motters is currently certified at Master level.

Name: Bob Mottram
Member since: 2002-06-08 19:03:04
Last Login: 2011-06-22 18:40:53

FOAF RDF Share This

Homepage: http://sluggish.homelinux.net

Notes:

I'm a self-styled robot addict living in Sheffield, England. Over the years I've built a couple of humanoids, and am mainly interested in building 3D occupancy grids for mobile robot navigation using SLAM algorithms and stereo vision.

Projects

Recent blog entries by motters

Syndication: RSS 2.0

Fitted a D525MW mini-ITX motherboard to the robot, and installed Linux Mint 11 and ROS onto a 16GB USB flash drive.

https://sluggish.homelinux.net/wiki/File:Mini-itx1.jpg

This makes a good minimalist onboard computer, and was considerably cheaper than buying an equivalent netbook. To set everything up I connected a keyboard, mouse and monitor as usual, but once the motherboard was installed on the robot it only requires the wifi adaptor and USB drive to be connected. I deliberately didn't want to use a hard drive (although I have a couple of old ones available) based upon bad experiences with mobile robots and hard drives in the past. Also I reused some old PC speakers which havn't seen the light of day for probably more than a decade. You never know when such things may come in useful.

https://sluggish.homelinux.net/images/f/f2/Grok2_electrical2.jpg

One trick with running the OS from a flash disk is to delete the existing casper-rw file, then create a partition labelled casper-rw. This enabled me to make use of the full USB drive, rather than being limited to 4GB of persistent storage.

The user interface of the robot currently consists of buttons and audio. When you press buttons the robot says something appropriate, so it's not so much a graphical user interface as an audio user interface. For the sorts of tasks I envisage the robot doing this is quite adequate, although if more elaborate instructions were needed I could add a small screen of some sort (finances permitting).

With the robot running I can then use either VNC or ssh to debug code or run different programs.

There's some tidying up remaining to be done on the head of the robot, Since the Kinect sensor's circuit boards are exposed and vulnerable to collisions. I'll devise some sort of covering to go over that.

An initial localising test run done earlier today indicates that everything seems to be working as expected, and the new computer can handle the processing demand. Even for a relatively simple differential drive robot like this there are a considerable number of electrical connections, and there's always some degree of trepidation over whether I've connected them back in the right order. Labelling everything helps a lot.

13 Jun 2011 (updated 13 Jun 2011 at 11:59 UTC) »

After a day of hacking, bashing and drilling I've slimmed down the GROK2 robot, reducing its width by 40mm on either side. This robot has an AL-101 chassis (Zagros robotics) and fortunately it's made from 3mm aluminium, which is just about sawable with some exertion.

This should give the robot more clearance when passing through doorways. It's still wide enough for a netbook, mini-itx or even a full sized motherboard but it's no longer wide enough to carry the laptop - at least not in the usual orientation.

It's always been in the plan to eventually have some permanent onboard PC, and at present it looks as if netbooks are just not quite up to the job unless they're the latest and most powerful devices (which are expensive). So I might have a go at installing a mini-itx, which are much cheaper than a high end netbook. I could then use a laptop or netbook to ssh into the robot. I have a couple of spare SATA hard drives which could be used, and also a couple of USB wireless adaptors. Another advantage of the mini-itx boards is that they can be run off of a 12 volt supply, which avoids the wasteful DC->AC->DC conversion.

All in all the future for robotics is looking very good, particularly for low hanging fruit applications, such as fetch and carry or just hawling stuff around. I think it would be quite feasible to build a prototype shop/supermarket shelf stacker robot, and also to add an autopilot feature to mobility scooters or wheelchairs.

9 Jun 2011 (updated 9 Jun 2011 at 23:07 UTC) »

It has been a while since my last blog entry here. As far as ambient events are concerned I continue to be an unemployed software engineer, with the prospects of re-employment looking increasingly remote, but in terms of robotics projects things are going very well indeed. In the last six months using ROS and the Kinect sensor I've made more progress than I'd made over the previous five years of SLAM and stereo vision development.

The GROK2 robot is now navigating well from one room to another. Tuning the localisation parameters took a while, but now the movement looks quite smooth and decisive. I've been able to have the robot navigate reliably to various locations in the kitchen, such as sink, kettle and table. It doesn't have any arms presently, but if I can get some object recognition going then adding an arm would be the next logical step. It's easy to become complacent, but the current level of navigation performance was, until only a few months ago, merely a vague ambition somewhere in the future.

One problem is that it looks as if the robot in its current form is just too wide to get through one particular doorway. This might mean that I need to do some mechanical hacking to thin it down a little and provide more clearance. The small amount of clearance currently available is just too narrow to realistically expect the localisation to be able to handle it reliably. As part of the redesign I may also add a dedicated onboard PC, rather than using a laptop.

Using this sort of system with a PC of some description and RGBD sensor the prospects for robotics over the next decade look far better than at any previous time. 2011 is probably going to be a watershed year in which both the software and the sensor technology became good enough for break-even navigation at a reasonable cost.

I've now added a Kinect sensor to the GROK2 robot, which is described here:

http://streebgreebling.blogspot.com/2011/01/grok2-kinect.html

I think that 2011 could be quite an exciting year for robotics, with some real progress being made on age-old problems.

I havn't done very much by way of a write up on the GROK2 robot so far, so here is some explanation of the story to date.

http://sluggish.homelinux.net/wiki/GROK2

The robot is still quite static, although it can be driven by joystick. The next stage is to create a URDF model and try out some of the ROS mapping/localisation to see whether it's suitable for use with stereo vision. From the navigation stack's point of view it shouldn't care what sensors are being used, since all it will be seeing is point cloud data.

80 older entries...

 

motters certified others as follows:

Others have certified motters as follows:

[ Certification disabled because you're not logged in. ]

Robot of the Day

Cronos2

Built by
Edward Rupp

Recent blogs

30 Sep 2014 shimniok (Journeyer)
21 Sep 2014 mwaibel (Master)
5 Aug 2014 svo (Master)
20 Jul 2014 Flanneltron (Journeyer)
3 Jul 2014 jmhenry (Journeyer)
3 Jul 2014 steve (Master)
2 Jul 2014 Petar.Kormushev (Master)
10 Jun 2014 robotvibes (Master)
10 May 2014 evilrobots (Observer)
2 Mar 2014 wedesoft (Master)
1 Dec 2013 AI4U (Observer)
13 Nov 2013 jlin (Master)
23 Jun 2013 Mubot (Master)
13 May 2013 JLaplace (Observer)
21 Apr 2013 Pi Robot (Master)
12 Apr 2013 Pontifier (Apprentice)
16 Mar 2013 gidesa (Journeyer)
12 Mar 2013 ixisuprflyixi (Master)

Newest Members

Newest Robots

7 Aug 2009 Titan EOD
13 May 2009 Spacechair
6 Feb 2009 K-bot
9 Jan 2009 3 in 1 Bot
15 Dec 2008 UMEEBOT
10 Nov 2008 Robot
10 Nov 2008 SAMM
24 Oct 2008 Romulus
30 Sep 2008 CD-Bot
26 Sep 2008 Little Johnny
X
Share this page