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2021-02-24 15:15:07 -0500 asked a question robot_localization drift when using simulated roll and pitch

robot_localization drift when using simulated roll and pitch I am seeing a large drift in the position output (from loca

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2019-03-05 14:57:25 -0500 marked best answer Error when creating snaps for ros subscriber/publisher tutorial

I am very new to snaps. I am following this tutorial to get started with ros and snaps.

https://insights.ubuntu.com/2017/03/2...

I was successful in creating the ros-base snap that contains roscore and the basic ros packages. When I try creating a snap for ros-app, I get an error

Unable to find package path: "/home/user/snap-apps/ros-app/parts/ros-app/src/src"

The problem I guess is that, it is looking the sub-directory src/src instread of just src/. Do I need to edit the snapcraft.yaml file to change some paths?

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2018-04-15 12:49:11 -0500 marked best answer Ros python packages __init__ level imports

I noticed that in native ROS packages all available modules seem to be imported at package level always. For example let us consider the rosbag python package. This is the output I see when I print the list of modules imported at package-level.

>>> import rosbag
>>> dir(rosbag)
['Bag', 'Compression', 'ROSBagException', 'ROSBagFormatException', 'ROSBagUnindexedException', '__builtins__', '__doc__', '__file__', '__name__', '__package__', '__path__', 'bag', 'migration', 'rosbag_main', 'rosbagmain']

However the __init__.py file of rosbag package does not explicitly import bag, migration and rosbag_main. How are these these modules getting imported by themselves?

In order to verify if this is something done by the catkin build system, I wrote my own ros python package. My custom package did't any modules imported at package level. So my question is what makes the ROS native python packages special to cause this behavior?

In order to understand this question better, if you want to access the rosbag source, see the link https://github.com/ros/ros_comm/tree/...

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2018-04-12 08:22:32 -0500 edited question Ros python packages __init__ level imports

Ros python packages __init__ level imports I noticed that in native ROS packages all available modules seem to be import

2018-04-11 22:46:50 -0500 asked a question Ros python packages __init__ level imports

Ros python packages __init__ level imports I noticed that in native ROS packages all available modules seem to be import

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2017-09-08 10:59:59 -0500 marked best answer Rosdep not finding packages that are in index.yaml

I am have ros-kinetic installed in Ubuntu 16.04. I cloned a couple of packages into my workspace and ran rosdep to get their dependencies. I ran rosdep from the root of my workspace using this line

rosdep install --from-paths src --ignore-src --rosdistro ${ROS_DISTRO} -y --as-root pip:no --skip-keys="gazebo"

Rosdep returns with a bunch of missing pacakages. The missing packages in my case are listed below.

dpkg-query: no packages found matching ros-kinetic-sick-tim
dpkg-query: no packages found matching ros-kinetic-gazebo-ros-control
dpkg-query: no packages found matching ros-kinetic-socketcan-bridge
dpkg-query: no packages found matching ros-kinetic-canopen-chain-node
dpkg-query: no packages found matching ros-kinetic-base-local-planner
dpkg-query: no packages found matching ros-kinetic-robot-localization
dpkg-query: no packages found matching ros-kinetic-effort-controllers
dpkg-query: no packages found matching ros-kinetic-joint-state-controller
dpkg-query: no packages found matching ros-kinetic-turtlebot-interactive-markers
dpkg-query: no packages found matching ros-kinetic-um7
dpkg-query: no packages found matching ros-kinetic-ros-controllers
dpkg-query: no packages found matching ros-kinetic-gmapping
dpkg-query: no packages found matching ros-kinetic-costmap-2d
dpkg-query: no packages found matching ros-kinetic-turtlebot-rviz-launchers
dpkg-query: no packages found matching python-opencv
dpkg-query: no packages found matching ros-kinetic-socketcan-interface
dpkg-query: no packages found matching python-shapely
dpkg-query: no packages found matching ros-kinetic-can-msgs
dpkg-query: no packages found matching ros-kinetic-turtlebot-gazebo
dpkg-query: no packages found matching ros-kinetic-joint-limits-interface
dpkg-query: no packages found matching ros-kinetic-turtlebot-teleop
dpkg-query: no packages found matching ros-kinetic-transmission-interface
dpkg-query: no packages found matching ros-kinetic-turtlebot-navigation
dpkg-query: no packages found matching ros-kinetic-tf2-sensor-msgs
dpkg-query: no packages found matching ros-kinetic-realsense-camera
dpkg-query: no packages found matching ros-kinetic-pointcloud-to-laserscan
dpkg-query: no packages found matching ros-kinetic-hardware-interface
dpkg-query: no packages found matching ros-kinetic-uuid-msgs
dpkg-query: no packages found matching ros-kinetic-turtlebot-simulator
dpkg-query: no packages found matching ros-kinetic-controller-manager
dpkg-query: no packages found matching ros-kinetic-amcl
dpkg-query: no packages found matching ros-kinetic-realtime-tools
dpkg-query: no packages found matching ros-kinetic-nav-core
dpkg-query: no packages found matching ros-kinetic-move-base
dpkg-query: no packages found matching ros-kinetic-hector-gazebo-plugins
dpkg-query: no packages found matching ros-kinetic-turtlebot-bringup
dpkg-query: no packages found matching ros-kinetic-usb-cam
dpkg-query: no packages found matching ros-kinetic-turtlebot-description
dpkg-query: no packages found matching ros-kinetic-move-base-msgs
dpkg-query: no packages found matching ros-kinetic-teb-local-planner
dpkg-query: no packages found matching ros-kinetic-turtlebot-capabilities
dpkg-query: no packages found matching ros-kinetic-map-server

