how to use robot_pose_ekf module to improve odom data and use that to produce better maps.

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Hello,

I am working on building maps of my office ( which is think is around 100 * 100 mts) . I using this tutorial for gmapping. This is the procedure i follow to create the map.

1) I run the robot in a loop ( around a huge rectangular cubical). I wrote a simple obstacle avoidance code in python for this. I am not teleoperating it.

2) i save /tf and Laserscan data in a bag file.

3) Once i collect the data, i follow above tutorial to build the map from logged data.

This is the map i got: C:\fakepath\1.png

Which you can see is a very bad map.

I can visualize in Rviz that the odometry drifts the more the run the robot around.

So i thought of using robot_pose_ekf tutorial to improve odometry. I include the follow command in my launch file:

<include file="$(find robot_pose_ekf)/robot_pose_ekf.launch"/>

To check whether it's working correctly or not, i run the following command:

rosservice call robot_pose_ekf/get_status

which gives me the following output:

status: Input:

• Odometry sensor
  • is active
  • received 5678 messages
  • listens to topic /odom
• IMU sensor
  • is active
  • received 4567 messages
  • listens to topic /mobile_base/sensors/imu_data
• Visual Odometry sensor
  • is NOT active
  • received 0 messages
  • listens to topic /vo Output:
• Robot pose ekf filter
  • is active
  • sent 4675 messages
  • pulishes on topics /robot_pose_ekf/odom_combined and /tf

I changed the odom and imu data topics it is listening to after follwoing some tutorials. It seems like it is getting imu data and odom data.

while i am running the robot around i also save /robot_pose_ekf/odom_combined data. And i plotted both odom and odom_combined data, which you can see below. As you can see their is no difference in both, blue is odom and red is odom_combined.

C:\fakepath\figure_1.png

Also in robot_pose_ekf tutorials it is said that it will provide a tf between odom_combined → base_footprint, but when i run the following command and see the tf tree i cannot find any tf between odom_combined → base_footprint

rosrun tf view frames

C:\fakepath\Screenshot from 2016-07-27 20:54:35.png

These are my question:

1) how can i correctly use robot_pose_ekf module to improve odom data?

2) and how can i get the tf between odom_combined → base_footprint?

3) How can i use this information to improve results of gmapping?

Can anyone please help me?

Thanks a ton