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on uwsim, orientation from topic pose and topic imu is different. Why?

asked 2016-02-29 18:21:31 -0500

ZYS gravatar image

on uwsim, orientation from topic pose and topic imu is different. I set the initial yaw of auv as 0 by modifying yaml file. Quaternion from topic pose is x=0 y=0 z=0 w=1. Quaternion from topic imu is x=0 y=0 z=1 w=0. They are different! why??

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answered 2016-03-01 05:28:13 -0500

Javier Perez gravatar image


The pose topic (I guess you are talking about /g500/pose) is used to send information between dynamics and simulator. So the dynamics is sending the pose to the visualizer. This pose is referenced from robot initial position (stated in the URDF, or 3D file). Meanwhile IMU topic is a simulated sensor that provides rotation with respect to the simulated world (plus some noise), so the quaternion you obtain from here has an additional rotation which is dependant on the world to initial robot position (offsetr inside simParams in config .xml files).

Short answer is they are different because they mean different things.

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Asked: 2016-02-29 18:21:31 -0500

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Last updated: Mar 01 '16