ChengXiang's profile - activity

Hi ppl,

I have been trying to use 2dnav with pr2 robot. The tutorial I followed is this. After I reached instruction 3.1 and started Rviz,I tried to set a goal in rViz for the robot to follow, however, the robot didn't move as expected.

In Rviz, the status of all the displays are "ok". This includes the local plan, global plan and planner plan, however when I set 2D NAV GOAL, the paths are not displayed at all. So does anyone have any idea what could be the issues?

Or does anyone knows which robot works well with 2dnav? So far I tried turtlebot and pr2, both gave me some errors. I am using ubuntu 12.01 with fuerte. Thanks for your help.

1st update

After doing rostopic info move_base_simple/goal, this is what i get,

Type: geometry_msgs/PoseStamped

Publishers:
 * /rviz_ubuntu_29082_5799833781995074337 (http://ubuntu:37754/)

Subscribers:
 * /move_base_node (http://ubuntu:46201/)

Hi I was following the simulator_gazebo tutorial on ROS wiki when I encountered this problem. First of all I spawned a model using " rosrun gazebo spawn_model -param coffee_cup_description -gazebo -model coffee_cup -x 0 -z 2 " and then I deleted it using " rosservice call gazebo/delete_model '{model_name: coffee_cup}' ". After I called the delete_model command,gazebo crashed unexpectedly and gave the following:

[gazebo_gui-3] process has died [pid 3162, exit code 139, cmd /opt/ros/fuerte/stacks/simulator_gazebo/gazebo/scripts/gui __name:=gazebo_gui __log:=/home/chengxiang/.ros/log/fba33798-f058-11e1-8139-0017c4794a79/gazebo_gui-3.log]. log file: /home/chengxiang/.ros/log/fba33798-f058-11e1-8139-0017c4794a79/gazebo_gui-3*.log

Other than this instance, gazebo also crashes unexpectedly sometimes when I was doing other stuffs like spawning models. Did any one of you encounter this issues before? Any advice will be appreciated. Thanks.

Hi, I recently came across a post that mentioned that we should never try to edit stuff in ros/fuerte/stacks, the correct way should be through overlay instead. This means I have been doing stuff the wrong way all along. I have been making changes to launch files in erratic_robot, which is located in stack.

I would like to know how does overlay works, the wiki page states that"The overlay now includes all packages that were installed in /opt/ros/fuerte." But it is not the case for me, my overlay (fuerte workspace) only contain a sandbox, turtlebot which i installed and some setup files.

In addition, when I installed a package (eg.erratic_robot), where should it be located? For me, the erratic_robot appears in ros/fuerte/stacks.

I appreciate your help, thank you.

Hi. When running turtlebot i keep getting a warning message

 Warning [RaySensor.cc:206] ranges not constructed yet (zero sized)

I understand from this website that it can be solved by moving a small part of the code upward. However, when I did a "locate" on the file RaySensor.cc, all the RaySensor.cc appears to be in the trash folder

chengxiang@ubuntu:~$ locate RaySensor.cc
/home/chengxiang/.local/share/Trash/files/gazebo-1.0.1/src/physics/bullet 
/BulletRaySensor.cc
/home/chengxiang/.local/share/Trash/files/gazebo-1.0.1/src/sensors/GpuRaySensor.cc
/home/chengxiang/.local/share/Trash/files/gazebo-1.0.1/src/sensors/RaySensor.cc
/home/chengxiang/.local/share/Trash/files/gazebo-1.2.0.1/src/physics/bullet   
/BulletRaySensor.cc
/home/chengxiang/.local/share/Trash/files/gazebo-1.2.0.1/src/sensors 
/GpuRaySensor.cc
/home/chengxiang/.local/share/Trash/files/gazebo-1.2.0.1/src/sensors/RaySensor.cc
/home/chengxiang/.local/share/Trash/files/gazebo-1.3.0.1/src/physics/bullet 
/BulletRaySensor.cc
/home/chengxiang/.local/share/Trash/files/gazebo-1.3.0.1/src/sensors 
/GpuRaySensor.cc
/home/chengxiang/.local/share/Trash/files/gazebo-1.3.0.1/src/sensors/RaySensor.cc
/home/chengxiang/.local/share/Trash/files/gazebo-1.4.0.1/build/src/sensors  
/CMakeFiles/gazebo_sensors.dir/GpuRaySensor.cc.o
/home/chengxiang/.local/share/Trash/files/gazebo-1.4.0.1/build/src/sensors 
/CMakeFiles/gazebo_sensors.dir/RaySensor.cc.o
/home/chengxiang/.local/share/Trash/files/gazebo-1.4.0.1/src/physics/bullet  
/BulletRaySensor.cc
/home/chengxiang/.local/share/Trash/files/gazebo-1.4.0.1/src/sensors 
/GpuRaySensor.cc
/home/chengxiang/.local/share/Trash/files/gazebo-1.4.0.1/src/sensors/RaySensor.cc

