Hi Eitan,<div>Thanks for the help, I'm finally getting velocity commands out. Relating to the application of the navigation stack for my project, i have some doubts.</div><div>The navigation stack requires a goal in order to move. My question is, if I want to traverse an unknown environment that has obstacles: an office corridor, for example, i can pass a goal with 1m forward..but if there is a turn in the path, the robot will not be able to turn accordingly since the goal represents a position in the global world.</div>
<div>Therefore, using the simple navigation goal will not suffice in the current scenario. Is it possible to give the robot goal commands in the local system?</div><div> <br><div class="gmail_quote">On Thu, Apr 15, 2010 at 1:06 AM, Eitan Marder-Eppstein <span dir="ltr"><<a href="mailto:eitan@willowgarage.com" target="_blank">eitan@willowgarage.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hitesh,<br><br>First off, it seems like something might be weird with your laser scans. You need to make sure of two things:<br>
<br>1) That the header in the laser messages sent out contain the correct frame_id and timestamp for tf to be able to use them.<br>
2) That the transform betweeen odom and [your_laser_frame_name] exists in your tf tree. You can "rosrun tf view_frames" to generate a pdf of your tf tree which you can check.<br><br>To verify that things are working, try to view laser scans in rviz with both fixed and target frame set to odom. If you see them show up... things are good.<br>
<br>Next, to use the navigation stack in the odometric frame, you'll have to change some of the parameters in the global_costmap_params.yaml file to tell it that you want it to operate in an odometric frame rather than using a static map. Something like the following configuration should work:<br>
<span></span><span></span><p><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span><span></span></p>
<pre style="font-family:arial,helvetica,sans-serif">global_costmap:<br> global_frame: odom<br> robot_base_frame: base_link<br> update_frequency: 5.0<br> publish_frequency: 0.0<br> static_map: false<br> rolling_window: true<br>
width: 20.0<br> height: 20.0<br> resolution: 0.05</pre>This will give you a 20m x 20m around the robot in which you can send goals in the odometric frame.<br><br>Hope this helps a bit,<br><font color="#888888"><br>Eitan</font><div>
<div></div><div><br><br><div class="gmail_quote">
On Wed, Apr 14, 2010 at 6:48 AM, hitesh dhiman <span dir="ltr"><<a href="mailto:hitesh.dhiman.1988@gmail.com" target="_blank">hitesh.dhiman.1988@gmail.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="border-left:1px solid rgb(204, 204, 204);margin:0pt 0pt 0pt 0.8ex;padding-left:1ex">
Hi,<div>actually i did use the tutorial to configure the robot. My setup is almost the same as the files listed in the tutorial, except that the costmap configuration is set to a differential robot.</div><div>From what i could see using rxgraph, i'm getting the following messages into move_base:</div>
<div><br></div><div>1) Odometry</div><div>2) Odometry tf </div><div>3) laser tf (base_link to base_laser)</div><div>4) laserscan</div><div><br></div><div>I'm not using a static map, so I removd amcl from move_base.launch.</div>
<div>When i start the move_base.launch file, i get the following:</div><div><br></div><div><div>[ INFO] 1271252548.078700000: Subscribed to Topics: laser_scan_sensor</div><div>[ INFO] 1271252548.178918000: MAP SIZE: 199, 199</div>
<div>[ INFO] 1271252548.185354000: Subscribed to Topics: laser_scan_sensor</div><div>[ WARN] 1271252563.370080000: MessageNotifier [topic=scan, target=/base_laser /base_laser ]: Dropped 100.00% of messages so far. Please turn the [ros.costmap_2d.message_notifier] rosconsole logger to DEBUG for more information.</div>
</div><div><br></div><div>Using rxloggerlevel to debug, here's the output:</div><div><br></div><div><div>[DEBUG] 1271251959.320831000: MessageNotifier [topic=scan, target=/odom /base_laser ]: Added message in frame laser at time 1271251959.264, count now 50</div>
