Six-direction indicator
A six-direction indicator is provided in an XYZ rectangular coordinate system and includes a shaft on an X axis, a rotation member rotatable around an axis inclined with respect to a rotation axis, guide pins provided upright on the rotation member, and a guide member provided around the X-axis to surround the rotation member. The guide member has a zigzag slit track bent alternately in a mountain-like shape and a valley-like shape in the X direction at intervals of 60° around the X-axis. The guide pins are inserted in the slit track and move around on the slit track by rotation of the shaft. The device indicates one of the positive and negative directions on the U, V, and W axes crossing one another at intervals of 60° around the X-axis.
1. A six-direction indicator provided in an XYZ rectangular coordinate system, comprising:
an inclined crank mechanism comprising a shaft that extends in an X-axis direction and a rotation member rotatable around an inclined axis inclined with respect to said shaft and coupled to said shaft;
a driving source that rotates said shaft around the X-axis; and
a guide member having a zigzag circumferential edge provided around the X-axis of said inclined crank mechanism and bent alternately in a mountain-like shape and a valley-like shape at intervals of 60° around the X-axis,
said rotation member comprising a guide pin provided around the inclined axis of said rotation member and in contact with said circumferential edge, said guide pin moving around on said circumferential edge by rotation of said shaft and indicating one of positive and negative directions on U, V, and W axes crossing one another at intervals of 60° around the X axis.
2. The six-direction indicator according to claim 1 , wherein said guide member comprises a circumferential wall provided around said X-axis, and
said circumferential edge is an end of said circumferential wall and has a mountain-like portion and a valley-like portion provided alternately at intervals of 60° around the X-axis.
3. The six-direction indicator according to claim 1 , wherein said guide member is provided on a side opposite to said driving source with said rotation member therebetween, and
said six-direction indicator further comprises an elastic member that provides said rotation member with force toward said guide member.
4. The six-direction indicator according to claim 3 , further comprising a plurality of said guide pins provided 90° or 180° apart from one another around the inclined axis, wherein said circumferential edge further has a depression in a position where any of said plurality of guide pins is in contact with said circumferential edge when said guide pin indicates any of the U, V, and W axes.
5. The six-direction indicator according to claim 1 , wherein said inclined axis is inclined at α° with respect to said shaft, said a ranging from 30° to 40°, and
said U, V, and W axes cross one another at β°, said β ranging from 80° to 100°.
6. The six-direction indicator according to claim 5 , further comprising:
a rotational angular velocity sensor provided at said rotation member to detect rotational angular velocity components ω U , ω V , and ω W around the U, V, and W axes;
a gravitational acceleration sensor provided at said rotation member to detect gravitational acceleration components g U , g V , and g W in the U, V, and W axis directions;
a measurer arranged to measure the rotational angular velocity components ω U , ω V , and ω W detected by said rotational angular velocity sensor and the gravitational acceleration components g U , g V , and g W detected by said gravitational acceleration sensor when said guide pin moves around on said track by rotation of said rotation shaft and indicates + and − directions on the U, V, and W axes;
a rotational angular velocity coordinate transformer arranged to coordinate-transform said measured rotational angular velocity components ω U , ω V and ω W into rotational angular velocity components ω X , ω Y , and ω Z ;
a gravitational acceleration coordinate transformer arranged to coordinate-transform said measured gravitational acceleration components g U , g V , and g W into gravitational acceleration components g X , g Y , and g Z ; and
an azimuth angle calculator arranged to calculate an azimuth angle ψ based on the obtained rotational angular velocity components ω X , ω Y , and ω Z and the obtained gravitational acceleration components g X , g Y , and g Z .
7. The six-direction indicator according to claim 6 , wherein said rotational angular velocity coordinate transformer coordinate-transforms said rotational angular velocity components ω U , ω V , and ω W into said rotational angular velocity components ω X , ω Y , and ω Z according to the following Expression (1):
[
ω
X
ω
Y
ω
Z
]
=
[
1
3
sin
α
1
3
sin
α
1
3
sin
α
-
1
3
cos
α
1
3
cos
α
0
-
1
3
cos
α
-
1
3
cos
α
2
3
cos
α
]
[
ω
U
ω
V
ω
W
]
(
1
)
said gravitational acceleration coordinate transformer coordinate-transforms said gravitational acceleration components g U , g V , and g W into said gravitational acceleration components g X , g Y , and g Z according to the following Expression (2):
[
g
X
g
Y
g
Z
]
=
[
1
3
sin
α
1
3
sin
α
1
3
sin
α
-
1
3
cos
α
1
3
cos
α
0
-
1
3
cos
α
-
1
3
cos
α
2
3
cos
α
]
[
g
U
g
V
g
W
]
(
2
)
and
said azimuth angle calculator calculates an azimuth angle ψ based on said rotational angular velocity components ω X , ω Y , and ω Z and said gravitational acceleration components g X , g Y , and g Z according to the following Expression (3):
ψ
=
tan
-
1
(
-
ω
Y
cos
ϕ
+
ω
Z
sin
ϕ
ω
X
cos
θ
-
ω
Y
sin
ϕsin
θ
+
ω
Z
cos
ϕsin
θ
)
ϕ
=
tan
-
1
(
g
Y
g
Z
)
θ
=
-
sin
-
1
(
g
X
G
)
G
=
g
X
2
+
g
Y
2
+
g
Z
2
(
3
)
8. The six-direction indicator according to claim 7 , wherein α is 35.26 and β is 90.
9. The six-direction indicator according to claim 1 , further comprising at least two of said guide pins, said guide pins being provided 180° apart from each other on the same straight line around said inclined axis.