Xiaojun,
Tully's right, we do a fair amount of work on the PR2 with calibration to make sure that things work. Even with that, we have some problems with false positives from time to time in our ground plane detection. The plan is to write a more robust filter at some point, but I'm not sure exactly when we'll get to that. You might have to write a different filter that works for your robot. Wish I had a better answer for you.
Hope all is well,
Eitan
On Wed, Oct 20, 2010 at 5:10 PM, Tully Foote
<tfoote@willowgarage.com> wrote:
Xiaojun,
It does sounds like you need to make sure your filters are setup accurately. On the PR2 we have optical flags for calibration on all joints. Plus we do full body and sensor calibration to make sure they are aligned. Also you will likely need to look at more parameters of the ground plane removal that you need to customize for your robot.
TullyOn Wed, Oct 20, 2010 at 8:10 AM, clarkwu
<wu.xiaojun@gmail.com> wrote:
Eitan,
Thanks for your reply.
You are right that the warning message refers to something wrong in the
laser filters.
What I found is in the source file sac_inc_ground_removal_standalone.cpp,
there are a few default settings for PR2 robot, such as
the robot_footprint_frame is "base_footprint"
the laser_tilt_mount_frame is "laser_tilt_mount_link"
the goal frame id for point cloud is "odom_combined"
and the function updateParametersFromServer() in fact doesn't update the
above parameters.
So I changed the codes for our own robot accordingly, and the
sac_inc_ground_removal_node node now runs properly!
Yet the result of topic /ground_object_cloud looks not so perfect, i.e.,
there are part of the ground close to the robot still left within the point
cloud of this topic. I also observed that in the output of
tilt_scan_shadow_filtered, the ground plane is not exactly in horizontal
level but looks more like a slope. So I guess this means the tilt controller
need further calibration to make sure its "0" position refers to the true
horizontal plane.
How did you handle this issue for PR2 robot?
thanks
xiaojun
--
View this message in context: http://ros-users.122217.n3.nabble.com/Navigation-stack-issue-about-ground-plane-detection-tp1707477p1739332.html
Tully Foote
Systems Engineer
Willow Garage, Inc.
tfoote@willowgarage.com
(650) 475-2827
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