Apparatus for determining linearity of tire characteristic
First Claim
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.
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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.
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Citations
6 Claims
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1. An apparatus for determining linearity of tire characteristic comprising:
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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. - View Dependent Claims (2, 4, 5)
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3. A program 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:
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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.
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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:
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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.
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Specification