<div>[DEBUG] 1271251959.320973000: MessageNotifier [topic=scan, target=/odom /base_laser ]: Removed oldest message because buffer is full, count now 50 (frame_id=laser, stamp=1271251958.043920)</div></div><div><br></div>
<div>
<div>[DEBUG] 1271251959.599588000: MessageNotifier [topic=scan, target=/base_laser /base_laser ]: Successful Transforms: 0, Failed Transforms: 4051196, Discarded due to age: 0, Transform messages received: 67611, Messages received: 26918, Total dropped: 26868</div>
</div><div><br></div><div>Also, to view the laser scan image in rviz, i get the following error:</div><div><br></div><div>TOPIC : No messages received</div><div>Transform[sender=/laser] : For frame [laser]: Frame [laser] does not exist</div>
<div><br></div><div><br></div><div>Any suggestions?</div><div><div></div><div><div><br><div class="gmail_quote">On Wed, Apr 14, 2010 at 1:01 AM, Eitan Marder-Eppstein <span dir="ltr"><<a href="mailto:eitan@willowgarage.com" target="_blank">eitan@willowgarage.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="border-left:1px solid rgb(204, 204, 204);margin:0pt 0pt 0pt 0.8ex;padding-left:1ex">Hitesh,<br><br>If you're trying to run the navigation stack on your own robot, I'd suggest reading the following tutorial first, <a href="http://www.ros.org/wiki/navigation/Tutorials/RobotSetup/" target="_blank">http://www.ros.org/wiki/navigation/Tutorials/RobotSetup/</a>, as it will explain how the pieces of the navigation stack work and how you'll need to configure your robot.<br>
<br>From the errors you listed, it looks like your robot may not be publishing odometry information to the navigation stack. Also, amcl will not work without a static map... so that's expected.<br><br>Hopefully, the tutorial will help, feel free to post again if you have other questions,<br>
<br>Eitan<br><br><div class="gmail_quote"><div><div></div><div>On Tue, Apr 13, 2010 at 5:49 AM, hitesh dhiman <span dir="ltr"><<a href="mailto:hitesh.dhiman.1988@gmail.com" target="_blank">hitesh.dhiman.1988@gmail.com</a>></span> wrote:<br>
</div></div><blockquote class="gmail_quote" style="border-left:1px solid rgb(204, 204, 204);margin:0pt 0pt 0pt 0.8ex;padding-left:1ex"><div><div></div><div>
Hi all,<div>I've been trying to run the navigation stack. However, upon running move_base.launch, i get the following message:</div><div><br></div><div><div>[ WARN] 1271162502.543875000: Costmap2DROS transform timeout. Current time: 1271162502.5438, global_pose stamp: 1271162501.8677, tolerance: 0.3000</div>
<div><br></div><div>I tried changing the tolerance value to 1. move_base.launch starts with the following:</div><div><div>[ INFO] 1271162733.968657000: Subscribed to Topics: laser_scan_sensor</div><div>[ INFO] 1271162734.066727000: MAP SIZE: 199, 199</div>
</div><div><br></div><div>A second later, i start getting these messages:</div><div><br></div><div><div><div>[ WARN] 1271162749.245438000: MessageNotifier [topic=scan, target=/odom /base_laser ]: Dropped 100.00% of messages so far. Please turn the [ros.costmap_2d.message_notifier] rosconsole logger to DEBUG for more information.</div>
</div></div><div><br></div><div>rxconsole gives the following:</div><div>Request for map failed, trying again... Warn /amcl</div><div>This could be because i'm not using any static map. Even so, move_base is not publishing any messages out.</div>
<div><br></div><div>Any help would be appreciated. I'm not able to figure out where the problem is.</div><br>-- <br>Regards,<br>Hitesh Dhiman<br>Electrical Engineering<br>National University of Singapore<br>
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<br></blockquote></div><br><br clear="all"><br>-- <br>Regards,<br>Hitesh Dhiman<br>Electrical Engineering<br>National University of Singapore<br>
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<br></blockquote></div><br><br clear="all"><br>-- <br>Regards,<br>Hitesh Dhiman<br>Electrical Engineering<br>National University of Singapore<br>
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