KR20100093641A - Vehicle stability control apparatus - Google Patents

Abstract

The present invention relates to a vehicle attitude control device that can control the attitude of the vehicle by varying the viscosity of the clutch installed on the stabilizer bar.

To this end, the present invention is a vehicle speed sensor for detecting the speed of the vehicle; A steering angle sensor for detecting a steering angle of the vehicle; A clutch having an MR fluid whose viscosity varies according to a magnetic field and intermittent with the stabilizer bar mounted on the vehicle; And an electronic control unit which controls the clutch and restrains the stabilizer bar when the detected vehicle speed is higher than a predetermined vehicle speed and the vehicle is turning.

Description

Vehicle attitude control device {VEHICLE STABILITY CONTROL APPARATUS}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle attitude control device, and more particularly, to a vehicle attitude control device having a simpler configuration, a smaller number of components, and a smaller number of components compared to a hydraulic actuator by controlling the stabilizer by using a clutch provided on the stabilizer bar.

In general, in the suspension system of a vehicle, a stabilizer bar is mounted to the vehicle body in a lateral direction so that the rolling of the vehicle body is generated by a change in the relative attitude of the left and right suspensions while driving. By relieving the roll stiffness as a medium, the behavioral attitude of the vehicle body is further stabilized.

In the application of the stabilizer bar, the inclination of the body is equal to the movement of the left and right wheels against the phenomenon that the outer wheel collides or the inner wheel springs up when cornering. Minimize and reduce the roll phenomenon of the vehicle body to stabilize the ride and the vehicle body.

The stabilizer bar has one predetermined roll stiffness depending on the bar shape. In particular, the active roll control system has an actuator for varying roll stiffness in addition to a stabilizer bar structure, and a control unit for controlling the roll, and has a low roll stiffness when driving straight to increase ride comfort and when turning. The roll stiffness is increased so that the vehicle roll motion is suppressed.

Unlike the general stabilizer bar structure, the active roll control system described above has a body roll stiffness suitable for the vehicle's movement situation, which is advantageous for ride comfort and posture control. Since the number of parts occupies a lot of space when mounted on the vehicle, there is a limit to the application of the vehicle, negative in fuel economy, high energy consumption and expensive.

An object of the present invention is to install a clutch on the stabilizer bar to vary the viscosity of the clutch during turning to control the stabilizer bar to stabilize the vehicle attitude by using a clutch having a simple configuration and a small number of components. In providing a device.

In order to achieve the above object, the vehicle attitude control device according to an embodiment of the present invention includes a vehicle speed sensor for detecting the speed of the vehicle; A steering angle sensor for detecting a steering angle of the vehicle; A clutch having an MR fluid whose viscosity varies according to a magnetic field and intermittent with the stabilizer bar mounted on the vehicle; And an electronic control unit which controls the clutch and restrains the stabilizer bar when the detected vehicle speed is higher than or equal to a predetermined vehicle speed and the vehicle is turning.

In this embodiment the clutch comprises a housing; First and second rotors rotatably installed in the housing; And a coil part installed at an outer circumference of the housing to form a magnetic field, wherein the MR fluid varies in viscosity by a magnetic field formed by the coil part and varies rotational forces of the first and second rotors.

In addition, the vehicle attitude control apparatus according to the present invention further includes a lateral acceleration sensor for detecting the lateral acceleration of the vehicle, the electronic control unit may vary the strength of the current to be applied to the clutch according to the lateral acceleration. .

According to the exemplary embodiment of the present invention, the viscosity of the clutch installed on the stabilizer bar is changed at the time of turning so that the stability of the vehicle can be secured by restraining the stabilizer bar. In particular, compared with a device for controlling a posture of a vehicle by installing a conventional hydraulic actuator on a stabilizer bar, the configuration is simple and the number of components is small.

In addition, according to an embodiment of the present invention by controlling the strength of the current to be applied to the clutch according to the lateral acceleration value of the vehicle, there is an effect that can be finely controlled the attitude of the vehicle according to the lateral acceleration value.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a view for explaining a vehicle attitude control device according to an embodiment of the present invention.

Referring to FIG. 1, a vehicle attitude control apparatus according to an exemplary embodiment of the present invention may include an electronic control unit 20 for controlling a clutch 35 installed in a vehicle speed sensor 11, a steering angle sensor 12, and a stabilizer bar 30. It is configured to include).

The vehicle speed sensor 11 is referred to as a wheel speed sensor that can sense the speed of the vehicle, and provides the detected speed signal to the electronic control unit 20 by detecting the speed of the vehicle.

The steering angle sensor 12 detects a steering angle of the vehicle and provides the detected steering angle signal to the electronic control unit 20. The steering angle sensor 12 is installed on a steering shaft (not shown) of the steering wheel, and detects the steering angle according to the driver's steering wheel manipulation.

The lateral acceleration sensor 13 detects lateral acceleration of the vehicle and provides the detected lateral acceleration signal to the electronic control unit 20.

