Hi All,

Regardless of whether the proposed event goes ahead or not, I'm going to be building my own bot!

Type: Clamper
Drive Type: 2WD
Drive Motor: Drills + Red Wheels
Drive ESC: Sabertooth 2*25
Weapon motor: Sensored Brushless 540-type
Weapon ESC: ~To Be Determined I need something that will nicely brake(not break) the motor upon stall ~ (Maybe I need a clutch?)
Armour/Frame: Aluminium Sheet (Thickness suggestions?) on Steel frame (I think clamper design will become quite large so need to save weight here).
Battery: 4s Li-Po, maybe 5Ah? don't quite remember what is required for a fight, but at least I don't have to run a spinner the whole time. (4s is in consideration of 12v drill motors)

I'll be updating progress here, please go nuts with thoughts and ideas! I have some basic CAD skills so I'll also be putting up some 3D models as well.

Heya,

Sounds like a good line up of ideas

Drills have gotten really expensive now it seems which is a bit of a bummer, but even at $40 each they're still half the price of the banebots p60s which are realistically the next step up.

Weapon esc could be tricky. The roboteq single channel ones can be setup to work as a servo with a decent current limiter. But they are rather huge. and pricey. Clutch is probably the best option. Although if you can dig up a linear actuator they usually will sit there stalled for quite some time given they are so underpowered.

5Ah is a massive battery for a non spinner robot. Half that should be tons. Though if you can afford the weight of the 5Ah pack you shouldn't have to recharge all day

For the armour - too hard to say without a general design
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www.demon50s.com - Minimoto parts
http://www.youtube.com/user/HyzerGlen - Videoooozzz

Hi Glen,

I actually already have a linear actuator! I'll stall the original brushed motor and see whether you are correct (Plan is to upgrade the motor to brushless, though I guess it may not even be necessary for clamping purposes...). It is in Sydney though so those tests will have to wait a while.

I saw on another thread there is a person selling $10 drill motors with gearbox? From what I gather, the issue is mounting with the round gearbox, as I have a 3D printer I should be able to overcome that fairly easily.

I should hopefully be able to get the CAD done next weekend when I have some free time, then we can talk armour. (It makes me happy to see armour spelt with a 'u' for once).

Rather than using a clutch (which are often prone to slipping and adjustment problems) how about a spring buffer between the actuator and the clamper jaws? that would help prevent motor overloading and maintain tension if the opponent moved in the clamper jaws.

Finding a brushless ESC that has reliable current limiting may be hard. Apart from the Roboteq model that Glen mentioned, there is nothing else around apart from even more expensive industrial units.

If you used that spring damper I suggested, you can mount a switch on the jaws so that it closes when the spring compresses enough grip your opponent. That will be accurate, repeatable and reliable.
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

I think I get what you're saying Nick, that's a great idea, my solutions were mostly distance based (i.e. how closed the jaws are), a force-based solution like that is infinitely better and pretty much the same as a current limit.

It looks like it'll take up quite a bit of space, this is sort of the picture in my head



I could always go Rambo on it and use a temperature sensor to stop me melting the motor.

If only I could make the jaws strong enough for there not to be any situation where it stalls (15kN anyone?)

That is what I was thinking; it may not be too bulky as you will not need all that much travel on the spring. I would look at telescoping the spring around the actuator, something like this:


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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

Look forward to seeing this Any sketches or CAD?
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<Patrician|Away> what does your robot do, sam
<bovril> it collects data about the surrounding environment, then discards it and drives into walls

I am struggling to make any progress on my CAD because I don't have the drill motor + Gearbox or Wheel dimensions (Parts in Sydney) (Will do an impression for Dimensions)

ALSO! I kinda want to go pneumatic, mainly so that I can get experience in the area for future designs... Now with a clamper I'd imagine that the rapid shutting of the clamp would make it 'Bounce' and give the opponent an opportunity to escape...

So even if I can't apply it in this bot, It's just Air Ram, Solenoid Valve and Pressurized Reservoir right?

Anyone ever fit a hydraulic system in a featherweight? The possibilities are endless... Down with Spinners!