May i know how can i find the file or is there another way of solving this issue? I am using ROS fuerte with Ubuntu 12.04. Thank you in advance.

update 1

An error occurs when launching turtlebot after i install from source using

rosws set simulator_gazebo --svn https://code.ros.org/svn/ros-pkg/stacks
/simulator_gazebo/trunk

Error message :

[spawn_turtlebot_model-3] process has died [pid 7428, exit code 1, cmd  
/home/chengxiang/sim_workspace/simulator_gazebo/gazebo/scripts/spawn_model  
-unpause -urdf -param robot_description -model turtlebot  
__name:=spawn_turtlebot_model __log:=/home/chengxiang/.ros/log/277d87f4-1c4d- 
11e2-92d5-0017c4794a79/spawn_turtlebot_model-3.log].
log file: /home/chengxiang/.ros/log/277d87f4-1c4d-11e2-92d5-0017c4794a79  
/spawn_turtlebot_model-3*.log

Hi. I am a new user to ROS and have some questions regarding the use of sensors in simulation.

I undrstand that in order to simulate a sensors, you need to write the gazebo extension for it in the robot's URDF file My doubts are mainly about the elements in the gazebo's extension block.

First of all, am I right to said that the controllers are what that operate the sensors in gazebo? So do I need to install drivers for sensors at all?

To use the controller, you need to choose the correct plugins, but where do we download the plugins from? The sensor's wiki page?

Lastly, how do we know what to include in the elements within the <controller> element? So far what I did is just refer the code block from robots like turtlebot without understanding what each part is for.

I checked this website, but it is still work in process.

Thank you.Pardon me if my questions sounds amatuerish.

Hi, i am a beginner and is using the navigation stack for my school project. The function that I am interested in is the base_local_ planner. On its web page section 4 generic local planning, it is mentioned that it is possible to create custom local planner. However, this is only for release 1.10.1. But I can't get navigation 1.10.1, even after running apt-get update. (mine is 1.8.3, after checking the Cmakelist). May i know if navigation 1.10.1 is out yet? If so how can i get it?

Hi, I am now doing the gazebo plugin tutorial and came across some difficulties doing rosmake. My cpp file is

#include "gazebo.hh"
#include "physics/physics.h" 
#include "common/Events.hh" 
#include "common/Plugin.hh" 
#include "common/Time.hh" 
#include "common/common.h"


namespace gazebo
{
  class PluginTemplate : public Plugin
  {
    public: PluginTemplate() : Plugin() 
            {
            }

    public: void Load( sdf::ElementPtr &_sdf )
            {
            };


  };

  GZ_REGISTER_PLUGIN(PluginTemplate)

}

However, I got the following error while running rosmake

"home/chengxiang/gazebo_tutorials/src/simple_world_plugin.cpp:26:1: error: expected constructor, destructor, or type conversion before ‘}’ token"

the "}" in question here is the last "}"

Could any kind soul please enlighten me on how to solve this issue?

Hi guys. I have been trying to do the gazebo plugin tutorial found here. When i try to rosmake the package I created, it first indicate an error that gazebo.h is not found. I then replaced gazebo.h with gazebo.hh (i can only locate gazebo.hh in my system). That solved my issue, but it then gave me another error " error: ISO C++ forbids declaration of ‘GZ_REGISTER_PLUGIN’ with no type [-fpermissive]" during rosmake.

My cpp file is the same as what is in the tutorial. Anyone here encountered this problem before?

In addition, may I know where can I learn to write and use a gazebo plugin? Since the ROS tutorial is "work in progress".

Hi everyone ! I have installed the linux OS Ubuntu 12.04 and gazebo-1.0.1 on my laptop. Although the installation of Ubuntu 12.04 is successful, I ran into some issues while running gazebo. I hope that you guys can give me some advices on how to resolve them.

I have already installed the debian package of gazebo 1.0.1 using the software centre and set the environment variables as described in the online instructions. However, when i tried to run " gzserver" in the terminal. it returned the following error

Msg Waiting for master Msg Connected to gazebo master @ http://localhost:11345 Error [RenderEngine.cc:356] Unable to load Ogre Plugin[/usr/lib/x86_64-linux-gnu/OGRE-1.7.4/Plugin_CgProgramManager.so]...Skipping

After that I added OGRE PPA, but it didn't help. I then downloaded and installed latest version of OGRE and run "gzserver" again, but it gave me another set of errors,

Exception [RenderEngine.cc:468] unable to find rendering system

Error [Rendering.cc:37] Failed to load the Rendering engine subsystem unable to find rendering system Exception [RenderEngine.cc:468] unable to find rendering system

Exception [Sensors.cc:39] Unable to load the rendering engine

terminate called after throwing an instance of 'gazebo::common::Exception' Aborted (core dumped)

Could anyone here help me with this issue? Thanks in advance.

Hi guys, I have some queries regarding the base local planner in the navigation stack. I am wondering if the base local planner are able to avoid moving obstacles or is it only good for stationary obstacles?

