Users Manual

13 Appendix
13.1 Pose formats
13.1.1 XYZABC format
The XYZABC format is used to express a pose by 6 values. π‘‹π‘Œ 𝑍 is the position in millimeters. 𝐴𝐡𝐢 are Euler
angles in degrees. The convention used for Euler angles is ZYX, i.e., 𝐴 rotates around the 𝑍 axis, 𝐡 rotates around
the π‘Œ axis, and 𝐢 rotates around the 𝑋 axis. The elements of the rotation matrix can be computed by using
π‘Ÿ
11
= cos 𝐡 cos 𝐴,
π‘Ÿ
12
= sin 𝐢 sin 𝐡 cos 𝐴 βˆ’ cos 𝐢 sin 𝐴,
π‘Ÿ
13
= cos 𝐢 sin 𝐡 cos 𝐴 + sin 𝐢 sin 𝐴,
π‘Ÿ
21
= cos 𝐡 sin 𝐴,
π‘Ÿ
22
= sin 𝐢 sin 𝐡 sin 𝐴 + cos 𝐢 cos 𝐴,
π‘Ÿ
23
= cos 𝐢 sin 𝐡 sin 𝐴 βˆ’ sin 𝐢 cos 𝐴,
π‘Ÿ
31
= βˆ’ sin 𝐡,
π‘Ÿ
32
= sin 𝐢 cos 𝐡, and
π‘Ÿ
33
= cos 𝐢 cos 𝐡.
Note: The trigonometric functions sin and cos are assumed to accept values in degrees. The argument needs
to be multiplied by the factor
πœ‹
180
if they expect their values in radians.
Using these values, the rotation matrix 𝑅 and translation vector 𝑇 are defined as
𝑅 =
βŽ›
⎝
π‘Ÿ
11
π‘Ÿ
12
π‘Ÿ
13
π‘Ÿ
21
π‘Ÿ
22
π‘Ÿ
23
π‘Ÿ
31
π‘Ÿ
32
π‘Ÿ
33
⎞
⎠
, 𝑇 =
βŽ›
⎝
𝑋
π‘Œ
𝑍
⎞
⎠
.
The transformation can be applied to a point 𝑃 by
𝑃
β€²
= 𝑅𝑃 + 𝑇.
13.1.2 XYZ+quaternion format
The XYZ+quaternion format is used to express a pose by a position and a unit quaternion. π‘‹π‘Œ 𝑍 is the position in
meters. The quaternion is a vector of length 1 that defines a rotation by four values, i.e., π‘ž = (
π‘Ž 𝑏 𝑐 𝑀
)
𝑇
with ||π‘ž|| = 1. The corresponding rotation matrix and translation vector are defined by
𝑅 = 2
βŽ›
⎝
1
2
βˆ’ 𝑏
2
βˆ’ 𝑐
2
π‘Žπ‘ βˆ’ 𝑐𝑀 π‘Žπ‘ + 𝑏𝑀
π‘Žπ‘ + 𝑐𝑀
1
2
βˆ’ π‘Ž
2
βˆ’ 𝑐
2
𝑏𝑐 βˆ’ π‘Žπ‘€
π‘Žπ‘ βˆ’ 𝑏𝑀 𝑏𝑐 + π‘Žπ‘€
1
2
βˆ’ π‘Ž
2
βˆ’ 𝑏
2
⎞
⎠
, 𝑇 =
βŽ›
⎝
𝑋
π‘Œ
𝑍
⎞
⎠
.
The transformation can be applied to a point 𝑃 by
𝑃
β€²
= 𝑅𝑃 + 𝑇.
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