JPH04328011A - Suspension control device for vehicle - Google Patents

Abstract

PURPOSE:A suspension control device for a vehicle which can reduce vibration shock when the vehicle runs on a not-yet paved bad road. CONSTITUTION:When the frequency of output signal from a vertical acceleration measuring means 10 is within a certain range (e.g. 3-13Hz) and the magnitude of acceleration is not less than a certain value (e.g. 0.25G), a control means 30 outputs a soft control signal to each of damping force change-over means 40-43 if output signal from a vehicle speed measuring means 20 is not more than a predetermined value (e.g. 30km/h), and outputs a medium control signal thereto if the output signal from the vehicle speed measuring means 20 is more than the predetermined value.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suspension control system for a vehicle.

0002

BACKGROUND OF THE INVENTION In recent years, cars for the general public have become more sophisticated, and users' demands for ease of driving, stability of the car body, and ride comfort have become increasingly strict. Therefore, various electronic suspension controls have been developed to control the attitude of the vehicle body while the vehicle is running.

[0003] One type of electronic suspension control is rough road responsive control for achieving both drivability and ride comfort when driving on rough roads.

As shown in FIG. 4, this means that when the frequency of the output signal of the vertical acceleration measuring means is within a certain range (for example, 3Hz to 13Hz) and the magnitude is above a certain value (for example, 0.25G), Sometimes it is set to medium to improve the contact with the road surface, and on the other hand, it is set to a certain value (for example, 0).
．． 25G) or less, the suspension is softly controlled.

[0005]

[Problems to be Solved by the Invention] However, in the above conventional example, generally on rough roads, the frequency of the output signal of the vertical acceleration measuring means is often within the range of 3Hz to 13Hz, and moreover, its magnitude is a constant value. (e.g. 0.25G)
Because of the above, the suspension is medium controlled. When you want to drive on rough roads like this in a sporty manner, there is no problem with medium suspension control to improve the contact with the road surface, but when driving on rough roads at low speeds to reduce the shock of body vibration, The disadvantage was that the medium-controlled suspension could not sufficiently cushion the shock.

[0006]

OBJECTS OF THE INVENTION An object of the present invention is to provide a suspension control device for a vehicle that is suitable for improving the disadvantages of the conventional example and particularly for alleviating the shock of vehicle body vibration when driving on rough, unpaved roads. There is a particular thing.

[0007]

[Means for Solving the Problems] Accordingly, the present invention provides a vertical acceleration measuring means for measuring the vertical acceleration applied to the vehicle body when the vehicle is running, a vehicle speed measuring means for measuring the running speed of the vehicle, and a vertical acceleration measuring means for measuring the running speed of the vehicle. performs predetermined calculations based on each output signal from the means and the vehicle speed measuring means, and switches the damping force switching means, which is equipped on the vehicle and is configured to be able to switch and set the vehicle suspension to a medium state or a soft state, as necessary. and switching control means for controlling. This switching control means constantly monitors the output signal of the vertical acceleration measuring means, and if the frequency is within a predetermined range and the magnitude is above a certain value, it immediately switches to the medium state setting. A medium mode setting function that outputs a medium control signal, constantly monitors whether the vehicle speed is above a predetermined value, and if the vehicle speed is below a predetermined value, a soft control signal for setting the soft state is given top priority. The configuration includes a soft mode setting function for output. This aims to achieve the above-mentioned purpose.

[0008]

[Operation] First, a vehicle speed data signal is input to the switching control means from the vehicle speed measuring means, and a vertical acceleration data signal is input from the vertical acceleration measuring means.

The output of the switching control means analyzes the input vertical acceleration data signal. The frequency of this vertical acceleration data signal is within a certain range (for example, 3Hz to 13Hz).
Hz), when the magnitude is above a certain value (for example, 0.25G), it is determined to be medium, and when it is less than that, it is determined to be soft.

When it is determined that the damping force is soft, a soft control signal is output from the switching control means to the damping force switching means. On the other hand, even when it is determined that the vehicle speed is medium, it is further checked whether the vehicle speed is equal to or higher than a predetermined value (for example, 30 km/h). Then, the vehicle speed is 30[k]
m/h], a soft control signal is output from the switching control means to the damping force switching means. Also, the vehicle speed is 30[k]
m/h], a medium control signal is output from the control means to the damping force switching means.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 4.

