an increasing function. Corresponding.) Thereafter, the voltage is converted into a voltage signal by multiplying the proportional solenoid valve voltage signal conversion coefficient Ksp by the calculation unit 26, and then input to the calculation unit 27.

Next, in the operation unit 27, the operation unit 2
Kbias (constant value) is added to the voltage signal from switch 6 and a voltage signal from switch 22 described later.
When there is no voltage signal from the controller (minimum 0 V), the voltage signal from the operation unit 26 plus Kbias (constant value) is applied to the limiter 28 of the proportional solenoid valve 5 to generate a proportional solenoid valve voltage command as a proportional solenoid valve voltage command. It is input to the valve driver 29.

On the other hand, the measurement unit 30 calculates the voltage between the wheel and the vehicle relative vertical speed from the wheel and vehicle vertical relative speed sensor (see the wheel and vehicle vertical relative speed / displacement sensor 11 in FIG. 1). After being converted into a speed by multiplying the measured relative physical speed conversion coefficient Gdw between the up-down relative speed between the wheel and the vehicle, the arithmetic unit 31 calculates
A bias value Cv (a constant value, for example, 2 cm / sec) is added to the arithmetic unit 2 in order to avoid unnecessary ON-OFF operation when the suspension of a switch 22 described later is stopped.
4 is input.

The arithmetic unit 24 multiplies the speed signals of the arithmetic unit 21 and the arithmetic unit 31, and the signal sw is input to the switch 22. In this switch 22, the signal
When sw is sw ≧ 0, in1 is output, that is, minimum 0V. When sw <0, in2 is output, ie, maximum Kbias (proportional solenoid valve fully open signal) × 5.
Output V. Therefore, when the voltage signal from the switch 22 is Kbias × 5V at the maximum, the arithmetic unit 27 adds the voltage signal from the arithmetic unit 26 and Kbias (constant value) to the result, and the result is applied to the limiter 28. It is input to the proportional solenoid valve driver 29 as a proportional solenoid valve voltage command.

Thus, when the damping force is at a minimum (min),
When the proportional solenoid valve 5 is fully opened to return the pressure oil to the low-pressure side (accumulator side), if a damping force is required, a damping force proportional to the vehicle body vertical speed is generated. Is squeezed in proportion to.

As can be seen from the graph of the suspension control performance (triangular wave time response) at each vehicle speed of the active control in FIG. 10 and the graph of the suspension control performance at each vehicle speed of the conventional semi-active control in FIG. In a high vehicle speed range, the two can obtain substantially the same riding comfort (damping effect), while the conventional semi-active control does not require a power source such as a hydraulic pump, so that energy consumption can be reduced. .

[0016]

However, in the conventional semi-active suspension as described above,
Since the gas spring at the time of the minimum damping force (Fd = min) at which one accumulator 4 is fully opened and the proportional solenoid valve 5 is fully opened is constant, when the vehicle speed is low, the gas spring becomes firm, and the vibration damping action is sufficient. There was a problem that it was not exhibited. Further, since the semi-active control also includes a passive control element, there is a problem that the damping effect is small when the vehicle speed is low (see the graphs of FIGS. 10 and 11).

The present invention has been made in view of the above-mentioned circumstances, and provides a suspension control device capable of exerting a sufficient damping action by changing a gas spring of a semi-active suspension, and changing the gas spring. It is an object of the present invention to provide a suspension control device capable of obtaining a large vibration damping effect in a wide range of vehicle speeds from a low speed to a high speed while reducing energy consumption by combining active control with semi-active control.

[0018]

According to the present invention, there is provided a suspension control device for a vehicle in which a vehicle body is supported via a hydraulic damper for each of a plurality of rolling wheels. And a hydraulic circuit that connects the accumulator with a proportional solenoid valve. A hydraulic circuit that is connected to at least another accumulator is branched from a hydraulic circuit between the proportional solenoid valve and the accumulator, and a gas spring is changed to the hydraulic circuit. When the damping force is minimum, the proportional solenoid valve is fully opened and the gas spring variable ON-OFF valve is opened. When damping force is required, the proportional solenoid valve is proportional to the vehicle vertical speed. And a controller that controls to close the gas spring variable ON-OFF valve.

Further, a hydraulic circuit from a hydraulic pump is connected to a hydraulic circuit between the hydraulic damper and the proportional solenoid valve, and a servo valve is interposed in the hydraulic circuit. The controller detects vibration or sway of the vehicle body. The servo valve is controlled to open and close so as to obtain a maximum flat feeling.

Further, the gas spring variable ON-OFF valve is controlled to open and close by switching an electromagnetic switching valve.

[0021]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a suspension control device according to the present invention.

