Method for determining absolute steering wheel angle from a single-turn steering wheel angle sensor
First Claim
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1. A method of determining a steering wheel angle of a vehicle steering mechanism, upon key-on of a vehicle, using a single-turn steering wheel angle sensor, the method comprising the steps of:
- sensing a steering wheel angle from the single-turn steering wheel angle sensor;
storing plausible absolute steering wheel angle positions formed from the sensed steering wheel angle;
sensing an output from a selected vehicle sensor that is input to a control system on the vehicle;
calculating an expected output of the selected vehicle sensor for the plausible steering wheel angle positions; and
outputting a single absolute steering wheel angle from the plausible steering wheel angle positions based on a comparison of the sensed output for the selected vehicle sensor for the sensed steering wheel angle against the calculated expected output of the vehicle sensor for a plausible absolute steering wheel angle position.
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Abstract
A method and algorithm for determining a steering wheel angle of a vehicle steering mechanism upon power up of a vehicle using a single-turn steering wheel angle sensor by eliminating plausible steering wheel angles until one and only one steering wheel angle possibility remains.
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Citations
31 Claims
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1. A method of determining a steering wheel angle of a vehicle steering mechanism, upon key-on of a vehicle, using a single-turn steering wheel angle sensor, the method comprising the steps of:
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sensing a steering wheel angle from the single-turn steering wheel angle sensor; storing plausible absolute steering wheel angle positions formed from the sensed steering wheel angle; sensing an output from a selected vehicle sensor that is input to a control system on the vehicle; calculating an expected output of the selected vehicle sensor for the plausible steering wheel angle positions; and outputting a single absolute steering wheel angle from the plausible steering wheel angle positions based on a comparison of the sensed output for the selected vehicle sensor for the sensed steering wheel angle against the calculated expected output of the vehicle sensor for a plausible absolute steering wheel angle position. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A control module algorithm for determining a steering wheel angle of a vehicle steering mechanism, upon power-up of a vehicle, using a single-turn steering wheel angle sensor, comprising:
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a sensed steering wheel angle input to the control module from the single-turn steering wheel angle sensor; a selected vehicle sensor signal input to the control module; a vehicle speed input to the control module; a vehicle stability check input to the control module; a steering wheel angle lock input; one or more plausible steering wheel angles at key-on; a calculated expected output for the selected vehicle sensor signal for each plausible steering wheel angle in the one or more plausible steering wheel angles; a threshold check of plausible steering wheel angles to the steering wheel angle lock input; a threshold check of the calculated expected output for each plausible steering wheel angle to an actual selected vehicle sensor signal; one and only one plausible steering wheel angle output as a result of eliminating plausible steering wheel angles that exceed the threshold checks. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27)
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28. A method of determining a steering wheel angle of a vehicle steering mechanism, upon power-up of a vehicle, using a single-turn steering wheel angle sensor, the method comprising the steps of:
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storing plausible absolute steering wheel angle positions formed from adding offsets of +n times a predetermined angle to a steering wheel angle provided from the single-turn steering wheel angle sensor; comparing the plausible steering wheel angle positions to predetermined maximum and minimum steering wheel angle threshold values, whereby each plausible absolute steering wheel angle position that exceeds either the maximum or minimum steering wheel angle threshold value is eliminated as a possibility; determining a vehicle stability check through the identification of at least one item of non-forward motion of the vehicle, a brake event in a traction control system, an engine event in a traction control system or an electronic stability program event; preventing the determination of a steering wheel angle of a vehicle steering mechanism upon any one of the vehicle stability check items being identified; calculating a yaw rate for each of the plausible absolute steering wheel angle positions, the calculated yaw rate being a product of a predetermined yaw rate error, a vehicle speed input and the plausible absolute steering wheel angle; and outputting a single steering wheel angle output through a comparison of a difference between the calculated yaw rate and a sensed vehicle yaw rate, whereby each difference that exceeds either a maximum or minimum threshold value is eliminated resulting in the elimination of all but one possibility from the plausible offset steering wheel angle positions. - View Dependent Claims (29, 30, 31)
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Specification