Method for determining a vehicle steering wheel center position

Claim 3

The method according to claim 1, wherein detecting vehicle operating conditions corresponding to a straight direction of vehicle travel comprises: sensing an angular position of the brushless motor; sensing a torque developed by the steering wheel; sensing a vehicle speed; determining a change in the sensed angular position of the brushless motor over a first predetermined time period; determining a change in the sensed torque developed by the steering wheel over a second predetermined time period; and detecting a straight direction of vehicle travel when (i) sensed vehicle speed is greater than a predetermined vehicle speed, (ii) the change in sensed torque is less than a predetermined change in torque, (iii) the change in sensed angular position of the brushless motor is less than a predetermined change in angular position, and (iv) sensed torque is less than a predetermined torque.

Claim 4

The method according to claim 1, wherein establishing a range of angular positions of the brushless motor about the estimated center position comprises: determining whether the estimated center position is one of less than the minimum position and greater than the maximum position of the range of angular positions; equating the minimum position with the estimated center position when the estimated center position is less than the minimum limit; and equating the maximum position with the estimated center position when the estimated center position is greater than the maximum limit.

Claim 5

The method according to claim 1, further comprising: determining a difference between the center position of the steering wheel and a predetermined center position; and indicating when the difference between the center position of the steering wheel and a predetermined center position is greater than a predetermined difference.

Claim 6

The method according to claim 3, further comprising: identifying a finite span of the range of angular positions as a difference between the minimum and maximum angular positions when the difference between the minimum and maximum angular positions remains unchanged over a predetermined time period; and limiting the range of angular positions to the finite span.

Claim 7

The method according to claim 1, further comprising: sensing an angular position of the brushless motor; sensing a vehicle speed; and updating the estimated center position by a percentage of a difference between the sensed angular position of the brushless motor and the estimated center position, the percentage being a function of the sensed vehicle speed with respect to a predetermined vehicle speed.