[First Embodiment] [Structure] FIG. 1 is a schematic diagram of a suspension control device according to a first embodiment of the present invention, FIG. 2 is a hydraulic circuit diagram, and FIG. 3 is a gas spring variable semi-active control. FIG. 1 to 3, the same members as those in FIGS. 7 and 8 are denoted by the same reference numerals, and redundant description will be omitted.

As shown in FIG. 1, a plurality (four in the figure)
The vehicle body 10 is supported (suspended) via the bell crank 2 and the hydraulic damper (suspension cylinder) 3 for each of the rolling wheels 1. And, between the vehicle body 10 and the wheel 1,
A vertical relative speed / displacement sensor 11 between the vehicle bodies is provided, and a vehicle vertical speed sensor 12 is attached to the vehicle body 10 close to the vertical relative speed / displacement sensor 11 between the wheel and the vehicle. Further, a pressure sensor (cylinder pressure sensor) 13 is attached to the hydraulic damper 3. These sensor outputs are supplied to a controller 6A described later.
Is input to

As shown in FIG. 2, a hydraulic circuit connected to another accumulator 14 branches from a hydraulic circuit connecting the proportional solenoid valve 5 and the accumulator 4 to a hydraulic circuit. An -OFF valve (open / close valve) 15 is interposed. This ON-OFF valve 15
Is controlled by the controller 6A via the electromagnetic switching valve 16.

The controller 6A operates as shown in Table 2 below.
In the control method shown in (1), the opening of the proportional solenoid valve 5 is adjusted, and the ON / OFF valve 15 is controlled to open and close to adjust the damping force. Other configurations are the same as those in FIG.

[0026]

[Table 2] In the above Table 2, vb-vw: Output of the vertical relative speed sensor between the wheel and the vehicle vb: Output of the vehicle vertical speed sensor Fd: Damping force min: Minimum damping force C: Coefficient

The control logic for achieving the above control method will be described with reference to the block diagram of the gas spring variable semi-active control shown in FIG.

According to this, the switch 2 described with reference to FIG.
2 is input to the arithmetic unit 27 and turned on.
The signal is applied to the limiter 32 of the -OFF valve 15, and when there is no voltage signal from the switch 22 (minimum 0 V),
OFF (close) signal is ON-OF as N-OFF valve command
When the voltage signal input to the F-valve driver 33 and the voltage signal from the switch 22 is Kbias × 5V at the maximum, the ON (open) signal is
The data is input to the N-OFF valve driver 33. Other configurations are the same as those in FIG.

In this embodiment, when the damping force is minimum (min), the proportional solenoid valve 5 is fully opened to return the pressure oil to the low pressure side (accumulator side) and
The N-OFF valve 15 is opened to enable the use of the accumulator 14 to soften the gas spring under the action of the two accumulators 4 and 14. On the other hand, when a damping force is required, the ON-OFF valve 15 is used to harden the gas spring. When closed, the accumulator 14 becomes unusable, and the proportional solenoid valve 5 is throttled in proportion to the vehicle body vertical speed in order to generate a damping force proportional to the vehicle body vertical speed.

This makes it possible to make the gas spring variable while using the advantage of the semi-active suspension, which does not require a power source such as a hydraulic pump and is also excellent in energy consumption, thereby exhibiting a sufficient vibration damping action (the gas spring shown in FIG. 12). Suspension control performance (triangle wave time response) at various vehicle speeds with variable semi-active control (see graph).

[Second Embodiment] [Configuration] FIG. 4 is a hydraulic circuit diagram of a suspension control device according to a second embodiment of the present invention, and FIG. 5 is a block diagram of the same active control. In FIG. 4, the same members as those in FIG. 2 are denoted by the same reference numerals, and redundant description will be omitted.

This embodiment combines active control with the gas spring variable semi-active control of the previous embodiment,
This is so-called hybrid control. That is, as shown in FIG. 4, a hydraulic circuit from a hydraulic pump is connected in the middle of a hydraulic circuit connecting the hydraulic damper 3 and the proportional solenoid valve 5, and a servo valve 17 and a downstream of the servo valve 17 (hydraulic damper 3) are connected in the middle of this hydraulic circuit. Side), a hydraulically driven active ON-OFF valve (open / close valve) 18 is interposed. The ON / OFF valve 18 is controlled to be opened and closed by a controller 6B via an electromagnetic switching valve 19, similarly to the servo valve 17.

The controller 6B controls the opening of the proportional solenoid valve 5 and controls the opening and closing of the ON-OFF valve 15 by the control method shown in Table 2 above. The opening is adjusted by the control logic shown. The ON-OFF valve 18 is a valve for switching only between semi-active control and (semi-active control-active control). Is always controlled to be open and the damping force is adjusted. Other configurations are the same as those in FIG.

