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2012-12-12 05:37:34 -0500 commented question How can I change ar_pose frequency?

The images come from a 640x480 gazebo simulated camera at 30FPS. I've tried to reduce resolution and FPS but time doesn't appear to change...

2012-12-09 21:28:35 -0500 asked a question How can I change ar_pose frequency?

Hi,

I'm trying to use ar_pose to estimate the robot pose for a simple controller. However ar_pose publishes a new estimation every 1/4 s. This frequency is too low for my problem :(

There is a way to increase ar_pose frequency?

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2012-03-02 03:34:56 -0500 asked a question Calibrate Gazebo Camera

Hi!

I have a robot in a gazebo environment. This robot has a camera (I use the libgazebo_ros_prosilica.so controller).

I have to use ar_pose to get the robot position in gazebo world through camera acquisition. But I have a big problem: how can I calibrate that camera? There is some ar_pose internal tools or I have to search for more esoteric solutions?

Thank you!

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2011-10-26 00:10:21 -0500 commented answer Gazebo object pose and getAsEuler
Thank you. :)
2011-10-26 00:08:21 -0500 marked best answer Gazebo object pose and getAsEuler

It depends what you want. The reason for the uncontinuity is that the angles are normalized. If you would use them incrementally values might grow arbitrarily, so they are not that nice to read (and which with huge values might lead to loss of precision). One solution would be to "renormalize" to the last angle, i.e.:

  • Remember the last angle
  • Get current (normalized) angle
  • add/substract 2*pi until (angle - last_angle) is smallest

The better solution would probably be to handle that nicely in the controller, but that depends on its functionality (e.g. if you calculate an angle difference in the controller normalize that difference). The angles packages provides: shortest_angular_distance for this.

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2011-10-25 04:09:10 -0500 asked a question Gazebo object pose and getAsEuler

Hello,

I'm working on a quad-rotor simulation in 3D space. I use the GetPose() method to get the current object pose in the space. And now there is the problem.

The GetPose() method return a Pose3D object. This object contains

  • A Vector3 for the body position.
  • A Quatern for the body orientation.

Now I should transform this quaternion in a Roll-Pitch-Yaw triple through the GetAsEuler() method of Quatern. Unfortunately this value is non-continue because it jump from pi to -pi and this cause trouble to my controller!

Exist any way to obtain a continue transformation from quaternion to euler triple?

2011-10-25 03:40:01 -0500 asked a question Change ODE integrator parameters from Gazebo

Hello

I would like to know if it's possible to change ODE parameters from the Gazebo world file. I have to much numeric noise in my simulation and I think that it's an integration related problem.

If it's possible, there is a documentation about Gazebo interface to ODE?

Thanks :)

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2011-10-05 08:17:52 -0500 marked best answer Installing ROS on Ubuntu 11.10 Oneric Ocelot

No Ubuntu Oneric packages are currently in the repository.

I would not expect to see them there until after Oneric is officially released by Ubuntu.

The answer above refers to the Ubuntu binaries. You can probably check out ROS sources and compile them on Oneric. There may be some problems with system dependencies or perhaps a new compiler version. If so, please report them. The ROS package maintainers will want to fix them.

2011-10-05 02:05:13 -0500 commented answer Installing ROS on Ubuntu 11.10 Oneric Ocelot
Ok. I think that I can wait for a week. :)
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2011-10-05 01:11:58 -0500 asked a question Installing ROS on Ubuntu 11.10 Oneric Ocelot

Is actually possible to install ROS on the upcoming Ubuntu 11.10 Oneric Ocelot through the ros repository?