Vehicle motion control device

• US 20050023895A1
• Filed: 07/26/2004
• Published: 02/03/2005
• Est. Priority Date: 07/30/2003
• Status: Active Grant

• Current Assignee: Advics Company Limited (Aisin Corp.)
• Original Assignee: Advics Company Limited (Aisin Corp.)
• Inventors: Kato, Kazuhiro, Yasutake, Toshio
• Granted Patent: US 7,216,942 B2
• Time in Patent Office: Days
• US Class Current: 303/146
• CPC Class Codes: B60T 8/1755 Brake regulation specially adapted to control the stability of the vehicle, e.g. taking into account yaw rate or transverse acceleration in a curve road vehicle drive control systems for control of driving stability otherwise than by controlling a particular sub-unit B60W30/02

Abstract

This device is applied to a vehicle having a dual circuit brake conduit (so-called X-conduit) comprising a circuit for a front-right wheel and a rear-left wheel and a circuit for a front-left wheel and a rear-right wheel. This device obtains basic control volume Gb based upon a vehicle body speed and a road friction coefficient during an understeer restraining control or oversteer restraining control, and obtains yaw control volume Gd based upon a deviation between a target yaw rate and actual yaw rate. Then, it exerts braking force according to the basic control volume Gb respectively on two wheels of one circuit to which front wheel at the outer side of the turning direction and the rear wheel at the inner side of the turning direction belong, to thereby decelerate the vehicle, and further exerts braking force according to the yaw control volume Gd on either one wheel of the same circuit, thereby producing a yawing moment for making the turning state close to the target state.

Claims

1. A vehicle motion control device applied to a vehicle provided with a brake conduit composed of a dual circuit comprising a circuit for supplying brake fluid pressure to each wheel cylinder of a front-right wheel and a rear-left wheel and a circuit for supplying brake fluid pressure to each wheel cylinder of a front-left wheel and a rear-right wheel, each of which is independent of each other, comprising:

turning state obtaining means that obtains a turning state of the vehicle; and

turning state control means that produces a predetermined yawing moment on the vehicle for bringing the turning state of the vehicle into a target state by respectively exerting braking force by brake fluid pressure on two wheels belonging to one of the above-mentioned dual circuit.

2. A vehicle motion control device claimed in claim 1, wherein the turning state control means is configured to exert braking force by brake fluid pressure such that the braking force exerted on the rear wheel at the inner side of the turning direction becomes greater than the braking force exerted on the front wheel at the outer side of the turning direction, when the turning state of the vehicle is in the understeer state, and to exert braking force by brake fluid pressure such that the braking force exerted on the front wheel at the outer side of the turning direction becomes greater than the braking force exerted on the rear wheel at the inner side of the turning direction, when the turning state of the vehicle is in the oversteer state.

3. A vehicle motion control device claimed in claim 2, wherein the turning state control means has:

basic control volume calculating means that calculates basic control volume for decelerating the vehicle based upon the running state of the vehicle; and

yaw control volume calculating means that calculates yaw control volume for producing the predetermined yawing moment on the vehicle based upon the turning state of the vehicle, wherein,

when the turning state of the vehicle is in the understeer state, the turning state control means is configured to exert the braking force by the brake fluid pressure according to the basic control volume on the front wheel at the outer side of the turning direction and exert the braking force, that is obtained by adding the braking force by the brake fluid pressure according to the yaw control volume to the braking force by the brake fluid pressure according to the basic control volume, on the rear wheel at the inner side of the turning direction, while,

when the turning state of the vehicle is in the oversteer state, the turning state control means is configured to exert the braking force by the brake fluid pressure according to the basic control volume on the rear wheel at the inner side of the turning direction and exert the braking force, that is obtained by adding the braking force by the brake fluid pressure according to the yaw control volume to the braking force by the brake fluid pressure according to the basic control volume, on the front wheel at the outer side of the turning direction.

4. A vehicle motion control device claimed in claim 3, wherein the yaw control volume calculating means is configured to calculate the yaw control volume based upon a deviation between a target yaw rate related amount, set based upon at least a vehicle body speed and a steering operation amount, and an actual yaw rate related amount exerted on the vehicle.

5. A vehicle motion control device claimed in claim 3, wherein the basic control volume calculating means is configured to calculate the basic control volume based upon at least one of the vehicle body speed and a road friction coefficient.

6. A vehicle motion control device claimed in claim 3, wherein the basic control volume calculating means is configured to calculate the basic control volume such that the changing speed of the basic control volume is limited according to the running state of the vehicle.

7. A vehicle motion control device claimed in claim 3, wherein the basic control volume calculating means is configured to calculate the basic control volume such that the basic control volume is limited according to the yaw control volume calculated by the yaw control volume calculating means.

8. A vehicle motion control device claimed in claim 3, wherein the turning state control means is configured to lower the output of the driving source of the vehicle according to the driving state of the vehicle and exert, on the two wheels, braking force by brake fluid pressure that is smaller than the braking force by the brake fluid pressure according to the basic control volume by the braking force corresponding to the decrease in the output of the driving source, instead of exerting the braking force by the brake fluid pressure according to the basic control volume on the two wheels.