Device for estimating turning characteristic of vehicle
First Claim
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1. A turning characteristic estimation method for a vehicle, comprising:
- obtaining an actual yaw rate of the vehicle;
obtaining a vehicle speed of the vehicle;
obtaining a steered angle of front wheels of the vehicle;
obtaining a lateral acceleration of the vehicle;
calculating a steady-state basic yaw rate based on the obtained vehicle speed, the obtained steered angle and the obtained lateral acceleration;
calculating a plurality of transient yaw rates based on the calculated basic yaw rate using a steering response equation in which the transient yaw rate is expressed as having a first order delay relative to the basic yaw rate,wherein the steering response equation comprises a time constant of the first order delay, andwherein each of the plurality of transient yaw rates is calculated based on a corresponding different reference value of a time constant coefficient which is a coefficient multiplied to the vehicle speed in the time constant of the first order delay;
calculating respective differences between each of the plurality of transient yaw rates and the obtained actual yaw rate;
selecting a reference value among the plurality of reference values corresponding to the transient yaw rate having a minimum difference to the actual yaw rate as an estimated time constant coefficient of the steering response, which represents the turning characteristic of the vehicle; and
updating each reference value based on the estimated time constant coefficient;
wherein the turning characteristic estimation of the vehicle is performed by an electronic control unit.
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Abstract
The device calculates a transient yaw rate of the vehicle on the basis of a standard yaw rate of the vehicle using an estimated value of a time constant coefficient of steering response, and adjusts the estimated value of a time constant coefficient of steering response on the basis of the relationship between a transient yaw rate of the vehicle and an actual yaw rate of the vehicle so that a transient yaw rate of the vehicle approaches an actual yaw rate of the vehicle.
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Citations
12 Claims
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1. A turning characteristic estimation method for a vehicle, comprising:
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obtaining an actual yaw rate of the vehicle; obtaining a vehicle speed of the vehicle; obtaining a steered angle of front wheels of the vehicle; obtaining a lateral acceleration of the vehicle; calculating a steady-state basic yaw rate based on the obtained vehicle speed, the obtained steered angle and the obtained lateral acceleration; calculating a plurality of transient yaw rates based on the calculated basic yaw rate using a steering response equation in which the transient yaw rate is expressed as having a first order delay relative to the basic yaw rate, wherein the steering response equation comprises a time constant of the first order delay, and wherein each of the plurality of transient yaw rates is calculated based on a corresponding different reference value of a time constant coefficient which is a coefficient multiplied to the vehicle speed in the time constant of the first order delay; calculating respective differences between each of the plurality of transient yaw rates and the obtained actual yaw rate; selecting a reference value among the plurality of reference values corresponding to the transient yaw rate having a minimum difference to the actual yaw rate as an estimated time constant coefficient of the steering response, which represents the turning characteristic of the vehicle; and updating each reference value based on the estimated time constant coefficient; wherein the turning characteristic estimation of the vehicle is performed by an electronic control unit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification