IMU Arbitrary Orientation

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A feature that allows arbitrary IMU orientation relative to the airframe may be 
helpful to those facing airframe constraints which prevent the traditional 
"flat and forward" orientation currently required by the APM code. The 
enhancement would allow, for example, the autopilot board / IMU shield 
combination to be placed on its side in an airframe.

I've written a patch to add this feature to the APM code (based on SVN trunk 
code). The patches, one for the main APM code and one for library code, are 
attached. A more detailed description of the patch can be found in the attached 
.txt file--it seemed a bit lengthy to include here.

I would be more than happy to make any modifications to the patch needed for 
its inclusion into the official APM code.

Thanks.

Original issue reported on code.google.com by timb...@gmail.com on 10 Jan 2011 at 5:22

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The post at http://diydrones.com/forum/topics/patch-for-arbitrary-imu has some 
additional comments related to this patch.

Original comment by timb...@gmail.com on 17 Jan 2011 at 12:45

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timb - I have only given your patch a cursory glance but I think it will mess 
up centripetal correction.  Any approach based on offsets to the eulers is not 
likely to work for any 90 degree change in orientation about either the pitch 
or yaw axis.

Original comment by dewei...@gmail.com on 21 Mar 2011 at 3:32

• Changed state: Accepted
• Added labels: Milestone-Later, Priority-Low, Type-Enhancement

[GoogleCodeExporter]

To be clearer, Timbaum posted revised patches in his forum topic.
I'm including these below for ease of access.

The revised approach does as Doug suggested and applies a rotation matrix to 
the oilpan gyro/imu values at the library level, so the orientation should be 
transparent to the the flow-on calculations now?

Original comment by justinbe...@gmail.com on 4 Dec 2011 at 11:24

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how do you apply the patch to the current verson of the source?

Original comment by MarcoL...@gmail.com on 27 Jan 2012 at 6:54

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I would also like to have the ablity to run my ardupilot sideways. What exactly 
would I have to change? What other parts of the ahrs correction would need to 
be changed?

Original comment by SHAL...@gmail.com on 19 Sep 2012 at 7:34

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M y question is also same;
"I would also like to have the ablity to run my ardupilot sideways. What 
exactly would I have to change? What other parts of the ahrs correction would 
need to be changed?" 

Original comment by narpat...@gmail.com on 3 Nov 2012 at 4:07

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done by tridge, yesterday. pls close this issue. 

Original comment by davidb...@gmail.com on 15 Jan 2013 at 5:17

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Original comment by rmackay...@gmail.com on 15 Jan 2013 at 10:02

• Changed state: Done