Ajax
Experienced Roboteer
Joined: 17 Jun 2004
Posts: 298
Location: Sydney
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Cutter Family - The War Lord - SA
This is a little story, that needs to be told about a little boy (not fiscally, just like’s playing with toys) that, one day, had a chat with his mate and was told about ‘RoboWars’ here in Australia.
He was given the web site and his brain started ticking.
All these thought came rushing at once, design concept’s, look, weapons, etc.
Therefore, the concept for a bot started.
Due to his job a concept design, specification & risk analysis was done.
First
, Write a scope of works.
The idea is to build a bot that is fast and cause’s massive amounts of damage.
In other words, everyone is too visible see the damage when it occurs.
The bot is not to be a back scratcher.
The bot has to be unique.
Second
, what are the possible weapons used?
Spikes, spinners, rammer, crushers, crimpers, grippers, pounders, thwak’s, wakers, walkers, talkers, axe’s, saw’s, etc, etc
Well you get the idea.
Third
, what defensive weapons are there?
Steel, steel, and more steel, spikes. Alternatively, make it so big that nothing could destroy it.
Fourth
, what are the main problems?
Weight.
Fifth
, what weapons cause what damage and grade damage level?
Spikes,
Minimal damage Tickle under the arms.
Very Low
Spinners
Every thing
High to Extremely high
Rammers,
Think of shoppers at a big stock take, sale at Myers. Just annoying
Etc, Well you get the Idea.
With this information collected and collated, the design concept starts.
Now just imagine.
A large high speed spinning blade around the body, a ball and chain swing from above, turbo charged engine, for the speed, and the hand of god, just to hit anything out of the way that is annoying.
Now that sounds good. BUT problems with design concept,
Weight
. There goes the ‘Hand of god.’
Next, Budget.
‘Turbo charged engine,’ gone
‘Ball and chain swing from above,’ gone
Now that leaves a spinning blade around the body.
Thoughts
It is possible to make
May not, cost too much to build
Could stay under weight limit
Not unique
“NOT UNIQUE”
, now this is a problem.
Solutions add a second blade spinning in the opposite direction and make the bot have the ability to drive flipped upside down or not.
Problem
Not all materials can be cut by the same blade.
Solutions
design to have interchangeable blades
Final bot design concept
The bot is to be fast.
The bot is to drive upside down
Have two blades spinning in opposite directions at high speed.
Have interchangeable blades. Must be quick change.
Next the specifications.
Shape: - Round
Size: -? (Will depend on, weight class)
Chase: - Not required
Armour: - will be determine once design is completed. (Weight factor)
Movement Speed: - Fast (Doesn’t have to be the fastest.)
Blade spinning speed: - 30,000 rpm (realistically maybe 1,000 to 2,000 rpm)
Blade type: - to be researched.
Testing Spec
Cut a lump of 4 x 2 in to wood chips when dropped into path on blades.
Now that the specs are done, what weight class should this bot be designed for? Good question.
There is going to be some research and testing for this bot, so I think it will need to be, say 3kg, for the prototype. Then make one for 12kg, and if I get adventures a 25kg bot.
Naming the bot
This is simple. The baby of the group will cut your toe off, so its name is ‘Toe Cutter’
its big brother will bit your ankle, therefor ‘ Ankle Bitter’
and the mother of the group. Let’s just keep going up the leg, ‘Knee Capper.’
The name of all three together, well that’s easy
Please welcome the
‘Cutter Family’
Design
Now the design can be started.
First, what motors am I going to use? For now the XU1 for drive train, weapon still need to be sourced.
Then wheels, Bunnings red wheels for starters.
Battery SLA for now, sort out other type later.
Controller, The ‘IBC’
Remote control receiver, good question!
The shopping list is getting bigger
2 x XU1 cordless drills
1 x SLA battery (determine size later)
2 x Red Wheels
1 x IBC Controller (order when starting to build)
1 x Remote controller
and there is nothing to hold it all together.
Now as I have some of the parts I can start drawing into CAD (using SolidWorks.)
All parts are drawn and looking good, let’s set the mass parameters, so the CAD package can calculate the total mass.
Problem
, Scales, I don’t have any. Add to shopping list 1 x scales.
Bought Scales 3kg max; accuracy to 1g. That will do the job.
Weigh all components and set mass properties for each drawing. Hehe it works.
Lets draw up the base and top plate, then make an assembly drawing and see how it looks.
Boring
Where’s the blade, need the blade, have to have the blade, (stop typing and draw one. Oh that’s a good idea, I might just do it.)
Now that is starting to look a bit better.
http://robowars.org/forum/album_pic.php?pic_id=159
Problem!
How do I connect the blade to the body and have it spin.
Due to the size that the blade is spinning around a bush is out of the question (Mainly safety reasons due to design, review at a later date.) Time for some research
Been to a couple of bearing suppliers and found some bearings that will do the job.
A turret bearing for ‘Knee Capper’ should do the job.
Problem!
Cost $300 - $400. In addition, the turret bearing is design for low speed. Testing required. Think it will be OK.
Found a bearing for ‘Toe cutter’ THK aren’t you wonderful.
Problem!
Cost $2,000. Yow, that hurt. I think ‘REDESIGN’ is in order.
Still looking for ‘Ankle Bitter’ bearing.
Me tink it is time to talk to work colleges.
I WANT A BOT TO PLAY WITH NOW.
As this looks as though it is going to be more of an engineering challenge, I think it is time for plan B
Now what is plan B.
A trip to Bunnings for inspiration is required.
I have inspiration, a couple of them.
Problem!
Can Petrel motors be run yet?
No prob, start a baby design that doesn’t need it, and it will become part of the ‘Pristidae Family’
Now that has you thinking doesn’t it.
Time for a new story about the
‘Pristidae Family’
I will update as advancement are made to the
‘Cutter family.’
_________________ It's all about the destruction.
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