liangfok's profile - activity

Is there a way to display statistics for all active ROS topics in a system? By statistics I mean bandwidth usage, publishing rate, number of messages dropped, etc. I looked at "rostopic bw" and "rostopic hz" but they only display information for one topic at a time.

I'm running into a situation where compiling a C++ program using Catkin results in a different behavior compared to executing the same compiler command directly in the command line. The compiler command executed by Catkin is obtained using:

catkin build --verbose -j1

Specifically, the header files that are found differ between the two scenarios. When compiled using Catkin, the compiler (incorrectly) finds and includes a header file in /opt/ros/indigo/include/. When I copy/paste Catkin's compiler command into the command line, the compiler (correctly) finds and links a header file in my_catkin_workspace/install/include/. Does anybody know why or how this could happen?

Fundamentally, I'd like to prioritize finding header files in my_catkin_workspace/install/include/ over header files in /opt/ros/indigo/include/. Does anyone know how to do that?

Has anyone integrated MoveSim, an open source vehicular traffic simulator, with ROS?

Yes, it's written in Java but there's ROS Java :).

Agreed. I thought (perhaps incorrectly) that URDF is deprecated and that SDF is its replacement, so my (perhaps wrong) assumption was the entire ROS ecosystem would eventually be upgraded to support SDF.

I reopened the question because I do not believe this is a Gazebo-specific question. To my knowledge, SDF is not Gazebo-specific and many other processes in the ROS ecosystem like controller, planners, visualizers, etc., may use the models specified within the SDF file.

According to SDF v 1.6's joint limit syntax, a joint limit's <lower> and <upper> elements are required ("Required: 1") but its text description states "Omit if joint is continuous".

Isn't this a contradiction? If the <lower> and <upper> elements can be omitted to support continuous joints, shouldn't the "Required: 1" be changed to "Required: 0"?

I'm working on a toolbox written in C++ that is outside of the ROS ecosystem but want to conditionally add ROS support if ROS is installed on the local machine. What is the best way to check if ROS is installed in my toolbox's CMakeLists.txt?

I'm currently checking for the existance of a local environment variable called "ROS_ROOT" as shown below.

if(DEFINED ENV{ROS_ROOT})
  find_package(roscpp REQUIRED)
  include_directories(${roscpp_INCLUDE_DIRS})
  ...
endif()

Is this an acceptable solution? Is there a better solution?

I'm running ROS Fuerte and Ubuntu 12.04. I downloaded the stack "pr2_mechanism" using the mercurial repository listed here. The command I executed was:

$ hg clone https://kforge.ros.org/pr2mechanism/hg pr2_mechanism

When I try to compile package "pr2_mechanism_diagnostics" within this stack, I get the following error:

Failed to invoke /opt/ros/fuerte/bin/rospack deps-manifests pr2_mechanism_diagnostics [rospack] Error: package/stack pr2_mechanism_diagnostics depends on non-existent package pr2_mechanism_msgs

The package "pr2_mechanism_msgs" should be in the stack "pr2_mechanism" since it appears in the repository's web interface. However, the package is not included when I clone this repository using the command above. The only packages included are:

1. pr2_controller_interface
2. pr2_controller_manager
3. pr2_hardware_interface
4. pr2_mechanism_diagnostics
5. pr2_mechanism_model
6. realtime_tools

Why is pr2_mechanism_msgs missing?

I'm running Ubuntu 12.04, ROS Hydro, and RTAI 3.9. I have a ROS node that instantiates an RTAI real-time thread and subscribes to various ROS topics. When another node publishes to one of these ROS topics and then disconnects, the ROS node containing the real-time thread crashes with a "boost::thread_resource_error".

Using gdb, I see that the cause is due to roscpp starting a thread upon disconnection of the remote node:

#7  0xb7c6c84c in void boost::throw_exception<boost::thread_resource_error>(boost::thread_resource_error const&) () from /opt/ros/hydro/lib/libroscpp.so
#8  0xb76853eb in boost::thread::start_thread() () from /usr/lib/libboost_thread.so.1.46.1
#9  0xb7c88c59 in ros::TimerManager<ros::WallTime, ros::WallDuration, ros::WallTimerEvent>::add(ros::WallDuration const&, boost::function<void (ros::WallTimerEvent const&)> const&, ros::CallbackQueueInterface*, boost::shared_ptr<void const> const&, bool) () from /opt/ros/hydro/lib/libroscpp.so
#10 0xb7cded9c in ros::TransportPublisherLink::onConnectionDropped(boost::shared_ptr<ros::Connection> const&, ros::Connection::DropReason) () from /opt/ros/hydro/lib/libroscpp.so

I'm fairly sure the problem is related to the use of RTAI because it does not occur when I disable the creation of an RTAI real-time thread.

The creation of the ROS topic subscribers is done by a non-real-time thread prior to creation of the RTAI real-time thread.

Does anybody know how to fix this problem?

I would like to convert arbitrary ROS messages into JSON format. Is there an official way of doing this?

My current workaround is to create a script called run_gazebo: https://bitbucket.org/cfok/hcrl_robot_models/src/23032a61c7299eaead51164eaf2703e0f4ab1868/hcrl_simulator/scripts/run_gazebo?at=develop The script is started by a launch file: https://bitbucket.org/cfok/hcrl_robot_models/src/23032a61c7299eaead51164eaf2703e0f4ab1868/stickbot_lowerleg_3dof/launch/gazebo.launch?at=develop

Unfortunately, I need to use Gazebo 3.0 because there is a critical flaw in previous versions of Gazebo that prevent me from accurately simulating my robot.

I recently upgraded to the most recent packages of ROS hydro and now when I launch gazebo using "rosrun gazebo_ros gazebo" I'm getting the following error:

gzserver: symbol lookup error: /opt/ros/hydro/lib/libgazebo_ros_paths_plugin.so: undefined symbol: _ZN3ros7package10getPluginsERKSsS2_RSt6vectorISsSaISsEE

gzclient: symbol lookup error: /opt/ros/hydro/lib/libgazebo_ros_paths_plugin.so: undefined symbol: _ZN3ros7package10getPluginsERKSsS2_RSt6vectorISsSaISsEE

Using c++filt or http://demangler.com/ , I see that the following method is undefined:

ros::package::getPlugins(std::string const&, std::string const&, std::vector<std::string, std::allocator<std::string=""> >&)

Does anyone know how to fix this?

Here are the ROS / Gazebo packages I have installed on my Ubuntu 12.04.4 64-bit computer:

$ dpkg -l | grep hydro | grep gazebo
ii  ros-hydro-gazebo3-msgs                      2.4.2-3precise                                                          Message and service data structures for interacting with Gazebo from ROS.
ii  ros-hydro-gazebo3-plugins                   2.4.2-3precise                                                          Robot-independent Gazebo plugins for sensors, motors and dynamic reconfigurable components.
ii  ros-hydro-gazebo3-ros                       2.4.2-3precise                                                          Provides ROS plugins that offer message and service publishers for interfacing with Gazebo through ROS. Formally simulator_gazebo/gazebo

$ dpkg -l | grep gazebo
ii  gazebo3                                     3.0.0-3~precise                                                         Open Source Robotics Simulator
ii  gazebo3-common                              3.0.0-3~precise                                                         Open Source Robotics Simulator - Shared files
ii  gazebo3-plugin-base                         3.0.0-3~precise                                                         Open Source Robotics Simulator - base plug-ins
ii  libgazebo-dev                               3.0.0-3~precise                                                         Open Source Robotics Simulator - Development Files