Edit: found Cobalt's build thread on another site but awaiting moderation so I can see images... Geez Hydraulic stuff is expensive

quote:

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Originally posted by Thomas AIC:
I am struggling to make any progress on my CAD because I don't have the drill motor + Gearbox or Wheel dimensions (Parts in Sydney) (Will do an impression for Dimensions)

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quote:

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ALSO! I kinda want to go pneumatic, mainly so that I can get experience in the area for future designs... Now with a clamper I'd imagine that the rapid shutting of the clamp would make it 'Bounce' and give the opponent an opportunity to escape...

So even if I can't apply it in this bot, It's just Air Ram, Solenoid Valve and Pressurized Reservoir right?

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quote:

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Anyone ever fit a hydraulic system in a featherweight? The possibilities are endless... Down with Spinners!

Edit: found Cobalt's build thread on another site but awaiting moderation so I can see images... Geez Hydraulic stuff is expensive

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Got tired of waiting and went and bought drills, wheels and associated hardware. Kmart did have the $22 12V drills when I went (They are not listed on the website), seemed the same as the old hardware which is good. Did the grub screw stuff and it all seems to work fine.

So I'm starting to do CAD today, just doing up each of the parts then I'll assemble them in various design configurations I think. Hydraulics seem prohibitively expensive so I guess it's back to electrical or pneumatics (If I can find some second-hand components).

Its a wise move to stay away from hydraulics; the parts are heavy and generally too large for a featherweight unless you custom make everything. Electrics is the most practical option and its cheap & easy to modify if you don't like the prototype. Pneumatics sits between these two systems; its not as heavy and expensive as hydraulics and more dangerous than electrics - if you get something wrong there can be shrapnel flying around the workshop before you know it. Just pay attention to safety at every step and doo plenty of research and you will be fine.
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Australian 2015 Featherweight champion
UK 2016 Gladiator champion

glen has a pretty good library of parts in rhinocad... if you ask nicely ;->
(although they are all scaled wrong lol)

Actually weren't there moves to put all our cad's online somewehere?
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Mechanical engineers build weapons, civil engineers build targets

I have to follow Nick in his remarks.
Commercial hydraulics are heavy and/or idiotic expensive.

Custom work , if you can't do it yourself, and you can't ask a metalworker with all the tools of the trade to do it for a few beers, it will be very very expensive.

Low pressure pneumatics can be done with second hand parts and hand tools. Unfortunatly, the storage bottle and regulator are annoying. Commercial regulators are big or expensive or very low flow.
Custom build regulators are rare. I know of only 1 that is made in a small quantity, the UK Trevor.

For me, Full Pressure CO2 pneumatics are the cheapest simplest way to go. But that's another story.
I can't recommend starting a FP setup for a first machine.
That's like hydraulics. With commercial stuff expensive or very heavy.
And custom, that takes a workshop.

Yup so Hydraulics and High Pressure Pneumatics out of the question for now.

I think Low Pressure pneumatics are a needless complication compared to Electric Actuation, so we'll stick with an electric actuator.

I did find a few models online already which saved a bit of time and effort (and they are way better than what I would have bothered/been able to do).

I've uploaded all my CAD files, if you want to view the final thing you'll need to download the folder then navigate to: CAD->Important->Robot Assembly.SLDASM
https://drive.google.com/folderview?id=0B1FOXasjh9vdSTRNdDZuSXFJeFU&usp=sharing
Something is messing up some of the mates when I download the files.. I'm not sure but if you just suppress/remove the conflicts you can still view everything fine.



Here are the important views... Should I reorient the actuator to face backwards? It kinda kills my front wedge though... Anyone with inhuman visualisation skills want to help me come up with a claw shape? Most of the design is flexible, I can move the Hinge along the robot if required.

Currently the design is with 6mm Aluminium for the body of the robot, we have about 4kg of mass to work with.



Robot Dimensions are: Length 45cm width 35cm weight: ~5kg

Are you trying for an electrically actuated lifter?
Keep an eye on the speed, they are usually pretty slow.
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Mechanical engineers build weapons, civil engineers build targets