Apparatus for determining linearity of tire characteristic

• US 6,823,245 B2
• Filed: 07/18/2003
• Issued: 11/23/2004
• Est. Priority Date: 07/19/2002
• Status: Expired due to Fees

• Current Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Original Assignee: Honda Giken Kogyo Kabushiki Kaisha (Honda Motor Company)
• Inventors: Kawano, Masaaki, Sugitani, Nobuo, Tsurumiya, Osamu
• Primary Examiner(s): ARTHUR JEANGLAUDE, GERTRUDE
• Application Number:
  US10/623,040
• Publication Number:
  US 20040016294A1
• Time in Patent Office: 494 Days
• Field of Search: 701/29, 701/34, 701/41, 701/63, 701/65, 340/438, 340/439, 340/440, 340/442
• US Class Current: 701/29
• CPC Class Codes: B60T 8/172 Determining control parameters used in the regulation, e.g. by calculations involving measured or detected parameters B60T8/17551 takes precedence
• CPC Class Codes: B60W 2510/20 Steering systems
• CPC Class Codes: B60W 2510/202 Steering torque
• CPC Class Codes: B60W 2520/14 Yaw
• CPC Class Codes: B60W 2530/20 Tyre data
• CPC Class Codes: B60W 2710/20 Steering systems
• CPC Class Codes: B60W 40/101 Side slip angle of tyre
• CPC Class Codes: B62D 1/12 Hand levers
• CPC Class Codes: B62D 5/006 power actuated
• CPC Class Codes: B62D 6/003 in order to control vehicle yaw movement, i.e. around a vertical axis B62D6/007 takes precedence
• CPC Class Codes: B62D 6/008 Control of feed-back to the steering input member, e.g. simulating road feel in steer-by-wire applications

Abstract

A non-linear region controller 45 calculates a standard yaw rate from an actual steering angle θr of steerable wheels detected by a steering angle sensor 10, a deviation from the standard yaw rate, of a yaw rate γr detected by a yaw rate sensor 23, and a rate of change of the yaw rate deviation. Based upon calculated results, the non-linear region controller 45 determines whether tires of a traveling vehicle are in a non-linear region of tire characteristic, and if determining so, exercises a steering amount reduction control to reduce an actual steering angle θr of the steerable wheels. The determination of linearity of tire characteristic can be made with comparative ease utilizing a commonly available sensor, and the vehicle is controlled using the determination result.

Claims

1. An apparatus for determining linearity of tire characteristic comprising:

a standard vehicle behavior arithmetic unit that calculates a standard vehicle behavior indicator based upon at least one of an operation amount of an operation unit with which a driver of a traveling vehicle performs a steering operation and an actually steered amount of steerable wheels of the traveling vehicle, wherein the operation amount of the operation unit is detected by an operation amount detector and the actually steered amount of the steerable wheels is detected by a steered amount detector; and

a tire characteristic linearity determination unit that compares an actual vehicle behavior indicator detected by a vehicle behavior detector with the standard vehicle behavior indicator, to determine whether tires of the traveling vehicle stand in a linear region or in a non-linear region of the tire characteristic.

2. An apparatus for determining linearity of tire characteristic according to claim 1, wherein the tire characteristic linearity determination unit includes:

a vehicle behavior deviation change rate arithmetic part that calculates a vehicle behavior deviation by subtracting the actual vehicle behavior indicator from the standard vehicle behavior indicator, and calculates a rate of change of the vehicle behavior deviation;

a sign determination part that determines a first sign of one of the vehicle behavior deviation and the rate of change of the vehicle behavior deviation, and a second sign of the actual vehicle behavior indicator;

a tire characteristic linearity determination part that determines linearity of tire characteristic, wherein if the first and second signs are both positive and the rate of change of the vehicle behavior deviation is greater than a first prescribed value, and if the first and second signs are both negative and the rate of change of the vehicle behavior deviation is less than a second prescribed value, it is determined that the tires of the traveling vehicle stand in the non-linear region of the tire characteristic.

