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Lintilla - NMO - Vic
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NMO
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Joined: 16 Jun 2004
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Location: Melbourne


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Lintilla - NMO - Vic

Robot Stats

Team name: NMO

Robot name : Lintilla

Team location : Victoria

Robot weight(Class): Feather weight

Type of Robot: Thwackbot

Drive system : 2 18Volt DSE Andrew mods

Type/size of wheels : Bunnings red wheels

Speed/motor control:

Power: 18V CP 2400's

Armour: Steel, UHWM, Rubber

Radio: Spektrum

Post Fri Jan 19, 2007 11:10 am 
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NMO
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So some questions for people.
What is the thinnest mild steel we can get away with these days against spinners?

I'm hoping the answer is 5mm. I know that copbra is 6mm and I think that some parts of spyder are 10mm or something.

Here's a concept drawing I've been working on for a few days

Post Fri Jan 19, 2007 11:11 am 
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Spockie-Tech
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"Shape" is probably important to the question of how thin the armour is required to defend against a spinner.

If you put a nice flat solid wall in the way of a high velocity bullet, you are going to get maximum energy absorbtion and hence damage.

A thinner angled traingulated angled structure will deflect a portion of the energy in another direction, destabilising the spinner and preventing you from experiencing the "jumped in front of a train" effect.

Think about force vectors and diverting the flow (like Judo) rather than taking the punch in the face. Spyder's body and wedge shapes are good examples of this.

A parallelogram shaped body with braces in the triangle corners for your thwack bot will give you a chance of diverting horizontal spinners as well as swecondary wedges that will work either way up. There was an American thwack bot that was built like this, but I forget its name right now. I think Gary knows it.

It may be more likely to be "caught" by vertical spinners, but as long as you leave the extremeties of the triangles empty, that would be air-armour.

Your dual-pipe walls look like they would be very structurally strong too, but are going to divert any hits above the 1/4 and below the 3/4 mark *into* the center join area rather than away from you.
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Post Fri Jan 19, 2007 12:44 pm 
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Daniel
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Location: Gold Coast


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If you want a steel tube for armor, steal a street sign. That's what Hellbringer was made out of.
But your better off deflecting hits rather then trying to absorb them. Just make some trapazoidal panels and weld them around the outside at 45 - 30 degrees. And at 30 degrees a 3mm thick panel looks 6mm thick to a hozrizontal spinner.

As for a thwack bots, try to get the wheels as close to the center of gravity as possible. Don't put the wheels in the center of the chasis but closer to the hammer and put all the batteries and electronics on the other side. That way it will naturally lift off the ground when spinning. Also I used 18V drills with 150mm wheels and 24V batteries in colorful version of Avenger and it had a mean thwack attack. As it spun the chasis and axe would lift so that the balance was perfect and the center of gravity was directly over the wheels.
http://www.youtube.com/watch?v=TBUkZ2yqzK8

Post Fri Jan 19, 2007 1:00 pm 
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Rotwang
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Joined: 15 Jun 2004
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Twrex or something likes that, and I agree about the centre of gravity thing, both versions of bane have the weight on the wheels.

Jolt doesn’t seem to respect angled armour the way it should, the holes in IG are in a smooth angled area where you would think it would deflect and its sliced through the tough stainless. 1.6mm isn’t thick enough, the laminated section on IG’s back held up well.

The 3 mm on the front of bane also held up well to Jolt and Orbit.

The VD’s are potentially more of a problem to the horizontal thwack as they can flip if they can grip the edge. Angling this area is a must.
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Post Fri Jan 19, 2007 2:49 pm 
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NMO
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Ok revisions after what people had to say. I had some 40mm OD tube in the shed but that won't do. Changed to 63mm OD 50mm ID pipe for armour. that's 6.5mm wall thickness.

Moved motors closer to the axe. looking at about 11 Kg's without the axe at this stage.

Post Fri Jan 19, 2007 6:08 pm 
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Rotwang
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You might need to triangulate the axe handle or move the motors further apart to being the handle between them to support the handle.

The 6.5 mm wall thickness might be strong enough to support the axe handle but there is a good chance it will get very wobbly after a hard fight.

Obviously that will make the body wider and add weight but the wider track gives more leverage to get the Axe moving, less top speed in the spin though.
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Post Fri Jan 19, 2007 6:49 pm 
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Rotwang
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http://www.battlebots.com/meet_the_robots3/meet_robot_specs.asp?id=463

T-Wrex Smile


High performance drive Custom control electronics Siaxially symmetrical morphology Titanium armor Cool
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Post Fri Jan 19, 2007 7:48 pm 
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NMO
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Been thinking about how to make the bot translate while spinning. IE move around the areana. The 2 ways I thought of was some sort of very hard to build, expensive, unreliable speedcontroller / processor on the 2 drive motors or a third drive motor with a cam on it made out of a red wheel. http://robowars.org/forum/album_pic.php?pic_id=1388
I had thought that if the bot had a cam run off a drill motor then it should be a simple matter of just turning the motor on and the bot would move in an almost straight line.
What does everyone think?

Post Wed Jan 31, 2007 7:51 am 
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NMO
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a second view of the concept

http://robowars.org/forum/album_pic.php?pic_id=1389

Post Wed Jan 31, 2007 7:54 am 
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Daniel
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When the broken red wheel lifts off the ground it won't have much load on it so it will be spinning faster then the other wheels. Then when it hits the ground again the load will be put back onto it and it'll slow down again, but probably slower then the drive motors. So it'll be spinning faster then the drive motors and then slower then the drive motors. Although I have no idea much of an effect it will have on the translation. As long as it averges out it should be fine.
I like it. Give it a go and see what happens.

How is the rubber going to stay on the wheel after you cut it? Would it be better to make a wheel out of MDF for a test run?

Post Wed Jan 31, 2007 8:23 am 
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Ali



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Location: Scotland


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Look for a US robot called Cyclone Bot , Im almost sure its got some sort of movement while spinning but im afraid im not sure how its done .
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Post Wed Jan 31, 2007 8:30 am 
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Rotwang
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The 3rd wheel idea is what I was working towards.

Move the centre hole on the wheel and spring load it so it parks in the up direction then sync the 3rd wheel speed to translate.

Controlling the speed of the other 2 wheels cant be done quick enough.

Tyres don’t grip and inertia in mechanicals causes problems even if electronics can deliver theoretically correct power to motors.
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Post Wed Jan 31, 2007 9:15 am 
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Valen
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I was looking at cyclone bot style of things and i think a controller can be done just with a counter on the wheels.
As for update speed, you can vary the power to the wheels with the ibc at 50hz assuming you need 4 "power settings" per revolution to translate you get 12.5 rps or 750 rpm.
your speed whilst translating is governed by the rate at which you can slow down and speed up the wheels.
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Post Wed Jan 31, 2007 9:22 am 
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dyrodium
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I bet rotational translational movement is quite possible using stepper motors. Smile
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Post Wed Jan 31, 2007 12:20 pm 
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