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2014-01-28 17:27:52 -0500 marked best answer Openni_manager service call to manually load Kinect driver

Hey,

I am trying (for days now) to manually control the nodelets that run my Kinect camera.

My scenario is a highly automated robot (turtlebot), with the capability to switch off Kinect just before going onto loading dock. Since the Kinect is powered by the Rommba motor outputs, it is switched off as soon as the Roomba starts reloading.

So I have to re-enable the Kinect stack after leaving the dock.

The Openni_manager I am using to run Kinect, provides rosservices (/openni_manager/load_nodelet) in order to achieve this. It is no problem to shut down a nodelet via service, but I am not able to put it back on properly.

The rosservice call in my program

load_nodelet_proxy("/openni_launch","openni_camera/OpenNINodelet",[],[], ["load openni_camera/OpenNINodelet openni_manager"], "1")

loads the driver with an output that looks fine and exactly the same as when I start the nodelet with launch file, but after a few seconds (possibly the timeout declared in the particular /openni_manager/bond message for that nodelet) it is automatically unloaded by the openni_manager!

What am I doing wrong?

Hopefully somebody can give some advice.

Cheers, Jasper

2014-01-28 17:27:15 -0500 marked best answer Calling nodelet manager service from console

Hey.

My question concerns how to use the nodelet manager service properly. Consider a nodelet manager has been started and is running. It's rosservice to load a nodelet (/manager/load_nodelet) is also available.

What do I have to call now to, let's say, start the openni_camera nodelet (openni_camera/driver) via this service.

rosservice call /manager/load_nodelet "/nodelet_name" "openni_camera/driver" [] [] [] "nodelet_name1"

tells my 'success' and /nodelet_name does appear under /manager/list topic for a couple of seconds, but vanishes after that with no debug message what so ever.

I am getting pretty frustrated over this, since the API has actually no documentation at all. (If you know different, PLEASE let me know about!)

Any suggestions? Would be deeply appreciated. Thanks.

Jasper

2014-01-28 17:26:46 -0500 marked best answer Multiple Goal Buttons in RVIZ?

Hi everyone,

I have to control more than one robot at a time. The robots are administered by a central ROS server and can be displayed and controlled using ROS RVIZ at the same time. Every robot runs in a distinct name space such that same topics (like 'move_base/simple_goal') of different robots do not collide.

I was now looking for multiple navigation goal buttons in the tool panel of RVIZ, one for each robot. Currently I have to change the goal topic of the tool each time I intend to give the next robot a moving command. That is not very sophisticated and annoying.

Is there a simple way to have multiple buttons on the toolbar with the same functionality? So far I found nothing that would help.

PS: I am not interested in running ROS cores on each robot and/or opening different instances of RVIZ, just in case someone is about to suggest anything like this ;)

Really appreciate any help and thanks in advance. J.Buesch

2014-01-28 17:25:00 -0500 marked best answer Can rosbridge set the timestamp of stamped messages?

Hello guys,

I am using rosbridge in my project and it would be great if the bridge could set the timestamps in messages passed through it as simple json messages. Is that supported somehow?

Cheers, J.B.

2014-01-28 17:24:58 -0500 marked best answer Bare, very slim ROS node running on DD-WRT router?

Hello everyone,

I am looking for information about having a ROS node running on a DD-WRT enabled router.

The node would be used to send status data back to the ROS main system about certain router parameters and thus doesn't need any fancy ROS features. Basically I am looking for something that is doing the ROS communication management (XML-RPC management and TCP/IP channel allocation) stuff for me.

I know that I could do that on my own, but I am not that deep into c++ programming (I don't want to use python due to the overhead) and any hints would save precious for time :)

Thanks for any help/hints in advance. J.B.

2013-12-10 22:48:27 -0500 commented answer turtlebot SCI Problem

Please open a new question for that. This is a Q&A platform and not a forum. Nobody will find your question in this post. And from what you wrote I have no idea at all. When you put a new question, please provide as much information as you can do in order to relieve people from guessing. :)

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2013-08-20 03:15:55 -0500 commented answer Openni in ROS ARM repository

Has there been any progress on that?

