Snow Day!

02 Feb 2011 robots ros I've been a bit quiet on this blog lately -- it's been a busy start to the new semester. Today however, the University closed due to inclement weather. So, I'll post a few updates on what I've been working on:

First, I just barely finished an entry in time for the ROS 3D contest. I had insisted on using the new OpenNI-based drivers, which had some issues under 32-bit systems until about a week before the contest deadline. This was also my first attempt using the ROS Point Cloud Library (PCL). My entry improves the ar_pose package to use depth data from the Kinect to improve the localization of the AR Markers. It also uses surface normal calculation from PCL to improve the orientation. While it's probably not the most technically interesting entry, I definitely did learn a bunch about PCL while working on it. You can read more about the entry here. Or watch the really horrible video (my normal camera stopped working about 12 hours before the deadline):

In creating the entry, I also quickly constructed another robot. This guy used an iRobot Create, Kinect, and a tripod to get the Kinect up to the "Standard Social Robot Minimum Height" that we've been applying to all our robots at Albany:

This tripod worked surprisingly well -- far better than anything I've previously built out of conduit.

Finally, I'm working on putting together a new robot based on an EX-106/RX-64 based arm, Kinect, and a bit larger mobile base..... pictures and video shortly. (his parts are stuck on UPS trucks somewhere in a snow storm).

Neato + SLAM

01 Jan 2011 robots ros slam

Here is yet another story for “the power of open source.

I’ve been spending quite a bit of time working on SLAM with the Neato XV-11 using both the built in laser and the Hokuyo URG-04LX-UG01. I had pretty much given up on gmapping working with the Neato – until earlier today we found an issue with the scan angle increment computation in gmapping not working with the Neato laser specifications. I probably wouldn’t have found this bug had it not been for a user of the Trossen Robotic Community pointing out some issues he was having with gmapping, as my version still had some modifications from my PML work earlier this year.

Anyways, for anyone wanting to use gmapping with the Neato robot, you can apply the following patch:

339c339
- gsp_laser_angle_increment_ = (angle_max - angle_min)/scan.ranges.size();
+ gsp_laser_angle_increment_ = scan.angle_increment;

to slam_gmapping.cpp. This uses the angle_increment from the laser scan, rather than the computed one, which is incorrect for full rotation scans. This will avoid issues with the scan being improperly inverted, and issues with scan matching.

Other SLAM Algorithms: CoreSLAM, Part 3

31 Dec 2010 robots ros slam I've now got the build system working as well as fixing a number of parameter issues to be more ROS-compliant. Documentation for the package has been uploaded to http://www.ros.org/wiki/coreslam

Here's another example map created (of the first floor of a home):

Next up on the docket of winter break projects: some updates to the ArbotiX ROS package, and a number of people perception algorithms.

Robot & Chisel

Snow Day!

Neato + SLAM

Other SLAM Algorithms: CoreSLAM, Part 3