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Robot_localization diagnostics topic question

asked 2016-05-08 10:29:05 -0600

b2256 gravatar image

I'm currently attempting to fine-tune an instance of (ekf) robot_localization using gps and single imu devices. In doing so, the diagnostic topic lists:

- 
    level: 1
    name: ekf_localization: Filter diagnostic updater
    message: Potentially erroneous data or settings detected for a robot_localization state estimation node.
    hardware_id: none
    values: 
      - 
        key: imu0_pose_covariance
        value: The covariance at position (35), which corresponds to YAW variance, was zero. This will be replaced with a small value to maintain filter stability, but should be corrected at the message origin node.
  -

The location of “position (35)” YAW covariance eludes me in attempting to revise the value. I've searched all the code for robot_localization and the code for the Phidgets 1044 imu to no avail. The ekf_localization launch file initial covariance is set (currently at a non-zero value of 0.035). The "message origin node" is the elusive part.

Aside from the ekf_localization initial_estimate_covariance, is there anywhere left to look for modification?

Thanks in advance for any insight.

B2256

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answered 2016-05-08 13:32:21 -0600

Tom Moore gravatar image

It's complaining about your IMU messages, not your r_l configuration. Do a rostopic echo on your IMU data, and I'm guessing you'll find that the value in the last index of your orientation covariance is 0.

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Yes, it appears that you're correct as all the orientation_covariances are zero at this timestamp. It is still unclear where to modify this value? Any advice?

b2256 gravatar imageb2256 ( 2016-05-08 14:33:37 -0600 )edit

Which ROS package are you using for the IMU?

Tom Moore gravatar imageTom Moore ( 2016-05-08 20:01:43 -0600 )edit

I'm using the ROS driver phidgets_imu by Ivan Dryanovski.

b2256 gravatar imageb2256 ( 2016-05-09 07:47:39 -0600 )edit

That driver doesn't appear to support orientation. I think it only gives angular velocity, linear acceleration, and raw mag data. You need to use another IMU filter like imu_filter_madgwick to get the orientation data, then feed that topic into r_l.

Tom Moore gravatar imageTom Moore ( 2016-05-09 08:09:40 -0600 )edit
1

It turns out that I was using imu_filter _madgwick indirectly. An earlier answer by Tom mentioned using dynamic_reconfigure with this driver; that was successful. Thank you as always.

b2256 gravatar imageb2256 ( 2016-05-11 23:57:35 -0600 )edit

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Asked: 2016-05-08 10:29:05 -0600

Seen: 327 times

Last updated: May 08 '16