Rear wheel steering angle control system for vehicle
First Claim
1. An apparatus for controlling a rear wheel steering angle of a vehicle comprising:
- first means for sensing vehicle speed to provide a signal indicative thereof;
second means for sensing an actual steered angle of a front wheel of the vehicle to provide a signal indicative thereof;
third means for deriving a first locus defined along a path of a first specific point on the front end of the vehicle based on the signals from said first and second means;
fourth means for determining a target steering angle for a rear wheel based on parameters associated with the vehicle speed and the actual steered angle of the front wheel sensed by said first and second means such that a second locus extending along a path of a second specific point on the rear end of the vehicle is defined within said first locus with respect to the center of the vehicle turning circle; and
fifth means for controlling the rear wheel actual steering angle based on said target steering angle to restrict the amount of overhand of the rear end of the vehicle during turning.
1 Assignment
0 Petitions
Accused Products
Abstract
A rear wheel steering angle control system for a 4WS vehicle is provided. This system includes a first circuit for deriving a locus defined by a specific point provided on the front end of the vehicle, a second circuit for deriving a locus defined by a specific point provided on the rear end of the vehicle, a third circuit for providing a target steering angle for the rear wheels so that a rear corner does not overhang outwardly during turning, and a controller for controlling an actual angle for steering the rear wheels. The third circuit determines the target steering angle so as to restrict the magnitude of offset of the rear specific point from the locus of the front specific point. The controller steers the rear wheels by the target steering angle to restrict the magnitude of overhang of the rear end of the vehicle and enables the vehicle to turn within the minimum possible turning circle.
-
Citations
22 Claims
-
1. An apparatus for controlling a rear wheel steering angle of a vehicle comprising:
-
first means for sensing vehicle speed to provide a signal indicative thereof; second means for sensing an actual steered angle of a front wheel of the vehicle to provide a signal indicative thereof; third means for deriving a first locus defined along a path of a first specific point on the front end of the vehicle based on the signals from said first and second means; fourth means for determining a target steering angle for a rear wheel based on parameters associated with the vehicle speed and the actual steered angle of the front wheel sensed by said first and second means such that a second locus extending along a path of a second specific point on the rear end of the vehicle is defined within said first locus with respect to the center of the vehicle turning circle; and fifth means for controlling the rear wheel actual steering angle based on said target steering angle to restrict the amount of overhand of the rear end of the vehicle during turning. - View Dependent Claims (3, 5, 6, 7)
-
- 2. An apparatus as set forth in claim 2, wherein a longitudinal line between said first and second specific points at the time the vehicle starts lies along said first locus.
-
8. Apparatus for controlling a rear wheel steering angle of a vehicle comprising:
-
first means for sensing vehicle speed to provide a signal indicative thereof; second means for sensing an actual steered angle of a front wheel of the vehicle to provide a signal indicative thereof; third means for determining a first rear wheel steering angle required for turning within a given target turning circle based on the signals from said first and second means and providing a signal indicative thereof; fourth means for deriving a first locus defined along a path of a first specific point on the front end of the vehicle based on the signals from said first and said second means; fifth means for determining a second rear wheel steering angle so that a second specific point defined on the rear end of the vehicle coincides with the first locus to provide a signal indicative thereof; sixth means for selecting the smaller of the absolute value of the first and second rear wheel steering angles to provide a rear wheel target steering angle so that a second locus, defined by the path of the second specific point, is positioned inside the first locus with respect to the center of a vehicle turning circle; and seventh means for controlling an actual steering angle for the rear wheel based on said rear wheel target steering angle. - View Dependent Claims (9, 10, 11, 12, 13, 14)
-
-
15. A system for controlling a rear wheel steering angle for a vehicle comprising:
-
