Dual weapon ant build diary

[Roboteernat]

So... I have machined my 4mm carbon fibre into the side plates, and I'm getting the impression there is a bit of glass fibre inside the mix. The fibres were deffinatly White in the centre, luckily I didn't pay for it and it was off cuts from a massive octorotor I machined for a friend, but still... It weighed 2g more than the acrylic ones.

The chassis printed well, but needed to modify it today due to weak areas. Sadly that meant adding more plastic to the chassis, so the weight is over now by 20 or so grams. The only way I can see it loosing the weight is in the tube. A wall thickness of 3mm prob isn't needed, and some decorative holes in it should be nice and reduce the weight without ruining the effectiveness.

I will need to sort the wiring out too, that should reduce a bit.

[joey_picus]

So... I have machined my 4mm carbon fibre into the side plates, and I'm getting the impression there is a bit of glass fibre inside the mix. The fibres were deffinatly White in the centre, luckily I didn't pay for it and it was off cuts from a massive octorotor I machined for a friend, but still... It weighed 2g more than the acrylic ones.

It's slightly depressing how much "carbon fibre" isn't proper carbon fibre I suspect carbon fibre is a bit denser than generic fibreglass #34 they use as filler, I have a few bits of proper 1/8" (grrrr America) carbon fibre lying around and they're surprisingly heavy!

The drum definitely doesn't need to have 3mm wall thickness! Holes could work quite nicely for weight reduction, as could taking one of the motors out and spinning it with just one; Jim (Hi Jim!!!! ) took both those approaches with Raoul (on right) and it worked very well.

[Roboteernat]

Holes could work quite nicely for weight reduction, as could taking one of the motors out and spinning it with just one; Jim (Hi Jim!!!! ) took both those approaches with Raoul (on right) and it worked very well.

Part of my inspiration was Raoul, its a good looking machine, Luckily i have the ability to machine exact hole angles on my mill at work - being the only Mech engineer here has its benefits!, so i was planning on machining holes around, potentially using them as the jutty bits that contact other robots as it rotates.
The drum is only powered by 1 motor, although the images show the motor mounted at both sides - i changed the solidworks model to match my wiring of the motor as apposed to changing 2 wires! The side plates are made symmetrical.

I am pleased with the results so far, and now i am back from holiday, i can continue to mod.
The 3d printed chassis, im not happy with as my support block i put in doesnt work, as the layers between the block and the actual chassis was too close. The support layer between the sacrificial block and the chasis was too strong, so i need to remove that and reprint. Or i could machine it off... hmmm...

More pics to come!

[Roboteernat]

Here is the ant so far after a lunch breaks machining of the bar
Current weight... Let me find my scales...
Weight is 23g. Still quite a bit, this is just the aluminium bar and the M4 CS screws.

Need to get it down.
Bearing 3G
CF side arm 12g
Bar motor and SC 30g
The chassis, drive motors and pololu wheels, nano controller about 56g
Battery nano etc 180mah 25-40C 13g
RX doesn't even register on own, but adds difference of 2g with another part so 2g

Total is 148g without top armour or flipper servo... Hmmmm
Servo is 9g
Flipper parts and armour 11g to 15g...

Wiring to be reduced so save weight there, and a new chassis design with holes should help.

We shall see...

[joey_picus]

I think you could probably lose grams out of the side armour with little effect - you can also (from experience) get away with a 120mah battery should you need to. Looking very nice :3

[Roboteernat]

Have been taking a look at the side armour and think I can reduce it down to 2mm CF, so that should half the weight well reduce it some what.
I have started to make the hinge and top chassis and it's looking nice, current weight is 160g.

[Roboteernat]

I have my new chassis printed and I have it built.
I'm not happy with these CF side arms as they are a bit bulky and weighty. May see if I can reduce the overall length of the not to reduce weight in parts and see if I can have some holes in the arms to reduce weight more.
Current weight is 165 and that's just a polycarbonate sheet as armour and no flipper. The servo is fitted, but no arm.
Will see if I can move the servo closer to the wheel motor and the battery, maybe this is why I can't see many dual weapon end bots! Just to check... It is 150 grams right.! Lol

Addition...
Maybe the aluminium bar tube is too weighty, it's currently 1.75mm walled, not 3mm I said before, but I'm pleased by the new motor mounts. Brought that back to my old style design.

Additional addition...
Turns out I used 2mm polycarbonate from work for the armour and not my 1mm stuff, that should reduce my weight

[Roboteernat]

Weight reduction on the bar
Managed to machine some bigger holes in the bar aswell as reducing the wall thickness and has saved me about 7g I think, it's 15g now without the 6 screws, will have to weigh it with them to get exact weight, but still pretty strong., total weight without armour is 147g so getting there, still have the sides to reduce thickness on so that should save 7g.

[Roboteernat]

I'm going to look at the wiring later today, and looking for suitable place to put a switch. Obviously needs to be away from the edges, the spinning tube and accessible, so am left with the top. Although the header jumper link is a good idea, I can see it being a weak point in a bit the potentially could chuck itself around, so will be using a very small switch SPST I got from some junk parts. Just need to reduce the capacitor size in the king Kong esc, I think a 16v should do it, or even 10v if I can find the correct value.

[Roboteernat]

The servos have arrived! and im quite impressed that they are still 9g even with brass gears!
The servos i got were the ones mentioned in a post a few days ago - the Turnigy TGY-50090M look great and have same footprint as the Towerpro, so i should have it fitted soon.
The wiring layout is looking good too. I originally had the brushless ESC motor just behind the motors and the bar itself, but i want as much weight forward from the wheel motors so that the flipper is on the ground and is not so much back end heavy. I will still have to add some supports to the back to hold it off but a rounded M3 bolt will suffice.