From my simulation in Gazebo testing a robot with a moving obstacle (with a slow speed of 1m/s) , it seems that the robot is unable to do so. I configure the base_local_planner to use DWA.

Could this be a case of the robot are unable to move fast enough?

Hi all, I have a query regarding converting yaw between frames.

The velocity commands (linear and angular) received from the base local planner are in term of robot's frame. Let says that I want to convert the velocity commands into the map's frame in gazebo, do I need to do conversion on the angular velocity?

My intuition is that since the orientation of z-axis in both robot frame and map frame are the same, the yaw in both frame should be the same right?

The reason I asked this question is because after I did an angular velocity conversion between the robot frame and world frame, the values I got are different.

1st update: The way I did the conversion is as such, rot is the double value of the original angular velocity.

(Q_is geometry_msg::quaternion , QS_ and QS_tr is geometry_msgs::QuaternionStamped )

 Q_ = tf::createQuaternionMsgFromYaw(rot_);
 QS_.header.frame_id = "base_link";
 QS_.header.stamp = ros::Time();
 QS_.quaternion = Q_;

 listener.transformQuaternion("/map", QS_, QS_tr);
 yaw = tf::getYaw(QS_tr.quaternion);

Hi, I was trying to checkout navigation 1.8.3 from github to my workspace. The commands I used are,

rosws set navigation --git https://github.com/ros-planning/navigation
/tree/navigation-1.8.3
rosws update

However, when doing update, I received the error:

[navigation] Fetching https://github.com/ros-planning/navigation
/tree/navigation-1.8.3 (version None) to /home/chengxiang/sim_workspace/navigation
WARNING [vcstools] Command failed: 'git clone --recursive https://github.com
/ros-planning/navigation/tree/navigation-1.8.3 /home/chengxiang/sim_workspace
/navigation'
 errcode: 128:
fatal: https://github.com/ros-planning/navigation/tree/navigation-1.8.3/info/refs 
not found: did you run git update-server-info on the server?
[/vcstools]
Exception caught during install: Error processing 'navigation' : [navigation]   
Checkout of https://github.com/ros-planning/navigation/tree/navigation-1.8.3 
version None into /home/chengxiang/sim_workspace/navigation failed.

ERROR in config: Error processing 'navigation' : [navigation] Checkout of   
https://github.com/ros-planning/navigation/tree/navigation-1.8.3 version None 
into /home/chengxiang/sim_workspace/navigation failed.

I am not familar with github at all so I don't have a clue what's wrong.Could anyone please advise? I am using ROS-fuerte on Ubuntu 12.04. Thanks in advance.

Hi, I am using simulating a laser sensor. However, I have some doubts about the meaning of some tags in the xml description. Even the ROS web page do not provide information on this.

The xml description look something like this

<gazebo reference="base_scan_link">
            <sensor:ray name="laser">
                <rayCount>683</rayCount>
                <rangeCount>683</rangeCount>
                <laserCount>1</laserCount>

                <origin>0.0 0.0 0.0</origin>
                <displayRays>false</displayRays>

                <minAngle>-135</minAngle>
                <maxAngle> 135</maxAngle>

                <minRange>0.06</minRange>
                <maxRange>4.0</maxRange>
                <resRange>0.001</resRange>
                <updateRate>10.0</updateRate>

                <controller:gazebo_ros_laser 
name="gazebo_ros_base_scan_link_controller" plugin="libgazebo_ros_laser.so">
                    <gaussianNoise>0.005</gaussianNoise>
                    <alwaysOn>true</alwaysOn>
                    <updateRate>10.0</updateRate>
                    <topicName>base_scan/scan</topicName>
                    <frameName>base_scan_link</frameName>
                    <interface:laser name="gazebo_ros_base_scan_link_iface"/>
                </controller:gazebo_ros_laser>
            </sensor:ray>
        </gazebo>

I wish to know what are the function of <raycount>, <rangecount>,<lasercount> and Gaussian noise. Can anyone explain what are the meanings of the above mentioned tags? Thank you.

Hi people. I am actually running a simulation of erratic robot on gazebo when this particular question strike me. The launch file I used is "erratic_navigation_apps demo_2dnav_slam.launch ".

For my project's purpose, I am trying to change the sources of odometry. When I do a rostopic check and tf_viewframe , I realised that the gazebo is producing the odometry information( the transformation from odom to base_footprint).

But when I run through all the launch files, I can't find which section is responsible for generating the transformation. Or is it that, in a Gazebo simulation, the odometry of the robot will be generated automatically?

In short, may I know which node in "erratic_navigation_apps demo_2dnav_slam.launch" is producing the odometry information? Thank you for your time.

Hi. I have some doubts regarding gmapping. On the wiki page, it is stated that gmapping make use of both laserscan and odometry data to build a map. However,it seems that the slam_mapping node only subscribe to “scan” topic but not to “odom” topic. So, is it that we only need to set the “odom_frame” parameter when launching gmapping to “odom” so that the gmapping receive odometry data? Thank you.