Method and system for estimating the neutral point of a steering wheel
First Claim
1. A method for estimating a neutral point of a steering wheel for a vehicle comprising the steps of:
- (a) determining whether the vehicle is in a straight ahead travel condition, including the sub-steps of,(a)(1) detecting whether the determination of said straight ahead travel condition has lasted for a specified time at said step (a), and(a)(2) detecting an output of a wheel angle sensor at intervals of a specified cycle, shorter than said specified time, until an elapse of said specified time is detected; and
(b) estimating said neutral point of said steering wheel based on said output of said wheel angle sensor when said straight ahead travel condition of the vehicle is determined in said step (a), said step (b) including the sub-steps of,(b)(1) determining a detection frequency distribution, corresponding to a series of wheel angles detected in said sub-step (a)(2), and(b)(2) determining said neutral point of said steering wheel from said detection frequency distribution.
1 Assignment
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Accused Products
Abstract
A method is provided which permits accurate estimation of the neutral point of a steering wheel while a vehicle is traveling. In this method, a wheel angle is detected whenever a condition, wherein the car speed has reached a specified speed or higher, the working pressure of a hydraulic power steering has not virtually risen yet, and the steering wheel has not yet virtually steered, lasts for a specified time; the detection frequency distribution, which corresponds to the detected wheel angles, is determined; the weighted mean value of the wheel angles is calculated from the detection frequency distribution; and the weighted mean value is estimated as the neutral point of the steering wheel.
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Citations
40 Claims
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1. A method for estimating a neutral point of a steering wheel for a vehicle comprising the steps of:
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(a) determining whether the vehicle is in a straight ahead travel condition, including the sub-steps of, (a)(1) detecting whether the determination of said straight ahead travel condition has lasted for a specified time at said step (a), and (a)(2) detecting an output of a wheel angle sensor at intervals of a specified cycle, shorter than said specified time, until an elapse of said specified time is detected; and (b) estimating said neutral point of said steering wheel based on said output of said wheel angle sensor when said straight ahead travel condition of the vehicle is determined in said step (a), said step (b) including the sub-steps of, (b)(1) determining a detection frequency distribution, corresponding to a series of wheel angles detected in said sub-step (a)(2), and (b)(2) determining said neutral point of said steering wheel from said detection frequency distribution. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A system for estimating a neutral point of a steering wheel of a vehicle, comprising:
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straight ahead travel determining means for determining whether the vehicle is in a straight ahead travel condition; first detecting means for detecting whether said straight ahead travel condition determined by said straight ahead travel determining means has lasted for a specified time; second detecting means for detecting an output of a wheel angle sensor at intervals of a specific cycle, shorter than said specified time, until an elapse of said specified time is detected; neutral point estimating means for estimating said neutral point of said steering wheel based on said output of said wheel angle sensor when said straight ahead travel condition of the vehicle is determined by said straight ahead travel determining means; distribution calculating means for determining a detection frequency distribution corresponding to a series of wheel angles detected by said second detecting means; and neutral point deciding means for determining said neutral point of said steering wheel from said detection frequency distribution. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A method for estimating a neutral point of a steering wheel for a vehicle comprising the steps of:
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(a) determining whether a vehicle angular velocity is at least a predetermined rate; (b) determining whether the vehicle has been in a straight-ahead travel condition at a straight-ahead wheel angle for a predetermined length of time; (c) incrementing by a predetermined unit value, an element of a wheel angle detection array corresponding to the straight-ahead wheel angle, to form a detection frequency distribution; (d) decrementing by the predetermined unit value, each element of the wheel angle detection array having a count of at least the predetermined unit value if a current straight-ahead wheel angle count has exceeded a predetermined maximum value; and (e) estimating the neutral point of the steering wheel by calculating a weighted mean value of the detection frequency distribution. - View Dependent Claims (28, 29, 30, 31, 32, 33)
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34. A system for estimating a neutral point of a steering wheel for a vehicle comprising:
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a vehicle velocity sensor for determining whether a vehicle angular velocity is at least a predetermined rate; straight-ahead travel determining means for determining whether said vehicle has been in a straight-ahead travel condition at a straight-ahead wheel angle for a predetermined length of time; detection frequency distribution determining means for determining a detection frequency distribution; estimating means for estimating the neutral point of said steering wheel by calculating a weighted mean value of the detection frequency distribution. - View Dependent Claims (35, 36, 37, 38, 39, 40)
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Specification