The traditional Team Picus approach to robotics tended to be along the lines of 'make a base, attach components to that base, and then attach top armour', which had some problems - most notoriously, the absence of any side armour, which presented issues with horizontal spinners in particular. During my leave of absence in Canada, I'd been thinking about how to overcome this, and S. D. F. was ultimately designed as a test of a new philosophy - instead of no sides, there would be too much sides, with thick side bars to which everything else was attached. This would allow me to use lighter materials for armour, as the entire robot would be stronger, and open up a wider variety of designs for the future.
Unfortunately, designing was one thing and execution proved an entirely more complicated process - making the aluminium/carbon fibre composite armour panels was easy, but even with the assistance of Harry Hills to make the thick sides, drilling straight and tapping was something I still hadn't fully understood, and my first attempt at the robot proved that my entire design process had been backwards in that I should have got the sides done first, before anything else. "S. D. F. G. T. I." - as it ended up being dubbed as the top didn't fit! - had been designed around M2 bolts but used M2.5 due to incompetence (I didn't know M2 required a 1.6-1.7mm hole rather than 2mm) and was badly assembled, slow, weak, and a very tough learning experience, losing all its fights at AWS 45.
I was determined going into 2015 to do better though, and - having got Harry to do all the holes this time, due to lack of a pillar drill - the new sides, made of quarter inch thick aluminium bar, worked far better, with the only bit carried over from the previous version being the electronics and motor mount bolts. S. D. F. proper was built over three weeks in March 2015, being finished well before the event but requiring some weight saving surgery - the visible evidence of this being nylon bolts and a hole cut in the composite top panel - and was an improvement in every way. Good looking, nimble, well balanced, fast, resilient, and surprisingly competitive, S. D. F. made the top 16 at AWS 46 in Reading, albeit with a lucky draw, and impressed a few people with how clean and simple it looked. I wasn't so lucky in subsequent events though - it went out early in both Caerphilly and Somerset (although in the former event it did have the slight handicap of having a large camera mounted on top of it). Against ExuberANT in Somerset, it even managed to get stranded on its side - a problem that really could have been fixed with side spikes, were the weight available - and some radio reception problems experienced due to the all-metal and carbon construction led to an external aerial being added, which got in the way of running upside down.
These lessons got incorporated into S. D. F. II (see below), but the only thing the two robots share is a basic design, allowing me to run both the old and new versions simultaneously. It's now been a full year and, new aerial aside, S. D. F. has needed hardly any maintenance, showing the basic resilience of the robot well. The plan is to carry on until something breaks irreparably, which might be a while...
The plan for S. D. F. II was a simple one; take the simple, proven (sort of) design of S. D. F., and improve on it with lighter sides, therefore allowing for more armour on the vulnerable front and back. I'd made the acquaintance of Kcut, a waterjet cutting company favoured by many in the roboteering community who happen to be based just over the Lune from where I live, and for very little money had managed to get the side panels for S. D. F. II and Jigsaw 64 watercut from 5mm Nylon 6, which weighed about a quarter of the previous aluminium panels. I had some grade 5 titanium front and rear panels cut at the same time, but had also ordered some 1mm stainless steel, just in case my weight calculations were correct, for once, and I came in well underweight!
As it happened, mechanically the construction of S. D. F. II was one of the easiest I'd experienced - the waterjet parts fit perfectly, and with the aid of a mini pillar drill the chassis went together in virtually no time at all, with the only real problem being that as I was sticking with composite top and base panels, and Harry Hills had kindly donated some 24h Araldite, I had a sleepless night babysitting them as the epoxy holding the carbon fibre on dried...electronically, though, it suffered from the same problems that plagued Jigsaw 64, as two of my speed controllers expired in quick succession. Having decided a couple of days before AWS 48 to focus on S. D. F. II, the only controller I had remaining, spare and working was a Scorpion HX, which weighed about 20 grams and was the size of eight Roryboards! Nevertheless, it just about fit inside, so with the aid of plenty of tape, S. D. F. II was running.
It was an inauspicious start for the new robot, as it won only one fight in Basingstoke, and that fight was plagued by the speed controller having a minor stroke and limiting me to forwards and backwards motion for much of it - I was very lucky Tom Baker's robot had an even worse control problem, and found the pit more or less of its own accord! At Ant Freeze III though, S. D. F. II fared far better, taking on and beating Why Wait and Test Robot Please Ignore more or less single handedly during the annihilator and suffering only a warped panel from the latter, as well as winning a few fights in the main competition before being caught in the arena floor! The future is so far looking bright for S. D. F. II - and not just because the Scorpion has green lights for forwards and red lights for reverse...