Embedded Motion Control 2013/FAQ

Ubuntu

I try connect to the svn but I need the GNOME keyring password.

1. Go to console

   cd ~/.subversion

   nano config

2. Go to [auth] and enter below [auth] the following "password-stores =".
3. Press ctrl+x and save the file with the same name (config).
4. Open a new console and now it works fine.

I start the jazz_simulator but my maze is blinking very fast (HP Elitebook 8540w).

1. Go to "System" --> "Administration" --> "Hardware Drivers".
2. Remove the "ATI/AMD proprietary FGLRX graphics driver" (Ubuntu recommended to install this)
3. Restart Ubuntu

Gazebo

Gazebo keeps crashing

1. Try to run it in gdb: enter

   gdb gzserver

   to start gdb and enter

   run

   to actually start the server. The same holds for the client (visualization):

   gdb gzclient

   and again type

   run

   to start it.

PICO does not drive and does not publish any odometry

1. Try rosmaking pico-gazebo with pre-cleaning:

   rosmake pico_gazebo --pre-clean

RViz

I cannot display odometry information in RViz

In order to visualize the odometry information, RViz needs a tf (transform) from /odom to /base_footprint which is not published by the simulated controller. Since this tf is not available on the real robot either, we will not add it to the simulator. If you really want to visualize the information, or need the transform for some other reason, you will have to publish the tf yourself. See http://ros.org/wiki/tf for more info.

I've got an error with RViz and it doesn't start

If the error looks like this:

  The program 'rviz' received an X Window System error.
  This probably reflects a bug in the program.
  The error was 'BadDrawable (invalid Pixmap or Window parameter)'.
 (Details: serial 22 error_code 9 request_code 136 minor_code 3)
 (Note to programmers: normally, X errors are reported asynchronously;
  that is, you will receive the error a while after causing it.
  To debug your program, run it with the --sync command line
  option to change this behavior. You can then get a meaningful
  backtrace from your debugger if you break on the gdk_x_error() function.)
  [rviz-6] process has died [pid 1978, exit code 1].

The following solutions can be tried:

In section 3.4 Segfault during startup from RViz troubleshooting page.

Open a terminal without Gazebo running and just type:

  export OGRE_RTT_MODE=Copy   

If this does not work, just follow the next steps:

1 rosrun rviz rviz --sync ( add the --sync it even says in the error message)
2 don't give up even with sync it will fail,maybe...try it 2-3 times
3 if it still fails do rosmake rviz rviz and repeat step 1

Graphics drivers issues

Using the wrong graphics drivers may cause Gazebo and/or rviz to crash. To solve this problem, please follow the following steps:

• First try installing/updating the graphics driver using Hardware Drivers (System->Administration->Hardware Drivers)

• When this does not solve the problem and you are using an ATI video card (for e.g. the 'shuttle' PC):
  • If installed, uninstall the proprietary ATI driver in Ubuntu
  • Download the Xorg ATI driver install script from http://www.2shared.com/file/meVhVXNB/ati-driver-installer-11-12-x86.html
  • Install the driver with
    • >> sudo ./http://www.2shared.com/file/meVhVXNB/ati-driver-installer-11-12-x86.run
    • Select the default options
• Restart PC

You can test the driver from working properly by launching AMIGO in Gazebo and looking at the pointcloud data. This data should be refreshed when AMIGO for instance drives around or if you draw a big block in front of AMIGO.

Global Q&A

Group 2
Q: Can it be assumed that all corners are 90 degrees?
A: Yes, it can (but be aware that in practice it may be 88 or 92 degrees as well...).
Q: Do arrows insinuate driving direction only or do they provide information on next crossroads as well?
A: The camera can only look in front of the robot meaning that arrows to the left or right in a corridor are hard to recognize. They will be placed in spots where you drive towards them. They only give information about the driving direction at the location of the arrow.

Group 1 - Wouter
Q: There was a ubuntu update (2013-10-11) which also updated gazebo, now my I cannot spawn any maps anymore.
A: To be certain; first remove all folders from ~/ros/emc/general/. Then do svn update. Now make all the nodes rosmake jazz_description jazz_gazebo jazz_visualization tue_gazebo_plugins gazebo_map_spawner. You should be able to spawn mazes again by now. However when you start rviz you will see that pico has errors regarding the RobotModel and the LaserScan, to fix this set the fixed frame in Global Options to /pico/base instead of /pico/odom