Jul 8 2010

PR2 + Beer

Done!!! Willow Garage proudly presents the first open source “beer fetching app” for robots! :)

Part of a 1-week project, together with a few of my colleagues, we programmed the PR2 robot to:

  • navigate and find a refrigerator
  • open its door by locating the fridge handle
  • position the robot’s manipulators so that the door doesn’t close while grasping things inside the fridge
  • automatically identify the types of beer available in the fridge (we trained models on about 9 beers - training involves simply storing a picture of the beer bottle you want to identify in a directory)
  • determine the types of beer the user selected from a web page, compute grasping points, move the arms and grasp them, and then move the beers onto a storing rack that we installed on the robot
  • close the fridge door
  • navigate the the delivery point selected by the user on the web page
  • identify people faces and perform delivery/hand-off beer + bottle opener
  • wait for bottle opener and resume!

Optionally, the robot can open the beer too! :)

The entire source code is available at:
https://code.ros.org/svn/wg-ros-pkg/stacks/pr2_drinks/trunk/ .

If you find it useful, PLEASE let us know! Obviously this app is “powered by PCL;-)

You can read our entire blog entry here: http://www.willowgarage.com/blog/2010/07/06/beer-me-robot. Cheers!

Edit: I just noticed that we got picked by Slashdot. Some of the comments posted are pretty funny.


May 18 2010

PCL :: Point Cloud Library

This is a post on one of my current projects (that seems to keep me up late these days) called PCL, short for Point Cloud Library. First, thanks to everyone that e-mailed and expressed interest on helping out to develop PCL faster. We were pleasantly surprised at ICRA to see how many of you consider this important, and I was personally overwhelmed by some of the e-mails that I received after meeting with you. Again, sincerely thank you!

Because not a lot of people know why we are doing this or how this started, here’s a few random bits on PCL…

  • PCL is a complete open source software package built as part of ROS, which stands for Robot Operating System/Robot Open Source. If you don’t know what ROS is yet, don’t worry, you will soon. We’re growing bigger everyday, and adding more functionality that will make your robots go “wheeeee” sooner than you think. :) Check out a few of them today to see them moving around, picking up objects, or simply just acting cool. ROS is a community driven open source effort (supported by Willow Garage) and the best way to think about it is a massive collection of tightly integrated software packages that enable robotics research and development. There’s probably over 100 useful packages in there, including OpenCV and OpenRave so don’t just take my word for it, go check it out yourself!
  • PCL was created as a successor to an earlier attempt of designing PointCloud data types, structures and algorithms that proved to be inefficient. Those days are gone now, and we’re proud to announce PointCloud…2. Yes, our new underlying data type that represents point cloud data is _really_ called PointCloud2. Call it an uninspired day to name things if you wish. PointCloud2 was designed with PCL in mind (or vice versa - same thing ;), and supports alignment (e.g. SSE), has a compact data size, and has a lower computational overhead in general (especially when used with nodelets - more on that later).
  • Because we want PCL to become for 3D and point cloud data processing what OpenCV is for 2D image processing, we are developing a large number of algorithms for operations such as: filtering, downsampling, 3D feature estimation, registration, surface reconstruction, segmentation, and many more, into PCL. To make things flexible and efficient on the long run, we designed PCL as a fully templated C++ library, with an Eigen backend, and lots of Boost goodies. Yes, porting it to an Android (or whatever) might be a bit of a challenge, but we’ll worry about that later. Right now, we just want robots to perceive and understand their surrounding environment better. The “robot sharing a cluster of cell phones” app will come naturally once we manage to correctly identify all the cell phones in a building ;)
  • We try to use explicit parallelization where possible in PCL, via OpenMP and TBB. We try to avoid parallelizing everything implicitly, because saving CPU cycles on those extra cores that your computer might have is a good thing ®. Basically you want to know when something is going all “parallel” and eating up all your resources on a robot. We ran into decent issues in the past, and learned a valuable lesson. I think.
  • Because we know that learning something new is hard, we’re trying to help you out. There’s documentation, API documentation, tutorials, videos, and more. We already have examples for you on how to do object recognition, and environment modeling, to name a few. And you need to understand that we just started. PCL is roughly 3-4 months old, give or take.

There’s lots more to be said, but for now, just go check it out! If you’re asking yourselves why bother, well… why not? It’s open source, it’s fast, and it’s easy to use (or so we hope). If you don’t like it, just e-mail us and we’ll fix it for you. Yup, just like that!

Here’s a teaser for one of the many things that can be done as of today with PCL. Though the video was generated before PCL was conceived, all the algorithms that are needed to obtain these results are present in PCL. In fact, we’ll create a tutorial soon to show you how to do it too in case you get stuck.

