How to write node for collecting data from P3AT robot

asked 2011-03-24 03:34:49 -0600

Jurica
97 ●4 ●6 ●12

updated 2011-03-24 04:54:35 -0600

I have question. I wish to collect velocity (left and right speed)data from Pioneer 3AT, and for that write node, and that data i want to use for odometry. I ask if someone can me direct on right path. There are some tutorials but i dont know which i need to look. If someone have idea, please to give me some suggestion. Thanks!

answered 2011-03-28 00:55:39 -0600

JKS
306 ●2 ●3 ●5

Hi,

Both p2os_driver and ROSARIA publish nav_msgs/Odometry on "pose" topic. Therefore, it suffices to subscribe to the "pose" topic and collect Odometry messages.

If you really need left and right wheel velocities, you should use specific robot parameters and get those speeds from linear and angular velocities that are reported in the Odometry message.

Just one more note, ROSARIA reported Pose in [mm] prior to Feb 24, 2011. As of that date, we've fixed it to report Pose in [m].

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Comments

Looking at the rosaria package summary it seems that you only have access to the estimated robot velocities but not the joint (the wheels) velocities. Am I missing something? Are these the actual measured encoder counts mapped through the kinematics or are they just the commanded robot velocities?

thill@tntech.edu ( 2015-09-22 22:29:07 -0600 )edit

The robot controller (dedicated microcontroller inside the robot) is already doing the integration of the wheel encoders and providing the pose (x,y,th). (You can request encoder counts using ARIA library but this is provided mainly as a diagnostic/testing feature.)