Device for estimating rolling condition of vehicle body with limits of roll angle and angular speed

• US 6,502,023 B1
• Filed: 02/08/1999
• Issued: 12/31/2002
• Est. Priority Date: 03/06/1998
• Status: Expired due to Term

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Fukada, Yoshiki
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): Broadhead, Brian J
• Application Number:
  US09/245,711
• Time in Patent Office: 1,422 Days
• Field of Search: 701/37, 701/38, 701/72, 701/91, 280/5.502, 280/5.506, 280/5.507
• US Class Current: 701/38
• 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 2400/0523 Yaw rate
• CPC Class Codes: B60G 2400/104 lateral or transversal with regard to vehicle
• CPC Class Codes: B60G 2400/204 Vehicle speed
• CPC Class Codes: B60G 2800/012 Rolling condition
• CPC Class Codes: B60G 2800/70 Estimating or calculating vehicle parameters or state variables

Abstract

A device for estimating a rolling condition of a body of a vehicle having: a unit for estimating a first quantity (φ, γV, Gy, Ff) corresponding to roll angle (φ) of the vehicle body around a rolling axis; a unit for estimating a second quantity corresponding to a change rate (φ) of the roll angle of the vehicle body; a unit for estimating a third quantity indicating a relative magnitude (φ/φ_limit, γV/(γV)_limit, Gy/Gy_limit, Ff/Ff_limit) of the first quantity with reference to a first limit value predetermined therefor; a unit for estimating a fourth quantity indicating a relative magnitude (φ/φ_limit) of the second quantity with reference to a second limit value predetermined therefor; and a unit for estimating the rolling condition as a combination of the third and fourth quantities such that the rolling condition is intensified along with increase of the third quantity as well as increase of the fourth quantity.

Claims

1. A device for estimating a rolling condition of a body of a vehicle having the vehicle body, a pair of front wheels, a pair of rear wheels, and suspension means for supporting the vehicle body on the pairs of front and rear wheels, the vehicle body being able to roll relative to the wheels around a virtual axis of rolling provided by the suspension means, the device comprising:

means for estimating a first quantity corresponding to roll angle of the vehicle body around the rolling axis with a selection from a plurality of parameters for representing the roll angle according to running conditions of the vehicle, the plurality of parameters being different in an earliness in a phase of changing thereof and susceptibleness to an error caused by at least one of vehicle speed and lateral inclination of road surface;

means for estimating a second quantity corresponding to a change rate of the roll angle of the vehicle body;

means for estimating a third quantity indicating a relative magnitude of the first quantity with reference to a first limit value predetermined therefor;

means for estimating a fourth quantity indicting a relative magnitude of the second quantity with reference to a second limit value predetermined therefor; and

means for estimating the rolling condition as a combination of the third and fourth quantities such that the rolling condition is intensified along with increase of the third quantity as well as increase of the fourth quantity.

2. A device according to claim 1, comprising means for detecting at least one selected from the group consisting of lateral acceleration Gy of the vehicle body, a combination yaw rate γ

of the vehicle body and vehicle speed V and a combination of yaw rate γ and

lateral acceleration Gy of the vehicle body, wherein the means for estimating the fourth quantity comprise means for cyclically conducting renewing calculations as follows

3. A device according to claim 2, wherein the means for estimating the third quantity estimates the third quantity by dividing one selected from the group consisting of φ

, γ

V, Gy and Ff by either one of limit values φ

_limit, (γ

V)_limit, Gy_limit and Ff_limit correspondingly predetermined therefor.

4. A device according to claim 2, comprising all of the means for detecting the yaw rate γ

, the vehicle speed V and the lateral acceleration Gy, and means for calculating lateral inclination θ

of road surface based upon a difference between γ

V and Gy, wherein the means for estimating the fourth quantity comprise means for cyclically conducting renewing calculations as follows

5. A device according to claim 4, wherein the means for estimating the third quantity estimates the third quantity by dividing the product γ

V by a limit value (γ

V)_limit predetermined therefor when the vehicle speed V is not larger than a threshold value Vc predetermined therefor and the lateral inclination θ

of the road surface is not larger than a threshold value θ

c predetermined therefor, while otherwise estimating the third quantity by dividing the lateral acceleration Gy by a limit value Gy_limit predetermined therefor.

6. A device according to claim 2, comprising all of the means for detecting the yaw rate γ

, the vehicle speed V and the lateral acceleration Gy, and means for calculating lateral inclination θ

of road surface based upon a difference between γ

V and Gy, wherein the means for estimating the fourth quantity comprise means for cyclically conducting renewing calculations as follows

7. A device according to claim 6, wherein the means for estimating the third quantity estimates the third quantity by dividing the product γ

V by a limit value (γ

V)_limit predetermined therefor when the vehicle speed V is not larger than a threshold value Vc predetermined therefor and the lateral inclination θ

of the road surface is not larger than a threshold value θ

c predetermined therefor, while otherwise estimating the third quantity by dividing the Ff by a limit value Ff_limit predetermined therefor.

8. A device according to claim 2, comprising all of the means for detecting the yaw rate γ

, the vehicle speed V and the lateral acceleration Gy, and means for calculating lateral inclination θ

of road surface based upon a difference between γ

V and Gy, means for calculating a first weighting factor Wr based upon the vehicle speed V so as to be gradually decreased along with increase of the vehicle speed, and means for calculating a second weighting factor Wi based upon the lateral inclination θ

so as to be gradually decreased along with increase of the lateral inclination, wherein the means for estimating the third quantity estimates the third quantity as follows

9. A device according to claim 2, comprising all of the means for detecting the yaw rate γ

, the vehicle speed V and the lateral acceleration Gy, and means for calculating lateral inclination θ

of road surface based upon a difference between γ

V and Gy, means for calculating a first weighting factor Wr based upon the vehicle speed V so as to be gradually decreased along with increase of the vehicle speed, and means for calculating a second weighting factor Wi based upon the lateral inclination θ

so as to be gradually decreased along with increase of the lateral inclination, wherein the means for estimating the third quantity estimates the third quantity as follows