I'm sure that Andrew or Nate will get back to you on this, but in
the meantime, here's my two cents (based on a little code-digging and
experimentation), with some more specific questions for the developers.
(btw, these guys are currently working with Gazebo 0.3.0, not CVS)
On Mon, 24 May 2004, Walter Macklem wrote:
> I'm trying to use the SegwayRMP robot on Gazebo and have encountered a
> few questions. Any help you can provide would be greatly appreciated.
> 1. My goal is to have the SegwayRMP mounted with a SICK Laser with
> the ability to tilt the laser from 0 to 45 degrees. Things I have
> A. I'm trying to use the SonyVID30 with the laser mounted on
> I would figure that tilting the Sony would also tilt the laser.
> the pan/tilt of the Sony simply changes the viewing perspective
> and does
> not change the physical orientation of the device in Gazebo.
The latest SonyVID30 model, in CVS, actually pans and tilts the camera.
However, an attached laser still doesn't move with the camera.
I'm guessing the reason is the laser gets attached to the *base* of
the camera, and the base of the camera doesn't move. Is there a way to
attach the laser to "end effector" of the camera?
> B. Use the truth() functionality to manually position the laser
> as needed,
> but this seems to only work in Stage and not Gazebo. Truth()
> only allow you to
> reposition the 2D coordinates, not the 3D coordinates.
The latest code, in CVS, has a 6-DOF TruthWidget, but the Player 'truth'
interface still only supports planar (x,y,yaw) coords. Perhaps you can
work within this constraint by arranging your laser so that changing
its yaw will do what you want? Alternatively, you could use skip Player
and use libgazebo directly, which would presumably give you full access to
> 2. I've mounted the SegwayRMP with the Sony and SICK over the center of
> of the robot. I am able to drive on the Ground Plane with no problem,
> but I also need to drive on to a Simple Solid object. When its on one
> of these
> objects, the Segway becomes very unstable and falls over. Even without
> the Sony
> and SICK mounted on the Segway, the robot will pitch back and forth on a
> SimpleSolid object. It seems like this may have something to do with
> how the
> center of mass of the Segway is defined, and adding objects to the robot
> forces the center of mass higher than expected. Any ideas on how to
> make the
> Segway more stable when driving on the SimpleSolid objects?
There are several physical parameters defined in SegwayRMP::OdeLoad. This
may not be the recommended way to do it, but you can get different dynamic
behavior by adjusting the masses there.
> 3. I'm unable to get Position3D data from the Segway. It grabs regular
> Position data,
> but switching to Position3D causes an error. I've made changes to the
> gazebo.cfg file, but
> it errors when running Player. It says it cannot find the driver for
> I've also tried using the "gz_position" driver from Position3D, but that
> does not work
> either. Any suggestions?
In CVS, there is now a "gz_position3d" driver. Unfortunately, the
SegwayRMP model still only produces 2D data, despite maintaining 3D data.
How hard would it be make the SegwayRMP model produce 3D data?
Brian P. Gerkey gerkey@...
Stanford AI Lab http://ai.stanford.edu/~gerkey