This was part of my 3rd year engineering group project to design a semi-autonomous wheelchair. Above is the SLAM simulation I produced in MATLAB using the Extended Kalman Filter. The implementation generates two motion estimates from laser scan matching and wheel odometry. The resulting pose estimate is a weighted average of the two estimates, which takes into account their relative uncertainties. The update step uses artificial landmarks such as RF beacons placed around the environment for pose correction. The diagram below summarises the system:

The code can be downloaded from the link below. Beware that it’s a bit messy and wasn’t produced with efficiency in mind.

Download Code

Alternatively if you use Git then you can clone the repository from GitHub using the command:
git clone https://github.com/jaijuneja/ekf-slam-matlab.git

Run the setup file to get started and you should be good to go!

UPDATES

• 08/12/2013 – Added a setup.m file to overcome the issues people have been having with setup.
• 03/10/2014 – A number of commenters noted that they were getting the error “Undefined function ‘pdist’ for input arguments of type ‘double'”. Andrew has kindly informed me that the error arises if you don’t have the statistical toolbox installed for Matlab (this comes pre-installed with the student edition). If you don’t want to buy/install the toolbox, you can manually download the pdist.m and pdistmex.cpp files, place them in the root folder of the SLAM program, and compile pdistmex.cpp into a MEX file for Matlab. There seems to be a version of these files at this link.

The web designers over at RocketTheme have done a fine job in making their free Afterburner template for phpBB, and I’m very grateful for all the open source scripts they provide. However, I encountered a number of fairly basic, yet fundamental bugs whilst using the template – all very easy to fix. Since RocketTheme require that I pay a minimum of $50 to register on their forums, I’m going to be a cheap-o and post the bug fixes here. Hopefully they will be of use to anyone using the template.

Warning: backup all files before performing any changes! Continue reading »

Taken during Matriculation.

The aim: look as ridiculous as possible.
The result: success!
Note: if you haven’t seen the original shot, Google Image “Bullingdon Club” and it’ll probably be the first result.

Here’s the latest article I wrote for the Cherwell (student newspaper) on extraterrestrial life.

Linkage

Life as we (don’t) know it

Planet Earth is under attack. Disc-like UFOs litter the night sky, radiating vertical beams through which silhouetted creatures descend. You clench onto your seat. It’s the movie’s climax: a fiery scene of human destruction and alien triumph. The orchestral music reaches a roaring crescendo and all too soon the film is over. But as realistic as CGI effects might be nowadays, there’s a reason they call it ‘science fiction’.

We often turn to sci-fi movies as a means of escaping from our comparatively mundane lives. But the question of extraterrestrial life is, to me, the greatest unsolved problem of science. Could it really be that, within the seemingly infinite expanse of the universe, our home is the only planet with the ingredients for life? If technologically advanced beings are ‘out there’, then why have we not found them? Continue reading »

‘The Maudy Dukes’ is a comedy group created in Balliol College, Oxford. This is a promotional poster I made for them, with the original photograph above it. You might be able to tell that I used some similar techniques in making this poster as I did in the Sin City edit.