Frantic Finale!

Apologies for the lack of updates, life got in the way a bit. But time for one final update as we reach the finish line ready for Robot Wars! I may have to split this over two posts if I reach the photo limit.

So last time, we'd relocated to Aberdeen, made some progress and shot our VT. At this point we had three-and-a-half weeks to get the robot finished and in a working condition.

Expansive to-do lists were a common feature at this point, and one of the main outstanding items remaining was to make outriggers. These would be needed to stop the robot tipping forward when trying to lift an opponent, helping to maintain traction between the wheels and the floor. Due to a whole heap of variables that hadn't been determined at the time of the CAD design of the front jaw assembly, the outriggers weren't incorporated into the plasma cutting process so had to be designed, fabricated and fitted by hand. The process started off with getting a rough shape from holding a piece of cardboard up to the side of the robot to work out angles and shapes. Once we were happy with the look, they were transferred to metal:

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We then clamped the pieces to the robot to check the fitting before continuing with the fabrication. The outriggers would have to double up as mounting points for the armour panels as, again, these weren't designed in CAD. By this point, any new work on the robot was being done ad hoc. We also realised that the two outrigger plates that would be the outermost panels on the left and right would have to have an extra crescent shape cut out of them to let us slide the wheels on and off without having to unbolt the jaw assembly every time. In addition to this, they needed some bracing plates across their width to try and stand up to horizontal spinner (cough, Carbide) attacks. Finally, to reduce the friction between the outriggers and the floor when lifting a robot thereby not impairing our ability to drive, we decided to fit Nylon blocks to the base of the riggers. When you put all of that into a picture, it looks like this:

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Who needs CNC? All cut and shaped by hand with a grinder, all holes marked by hand and drilled on a pillar drill. Without blowing my own trumpet, I surprised myself a few times during the build with what could be achieved by hand with some care, precision and effort.

The outriggers then had to be welded on to the front jaw assembly, and once they were, we could test they worked properly:

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What a relief that was! I was worried about the ability of the actuators to lift heavy weights and while I'm only 76kg, it didn't appear to struggle too much so I was confident in its fighting capabilities.
The eagle-eyed among you may also notice bike tyre screwed to the wheels. Having had problems with the same tyres on PP3D in Series 1/8, which were solved with bike tyre, we opted to go straight to that solution before even being near the arena. It also helped to give the robot a slightly more industrial look.

With robot builds, getting the big things out the way is important, but often the little things take up just as much time or are easy to forget. Another thing to tick off the list was power LEDs. We opted to go for 12V orange LED strips (not as easy to find compared to the standard colours!) which were mounted in the underside of the top jaw. We put a thin layer of polypropylene over the eye holes to diffuse the light and give a menacing glow. Looked great in a dark room but we found during filming that it was easily washed out by the studio arena lights, so wasn't that effective in practice:

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Another LED feature that didn't really get covered on the show was a couple of RGB strip LEDs running down the back panel of the robot. The original plan for these was both to try and convey the 'mood' of Coyote and to double up as a rev indicator for the chainsaw (dim being low revs, bright being high). Rachel created the circuitry for them using an Arduino and bluetooth module which allowed the LEDs to be controlled from a phone app, giving a full range of colours and intensity. Again in practice and the heat of battle, it proved difficult to match the LEDs to the situation, so they became primarily aesthetic:

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Before starting work on cutting the armour panels, which were to be a 5mm steel sub-structure with 10-20mm HDPE on top, we stuck everything we had on the scales to see where we were sitting:

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Talk about close! Thankfully the wooden board we put on the scales to increase the surface area weighed 6kg so that, along with weighing full sheets of material but knowing we wouldn't use it all, meant we should be comfortably in weight. Fingers crossed!

We cracked on with the armour. The steel plates took the longest to cut and shape as they were pretty large and a bit awkward, though the brackets to mount the armour to the chassis at the rear were equally as time consuming despite being a fraction of the size. Nevertheless we managed to get them done, as well as knock together a top panel of aluminium and angled HDPE. Nothing great, certainly not Thor or Terrorhurtz proof, but it would give us protection at least. Pretendo-bot time:

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Adding these panels gave a sense of scale to the robot previously missing. Coyote's on the small side, especially when it's sharing a garage with PP3D, but finally it looked like a heavyweight robot size wise! I couldn't help but grin when looking at the robot like this. Still a long way to go though.

I've reached the picture limit so will continue this in another post below.