The control logic of the servo valve 17 is shown in FIG.
This will be described with reference to the block diagram of the active control shown in FIG.

First, a vehicle body vertical speed measurement voltage from the vehicle body vertical speed sensor 12 (see FIG. 1) is converted into a speed by a calculation unit 34 by multiplying the vehicle body vertical speed measured voltage physical quantity conversion coefficient Gdzb, and then a predetermined gain is obtained. The result is multiplied by K1 and input to the calculation unit 39.

The measurement voltage of the vehicle body vertical displacement is calculated by the arithmetic unit 3.
After being converted into a displacement by multiplying the vehicle body vertical displacement measurement voltage physical quantity conversion coefficient Gzb at 5, the displacement is multiplied by a predetermined gain K2 and input to the calculation unit 39. The vehicle body vertical displacement is calculated by integrating the vehicle body vertical speed.

Further, the voltage for measuring the vertical speed of the rolling wheel from the vertical relative speed / displacement sensor 11 (see FIG. 1) between the rolling wheel and the vehicle body is expressed by:
The calculation unit 36 calculates the rolling wheel vertical speed measured voltage physical quantity conversion coefficient Gdw
, And is converted into a speed, multiplied by a predetermined gain K3, and input to the calculation unit 39. The rolling wheel vertical speed is obtained by subtracting the rolling wheel-vehicle vertical relative speed from the vehicle body vertical speed.

The measured voltage of the vertical displacement of the wheel is calculated by the arithmetic unit 3.
After being converted into a displacement by multiplying the rolling wheel vertical displacement measurement voltage physical quantity conversion coefficient Gw at 7, the displacement is multiplied by a predetermined gain K4 and input to the calculation unit 39. Note that the rolling wheel vertical displacement is obtained by subtracting the rolling wheel-vehicle vertical relative displacement from the vehicle body vertical displacement.

After the cylinder pressure measurement voltage from the pressure sensor 13 (see FIG. 1) is converted into a pressure by the calculation unit 38 by multiplying the cylinder pressure measurement voltage physical quantity conversion coefficient Gp,
The signal is multiplied by a predetermined gain K5 and input to the calculation unit 39.

The arithmetic section 39 subtracts all of the five signals to generate a control signal. After the control signal is multiplied by the servo valve voltage signal conversion coefficient Ks in the arithmetic section 40, the control signal is converted into a voltage signal. Are input to the servo valve driver 41. An ON / OFF signal is appropriately input to the ON-OFF valve driver 42 of the ON-OFF valve 18.

[Operation / Effect] As described above, under the active control, the vehicle body vertical speed sensor 12, the wheel-
Vertical relative speed / displacement sensor 11 and pressure sensor 1 between vehicle bodies
3, the suspension cylinder (hydraulic damper) 3 is continuously operated so as to obtain a maximum flat feeling, thereby achieving a high level of both riding comfort and steering stability (each of the active control in FIG. 10). Suspension control performance at vehicle speed (triangle wave time response) graph).

Therefore, each of the gains K1, K2, K3, K4, K5
(This makes it possible to reduce the energy consumption of the hydraulic pump), and if the active control and the gas spring variable semi-active control are used in combination by opening the ON-OFF valve 18 at all times, that is, if the hybrid control is performed, the region where the vehicle speed is low is reduced. The region with high vehicle speed can be provided by the active control, and the gas spring variable semi-active control can be provided by the gas spring variable semi-active control. A large vibration suppression effect can be obtained in a wide range of vehicle speed from low speed to high speed while reducing energy consumption. When performing the above-described hybrid control, the ON-OFF valve 18 may not be particularly provided.

In the above embodiment, each of the gains K1, K
2, K3, K4, K5 are increased, and the area where the vehicle speed is low is ON-OF.
Active control is performed by opening the F valve 18 (in this case, it is necessary to control the proportional solenoid valve 5 to a fixed opening to keep the damping force constant), and close the ON-OFF valve 18 in a region where the vehicle speed is high. To switch to gas spring variable semi-active control. Also in this case, a large vibration damping effect can be obtained in a wide range of vehicle speeds from a low speed to a high speed while reducing energy consumption as much as possible. Needless to say, only the gas spring variable semi-active control can be performed by always closing the ON-OFF valve 18.

[Third Embodiment] [Configuration] FIG. 6 is a block diagram of active control according to a third embodiment of the present invention.

In the active control block diagram of FIG. 5 in the second embodiment, a low-pass filter 45 is inserted between the operation unit 39 and the operation unit 40, and the active control is performed at a frequency lower than the set frequency. This is an example in which a signal is attenuated at a frequency higher than the set frequency to attenuate the control operation of the active control.

According to this, at a frequency higher than the set frequency, the gas spring variable semi-active control has an effect and the active control is attenuated, so that the power consumption is small. The set frequency of the low-pass filter 45 is set near the resonance frequency of the system including the vehicle and the suspension.