3. A program embodied on a computer readable medium for determining linearity of tire characteristic, which causes a computer to execute a process to determine whether tires of a traveling vehicle stand in a linear region or in a non-linear region of the tire characteristic, the process comprising the steps of:

receiving at least one of an operation amount of an operation unit with which a driver of the traveling vehicle performs a steering operation and an actually steered amount of steerable wheels of the traveling vehicle, which are detected by an operation amount detector and a steered amount detector, respectively;

calculating a standard vehicle behavior indicator based upon the at least one of the operation amount of the operation unit and the actually steered amount of the steerable wheels;

receiving an actual vehicle behavior indicator detected by a vehicle behavior detector;

calculating a vehicle behavior deviation by subtracting the actual vehicle behavior indicator from the standard vehicle behavior indicator;

calculating a rate of change of the vehicle behavior deviation;

determining a first sign of one of the vehicle behavior deviation and the rate of change of the vehicle behavior deviation, and a second sign of the actual vehicle behavior indicator;

if the first and second signs are both positive and the rate of change of the vehicle behavior deviation is greater than a first prescribed value, determining that the tires of the traveling vehicle stand in the non-linear region of the tire characteristic; and

if the first and second signs are both negative and the rate of change of the vehicle behavior deviation is less than a second prescribed value, determining that the tires of the traveling vehicle stand in the non-linear region of the tire characteristic.

4. A vehicular driving operation apparatus comprising:

an operation unit with which a driver of a traveling vehicle performs a steering operation;

a steering amount detection unit including at least one of an operation amount detector that detects an operation amount of the operation unit and a steered amount detector that detects an actually steered amount of steerable wheels of the traveling vehicle;

a steering motor that drives the steerable wheels to be steered;

a control unit that controls the steering motor based upon at least one of the operation amount of the operation unit and the actually steered amount of the steerable wheels;

a vehicle behavior detector that detects an actual vehicle behavior indicator;

an apparatus for determining linearity of tire characteristic comprising;

a standard vehicle behavior arithmetic unit that calculates a standard vehicle behavior indicator based upon at least one of an operation amount of an operation unit with which a driver of a traveling vehicle performs a steering operation and an actually steered amount of steerable wheels of the traveling vehicle, wherein the operation amount of the operation unit is detected by an operation amount detector and the actually steered amount of the steerable wheels is detected by a steered amount detector; and

a tire characteristic linearity determination unit that compares an actual vehicle behavior indicator detected by a vehicle behavior detector with the standard vehicle behavior indicator, to determine whether tires of the traveling vehicle stand in a linear region or in a non-linear region of the tire characteristic; and

a steering amount reduction control unit that controls the steering motor so that the steering motor drives the steerable wheels to be steered back if the tire characteristic linearity determination unit determines that the tires of the traveling vehicle stand in the non-linear region of the tire characteristic.

5. A vehicular driving operation apparatus comprising:

an operation unit with which a driver of a traveling vehicle performs a steering operation;

a reaction force motor that gives a reaction force against operation of the operation unit;

a steering amount detection unit including at least one of an operation amount detector that detects an operation amount of the operation unit and a steered amount detector that detects an actually steered amount of steerable wheels of the traveling vehicle;

a steering motor that drives the steerable wheels to be steered;

a control unit that controls the steering motor based upon at least one of the operation amount of the operation unit and the actually steered amount of the steerable wheels;

a vehicle behavior detector that detects an actual vehicle behavior indicator;

an apparatus for determining linearity of tire characteristic comprising;

a standard vehicle behavior arithmetic unit that calculates a standard vehicle behavior indicator based upon at least one of an operation amount of an operation unit with which a driver of a traveling vehicle performs a steering operation and an actually steered amount of steerable wheels of the traveling vehicle, wherein the operation amount of the operation unit is detected by an operation amount detector and the actually steered amount of the steerable wheels is detected by a steered amount detector; and

a tire characteristic linearity determination unit that compares an actual vehicle behavior indicator detected by a vehicle behavior detector with the standard vehicle behavior indicator, to determine whether tires of the traveling vehicle stand in a linear region or in anon-linear region of the tire characteristic; and

a steering amount reduction control unit that controls the reaction force motor so that the reaction force motor drives the operation unit to move back toward a neutral position if the tire characteristic linearity determination unit determines that the tires of the traveling vehicle stand in the non-linear region of the tire characteristic.

6. A steering control method for a steer-by-wire vehicle having a steer-by-wire system which includes an operation unit with which a driver performs a steering operation, a steering motor that drives steerable wheels to be steered, and a reaction force motor that gives a reaction force against operation of the operation unit, to perform a steering operation through electric connections, the method comprising:

calculating a standard vehicle behavior indicator based upon at least one of an operation amount of the operation unit and an actually steered amount of the steerable wheels;

comparing an actual vehicle behavior indicator obtained by detection with the standard vehicle behavior indicator, to determine whether tires of the vehicle during traveling stand in a linear region or in a non-linear region of tire characteristic; and

if it is determined that the tires of the traveling vehicle stand in the non-linear region of the tire characteristic, controlling at least one of the reaction force motor and the steering motor to steer the steerable wheels toward such a direction as to reduce the steering amount thereof.