Steering angle detecting apparatus for vehicle and electric power steering apparatus

摘要

When an ignition is turned off, an absolute steering angle detection value immediately before the ignition is turned off is stored as an absolute steering angle stored value in a memory and a CAN relative steering angle immediately before the ignition is turned off is stored as a relative steering angle stored value in the memory. When the ignition is turned on, a value obtained by correcting the absolute steering angle stored value with an angle value and the CAN relative steering angle) by which steering is performed during a period from the time when the ignition is turned off until the time when the ignition is turned on is set as an initial value of the absolute steering angle. A provisional absolute steering angle calculated value is calculated based on the relative steering angle, using the initial value of the absolute steering angle as a reference.

主权项

1. A steering angle detecting apparatus for a vehicle comprising:
a relative steering angle sensor connected to a CAN bus, the relative steering angle sensor continuously detecting a relative steering angle of a steering mechanism for steering steered wheels of the vehicle during a system startup while an ignition switch is in an ON state and during a system shutdown while the ignition switch is in an OFF state; an absolute steering angle storage unit including a non-volatile memory in which a steering angle detection value of the steering mechanism outputted immediately before the system shutdown is stored as an absolute steering angle stored value; a provisional absolute steering angle value calculating device that is a hardware component of a computer and that is configured to set, immediately after the system startup begins, a value obtained by correcting the absolute steering angle stored value stored in the non-volatile memory with a variation in the relative steering angle of the steering mechanism detected by the relative steering angle sensor from a last system shutdown until a present system startup, as an initial value of an absolute steering angle of the steering mechanism, and to calculate a provisional absolute steering angle value on the basis of the relative steering angle detected by the relative steering angle sensor, using the initial value of the absolute steering angle as a reference so as to output the provisional absolute steering angle value, during the system startup; and a relative steering angle storage including the non-volatile memory in which the relative steering angle detected by the relative steering angle sensor, but not the absolute steering angle, is stored as a relative steering angle stored value immediately before the system shutdown, wherein the provisional absolute steering angle value calculating device adds a difference between the relative steering angle stored value stored in the non-volatile memory and the relative steering angle detected by the relative steering angle sensor to the absolute steering angle stored value stored in the non-volatile memory so as to calculate the provisional absolute steering angle value immediately after the system startup begins, and steering assist control is performed on the basis of the steering angle detection value detected by the steering angle detecting apparatus.