The present invention is not limited to the above embodiments,
The accumulator is set to 3 without departing from the gist of the present invention.
Various changes such as the above can be made.

[0048]

As described above in detail, the suspension control apparatus according to the first aspect of the present invention is a suspension control apparatus for a vehicle in which a vehicle body is supported via a hydraulic damper for each of a plurality of wheels. A hydraulic circuit connecting the hydraulic damper and the accumulator is provided with a proportional solenoid valve, and a hydraulic circuit connected to at least another accumulator is branched from a hydraulic circuit between the proportional solenoid valve and the accumulator to form a hydraulic circuit. When the damping force is at a minimum, the proportional solenoid valve is fully opened and the gas spring variable ON-OFF valve is opened. A controller is provided to control the throttle in proportion to the speed and to close the gas spring variable ON / OFF valve. While soften gas spring under the action of two accumulators, if the damping force is required 1
The gas spring can be hardened under the action of a single accumulator, eliminating the need for a power source such as a hydraulic pump and making use of the advantage of a semi-active suspension, which is also excellent in energy consumption. Is exhibited.

The suspension control device according to claim 2 of the present invention
A hydraulic circuit from a hydraulic pump is connected to a hydraulic circuit between the hydraulic damper and the proportional solenoid valve, and a servo valve is interposed in the hydraulic circuit. Since the opening and closing control of the servo valve is obtained so as to obtain a flat feeling, the active control and the gas spring variable semi-active control can be used together by reducing various control gains by the controller, that is, the hybrid control can be performed. A region with a low vehicle speed is provided with active control, and a region with a high vehicle speed is provided with gas spring variable semi-active control, so that a large vibration suppression effect can be obtained in a wide range of vehicle speeds from low to high while reducing energy consumption.

A suspension control device according to a third aspect of the present invention comprises:
Since the gas spring variable ON-OFF valve is controlled to open and close by switching an electromagnetic switching valve, power consumption can be suppressed by effectively using circuit pressure.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a suspension control device according to a first embodiment of the present invention.

FIG. 2 is a hydraulic circuit diagram.

FIG. 3 is a block diagram of a gas spring variable semi-active control.

FIG. 4 is a hydraulic circuit diagram of a suspension control device according to a second embodiment of the present invention.

FIG. 5 is a block diagram of active control.

FIG. 6 is a block diagram of active control according to a third embodiment of the present invention.

FIG. 7 is a hydraulic circuit diagram of a conventional suspension control device.

FIG. 8 is a block diagram of semi-active control.

FIG. 9 is a graph showing a relationship between a proportional electromagnetic valve opening and a vehicle body vertical absolute speed.

FIG. 10 is a graph of suspension control performance (triangular wave time response) at each vehicle speed of active control.

FIG. 11 is a graph of suspension control performance (triangular wave time response) at each vehicle speed in the conventional semi-active control.

FIG. 12 is a graph of suspension control performance (triangular wave time response) at each vehicle speed of the gas spring variable semi-active control.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Roller wheel 2 Bell crank 3 Suspension cylinder (hydraulic damper) 4 Accumulator 5 Proportional solenoid valve 6, 6A, 6B controller 7 Relief valve 8 Automatic switching valve 9 Passive control element 11 Roller-vehicle relative vertical speed / displacement sensor 12 Body Vertical speed sensor 13 Pressure sensor (cylinder pressure sensor) 14 Accumulator 15 ON-OFF valve 16 Solenoid switching valve 17 Servo valve 18 ON-OFF valve 19 Solenoid switching valve

Claims (3)

[Claims] 1. A suspension control device for a vehicle in which a vehicle body is supported via a hydraulic damper for each of a plurality of wheels,
A hydraulic circuit connecting the hydraulic damper and the accumulator is provided with a proportional solenoid valve, and a hydraulic circuit connected to at least another accumulator is branched from a hydraulic circuit between the proportional solenoid valve and the accumulator to form a hydraulic circuit. When the damping force is at a minimum, the proportional solenoid valve is fully opened and the gas spring variable ON-OFF valve is opened. A suspension control device provided with a controller for controlling the throttle in proportion to the speed and closing the gas spring variable ON-OFF valve. 2. A hydraulic circuit from a hydraulic pump is connected to a hydraulic circuit between the hydraulic damper and the proportional solenoid valve, and a servo valve is interposed in the hydraulic circuit. The controller detects vibration and sway of the vehicle body. 2. The suspension control device according to claim 1, wherein the servo valve is opened and closed so as to obtain a maximum flat feeling. 3. The suspension control device according to claim 1, wherein the gas spring variable ON-OFF valve is opened and closed by switching an electromagnetic switching valve.