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Nick
Experienced Roboteer
Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW
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It might not be the best or only way to promote the sport, but I have organised some definite action. I am writing up a multi-part construction story for Servo Magazine, featuring a simple 4WD wedge bot. That might not sound so useful over here In Australia, however all the blueprints, parts lists, weight calculations, etc will be online on our web site - there may also be some of the editorial or extras as well.
Having a design published in a magazine gives it MAJOR cred with schools & TAFE - we can really use that as a promotional tool.
The design is based on Mitch, the very simple yet effective wedge put together by Ray and the guys at Hardcore Robotics:
With a 7Kg Bisalloy wedge, shock mounts and 25mm thick aluminium sides, this bot will take an absolute pounding! If anyone would like to contribute ideas for the design, I'm all ears. Suggestions for getting bargain parts, solving construction problems will all be gratefully received and credited.
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Mon Dec 28, 2009 5:18 pm |
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Nick
Experienced Roboteer
Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW
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True, steel is cheaper than aluminium. The idea with the frame is to have something that will stand up to spinners and have a real chance of winning matches, even events. Mild steel box & angle is too easily carved up by spinners nowadays and if it was welded for strength, builders would end up replacing their frame too often IMHO. Aluminium is very easy to work with and a bolted frame can be repaired easily. I'm not exactly going for the lowest budget, more ease of assembly. That means using commercial parts from places like the RMP, Banebots, Kitbots etc. Interestingly, a set of 4 gearboxes, mounts, hubs and wheels is $78 USD cheaper from Banebots than drill motors from Kitbots - not what I was expecting!
I forgot to mention that the bot will have two build tracks; a premium and basic versions. The basic one will have less machining and cheaper parts where possible. There will definitely be discussion on why particular design and material choices were made, along with engineering topics like avoiding stress risers and practical stuff like tapping holes. If you liked Grant Imahara's excellent Kicking Bot book, this will the the more focussed and abbreviated version
Re controllers: Since its a 4 motor design, I can't see the XXL as a practical choice. A pair of Victors would be my first choice, followed by a sidewinder. If the Firecrackers ever get released, then they might fit in between these two. Any other ideas for a tough controller in that class?
Unfortunately, I can't do a build thread on this one, it has to appear in print first.
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Mon Dec 28, 2009 6:06 pm |
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Nick
Experienced Roboteer
Joined: 16 Jun 2004
Posts: 11802
Location: Sydney, NSW
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Budget = no idea yet, I only got the green light 2 days ago
Its easier to get steel than aluminium in Australia, but most other countries its fairly even and I have to appease a US editor. I'm hoping to have lined up a local source and places like TAFE can get materials we find difficult ( just read Glen's post, we will have to get an answer on the TAFE supply question)
The reason for picking aluminium has several good reasons behind it:
* Easy to work with (tapping, sawing, drilling etc)
* bolted design makes replacing parts easy & quick
* Better material choice than steel - see page 88 in the Riobotz book
I need to present a bot that I am really confident will survive a full event with only cosmetic damage, even if it comes up against a really tough spinner. Sure, steel bots like Cobra can do that, but its hardly something that a beginner can weld up.
The idea of this bot is to over-come two difficulties that many builders cite: the "Its too difficult" and the "Its going to break first time out" hurdles. I will try to keep the "its too expensive" hurdle as low as possible, but it WILL get sacrificed where necessary.
@ Glen: Thanks for the info on TAFE buying, I didn't know they had O/S policies like that. The problem with a small mild steel wedge running two drill motors and red wheels is that its going to get beaten almost all the time. I can still recall coming 2nd at the first bot event I went to - it was a total blast and definitely kept me going in the sport. If my bot had been smashed to bits in the first match, I might have moved on to a less exciting but safer hobby. Nowadays, I would need much more than a 5mm aluminium frame and a plastic wedge
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Mon Dec 28, 2009 8:26 pm |
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