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move_base robot movement wrong direction

asked 2013-05-02 23:33:31 -0500

mharms gravatar image

updated 2013-05-05 07:53:15 -0500

Hallo @All,

I am using a custom robot. I want to use move_base, either with defining a goal by clicking in the map, ob by using a move_base_square.py script. In rviz I see the thin blue line, as the computed path, but the robot is moving in an other direction, with short flashing red line in different directions. When using a nave-Square script or using the arbotixGUI the robot ist moving correct. A screenshot of rviz you can find here: www.kunst-raum.de/files/screenshot.png Because I am very new to ROS I actually have no idea where to look to solve this problem.

I hope that somebody here may help me in this point.

Thanks a lot

Michael, Berlin, Germany

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answered 2013-05-05 10:45:35 -0500

Gav gravatar image

Hi Michael,

How many and what is the relationship of the coordinate frames are you using? Try adding a 'TF' tree to the view in RVIZ, and see if they are displaying as expected.

You can also look at section 2 here and see if that helps: http://www.ros.org/wiki/navigation/Tutorials/Navigation%20Tuning%20Guide

Cheers, Gavin

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Hi Gavin, in the TF-Tree I see /base_link, /map, /odom all with transform ok. Changing fixed_frame in Global from map to something else didnt change the reaction. The real robot is moving forward for about one second then moves backward since it leaves the map. At this point I use no laser

mharms gravatar image mharms  ( 2013-05-06 00:28:14 -0500 )edit

Can you view the output to the motor (rostopic echo /cmd_vel) and see if it's giving you a positive x command?

Gav gravatar image Gav  ( 2013-05-06 07:24:32 -0500 )edit

Hi Gavin, first of all I would like to thank you for your friendly answers. I updated my question to respond to your question. Today I will try to rewrite our basecontroller_node, to see if something will change. btw. Nice Hackerspace you have.

mharms gravatar image mharms  ( 2013-05-06 21:19:38 -0500 )edit
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answered 2013-05-06 21:15:31 -0500

mharms gravatar image

updated 2013-05-06 21:16:30 -0500

UPDATE: I get the following output from rostopic echo cmd_vel:

linear: x: 0.114285714286 y: 0.0 z: 0.0 angular: x: 0.0 y: 0.0

z: 0.572631578947

linear: x: 0.308710925188 y: 0.0 z: 0.0 angular: x: 0.0 y: 0.0

z: 1.94081725597

linear: x: -0.1 y: 0.0 z: 0.0 angular: x: 0.0 y: 0.0

z: 0.0

and so on This means the robot is shortly(1 sec?) moving foreward and turn somewhere, than move constantly backwards in the wrong direction with yellow arrows in foreward direction. untill the end of the map. When I compare the turtlebot_node and ours, the main difference seems that we do all the calculation and odometry stuff in combination with the Motor/cmd_vel and not as a function in spin(). My only idea is to change this, but I am not sure if this may solve the problem.

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Hey, I have encountered the same problem with my robot. How did you eventually solve this problem? Did just adding the decimal point at your robot footprint solve this problem??

peterwe gravatar image peterwe  ( 2017-05-17 08:09:57 -0500 )edit

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Asked: 2013-05-02 23:33:31 -0500

Seen: 1,700 times

Last updated: May 06 '13