Rotation angle detection device

Patent metadata

Field	Value
Publication number	US-9121729-B2
Application number	US-201113326701-A
Country	US
Kind code	B2
Filing date	Dec 15, 2011
Priority date	Dec 15, 2010
Publication date	Sep 1, 2015
Grant date	Sep 1, 2015

Abstract

A rotation angle calculation unit includes a first rotation angle calculation portion, a second rotation angle calculation portion, a third rotation angle calculation portion, an abnormality monitoring portion, and a final rotation angle calculation portion. The abnormality monitoring portion determines, based on a first output signal, a second output signal, and a third output signal, whether the first to third output signals are each normal or abnormal. The final rotation angle calculation portion calculates a final rotation angle based on the final determination result obtained by the abnormality monitoring portion and the first to third rotation angles calculated by the first to third rotation angle calculation portions, respectively.

First claim

What is claimed is:

1. A rotation angle detection device that includes a first sensor, a second sensor, and a third sensor that output, respectively, a first sinusoidal signal, a second sinusoidal signal, and a third sinusoidal signal, which are different in phase from each other, according to rotation of a rotor, and that detects a rotation angle of the rotor based on the first, second, and third sinusoidal signals, comprising:
a determination unit that determines, based on the first sinusoidal signal, the second sinusoidal signal, and the third sinusoidal signal, whether the first sinusoidal signal, the second sinusoidal signal, and the third sinusoidal signal are each normal or abnormal, the determination unit comprising:
a first determination unit that determines, based on the first and second sinusoidal signals, whether there is a possibility that at least one of the first and second sinusoidal signals is presently abnormal;
a second determination unit that determines, based on the first and third sinusoidal signals, whether there is a possibility that at least one of the first and third sinusoidal signals is presently abnormal;
a third determination unit that determines, based on the second and third sinusoidal signals, whether there is a possibility that at least one of the second and third sinusoidal signals is presently abnormal; and
a fourth determination unit that determines, based on results of determinations made by the first, second, and third determination units, whether the first sinusoidal signal, the second sinusoidal signal, and the third sinusoidal signal are each normal or abnormal; and

a rotation angle calculation unit that calculates the rotation angle of the rotor based on at least two sinusoidal signals that are among the first sinusoidal signal, the second sinusoidal signal, and the third sinusoidal signal, and that are determined as being normal by the determination unit.

2. The rotation angle detection device according to claim 1 , wherein:
the first sensor is a sensor that outputs, as the first sinusoidal signal, a first sinusoidal signal V 1 corresponding to a rotation angle θ as the rotation angle of the rotor, the first sinusoidal signal V 1 being expressed as V 1 =sin θ;
the second sensor is a sensor that outputs, as the second sinusoidal signal, a second sinusoidal signal V 2 corresponding to the rotation angle θ of the rotor, the second sinusoidal signal V 2 being expressed as V 2 =sin(θ+α) where α represents a phase difference between the first and second sinusoidal signals;
the third sensor is a sensor that outputs, as the third sinusoidal signal, a third sinusoidal signal V 3 corresponding to the rotation angle θ of the rotor, the third sinusoidal signal V 3 being expressed as V 3 =sin(θ+β) where β represents a phase difference between the first and third sinusoidal signals;
the first determination unit determines whether there is a possibility that at least one of the first and second sinusoidal signals is presently abnormal, based on whether a first condition represented by an expression (i) is satisfied;
the second determination unit determines whether there is a possibility that at least one of the first and third sinusoidal signals is presently abnormal, based on whether a second condition represented by an expression (ii) is satisfied; and
the third determination unit determines whether there is a possibility that at least one of the second and third sinusoidal signals is presently abnormal, based on whether a third condition represented by an expression (iii) is satisfied,
the first expression (i), the second expression (ii), and the third expression (iii) being

1
-
d

≦

V
⁢

⁢

1
2

+

V
12
2

≦

1
+
d

⁢

⁢
where
⁢

⁢

V
12

=

V
⁢

⁢
2

-

V
⁢

⁢

1
·
cos

⁢

⁢
α

sin
⁢

⁢
α

(
i
)

1
-
d

≦

V
⁢

⁢

1
2

+

V
13
2

≦

1
+
d

⁢

⁢
where
⁢

⁢

Assignees

• Ueda Takeshi
• Jtekt Corp

Inventors

• Ueda Takeshi

Classifications

• G01D5/24461

  by redundancy or plausibility · CPC title

• G01D5/244 Primary

  influencing characteristics of pulses or pulse trains; generating pulses or pulse trains · CPC title

• G01D5/3473

  Circular or rotary encoders · CPC title