Wheel ground-contact state judging device and method and vehicle motion control device

• US 20060006017A1
• Filed: 07/11/2005
• Published: 01/12/2006
• Est. Priority Date: 07/12/2004
• Status: Active Grant

• Current Assignee: Subaru Corp.
• Original Assignee: Fuji Heavy Industries Limited (Subaru Corp.)
• Inventors: Tsukasaki, Yuichiro, Kogure, Masaru
• Granted Patent: US 7,797,093 B2
• Time in Patent Office: Days
• US Class Current: 180/233
• CPC Class Codes: B60G 17/0162 mainly during a motion involving steering operation, e.g. cornering, overtaking B60G17/0164 takes precedence
• CPC Class Codes: B60G 21/0555 including an actuator inducing vehicle roll
• CPC Class Codes: B60G 2400/104 lateral or transversal with regard to vehicle
• CPC Class Codes: B60G 2400/822 Road friction coefficient determination affecting wheel traction
• CPC Class Codes: B60G 2600/02 Retarders, delaying means, dead zones, threshold values, cut-off frequency, timer interruption
• CPC Class Codes: B60G 2800/214 by varying the load distribution
• CPC Class Codes: B60G 2800/24 Steering, cornering
• CPC Class Codes: B60G 2800/702 Improving accuracy of a sensor signal
• CPC Class Codes: B60G 2800/9122 ARS - Anti-Roll System Control

Abstract

In wheel ground-contact state judging device and method, a detector directly detects a lateral force acting in a direction perpendicular to the wheel center plane of a wheel. An acceleration sensor detects an acceleration in the lateral direction of a vehicle. A calculator calculates a cornering force acting on each wheel on the basis of the acceleration in the lateral direction thus detected. A judging unit compares the detected lateral force with the calculated cornering force to judge whether the ground-contact state of the wheel is good or not.

Claims

1. A wheel ground-contact state judging device comprising:

a detector for directly detecting, as a lateral force, a force acting in a direction perpendicular to a wheel center plane of a wheel;

an acceleration sensor for detecting an acceleration in the lateral direction of a vehicle;

a calculator for calculating a cornering force acting on the wheels on the basis of the acceleration in the lateral direction detected by the acceleration sensor; and

a judging unit for comparing the detected lateral force with the calculated cornering force and judging the ground-contact state of the wheels.

2. The wheel ground-contact state judging device according to claim 1, wherein the detector detects the lateral force with respect to each of plural wheels provided to the vehicle as a detection target, the calculator calculates the total of the cornering forces acting on the respective wheels, and the judging unit compares the total of the lateral forces detected for the respective wheels with the calculated total of the cornering forces and judges the ground-contact state with the whole of the plural wheels set as a judging unit.

3. The wheel ground-contact state judging device according to claim 1, further comprising a yaw rate sensor for detecting the yaw rate of the vehicle is further provided, wherein the detector detects the lateral force with respect to each of plural wheels provided at the front and rear sides of the vehicle as a detection target, the calculator calculates the total of the cornering forces acting on the front wheels and the total of the cornering forces acting on the rear wheels on the basis of the detected yaw rate and the detected acceleration, and the judging unit compares the total of the lateral forces detected for the front wheels with the calculated total of the cornering forces acting on the front wheels to judge the ground-contact state of the front wheels and also compares the total of the lateral forces detected for the rear wheels with the calculated total of the cornering forces acting on the rear wheels to judge the ground-contact state of the rear wheels.

4. The wheel ground-contact state judging device according to claim 1, further comprising:

a controller for controlling the roll rigidity of the vehicle on the basis of the judgment result of the ground-contact state judging device.

5. A wheel ground-contact state judging device comprising:

a detector for directly detecting, as a vertical force, a force acting in a direction vertical to a wheel center plane of a wheel with respect to each of plural wheels provided to a vehicle as a detection target; and

a judging unit for comparing the total of detected vertical forces detected for the respective wheels with a judgment value to judge the ground-contact state of the wheels.

6. The wheel ground-contact state judging device according to claim 5, wherein the judgment value is set on the basis of the total of the vertical forces detected for the respective wheels when the vehicle is at a standstill.

7. The wheel ground-contact state judging device according to claim 5, further comprising:

a controller for controlling the roll rigidity of the vehicle on the basis of the judgment result of the ground-contact state judging device.

8. A wheel ground-contact state judging method comprising:

a first step of directly detecting, as a lateral force, a force acting in a direction perpendicular to a wheel center plane of a wheel;

a second step of detecting an acceleration in the lateral direction of a vehicle;

a third step of calculating a cornering force acting on the wheels on the basis of the acceleration in the lateral direction thus detected; and

a fourth step of comparing the detected lateral force with the calculated cornering force and judging the ground-contact state of the wheels.