"Robot Of No Name Yet"
| This is our first ant-weight robot:
"Robot Of No Name Yet" |
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Build Diary
2002
2003
2004
2005
2006
2007
2008
2009
3 January 2004
Reading Robot Club. Still sporting front end damage from AWS12 and held together with double-sided tape, R.O.N.N.Y. went out in the first round, but managed to win the loser's melee.
January 2004
Time to start on a new bodyshell... A wooden pattern was carved out of balsa wood. The biggest balsa we could find was 2" x 2", so two bits were glued together. The shape is basically the latest R.O.N.N.Y. shape with all the edges rounded off, which will hopefully make it less vulnerable to spinners. The pattern was skimmed with filler and sanded to get rid of the woodgrain effect, then given several coats of varnish to seal it and give a really smooth finish.
A two-part mould would be necessary, with a split line running front to back. After much head-scratching, the obvious simple solution was to use a cardboard barrier and make one half of the mould, remove the cardboard and make the second half of the mould by moulding up to the first half!
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Three layers of fibreglass were used for the mould, with a nice big lip along the split line to allow the two halves to be securely bolted together. Petroleum jelly was used as a release agent, and seemed to work fairly well, but the varnish was a quick-drying water-based type which seemed to be attacked by the resin. The cardboard divider was simply covered with self-adhesive tape which was fine, so when the second half mould is made the pattern will be covered in tape. |
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21 February 2004
| AWS13 - Brighton. Unfortunately the cold weather had put a stop to progress on the new bodyshell, so R.O.N.N.Y entered AWS13 with a rather hastily-rebuilt body using some rather tired polycarbonate panels and plenty of Araldite! During the rebuild I had tried to "speed hack" the Naro HP/BB servos to give more speed. Unfortunately, this reduces the torque to such an extent that any friction in the system stops the wheels dead. My mechanical skills are such that R.O.N.N.Y was left thoroughly unreliable, and despite working fine in numerous kitchen table test-drives it refused to work on the day! Hence another hurried strip-down to put the original gears back which fortunately worked fine. So R.O.N.N.Y entered the arena looking in perfect health... |
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R.O.N.N.Y progressed to round 3 where it met Chimera, a walker with a front spinning disc. R.O.N.N.Y got cornered by the disc and here are the results! Eventually we surrendered when the receiver was totally unprotected and looking like the next thing the disc was going to hit. It was not until we picked up the pieces that we realised the aerial wire had been cut through just 15mm from the receiver. A close shave indeed!
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Here is R.O.N.N.Y with the five pieces of armour smashed off by Chimera, and the aerial which was cut off and in fact cut into four pieces where it was coiled up. The strip of balsa was the stiffening spine for the flipper. Several other small pieces of balsa simply disappeared into splinters. |
| Here is the new front view, showing how exposed the receiver was by the end. In fact, the receiver had been pulled forward by the aerial wire and was even more vulnerable than these pictures show! |
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From the side views you can see how much of the armour is missing. All of the left side front panels were torn away, the 5mm overlapped epoxied joints were just not strong enough. |
| The flipper did have some nicks in the edge from previous encounters with spinning weapons, but Chimera has clearly ripped the 25mm wide, 1mm thick flipper in half. The edge also got fairly damaged further up (top left of picture), at the point where the adjacent panel was torn off! |
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The force of the impacts on the flipper arm even bent the pivot pin which is 1mm steel piano wire. Given the relative sizes of everything (the flipper is 25mm wide, the brass angle is 3mm) I think the forces involved must have been quite high to say the least! At least the "patented" wire staples held the flipper arm to the brass angle ... that just meant something else had to give! The flipper servo was also torn from its mountings, but it was only glued to some balsa wood so maybe it's not too surprising it gave up. |
So now R.O.N.N.Y. really does need a new bodyshell ... Time to get moulding the carbon fibre.
April 2004
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At last time and reasonable weather allowed the second half of the mould to be made. Unfortunately it proved extremely difficult to get the moulds off of the pattern as they had stuck firmly together. In the end I resorted to the hacksaw and found that the problem was resin running under the first half-mould sticking the moulds to each other and the pattern. Eventually it all came apart and the moulds were at least usable if not perfect. 4mm screws and nuts hold the two halves together. The mould was lined with self-adhesive tape to cover the gap left by the saw and prevent the carbon-fibre sticking to the mould. |
May 2004
| Finally I got a chance to attempt the carbon-fibre shell. The front consists of about 3 layers of cloth, the rest is mostly 2 layers but it was all a bit hit-and-miss due to the slightly awkward shape and my inexpert moulding techniques! After curing for a day or so in the garage, it was time to see what had happened. With some persuasion and a bit of a struggle the two mould halves came off and the shell looks fairly respectable. The photo shows it straight off the mould, the edges need trimming and holes need cutting for wheels, flipper etc. The front is going to remain solid to keep its strength. There will be a hole in the top for the flipper hinge and linkage, then the flipper will lay over the top of the bodyshell. |
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June 2004
| With the 3rd Reading Robot Club meeting looming, and with it the only chance to test the carbon fibre before AWS14, it was time to put R.O.N.N.Y. back together. The flipper design is proving slightly complicated and a "bomb-proof" flipper will take some time to build. The decision was taken to run R.O.N.N.Y. as a pusher at RRC. With the flipper servo, but without a flipper arm or linkage, R.O.N.N.Y. is only a few grams under 150g. A lighter chassis material is required, since the current fibreglass (PCB material) chassis won't take many more holes... These pictures show R.O.N.N.Y. looking fairly mean'n'moody, only the logos still to add. |
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| R.O.N.N.Y. proved to be a bit of a toothless wonder without the flipper! RRC only provided a minor encounter with Cannon Fodder but the carbon fibre shell stood up well. The next objective was to add the flipper mechanism to return R.O.N.N.Y. to full strength. First a lighter chassis was required. A recycled PYO strawberry container proved a useful source of "Coriflute" which gives a fairly rigid base for next to no weight. All of a sudden 15g or so was available for the flipper arm. The flipper was fabricated out of 1mm aluminium. The hinge pin is an M2 screw. The fixed parts of the hinge are 1mm polycarbonate pieces which feed through holes in the top of the carbon fibre body and are epoxied in place inside the body. The polycarbonate inside the body is much bigger than the hole, so it cannot possibly pull through even if the glue fails. The only way this hinge will fail is if the screw pulls sideways through the polycarbonate. Hopefully this flipper really is spinner-proof! R.O.N.N.Y. is now almost 10g underweight, so if the polycarbonate hinge parts should fail, there is weight available to go to an all-metal construction... Meanwhile, here are the pictures of R.O.N.N.Y. complete and ready for AWS14. |
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Last updated June 2004
Email us at gary.aylward@ntlworld.com