Robot & Chisel

stuff by michael ferguson. robots, woodworking, etc.

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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.

Other SLAM Algorithms: CoreSLAM, Part 2

25 Dec 2010 robots  ros  slam  I've now get the Monte Carlo Localization turned on, map publishing working in ROS, and a number of parameters defined. This required some hacking of the CoreSLAM library, in particular I removed all of the references to differential drive odometry, instead loading odometry externally from TF.

Here's an updated map using the 12-12-neato-ils bag file:



There's still some work to fix the way that the map->odom transform is handled, and allow a configurable map size and resolution (both of which will require reworking some more of the underlying library). I'm hoping to have the code released shortly.