Method for measuring absolute steering angle of steering shaft for vehicle

• US 20050137768A1
• Filed: 12/03/2004
• Published: 06/23/2005
• Est. Priority Date: 12/23/2003
• Status: Active Grant

• Current Assignee: Hyundai Mobis Co., Ltd.
• Original Assignee: Hyundai Mobis Co., Ltd.
• Inventors: Lee, Jong-Hwa
• Granted Patent: US 7,447,580 B2
• Time in Patent Office: Days
• US Class Current: 701/41
• CPC Class Codes: B62D 15/021 Determination of steering angle
• CPC Class Codes: B62D 15/0245 Means or methods for determination of the central position of the steering system, e.g. straight ahead position
• CPC Class Codes: G01D 2205/26 Details of encoders or position sensors specially adapted to detect rotation beyond a full turn of 360°, e.g. multi-rotation
• CPC Class Codes: G01D 5/2452 incorporating two or more tracks having an (n, n+1, ...) relationship

Abstract

A method for measuring an absolute steering angle of a steering shaft for a vehicle using two rotatable bodies that rotate together with the steering shaft of the vehicle at a predetermined rotation ratio.

Claims

1. A method for measuring an absolute steering angle of a steering shaft for a vehicle using a first rotatable body and a second rotatable body that rotate together with the steering shaft of the vehicle at a predetermined rotation ratio, respectively, the method comprising:

obtaining a Ψ

_M′

value by measuring a relative rotational angle Ψ

′

of the first rotatable body by a first angle sensor whose measurement range is Ω

, and obtaining a θ

_M′

value by measuring a relative rotational angle θ

′

of the second rotatable body by a second angle sensor whose measurement range is Ω

;

calculating a plurality of relative rotational angles θ

′

s of the second rotational body that correspond to the Ψ

_M′

, by using a relation between the relative rotational angle Ψ

′

of the first rotatable body and the relative rotational angle θ

′

of the second rotatable body, and obtaining calculation of θ

c′

s;

obtaining a frequency i of the first rotatably body by comparing the plurality of θ

c′

s to the θ

_M′

;

obtaining an absolute rotational angle Ψ

of the first rotatable body by using the i, and obtaining an absolute rotational angle Φ

1 of a steering shaft out of a relation between the Ψ and

the θ

;

obtaining an absolute steering angle Φ

a of a steering shaft that corresponds to the Ψ

_M′ and

the θ

_M′

, by using a relation between Ψ

−

θ

, a difference between the absolute rotational angle of the first rotatable body and the absolute rotational angle of the second rotatably body, and the absolute steering angle of the steering shaft, and

if a difference between the Φ

1 and the Φ

a is greater than a predetermined value, adding/subtracting to/from the Φ

1 a value that is obtained by dividing the Ω

by a rotation ratio of the first rotatably body.