GPS-controlled Autonomous Earth Driver

Mon, 30/07/2007 - 21:39 — balint

My major project for PHYS2601 'Computer Applications 2' in 2003. You can read the actual report (PDF) or report (broken Word-exported HTML), which details the design, electronics, firmware and testing.

Unfortunately after showing my supervisor, it took off into a brick wall. This was due to my using super-charged batteries and overriding the automatic speed control. The spectacular collision left all the components scattered over the concrete and fried my PIC. (Luckily not the GPS though, which was kindly lent to me by the Department of Surveying and Spatial Information Systems - many thanks to Dr Joel Barnes!) Thanks also go to: Dr John Smith for letting me pick his brain, Mick Benton for parts and Ashley "Mac-Man" Butterworth for the interest.

The MBasic source code that drives the AED is attached at the bottom of this page. Please read the notes at the top of the source file as it outlines hardcoded variables I used for testing - I couldn't be bothered typing in the same waypoints over and over again, so I put them in the source (sorry I haven't taken them out, but it should be pretty obvious). Also, I have included my MBasic source 'library' of very useful non-native math routines. These are: integer and floating-point square root (sqrt, fsqrt), and inverse trigonometric functions arctan, arcsin, and arccos (atan, asin, acos). I have included a comparison of numeric accuracy at the bottom of that source file.

In January 2007, I presented this project (though not its physical manifestation) at Dorkbot-Syd, which for that session was held at the Australian Centre for Field Robotics at the University of Sydney.

For the presentation I prepared a small slideshow to depict what happened on 'that fateful day'. The aerial photographs are of a car park at the University of New South Wales where I performed much of my testing. The yellow curves indicate the approximate tracks I would attempt to program into the car as waypoints.