2013-06-19 15:58:22 -0500 received badge  Famous Question (source)
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2013-05-20 23:52:48 -0500 asked a question ROS Android apps keep crashing on Nexus 4

Hey guys,

I hadn't time to investigate this further, maybe someone already knows a quick answer.

On my Nexus 4 with standard Android 4.2.2 the ROS apps available on Google Play keep crashing after selecting a running master. The only app that I was able to use so far is CameraTutorial, which I compiled myself btw. Maybe this is the problem. Maybe I have to download the sources and compile by hand. But then I would recommend not making it available for this andoird version.

Anyone else experiencing these problems?

Cheers, Jasper

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2013-02-11 01:43:43 -0500 answered a question Kinect laser range - strange values.

The reason is that Kinect doesn't use single laser beams to get the distance, but a laser image, that is projected into the room. A camera slightly apart from this laser image source 'sees' this image from a slightly different angle and can hence calculate the distances. To do this successfully, objects must have a minimum distance to the Kinect - usually 60cm.

That the sensor reports 11m, when you cover it with your hand, means it has no reasonable values to offer and reports invalid ones. Have a look at range_max value. It will pretty sure be 10m in your case.

If that's the case, everything is ok. Although there should be reasonable values in the laser array, if distances in front of the camera range from 60cm - 6m.

2012-12-11 08:20:00 -0500 received badge  Notable Question (source)
2012-11-07 11:01:31 -0500 answered a question turtlebot SCI Problem

The problem comes not from the dashboard. It starts earlier:

[ERROR] [WallTime: 1352283377.066618] Failed to open port /dev/ttyUSB0. Please make sure the Create cable is plugged into the computer.

This means that turtlebot_node.py was never even able to connect to your iRobot device in the first place. I would suggest you start with a simple

rosrun turtlebot_node turtlebot_node.py

in order to see clearer what it going wrong. Once you figured that out, continue with the big launch file. Why turtlebot_node.py actually gets no connection to your iRobot device can have different reasons.

  • Does your user have permission to open a serial port?
  • On my setup it happens, that I have to replug the serial converter once after rebooting my laptop for god knows what reasons. After that it works like a charm.
  • Are there probably more serial-usb devices on your system and /dev/ttyUSB0 is already occupied?

A good starting point might be to manually connect to serial port and see if that works.

Good luck. :)

2012-11-01 06:02:53 -0500 commented answer Simple odometry question

Nice to hear that. Things can be confusing when getting started with ROS. But makes still great fun though.

2012-10-29 23:28:12 -0500 received badge  Popular Question (source)
2012-10-29 08:00:13 -0500 answered a question How do you exit back to safe mode after running a roslaunch file?

I had the same problem and altered the turtlebot_node.py by adding self._robot_reboot() in the last line of spin(). By doing so, roomba is soft-rebooted in the end (after killing the process from terminal).

This way you cannot forget to put it back to passive mode my rosservice.

2012-10-28 23:23:50 -0500 answered a question Openni_manager service call to manually load Kinect driver

I am now using app_manager for this purpose and it is working quite good. If somebody stumbles over the need of loading/unloading the kinect driver remotely (necessary when the kinect is unpowered during opereration) I can recommend this approach.

2012-10-28 23:21:21 -0500 answered a question Calling nodelet manager service from console

I am going now with another approach and just wanted to close this question. Now I am using app_manager to run the nodelet launch file remotely. This actually works quiet smooth and exactly as I need it. Cheers!

2012-10-26 10:17:36 -0500 commented answer Simple odometry question

The vision shows an angle difference of approx 45 degrees, as you also confirmed, but when you look at the odom frame it has rotated less. Good luck and have fun!

2012-10-26 10:15:20 -0500 commented answer Simple odometry question

...parts of the suroundings. If you'd run something like a obstacle grid, the outlines of the room would materialize. From the pics I can see though that there is a slight discrepancy which comes from a non well calibrated odom (factor >1 needed). Try to calibrate and go on. It looks alright now! :)

2012-10-26 10:10:41 -0500 commented answer Simple odometry question

Well, with your pictures (great idea) my first clou doesn't hold any longer, but I have great news for you. Why do you think this is not right? I mean, since your scanner is mounted on the robot, of course it is rotating as well and its 'vision' moves along too, showing different (cont'd)