Using the brown-ros-pkg driver for the Creates we've found the odometry to be good enough that gmapping/amcl can handle the error (with the shorter range URG-04LX-UG01 lidar). However, I can't say we've gone more than maybe an hour during any particular run. (also, just a note, I can't seem to find the reference anywhere, but I seem to recall the Create encoders being 26 cpr of the drive wheel) Mike Ferguson ILS Social Robotics Lab SUNY Albany On Sat, Dec 4, 2010 at 3:18 PM, Ken Conley wrote: > 2010/12/4 Gonçalo Cabrita : > > out. Also the Create can have that green block, the Command Module that > I > > believe can be used to connect a bunch of stuff that can be accessed over > > the iRobot OI protocol. > > We ended up not using the Command Module. To the best of my > understanding, it's meant to be used as alternative to mounting your > own laptop. The OI protocol appears to be disabled whenever the > Command Module is connected. > > > Still, bottom line, if the Roomba's odometry proves to be better I would > go > > for the Roomba. However that ROS vision odometry stack could solve the > > odometry problem if one could use a cheap one camera system (at the > expense > > of extra computational power, which in our case is really bad since we > have > > tiny EeePCs!!!). > > We've thought about trying the Neato XV-11's instead -- they're more > expensive, but you get LIDAR. However, they don't sell stripped down > units nor publish their documentation like iRobot does, so we're going > with the Creates for now. > > - Ken > > > Gonçalo Cabrita > > ISR - University of Coimbra > > Portugal > > On Dec 4, 2010, at 7:22 PM, Ken Conley wrote: > > > > FYI: We're starting an effort here at WG to use Creates. We didn't > > benchmark against the Roombas, and perhaps some of those will end up > > in our arsenal as well. Also, we've noticed Gonçalo's great > > documentation coming online, so we hope we can build on each other's > > efforts. We're using it to integrate some of our main libraries > > (navigation, OpenCV, PCL) into a low-cost platform. We've already > > posted our Kinect + Create tutorial, which is part of this effort. > > > > One main difference between the Creates and the 500 series is (IIRC) > > that you can't read the raw encoder counts off the Create. The Open > > Interface for the Create only goes up to Packet 42. The 500 Open > > Interface adds Packets 43-58, which include encoders, light bumper, > > motor currents, and stasis caster. I assume this means the odometry > > with the Create will be worse, but, like Gonçalo, I don't have > > experience with both. > > > > Our driver right now is in Python and uses Damon Kohler's PyRobot, > > plus bits and pieces for other ROS drivers. The stack is still a work > > in progress and will move soon, but for now you can find it here: > > > https://code.ros.org/svn/ros-pkg/branches/trunk_cturtle/stacks/create_robot/ > > > > - Ken > > > > 2010/12/4 Gonçalo Cabrita : > > > > Hi Alex, > > > > Hope you don't mind I started a new thread for this. > > > > Buying the Roomba instead of the Create was not an option for us. At > first > > > > we were aiming for the Create since it was designed having research in > mind, > > > > but the Portuguese iRobot reseller told us we could only acquire the > Create > > > > on the United States. So we got a sweet deal on a bunch of Roombas > instead. > > > > Let it be clear that I never worked with a Create in my life, so I cannot > > > > make a comparison between both robots. > > > > When we first got the Roombas we had some trouble with the odometry... ok > a > > > > lot of trouble! The Roombas have very poor encoders, single channel, 4 > > > > pulses per motor shaft turn (I believe direction is determined from the > > > > motor speed, I don't think you can even call this an encoder). Also, > > > > initially we were getting distance travelled and amount turned from the > > > > robot, which resets after each read, so at the speed we were polling the > > > > Roomba (10Hz) and due to the low resolution on these values (1 degree for > > > > the angle for example), we were getting really bad odometry readings. > Later > > > > we decided to poll the encoder counts instead, which greatly improved our > > > > odometry (this is how the roomba_500_series package works) however we > bumped > > > > into another problem. Usually encoder counts increase as the wheel moves > > > > forward and decrease as the wheel moves backwards. However on some > Roombas > > > > encoder counts only increase. You can still make a quick fix using the > motor > > > > speeds as an indicator of the wheel direction, but the odometry on these > > > > robots is far worse. Now that i think of it, this should go into the > > > > roomba_500_series troubleshoot section! We recently got a batch of 555, > non > > > > of them seem to have this problem. However some of the 530 and 560 we > have > > > > suffer from the "crappy" encoder problem. > > > > Globally the Roomba is a very robust platform, it can take a lot of > beating. > > > > It also brings a nice package of sensors and actuators. iRobot 's > > > > documentation on the communication protocol is very good, you get access > to > > > > pretty much everything the Roomba has. The docking station is very cool, > we > > > > love it. The battery usually holds for 2-3 hours pumping juice to the > Roomba > > > > and an Hokuyo laser. We run it with the ROS navigation_stack and it moves > > > > without problems > > > > Finally I guess for the money we spent we couldn't expect better, the > value > > > > for money is great, specially for us, we have a lot of Roombas for swarm > and > > > > multi-robot experiments. You can't compare it to a robot designed > > > > specifically for research though. > > > > Now I guess people who are using the Create could give their opinion on > this > > > > matter :) > > > > Hope this helps! > > > > Gonçalo Cabrita > > > > ISR - University of Coimbra > > > > Portugal > > > > On Dec 4, 2010, at 6:01 PM, Alex Bravo wrote: > > > > Goncalo, > > > > I've been looking at the package you created for Roomba > > > > 560 http://www.ros.org/wiki/roomba_500_series > > > > and I just wanted to say thank you for such an excellent job! > > > > We are considering purchase of iRobot and wondering if extra expense of > > > > Roomba 535/560/570 is worth it compared to iRobot Create. We also see > that, > > > > say Brown University still uses iRobot Create. > > > > Considering your experience (if I remeber correctly, you were mentioning > > > > those robots a year ago), what are you thoughts on the > > > > advantages/disadvantages between those models? > > > > Thank you, > > > > Alex Bravo > > > > _______________________________________________ > > > > ros-users mailing list > > > > ros-users@code.ros.org > > > > https://code.ros.org/mailman/listinfo/ros-users > > > > > > _______________________________________________ > > ros-users mailing list > > ros-users@code.ros.org > > https://code.ros.org/mailman/listinfo/ros-users > > > > > > _______________________________________________ > > ros-users mailing list > > ros-users@code.ros.org > > https://code.ros.org/mailman/listinfo/ros-users > > > > > _______________________________________________ > ros-users mailing list > ros-users@code.ros.org > https://code.ros.org/mailman/listinfo/ros-users >