First, the embodiment shown in FIGS. 1 and 2 includes a vertical acceleration sensor 10 as a vertical acceleration measuring means for measuring vertical acceleration applied to the vehicle body when the vehicle 1 is running;
A vehicle speed sensor 20 serving as a vehicle speed measuring means for measuring the traveling speed of the vehicle 1 performs predetermined calculations based on each output signal from the vertical acceleration sensor 10 and the vehicle speed sensor 20, and also performs a predetermined calculation based on the vehicle suspension installed in the vehicle 1. a switching control means 30 for switching and controlling the first to fourth damping force switching actuators 40, 41, 42, 43 as damping force switching means configured to be able to switch to a medium state or a soft state; We are prepared. This switching control means 30 controls the vertical acceleration sensor 10.
a medium mode setting function that constantly monitors the output signal of the output signal and immediately outputs a medium control signal for medium state setting if the frequency is within a predetermined range and the magnitude is above a certain value; It has a soft mode setting function that constantly monitors whether the vehicle speed is above a predetermined value and outputs a soft control signal for setting the soft state with the highest priority when the vehicle speed is below a predetermined value. In FIG. 2, numeral 2 indicates a steering wheel, and numeral 3 indicates a steering sensor. Also, codes 41, 42, 43, 4
Reference numerals 4 and 52 respectively indicate wheel dampers, and reference numerals 51 and 52 indicate springs installed in the dampers 41 and 42, respectively.

Next, the operation of this embodiment will be explained with reference to the flowchart shown in FIG.

(2) A vehicle speed data signal is input from the vehicle speed sensor 20 to the control means 30 (S10 in FIG. 3).

■ A vertical acceleration data signal is input from the vertical acceleration sensor 10 to the control means 30 (S20 in FIG. 3).
.

(2) The vertical acceleration data signal inputted to the control means 30 is analyzed (S30 in FIG. 3).

■As shown in Figure 4, when the frequency of the signal is within a certain range (for example 3Hz to 13Hz) and the magnitude is above a certain value (for example 0.25G), it is medium, and when it is below, it is soft. It is determined that (S40 in FIG. 3).

■When it is determined that the software is soft, the control means 3
0 to each damping force switching actuator 40, 41, 42,
A soft control signal is output to 43 (S70 in FIG. 3).

■ Even when it is determined that the vehicle speed is medium, the vehicle speed is set to a predetermined constant value (for example, 30km/h).
m/h) or higher (S50 in FIG. 3).
).

(2) In (2) above, if the vehicle speed is 30 km/h or less, a soft control signal is output from the control means 30 to each damping force switching actuator 40, 41, 42, 43 (S70 in FIG. 3).

(2) In (2) above, if the vehicle speed is 30 km/h or more, a medium control signal is output from the control means 30 to each damping force switching actuator 40, 41, 42, 43 (S60 in FIG. 3).

In the above description of the operation of this embodiment, the frequency threshold of the vertical acceleration data signal is set to 3Hz to 13Hz,
Although the threshold value of the magnitude is 0.25G and the threshold value of the vehicle speed data signal is 30 km/h, the present invention is not limited to these values.

[0023]

As described above, according to the present invention, since the present invention includes the control means for controlling the suspension damping force switching means based on the output signal of the vertical acceleration measuring means and the output signal of the vehicle speed measuring means, Even if the magnitude and frequency of vertical acceleration are large, the damping force of the suspension can be controlled to a soft state when driving at low speed. Because of this,
It is possible to provide an unprecedented and excellent suspension control device for a vehicle that can sufficiently reduce the shock of vehicle body vibration by driving at low speed even on rough unpaved roads such as Belgian roads.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention.

FIG. 2 is a configuration diagram showing an embodiment of the present invention.

FIG. 3 is a flowchart showing the operation of an embodiment of the present invention.

FIG. 4 is a map showing a conventional control method.

[Explanation of symbols]

1 Vehicle 10 Vertical acceleration sensor 20 as vertical acceleration measuring means Vehicle speed sensor 30 as vehicle speed measuring means Switching control means 40 Damping force actuator 41 as first damping force switching means Damping force actuator as second damping force switching means 42 Damping force actuator as third damping force switching means 43 Damping force actuator as fourth damping force switching means

Claims (1)

[Claims] 1. Vertical acceleration measuring means for measuring vertical acceleration applied to the vehicle body when the vehicle is running; vehicle speed measuring means for measuring the running speed of the vehicle; and outputs from the vertical acceleration measuring means and the vehicle speed measuring means. a switching control means that performs a predetermined calculation based on the signal and controls switching of a damping force switching means, which is installed in the vehicle and is configured to be able to switch and set a vehicle suspension to a medium state or a soft state, as necessary; This switching control means constantly monitors the output signal of the vertical acceleration measuring means, and if the frequency is within a predetermined range and the magnitude is above a certain value, it immediately switches to the medium state setting. A medium mode setting function that outputs a medium control signal, constantly monitors whether the vehicle speed is above a predetermined value, and if the vehicle speed is below a predetermined value, a soft control signal for setting the soft state is given top priority. A vehicle suspension control device characterized by having a soft mode setting function for output.