Attitude Adjuster (Beetleweight)

[scott]

Made quite a bit of progress since the last update, so I have a lot to post here (evidenced by the fact I maxed out the images that I can attach ). Apologies that all the images are sideways :/.

I have access to a laser cutter that can cut perspex, so I made a drilling template for the side bulkheads, based on my CAD. I drilled out the holes for the side bulkheads and then used a Forstner bit to drill out the holes for the drive motors, making a satisfying shaving as they did so.

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I then added the threaded inserts to the back of the side bulkheads and drilled holes in the rear bulkhead using a similar method. However, the holes didn't quite line up so I had to use a Dremel and needle file combo to make it fit. Then I could fit the drive motors to the side bulkheads and attach the rear to the sides!

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Then I was ready to attach the front to the sides. I decided to use the "really long wood screws" approach, so drilled out pilot holes and then attached them.

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...And then I realised that the front was upside down. Oops. Anyway, I put the chassis on the right way up and attached the Fingertech foam wheels and had a rolling chassis to decorate the spare room.

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I decided to make use of the laser cutter to make a perspex prototype of the weapon bulkheads, again based on my CAD, so that I could see how the components all fit together. If only I could laser cut the HDPE and polycarb for the rest of the robot! I only had access to 3mm perspex so I had to make 3 layers per side. I jammed all the components inside the robot after putting together the perspex weapon bulkheads and realised that it's going to be a tight squeeze with the wiring...

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With the robot looking vaguely robot shaped, I was about to go on holiday for 3 weeks. However, before I left I decided to cut the polycarb baseplate using a mitre saw. This was a mistake, as the sheet of polycarb shattered, and bits went flying everywhere. Safety goggles are important, people. I learnt that I should've used a jigsaw to do this. Oops. This was the result.

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When I got back I focussed my attention on the baseplate. I again cut out a prototype in perspex, and duct taped it to the bottom of the robot. Again, if only I could do the rest of it in the laser cutter! I used that to cut out the real baseplate out of polycarb, using a jigsaw this time. I discovered I can't cut straight at all, but I've made it work for this. I decided to attach the baseplate using brackets similar to Fingertech's Nutstrip (https://www.fingertechrobotics.com/p...?prod=nutstrip). Sadly, this isn't available in metric, so I made my own. I had two bits of 6082T6 aluminium bar stock, which I drilled M4 holes at 12mm intervals. The first one seemed straight enough, but the second one went a bit wonky... I'll probably scrap that one and do it again.

I finally made enough to be able to cut it into strips small enough for me to attach the baseplate. I went for 6 bolts, 3 at the front and 3 at the back. While the weather outside was "taps aff", I was doing some tapping of my own. I eventually tapped enough brackets to be able to attach the baseplate. I now need to update my CAD to take these into account.

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Today I worked on the wiring. I made a wiring loom for the main wire, which includes a removable link. I stole the method of attaching the ESCs to the main battery from somewhere, but unfortunately I can't remember where. It involves crimping ring connectors and attaching them together using an M3 bolt and nut. I then put everything together and once again had something that I can scare the cat with.

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As I saw earlier, there isn't a lot of room to play with in there when you add in the wires, so I'm a little worried about that. One possible option if space is tight is to swap out the Sabertooth for Vex 29s or Botbitz 10a ESCs. A lot of builders seem to be wary of the Sabertooth, and it's a little bit big and heavy. For now though, I'm glad to have something robot shaped. Tomorrow is the last chance I'll have to do something uninterrupted, before I have to go back to work. I'm planning to tidy up the wiring and possibly try and do the weapon bulkheads. I need to finalise the design for that piece, or I might just start building and see what I end up with...