[question] Void messages in /imu/data topic

[carlosjoserg]

Hi, I'm trying the imu_filter_madgwick installed from synaptics with all default parameters (with out Mag.)

I publish the sensor data in /imu/data_raw and messages are there, I can see how the acceleration vector changes according to the orientation.

I see in the node graph that the imu_filter_madgwick is subscribed to that topic, so it should be receiving what I'm publishing (I also tried the nodelet interface)

I can see that the /imu/data topic is there with rostopic list but nothing is coming from there when I use rostopic echo /imu/data. In fact, that topic does not appear in the node graph.

Am I missing something in the setup? For instance, I see in Seb's videos that he starts with a certain configuration of the IMU and wait some seconds before moving it around.

[carlosjoserg]

Forgot to say, Ubuntu 14.04/Indigo

[mintar]

Could you record a rosbag of the data_raw topic please?

Diese Nachricht wurde von meinem Android-Mobiltelefon mit K-9 Mail gesendet.

[carlosjoserg]

Here it is.

I moved from the initial pose, twice to one direction, and twice to the other direction, and finish at the same initial position.

[mintar]

With the following commands, I was able to run everything without problems:

$ roscore
$ rosparam set use_sim_time true
$ rosbag play --clock --loop 2015-09-24-23-58-09.bag
$ roslaunch imu.launch

This is the imu.launch I used:

<launch>
  <!-- Nodelet manager -->
  <node pkg="nodelet" type="nodelet" name="imu_manager" 
    args="manager" output="screen" />

  <!-- IMU Orientation Filter -->
  <node pkg="nodelet" type="nodelet" name="ImuFilterNodelet" 
    args="load imu_filter_madgwick/ImuFilterNodelet imu_manager" 
    output="screen">

    <param name="use_magnetic_field_msg" value="false"/>
    <param name="use_mag" value="false"/>
    <param name="fixed_frame" value="odom" />
    <param name="publish_tf" value="true" />
  </node>
</launch>

The fixed_frame and publish_tf params are just for debug, so you can visualize the tf topic in RViz (you need to set the RViz fixed frame to odom). In a real system, you'd feed the /data/imu topic into something like robot_pose_ekf instead, which in turn would produce the proper tfs.

By the way, the messages in your bagfile have frame_id "world"; this has to be the IMU frame, so it's a bit of a strange name for that.

[carlosjoserg]

Ok, I was launching similarly but without setting any parameter, i.e. using the default ones.

The only difference is that you explicitly set use_mag parameter to false, and it is default to true here. I don't see how that can affect, but now it is working here as well.

Thanks @mintar, I'll close the issue.