The stabilizer bar 30 is provided along the vehicle body A in the transverse direction. The stabilizer bar 30 functions as an auxiliary spring for supporting the left and right wheels generated when the vehicle body A rolls, and does not receive a force when the left and right wheels move in phase, and in the case of moving in reverse phase, By restraining the movement of the left and right wheels to reduce the roll behavior of the vehicle body (A).

In particular, the stabilizer bar 30 maintains the vehicle equilibrium by reducing the inclination of the vehicle body A by the force generated when the left and right wheels reverse the vertical movement to each other.

Both ends of the stabilizer bar 30 are bent relative to the middle portion and are connected to the wheel B via the control link 40. In addition, the mounting bar 32 is provided with the stabilizer bar 30. Although not shown, the bearing is mounted inside the mounting bracket 32.

Referring to FIG. 2, a clutch 35 filled with MR fluid (Magnetorheologic Fluid) 354 is installed at the center of the stabilizer bar 30 described above. The clutch 35 is a means for separating or restraining the stabilizer bar 30 in accordance with a control signal applied from the electronic control unit 20.

That is, the clutch 35 is an MR clutch utilizing the characteristics of the MR fluid 354 whose viscosity varies according to the magnetic field strength. The clutch 35 varies the magnetic field strength of the electromagnet and the viscosity of the MR fluid through current control to increase the torque transmission force of the clutch. Control linearly. In addition, the clutch 35 places the MR fluid 354 between the first and second rotors 352 and 353 which are two relatively rotating members, and the magnetic flow by the coil part 355 passes through the MR fluid. The viscosity of the MR fluid 354 is changed according to the current strength applied to the portion 355.

The above-described clutch 35 has a housing 351 having a plate-shaped cylinder, and first and second rotors 352 and 353 rotatably installed in the housing 351, and the first and second rotors 352. MR fluid 354 is filled between 353.

In addition, a coil part 355 is wound around the outer circumference of the housing 351, and a magnetic field is formed as a current is supplied to the coil part 355. In addition, the MR fluid 354 is made of a fluid containing a material that is formed in the magnetic field, the viscosity of the MR fluid 354 increases according to the strength of the magnetic field.

On the other hand, the coil unit 355 is controlled by the current supply of the electronic control unit 20, thereby adjusting the intensity of the magnetic field. Here, the electronic control unit 20 detects the movement state of the vehicle from various sensors such as the vehicle speed sensor 11, the steering angle sensor 12, the lateral acceleration sensor 13, and changes the damping force according to the movement state of the vehicle. The operation of the coil unit 355 is controlled.

In particular, a magnetic field is generated as a current is supplied to the coil part 355 of the clutch 35, and the viscosity of the MR fluid 354 is changed by the magnetic field, thereby rubbing the first and second rotors 352 and 353. Variable resistance.

That is, when the amount of current supplied to the coil unit 355 increases, a large magnetic field is formed to increase the frictional resistance of the first and second rotors 352 and 353 as the viscosity of the MR fluid 354 increases. When the amount of current supplied to the portion 355 decreases, the magnetic field is weakened, which lowers the viscosity of the MR fluid 354 and reduces the frictional resistance of the first and second rotors 352 and 353.

The clutch 35 may further include a seal 356 for preventing leakage of the MR fluid 354.

Reference numeral 50 is a damper.

In the present embodiment, the electronic control unit 20 switches to separate the stabilizer bar 30 when driving on a flat road, and switches to restrain the stabilizer bar 30 when the vehicle is turning at a certain speed or more and turns to stabilize the stabilizer bar 30. By restraining the stability can be improved.

Specifically, the electronic control unit 20 applies a current control signal to the clutch 35 when the vehicle speed received from the vehicle speed sensor 11 is turning over while being a predetermined vehicle speed. The clutch 35 has a magnetic field formed by the coil unit 355 according to the current control signal of the electronic control unit 20, and the viscosity of the MR fluid 354 increases due to the magnetic field. This viscosity increases the frictional resistance of the first and second rotors 352 and 353, thereby applying a force against the shear stress of the stabilizer bar 30, thereby suppressing rolling of the vehicle body with a stronger force.

The electronic control unit 20 is a stabilizer bar installed on the front and rear wheels, respectively, by using the vehicle's speed, steering angle, and lateral acceleration received from the vehicle speed sensor 11, the steering angle sensor 12, and the lateral acceleration sensor 13. It functions to control the operation of the clutch 35 to control the 30. In particular, the electronic control unit 20 to separate or restrain the stabilizer bar 30, the clutch 35 is installed to optimally control the driving state of the vehicle, that is, the attitude and stability of the vehicle.

