Pigeon 2.0
User’s Guide
___ www.ctr-electronics.com ______________________ 1/31/2022
Cross The Road Electronics Page 21 ____________________________ 1/31/2022
6.4.
Does X/Y Axis placement matter?
Many users simply want to measure Yaw for ground-based vehicles. In which case the purpose of ensuring X or Y
axis points to the front/rear/or side of the platform may not be critically necessary. This choice determines which
tilt axis is considered Pitch and Roll, and signages (positive Roll vs negative Roll), which some applications may not
require.
If deploying multiple platforms, the best strategy is to be consistent with the mounting orientation across the
entire fleet of vehicles, or individually tune configuration so Yaw, Pitch, Roll behave the same on each vehicle.
6.5.
Default Mounting Orientation
The default orientation for calculating Euler Angles, Gravity Vector, and Quaternion matches the XYZ logo on the
enclosure. In this configuration,
Gimble Lock
will occur if
enclosure X axis is parallel to gravity (points to sky or
ground)
.
If the orientation ensures
enclosure X axis
is not near parallel to gravity, then the
default Mount Orientation
settings are acceptable.
This includes common orientations where the Pigeon 2.0 is
Z-up, Z-down, Y-up, and Y-
down
.
Alterative orientations that risk
enclosure X axis
reaching
near parallel to gravity
should use a
Custom Mounting
Orientation
configuration to avoid Gimble Lock.
6.6.
Custom Mounting Orientation
An improvement over the original Pigeon is that the Pigeon 2.0 can
apply an internal rotation
to adjust the
reported
Gravity Vector
,
Euler Angles
, and
Quaternion
.
This is important if the mounted orientation of the Pigeon risks placing the IMU into Gimble Lock. In fact, this
method essentially moves where Gimble Lock occurs, ideally to a position your mechanism will never reach.
Custom mount orientation may also be used to effectively
zero Pitch and Roll
. This can be useful for balance
applications (arm for example).
There are two methods for configuring the Mount Orientation:
-
Specify them explicitly in Tuner Configuration Tab or Phoenix API routines.
-
Use Phoenix Tuner to calculate these values