Power steering system

摘要

In a power steering system, when power is on, a normal mode process is executed and a target rotational speed is set based on a rotational speed map for a normal mode. When the normal mode process is being executed, if a first mode switching condition that a detected vehicle speed is equal to or lower than a prescribed value, the absolute value of a detected steering angle is equal to or greater than a prescribed value, and the absolute value of a detected steering, angular velocity is equal to or less than a prescribed value is satisfied, the target rotational speed is set based on a rotational speed map for a rack end mode.

主权项

1. A power steering system comprising:
an electric motor; a hydraulic pump that is driven by the electric motor to generate steering assist force; and a controller that controls the electric motor, the controller being configured to
(i) operate in a first mode that controls a rotational speed of the electric motor based on a steering angular velocity and a vehicle speed,(ii) operate in a second mode that controls the rotational speed of the electric motor based on a steering angle, wherein a target rotational speed in the second mode varies based on the steering angle, and(iii) switch a control mode from rotational speed control by the first mode to rotational speed control by the second mode when the vehicle speed is equal to or less than a first threshold and an absolute value of the steering angle is equal to or greater than a second threshold.