In more detail, the electronic control unit 20 determines whether the vehicle speed received from the vehicle speed sensor 11 is equal to or greater than a predetermined vehicle speed, and further, depending on whether the steering angle received from the steering angle sensor 12 exceeds the reference angle. If it is determined that the vehicle is turning, as a result, when the vehicle is turning, the current control signal is applied to the clutch 35 to restrain the stabilizer bar 30, and if the vehicle is not turning, or the vehicle is not turning. Do not apply the current control signal to the clutch 35. At this time, when a current control signal is applied to the clutch 35, a magnetic field is formed to increase the viscosity of the MR fluid 354, thereby increasing the frictional resistance of the first and second rotors 352 and 353 and connecting them to the left and right sides. The stabilizer bar 30 is fixedly connected to reduce rolling of the vehicle body. On the other hand, when the current control signal is not applied to the clincher 35, the magnetic field is not formed, and thus the viscosity of the MR fluid 354 becomes low, thereby reducing the frictional resistance of the first and second rotors 352 and 353. The left and right wheels can independently move up and down to improve the riding comfort.

In the present embodiment, it is determined whether the vehicle is turning by comparing the steering angle received by the steering angle sensor 12 with the reference angle, but the present invention is not necessarily limited thereto, and for example, determining whether the vehicle is turning by using a transmission or the like. can do.

On the other hand, the electronic control unit 20 is preferably implemented to vary the current control signal to be applied to the clutch 35 according to the lateral acceleration value received by the lateral acceleration sensor 13 in order to increase the roll rigidity of the vehicle body. . In addition, the degree of restraint of the stabilizer bar 30 is a moment for reducing roll generation, and more preferably proportional to the degree of turning of the vehicle.

The attitude control method of the vehicle attitude control device having such a configuration will be described below with reference to FIG. 3.

3 is a flowchart illustrating an attitude control method of a vehicle attitude control device according to an exemplary embodiment of the present invention.

The electronic control unit 20 receives the speed, the steering angle, and the lateral acceleration of the vehicle detected from the vehicle speed sensor 11, the steering angle sensor 12, and the lateral acceleration sensor 13 (S101).

Next, the electronic control unit 20 determines whether the speed of the vehicle received by the vehicle speed sensor 11 is equal to or greater than a predetermined vehicle speed (S103).

As a result of the determination in step S103, when the speed of the vehicle received by the vehicle speed sensor 11 is less than the predetermined vehicle speed, the electronic control unit 20 does not apply the current control signal to the clutch 35, thereby moving the vehicle body in the lateral direction. , Control to separate the left and right stabilizer bar 30 installed in the rear wheel (S104).

As a result of the determination in step S103, when the vehicle speed received by the vehicle speed sensor 11 is equal to or greater than a predetermined vehicle speed, the electronic control unit 20 determines whether the steering angle received by the steering angle sensor 12 exceeds a reference angle. (S105). That is, the electronic control unit 20 determines whether the vehicle is turning.

As a result of the determination in step S105, when the vehicle is not turning, the electronic control unit 20 moves the process to step S104 described above.

As a result of the determination in step S105, when the vehicle is turning, the electronic control unit 20 applies a predetermined current control signal to the clutch 35 (S107).

Next, the clutch 35 has a magnetic field formed according to the current control signal applied from the electronic control unit 20, and the viscosity of the MR fluid 354 is increased by the formed magnetic field so that the first and second rotors 352 and 353 By reducing the frictional resistance of the restraint the stabilizer bar 30 installed in the front and rear wheels, respectively.

By doing so, not only the rolling of the vehicle can be suppressed at the time of turning of the vehicle but also the independent movement of the wheels can be improved at the time of straight driving and the riding comfort can be improved.

The invention being thus described, it will be obvious that the same way may be varied in many ways. Such modifications are intended to be within the spirit and scope of the invention as defined by the appended claims.

1 is a view for explaining a vehicle attitude control device according to an embodiment of the present invention.

2 is a view for explaining the clutch shown in FIG.

3 is a flowchart illustrating an attitude control method of a vehicle attitude control device according to an embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

11: vehicle speed sensor 12: steering angle sensor

13: lateral acceleration sensor 20: electronic control unit

30: stabilizer bar 35: clutch

351: housing 352, 353: first and second rotor

354 MR fluid 355 Coil part

356: seal 40: control link

50: damper

Claims (3)

A vehicle speed sensor detecting a speed of the vehicle; A steering angle sensor for detecting a steering angle of the vehicle; A clutch having an MR fluid whose viscosity varies according to a magnetic field and intermittent with the stabilizer bar mounted on the vehicle; And And an electronic control unit for controlling the clutch to restrain the stabilizer bar when the detected vehicle speed is higher than or equal to a predetermined vehicle speed and the vehicle is turning. The method according to claim 1, The clutch is housing; First and second rotors rotatably installed in the housing; And A coil part installed at an outer circumference of the housing to form a magnetic field, The MR fluid is a vehicle attitude control device characterized in that the viscosity is changed by the magnetic field formed by the coil unit and the rotational force of the first and second rotors. The method according to claim 1, Further comprising a lateral acceleration sensor for detecting the lateral acceleration of the vehicle, And the electronic control unit varies an intensity of a current to be applied to the clutch according to the lateral acceleration.

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