Vehicle steering system

• US 7,392,121 B2
• Filed: 06/08/2007
• Issued: 06/24/2008
• Est. Priority Date: 06/13/2006
• Status: Active Grant

• Current Assignee: Jtekt Corporation (Toyota Motor Corporation)
• Original Assignee: Jtekt Corporation (Toyota Motor Corporation)
• Inventors: Maeda, Naoki, Maeda, Shingo, Yamanaka, Kosuke, Maeda, Daisuke, Arima, Masanori, Kouchi, Tatsuma, Ishihara, Atsushi
• Primary Examiner(s): Nguyen; Cuong H
• Application Number:
  US11/760,311
• Publication Number:
  US 20070288144A1
• Time in Patent Office: 382 Days
• Field of Search: 701/41, 701/42, 701/70, 180/204, 180/411, 180/6.24
• US Class Current: 701/41
• CPC Class Codes: B62D 15/0285 Parking performed automatically
• CPC Class Codes: B62D 5/0481 monitoring the steering system, e.g. failures
• CPC Class Codes: B62D 5/0496 by using a temperature sensor

Abstract

An automatic parking control is cancelled when a motor current has not yet reached a maximum current value I_max with a steering angle deviation exceeding a deviation threshold value. In addition, the automatic parking control is cancelled when a steering speed has not yet reached a maximum steering speed with a state where the motor current has reached and remains at the maximum steering speed continuing over a first time period. On the other hand, when a state where the steering speed has reached and remains at the maximum steering speed continues over a second time period, it is determined that there occurs an output shortage of a steering actuator, an automatic parking condition is recalculated, so as to allow the automatic parking continue to continue.

Claims

1. A vehicle steering system comprising:

a steering actuator that imparts a steering force to a steering mechanism of a vehicle;

an automatic steering controller that performs an automatic steering control by controlling the steering actuator based on a target steering angle;

a steering angle detector that detects an actual steering angle of the steering mechanism;

a steering angle deviation determination unit that determines whether or not a steering angle deviation which is a deviation of an actual steering angle detected by the steering angle detector relative to the target steering angle exceeds a predetermined threshold value;

a deviation factor determination unit that determines whether or not an output shortage of the steering actuator constitutes a factor of the deviation when the steering angle deviation determination unit determines that the steering angle deviation exceeds the predetermined threshold value; and

an automatic steering cancellation unit that causes the automatic steering control by the automatic steering controller to continue when the deviation factor determination unit determines that the output shortage of the steering actuator constitutes the factor of the deviation, and cancels the automatic steering control by the automatic steering controller when the deviation factor determination unit determines that the output shortage of the steering actuator does not constitute the factor of the deviation.

2. The vehicle steering system according to claim 1 further comprising an automatic steering condition changing unit that changes a condition for the automatic steering control by the automatic steering controller when the deviation factor determination unit determines that the output shortage of the steering actuator constitutes the factor of the deviation.