Hi! We just recently purchased a Roomba 555 + Turtlebot equipment and have been asking ourselves why the odometry is so disappointing. A quick measurement resulted in an error of +2 meters on a 2 meter run (!). Obviously, this renders the robot unable to create usable maps. Goncalo, you stated in your initial post that you encountered a similar problem with a couple of Roombas. Did you manage to solve it? Is it likely to be a production failure? kind regards, Máté 2010/12/5 Jenkins, Odest Chadwicke : > I do not really think there is much difference between using the > Roomba and the Create.  We have used the Create and a number of > variations on the Roomba over the last 5 years.  Translating between > the two open interface descriptions is relatively simple. > > I believe the Create is a better bargain because the Roomba incurs the > extra cost (and weight) of a vacuum.  The 25-pin port is also nice for > powering onboard computing.  The additional wheel on the back of the > Create is useful for keeping the base steady.  All of this said, both > platforms have performed well for our needs. > > It is disappointing that iRobot does not sell the Create in Europe. > > I think the real question now is using the Create/Roomba versus the > Neato and other next gen vacuums: > >  http://www.engadget.com/2010/11/29/neato-xv-11-robot-vacuum-gets-its-very-own-open-source-lidar-hac/ > > -Chad > > Date: Sat, 4 Dec 2010 11:22:15 -0800 > From: Ken Conley > Subject: Re: [ros-users] iRobot - Roomba vs Create > To: User discussions > Message-ID: >       > Content-Type: text/plain; charset=ISO-8859-1 > > 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 Gon?alo'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 Gon?alo, 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 Gon?alo 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! >> Gon?alo 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 >