Motion control device of vehicle

• US 6,910,746 B2
• Filed: 07/28/2003
• Issued: 06/28/2005
• Est. Priority Date: 08/06/2002
• Status: Expired due to Fees

• Current Assignee: Advics Company Limited (Aisin Corp.), Daihatsu Motor Company Limited (Toyota Motor Corporation)
• Original Assignee: Advics Company Limited (Aisin Corp.), Daihatsu Motor Company Limited (Toyota Motor Corporation)
• Inventors: Fukami, Masanobu, Kato, Toshihisa, Yakushijin, Tokio
• Primary Examiner(s): Butler, Douglas C.
• Application Number:
  US10/491,368
• Publication Number:
  US 20040239179A1
• Time in Patent Office: 701 Days
• Field of Search: 303/140, 303/146, 303/147, 303/148, 303/139, 701/72, 701/78, 180/197
• US Class Current: 303/140
• CPC Class Codes: B60G 2800/0124 Roll-over conditions
• CPC Class Codes: B60G 2800/215 by applying a braking action on each wheel individually
• CPC Class Codes: B60G 2800/922 EBV - Electronic brake force distribution
• CPC Class Codes: B60T 2230/03 Overturn, rollover
• CPC Class Codes: B60T 8/17554 specially adapted for enhancing stability around the vehicles longitudinal axle, i.e. roll-over prevention road vehicle drive control systems for roll-over prevention otherwise than by controlling a particular sub-unit B60W30/04
• CPC Class Codes: B60T 8/1766 Proportioning of brake forces according to vehicle axle loads, e.g. front to rear of vehicle
• CPC Class Codes: B60T 8/241 Lateral vehicle inclination
• CPC Class Codes: B60T 8/246 Change of direction

Abstract

A motion control device 10 for a vehicle exerts braking force only on the rear wheel at the inner side of the turning direction for generating a yawing moment on the vehicle only in the turning direction of the vehicle when an absolute value of an actual lateral acceleration Gy is not more than a value Gyth, i.e., when there is a small possibility of the occurrence of an excessive roll angle on the vehicle body, in case where the turning state of the vehicle is the understeer state. On the other hand, it exerts braking force not only on the rear wheel at the inner side of the turning direction, but also on the front and rear wheels at the outer side of the turning direction for generating a yawing moment in the direction opposite to the turning direction too, when the absolute value of the actual lateral acceleration Gy exceeds the value Gyth, i.e., when there is a great possibility of the occurrence of the excessive roll angle on the vehicle body, in case where the turning state of the vehicle is the understeer state.

Claims

1. A motion control device for a vehicle provided with:

understeer judging means for judging whether the turning state of the vehicle is an understeer state or not; and

braking force controlling means that exerts braking force on a rear wheel at an inner side in a turning direction of the vehicle for generating a yawing moment in the turning direction of the vehicle in case where the turning state of the vehicle is judged to be the understeer state, comprising;

actual lateral acceleration related amount obtaining means for obtaining an actual amount of a lateral acceleration related amount, that shows a degree of the turn of the vehicle, as an actual lateral acceleration related amount, wherein

the braking force controlling means is configured to exert braking force for generating a yawing moment in the turning direction of the vehicle on the rear wheel at the inner side in the turning direction and to exert braking force for generating a yawing moment in the direction opposite to the turning direction of the vehicle on at least one of the front and rear wheels at the outer side in the turning direction, when the absolute value of the actual lateral acceleration related amount exceeds a predetermined value in the case where the turning state of the vehicle is judged to be the understeer state; and

the braking force controlling means increases the braking force exerted on at least one of the front and rear wheels at the outer side in the turning direction according to the increase in the absolute value of the actual lateral acceleration related amount when the absolute value of the actual lateral acceleration related amount exceeds the predetermined value, and reduces the braking force exerted on the rear wheel at the inner side in the turning direction according to the increase in the absolute value of the actual lateral acceleration related amount when the absolute value of the actual lateral acceleration related amount exceeds an other predetermined value, in case where the turning state of the vehicle is judged to be the understeer state.

2. A motion control device for a vehicle claimed in claim 1, further comprising:

body speed obtaining means for obtaining a body speed of the vehicle;

steering operation amount obtaining means for obtaining an operation amount of a steering that changes a turning angle of a steering wheel of the vehicle; and

target lateral acceleration related amount calculating means for calculating, as a target lateral acceleration related amount, a target value of the lateral acceleration related amount according to a predetermined rule based upon at least the body speed and the steering operation amount, wherein the understeer judging means judges that the turning state of the vehicle is an understeer state when the value obtained by subtracting the absolute value of the actual lateral acceleration related amount from the absolute value of the target lateral acceleration related amount is not less than a positive predetermined value.