Finally, don’t forget to check out the slides from our class at Stanford for more information about PCL and point clouds. I’ve also uploaded my ICRA 2010 PCL talk/presentation slides here.


Feb 20 2009

Replanning/Perception demo

During my Willow Garage internship, Ioan and I worked on a few things with the PR2 mobile robot. Here’s one of them. :) You can also try here if the above link doesn’t take you directly there.

WG Demo #1


Feb 18 2009

Modern Boost warnings

From the book of life, the universe and pretty much everything else, here’s what Boost warnings look like these days…


/usr/include/boost/spirit/home/classic/core/non_terminal/subrule.hpp:262: instantiated from âtypename boost::spirit::parser_result, ScannerT>::type boost::spirit::subrule::parse_main(const ScannerT&) const [with ScannerT = boost::spirit::subrules_scanner, std::allocator > >, boost::spirit::nil_t>, boost::spirit::scanner_policies >, boost::spirit::subrule_list<0, boost::spirit::sequence, boost::spirit::eol_parser> > >, boost::spirit::functor_parser >, boost::spirit::action, phoenix::actor
>, phoenix::actor
>, phoenix::nil_t, phoenix::nil_t> > > >, boost::spirit::alternative, boost::spirit::kleene_star >, boost::spirit::functor_parser >, boost::spirit::optional<4, boost::spirit::parser_context >, cpp::SetSpecialToken>, phoenix::actor
>, phoenix::actor
>, phoenix::nil_t, phoenix::nil_t> > > > >, boost::spirit::action<2, boost::spirit::parser_context >, cpp::SetSpecialToken> >, boost::spirit::action<3, boost::spirit::parser_context >, cpp::SetSpecialToken> >, boost::spirit::action >, boost::spirit::action >, boost::spirit::action >, boost::spirit::action >, boost::spirit::action >, boost::spirit::action >, cpp::SetOperatorToken> > >, boost::spirit::action
<0, phoenix::closure > >,phoenix::actor
>, phoenix::nil_t, phoenix::nil_t> > > >, boost::spirit::parser_context >, boost::spirit::subrule_list<4, boost::spirit::sequence, boost::spirit::subrule<1, boost::spirit::parser_context > >, boost::spirit::parser_context >, boost::spirit::subrule_list<3, boost::spirit::sequence, boost::spirit::kleene_star > > >, boost::spirit::strlit >, boost::spirit::parser_context >, boost::spirit::subrule_list<2, boost::spirit::sequence, boost::spirit::subrule<1, boost::spirit::parser_context > >, boost::spirit::parser_context >, boost::spirit::subrule_list<1, boost::spirit::kleene_star, boost::spirit::eol_parser>, boost::spirit::difference > >, boost::spirit::parser_context >, boost::spirit::nil_t> > > > > >, boost::spirit::subrule_list<0, boost::spirit::action<1, boost::spirit::parser_context >, boost::spirit::subrule<2, boost::spirit::parser_context > >, boost::spirit::subrule<3, boost::spirit::parser_context > >,boost::spirit::subrule<4, boost::spirit::parser_context > >, phoenix::actor
<0, phoenix::closure, std::allocator >, phoenix::nil_t, phoenix::nil_t> > >, phoenix::actor
, std::allocator > >, phoenix::actor
<0> >, phoenix::actor
<1> >, phoenix::nil_t, phoenix::nil_t> >, phoenix::nil_t, phoenix::nil_t> > >, boost::spirit::parser_context >, boost::spirit::subrule_list<5, boost::spirit::optional, boost::spirit::chlit > > >, boost::spirit::parser_context >, boost::spirit::subrule_list<4, cpp::private_stuff::CHARACTER_LITERAL, boost::spirit::parser_context >, boost::spirit::subrule_list<3, boost::spirit::contiguous, boost::spirit::subrule<5, boost::spirit::parser_context > > >, boost::spirit::parser_context >, boost::spirit::subrule_list<2, boost::spirit::contiguous, boost::spirit::positive > >, boost::spirit::subrule<5, boost::spirit::parser_context > > >, boost::spirit::parser_context >, boost::spirit::subrule_list<1, boost::spirit::contiguous, boost::spirit::inhibit_case > >, boost::spirit::positive >, boost::spirit::subrule<5, boost::spirit::parser_context > > >, boost::spirit::parser_context >, boost::spirit::nil_t> > > > > > >, int ID = 0, ContextT = boost::spirit::parser_context]â


Jan 7 2009

Atlas/Lapack issue

Just a quick note if you run into an error like the one below…

$ ./bla
./bla: symbol lookup error: /usr/lib/sse2/atlas/liblapack.so.3gf: undefined symbol: _gfortran_pow_r8_i4
# dpkg -l | grep atlas | awk {’print $2′} | xargs apt-get remove –purge -y

$ ./bla
Hello world!