Offset calibration of a semi-relative steering wheel angle sensor
First Claim
Patent Images
1. A method for determining an actual steering wheel angle θ
- of a vehicle steering mechanism, the vehicle steering mechanism having an initial steering wheel angle θ
1 when the vehicle enters an ignition-on state, the vehicle steering mechanism having a center steering wheel angle θ
0 when the vehicle is heading straight-forward, the method comprising the steps of;
determining a semi-relative steering wheel angle offset Δ
θ
representing the difference between θ
1 and θ
0;
storing Δ
θ
in erasable programmable read-only memory when said vehicle enters an ignition-off state;
measuring a relative steering wheel angle θ
R from a semi-relative steering wheel angle sensor during the ignition-off state;
retrieving Δ
θ
from the erasable programmable read-only memory when said vehicle enters an ignition-on state;
continuing to measure the relative steering wheel angle θ
R from the semi-relative steering wheel angle sensor during the ignition-on state; and
determining said steering wheel angle θ
based on θ
R and Δ
θ
.
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Abstract
A new method for determining an actual steering wheel angle is provided that does not require re-calculation of a steering center upon each ignition of the vehicle. Accordingly, the vehicle dynamic controller may be activated very quickly after ignition, while a less costly relative steering wheel angle sensor may be employed.
30 Citations
22 Claims
-
1. A method for determining an actual steering wheel angle θ
- of a vehicle steering mechanism, the vehicle steering mechanism having an initial steering wheel angle θ
1 when the vehicle enters an ignition-on state, the vehicle steering mechanism having a center steering wheel angle θ
0 when the vehicle is heading straight-forward, the method comprising the steps of;determining a semi-relative steering wheel angle offset Δ
θ
representing the difference between θ
1 and θ
0;
storing Δ
θ
in erasable programmable read-only memory when said vehicle enters an ignition-off state;
measuring a relative steering wheel angle θ
R from a semi-relative steering wheel angle sensor during the ignition-off state;
retrieving Δ
θ
from the erasable programmable read-only memory when said vehicle enters an ignition-on state;
continuing to measure the relative steering wheel angle θ
R from the semi-relative steering wheel angle sensor during the ignition-on state; and
determining said steering wheel angle θ
based on θ
R and Δ
θ
. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
- of a vehicle steering mechanism, the vehicle steering mechanism having an initial steering wheel angle θ
-
9. A method of determining an actual steering wheel angle θ
- of a steering mechanism in a vehicle, the vehicle including an electrical control unit in communication with a calibration module, a sensor module and an erasable programmable read-only memory, the calibration module including a semi-relative steering wheel angle sensor reading the relative movement of the steering mechanism, the sensor module including a yaw rate sensor, the method comprising the steps of;
reading a last known semi-relative steering wheel angle offset value Δ
θ
(tn) from the eraseable programmable read-only memory to the electrical control unit;
determining whether power to calibration module has been terminated determining whether a failure has occurred with the sensor module; and
setting the last known semi-relative steering wheel angle offset value Δ
θ
(tn) as an initial semi-relative steering wheel angle offset value Δ
θ
(t0) if power to the calibration module was not terminated and no failure occurred with the sensor module. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17)
- of a steering mechanism in a vehicle, the vehicle including an electrical control unit in communication with a calibration module, a sensor module and an erasable programmable read-only memory, the calibration module including a semi-relative steering wheel angle sensor reading the relative movement of the steering mechanism, the sensor module including a yaw rate sensor, the method comprising the steps of;
-
18. A method for determining a steering wheel angle θ
- of a steering mechanism for a vehicle, the method comprising the steps of;
measuring a relative steering wheel angle θ
R from a semi-relative steering wheel angle sensor during both ignition-off and ignition-on states of said vehicle;
retrieving a semi-relative steering wheel angle offset Δ
θ
from the erasable programmable read-only memory when said vehicle enters an ignition-on state; and
determining said steering wheel angle θ
based on θ
R and Δ
θ
. - View Dependent Claims (19, 20, 21, 22)
- of a steering mechanism for a vehicle, the method comprising the steps of;
Specification