Most of these packages are found in the ros distro index file. I am able to install them manually using apt-get. Why is rosdep failing to find them?

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2017-08-24 12:02:04 -0500 answered a question Rosdep not finding packages that are in index.yaml

In case some package is mispelled or if there is some other reason preventing rosdep from installing some package. That

2017-08-24 12:00:20 -0500 commented question Rosdep not finding packages that are in index.yaml

That was the problem. I had misspelled a different package that prevented rosdep from continuing and installing more stu

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2017-08-23 18:19:55 -0500 edited question Rosdep not finding packages that are in index.yaml

Rosdep not finding packages that are in index.yaml I am have ros-kinetic installed in Ubuntu 16.04. I cloned a couple of

2017-08-23 18:17:48 -0500 asked a question Rosdep not finding packages that are in index.yaml

Rosdep not finding packages that are in index.yaml I am have ros-kinetic installed in Ubuntu 16.04. I cloned a couple of

2017-05-04 08:23:04 -0500 commented answer Error when creating snaps for ros subscriber/publisher tutorial

I will try again and let you know.

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2017-05-01 09:29:02 -0500 commented question Error when creating snaps for ros subscriber/publisher tutorial

Snapcraft version: 2.29

2017-04-28 11:26:37 -0500 asked a question Error when creating snaps for ros subscriber/publisher tutorial

Error when creating snaps for ros subscriber/publisher tutorial I am very new to snaps. I am following this tutorial to

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2016-09-28 12:54:40 -0500 asked a question Bringing up a node through roslaunch from a remote machine and through local roslaunch gives different publishing rates

I have two machines A and B. I want to start node N on machine B. Node N publishes topic T.

case 1: Use launch file in machine A to remotely launch node N on machine B. case 2: Ssh in to machine B and launch node N on machine B locally.

I assumed both these cases were identical with regards to the ROS system. However I am seeing significant differences and I would like some help understanding them.

When I do a rostopic hz on topic T, I see different results between case 1 and case 2

case 1: 6 hz on B, 5 hz on A
case 2: 14 hz on B, 13 hz on A

I understand that small variations between rostopic hz numbers between machines A and B could be due to my network loads. I don't understand the big drop in hz values between case 1 and case 2.

Any help would be great. Thanks.

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2014-11-05 11:36:24 -0500 commented answer Arduino mega and rosserial problem

I didn't know about this. I will try limiting my string usage and see if I can get through it.

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2014-10-29 19:48:57 -0500 asked a question Arduino mega and rosserial problem

I am using the arduino mega pro board https://www.sparkfun.com/products/10743

I have tested this board using stand alone sketches without ros and have no issues with that. Any sketch below 30kb works with rosserial and arduino mega pro smoothly.

As soon as my sketch size increases beyond 30kb, I start getting the error:

Unable to sync with device; possible link problem or link software version mismatch such as hydro rosserial_python with groovy Arduino

If I comment some functions in my sketch to bring the size below 30kb, things are working again.

One reason why I am using this board over arduino uno is that arduino mega lets me upload sketches over 32k (which is the maximum sketch size for arduino uno).

Any idea why this is happening? Does ros think that my mega pro board has a memory of 32k and failing when the sketch size goes beyond that.

Any help would be appreciated. Thanks.

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2013-05-28 05:48:19 -0500 commented answer Error building cv_bridge on RaspberryPi

I am also having error with installing cv_bridge on raspbian. About installing opencv from source, are you referring to vision_opencv that comes with ros or the opencv from debian repositories?

2013-05-28 05:47:12 -0500 answered a question Error building cv_bridge on RaspberryPi

I am also having error with installing cv_bridge on raspbian. About installing opencv from source, are you referring to vision_opencv that comes with ros or the opencv from debian repositories?

2012-08-30 13:01:52 -0500 answered a question problem using Turtlebot Interactive Markers

Hey Barriere,

Were you able to figure this out. I am getting the same issue.

I tried "rostopic echo /cmd_vel", it give me correct values corresponding to motion. But the robot doesn't move. The circle is blue not green like you mentioned.

Thanks