first means for sensing vehicle speed to provide a signal indicative thereof; second means for sensing an actual steered angle of front wheels of the vehicle to provide a signal indicative thereof; third means for determining a first rear wheel steering angle required for turning within a given target turning circle as a function of the vehicle speed and the actual steered angle of the front wheel sensed by said first and second means and providing a signal indicative thereof; fourth means for providing a first locus defined along a path of a first specific point on the front end of the vehicle based on the signals from, the first locus including a longitudinal line extending between the first specific point and a second specific point on the rear end of the vehicle as part of the first locus at the time the system starts; fifth means for determining a second rear wheel steering angle resulting in the second specific point intersecting the first locus at a point where a line extending between center points of the rear wheels intersects the first locus and providing a signal indicative thereof; sixth means for selecting the smaller of the absolute values of the first and second rear wheel steering angles to provide a rear wheel target steering angle to cause the second locus to be positioned inside the first locus with respect to the center of the vehicle turning circle; and seventh means for controlling the rear wheel actual steering angle based on said rear wheel target steering angle. - View Dependent Claims (16, 17, 18, 19)
-
-
20. Apparatus for controlling a rear wheel steering angle of a vehicle in response to first and second signals respectively indicative of sensed vehicle speed and an actual steered angle of a front wheel of the vehicle comprising
means responsive to the first and second signals for: -
(a) deriving a first locus extending along a path defined by a first specific point on the front end of the vehicle based on parameters associated with the vehicle speed and the actual steered angle of the front wheel, (b) determining a target steering angle for a rear wheel based on parameters associated with the vehicle speed and the actual steered angle of the front wheel such that a second locus extending along a path of a second specific point on the rear end of the vehicle is defined within said first locus with respect to the center of the vehicle turning circle, and (c) deriving a control signal for the rear wheel actual steering angle base on said target steering angle to restrict the amount of overhand to the rear end of the vehicle during turning; and means for supplying the control signal to a mechanism for controlling the rear wheel steering angle.
-
-
21. Apparatus for controlling a rear wheel steering angle of a vehicle in response to first and second signals respectively indicative of sensed vehicle speed and an actual steered angle of a front wheel of the vehicle comprising
means responsive to the first and second signals for: -
(a) determining a first rear wheel steering angle required for turning within a given target turning circle based on parameters associated with the vehicle speed and the actual steered angle of the front wheel and deriving a signal indicative thereof, (b) deriving a first locus defined along a path of a first specific point on the front end of the vehicle based on parameters associated with the vehicle speed and the actual steered angle of the front wheel, (c) determining a second rear wheel steering angle so that a second specific point defined on the rear end of the vehicle coincides with the first locus, (d) selecting the smaller of the absolute values of the first and second rear wheel steering angles to provide a rear wheel target steering angle so that a second locus, defined by the path of the second specific point, is positioned inside the first locus with respect to the center of a vehicle turning circle, and (e) deriving a control signal for an actual steering angle for the rear wheel based on said rear wheel target steering angle; and means for supplying the control signal to a mechanism for controlling the rear wheel steering angle.
-
-
22. Apparatus for controlling a rear wheel steering angle of a vehicle in response to first and second signals respectively indicative of sensed vehicle speed and an actual steering angle of a front wheel of the vehicle comprising:
-
means responsive to the first and second signals for; (a) determining a first rear wheel steering angle required for turning within a given target turning circle as a function of the vehicle speed and the actual steered angle of the front wheel, (b) determining a first locus as along a path of a first specific point on to the front end of the vehicle based on parameters associated with the vehicle speed and the actual steered angle of the front wheel, the first locus including a longitudinal line extending between the first specific point and a second specific point on the rear end of the vehicle as part of the first locus at the time the system starts, (c) determining a second rear wheel steering angle resulting in the second specific point intersecting the first locus at a point where a line extending between center points of the rear wheels intersects the first locus and providing a signal indicative thereof, (d) selecting the smaller of the absolute values of the first and second rear wheel steering angles and to provide a rear wheel target steering angle to cause the second locus to be positioned inside the first locus with respect to the center of the vehicle turning circle, (e) deriving a control signal for an actual steering angle for the rear wheel based on said rear wheel target steering angle, and means for supplying the control signal to a mechanism for controlling the rear wheel steering angle.
-
Specification