Yuliang Sun's profile - activity

Hello, I want to driver my Laserscanner under Android system (a smartphone or a tab). I am using Hokoyo Laserscanner UTM-30LX. Does anyone have experience?

How to supply the Laserscanner from smartphone or tab? Do I need an adapter to give the scanner appropriate Voltage?

Normally the USB in smartphone or tab has a mini USB. How can I use a Y cable to connect the Laserscanner and the smartphone or tab?

For your answer my heartfelt appreciation!

I already created a map with hector_slam (without reliable odometry). What I try to figure out is, if it is possible to use odometry data with hector_slam by writing an odometry node or something, which will gain the data from real odometry sensor.

I just want to run gmapping with real sensor data. And I have no clue about it. Should I run "rosparam set use_sim_time false at first" then is "rosrun gmapping slam_gmapping scan:=base_scan" . and then? which commend should I enter? my tf tree is not right. only has /map to /odom. It should be /map -> /odom -> base_link -> base_laser. But I do not know how to change my tf tree. With which commend? Sorry i am not really good at that. And really hope you can help me. thank you so much!

Hi everyone.

I have already used Hector slam (without odometry data) to create a mapping process successfully. But now I want to use odometry data from my mobile Robot with hector slam node.

Is it possible? How can I achieve it? Can anyone share experience in writing an odometry node?

Thank you so much for helping me!

BTW, I am using fuerte 12.04.

Thank you for explaining. I already used hector_slam (without odometry) to get a mapping process in rviz. So the laserscanner functions well. Now I tried to use gmapping because gmapping can provide odometry and the result is better. As I reedited my question, I have some problems in gmapping.

Hello everyone. I am new to ROS (fuerte 12.04). I am trying to use gmapping to build a map in rviz with a Hokuyo laserscanner(UTM-30LX) and a mobile robot, which can provide odometry data.

I have already followed the tutorial MappingFromLoggedData. I run "rosrun gmapping slam_gmapping scan:=base_scan", and an already existed mapping bag runs in rviz rightly. But when I try to create my own map (e.g. my room) and run rosrun gmapping slam_gmapping, it shows "/use_sim_time set to true and no clock published. still waiting for valid time."

Did I follow the right tutorial? What else shoould I follow?

I also don't know how to set the parameter of gmapping like tf trees. which command should I use to set the parameter and run gmapping sucessfully? I am really confused.

Thank you so much for answering my question!

Now I set the time to sim_time false with command "rosparam set use_sim_time false"

In terminal 2 I enter the command like in the tutorial "rosrun gmapping slam_gmapping scan:=base_scan"

In terminal 3 I enter "rosbag record -O mylaserdata /base_scan /tf". It shows

In terminal 4 I try to record my bag with "rosbag play mylaserdata.bag". It shows

Waiting 0.2 seconds after advertising topics... done.

And I open the rviz with commend "rosrun rviz rviz" and add a map set to the topic /map but nothing in rviz.

In terminal 2 the errors show up just after I enter "rosbag play mylaserdata.bag"

in terminal 4. here are the errors. TF_OLD_DATA ignoring data from the past for frame /odom at time 1.38987e+09 according to authority /play_1389877419301103194 Possible reasons are listed at

I am confused. Thank you for helping!