Andron4000 HW crusher build

[Andron4000]

It would be interesting to see how the hardox fails. The mild steel just peeled away and split. It didnt offer much resistance once it had made a hole

[MattLampitt]

As much as I'v always loved Razer and how it looked, Iv always thought that the beak would have been more effective at causing internal damage if it didn't have the increase in diameter the further in it pierced. If you had a 200mm long, 10 or 12mm sharpened titanium shaft bent to the same angle as the beak and used that, then once your through the armour it will go rite down in there going through anything in its path. Or at least for 200mm anyway. Lol

[Andy]

They probably did it that way for more strength, also once the tip is through the shell the wider part of the claw can follow through anyway, not sure how deep it would get through hardox mind..but Razer was designed way before hardox was a common thing on robots so..

[MattLampitt]

So...., what's kind of been said here is you can pierce a 3mm thick piece of hardox sheet with 4 tonn of tip pressure. Would the tip material made of EN36 grade steel be adequate for that though? And is that grade better/ worse than a shapenned hardox tip or Grade 5 titanium or even s7 tool steel ?

[Andron4000]

In terms of penetrating, I think that the 4 tonnes is enough, as long as you have a harder material (please correct me if I'm wrong guys!)
The EN36 is (slightly) less hard than Hardox, so may begin to deform before puncture, but is less brittle,so less likely to shatter in impact or under extreme loads. You could also case harden it, but again your moving more towards the failure mode being fracture.
We chose EN36 for our trials, and probably will be using it for our final design, the only change being a sharper attack angle

puncture scxreen grab.JPG



In terms of our build, our motors and speed controllers are all finally out of customs!

IMG_7596.jpgIMG_7584.JPGIMG_7585.jpg

They are terrifying now that we have them in front of us. The photos don't really give a sense of the scale. We are all quite humbled.

We have put some puncture proof wheels on order to get a rolling chassis under way.
https://www.amazon.co.uk/Pandamoto-Y...3EZ3P0PMR&th=1

And also ordered some RC gear
https://www.amazon.co.uk/Helicopter-...rds=FLYSKY#Ask

We went for the Flysky as it was recommended to us, and has pretty good reviews. It is also very cheap when compared to the spektrum alternative, and our budget has took a bit of a beating with the purchased components and customs charges!



In terms of having a rolling robot, we still need to spec lipos, a fuse and a removable link. Do we need anything else?


With the lipos, I found this very good guide.
http://rogershobbycenter.com/lipoguide/

Can somebody please weigh in on my thinking here?


If we are running 2 NPC-T64's at 8s, 29.6V
The stall Current is 110A x 2 = 220A (So the C value must be more than this)
For the mAh value, if we assume half of the stall current for operation
55A x 2 = 110A
And we look to run this for 3 mins 110A x 3= 330A in 3 mins.
for the Hour, 330A/ (60/3)= 16.5Ah
so 16500mAh? with a saftey factor on the 55A draw assumption

Looking at using the optipower partnership...
http://www.optipower.co.uk/Catalogue...cat=126&cnode=

Will 4 of these, 2 parallel and 2 series give me the equivalent of 8s, 16 000mah at 50c (800 amps)?

[daveimi]

To run 110A for an 60 min you'd need 110Ahr battery (theoretically).

To run 110A for 1 min: 110Ahr / 60 = 1.83Ahr battery

To run 110A for 3 min: 1.83Ahr x 3 = 5.5/Ahr battery


So say 6Ahr or 7Ahr to be safe. Any more and you're wasting weight.

Couple of these in parallel to give capacity and discharge, for 2KG maybe? Stay at 24V to look after your expensive motors.

http://www.hobbyking.co.uk/hobbyking...Lipo_Pack.html

[maddox10]

I do have a few 4S Zippy 30C 8000mAh packs I could send you to test with. Those were used in Kan Opener, and even if they look gaffataped, the cells themselfs are in balance.(last time I checked)

[Andron4000]

Thank you so much!
I will send you a PM Maddox
I originally had 6000mAh and managed to talk myself out of it and tie myself in knots with the numbers..

The lead time is a month on the transmitter so we're looking at this one instead.
http://www.ebay.co.uk/itm/Flysky-FS-...wo0JWQQPs#shId

Will our speed controllers just plug straight into this?
http://www.ampflow.com/motor_controller.htm
We have these two, the dual for the drive and the single for the weapon

[mattsdragons]

Go for a spektrum Dx6i, it's pretty much the standard in terms of robots and comes with a few features that you won't think you need till you have them

[typhoon_driver]

The DX6 is now the new version of it.

[Mouldy]

We used the NPC T-64'S with the same puncture proof wheels in Carbide, using 2 x optipower 4s 5000's in series, and we never ran short of capacity.

If your budget will allow- id stick with the optipowers.

[Andron4000]

I think I'll end up going for the optipower because of the discount scheme. Can you reccomend a charger?
How many batteries did you use for your etek?
Also the wheels came in and seem slippy.
Did you have any traction problems? I tried degreaser and it didnt help. Sanding them helped a bit.

[Andron4000]

Lots of progress on the design.

PROGRESS, 2016-10-04.JPG
We have struggled with the locking mechanism for the electric arm.
The resultant forces from the hydraulic cylinder arm are at a ratio of about 3:1, so 24 tonnes of force to resist!
With a shot bolt or ratchet set up, the material would just deform, or needed to be very bulky. the failure mode is also pretty catastrophic.

We have decided to go with a band brake driven by a 32bore hydraulic cylinder.
http://www.tribology-abc.com/calculators/e3_5d.htm
It is a lighter set up, it has a much kinder failure, in that the drum will just slip, and it should still give us enough holding force to give us our 8 tonnes at the tip.

All of these mechanisms have took their toll on our weight budget. Everything in the photo is 97kg currently, and we still have to add hydraulic oil, hoses and Armour ( which will probably be mostly 15mm PE)

The remaining design work will mainly be taking weight out of the existing components to free up weight for armour. We hope the design will be finished within a week!


Most of the components are laser or water cut, so we are hoping the rest will go together pretty smoothly...

[Andron4000]

Lots of progress on the design.


PROGRESS, 2016-10-04.JPG

We have struggled with the locking mechanism for the electric arm.
The resultant forces from the hydraulic cylinder arm are at a ratio of about 3:1, so 24 tonnes of force to resist!
With a shot bolt or ratchet set up, the material would just deform, or needed to be very bulky. the failure mode is also pretty catastrophic.

We have decided to go with a band brake driven by a 32bore hydraulic cylinder.
http://www.tribology-abc.com/calculators/e3_5d.htm
It is a lighter set up, it has a much kinder failure, in that the drum will just slip, and it should still give us enough holding force to give us our 8 tonnes at the tip.

All of these mechanisms have took their toll on our weight budget. Everything in the photo is 97kg currently, and we still have to add hydraulic oil, hoses and Armour ( which will probably be mostly 15mm PE)

The remaining design work will mainly be taking weight out of the existing components to free up weight for armour. We hope the design will be finished within a week!


Most of the components are laser or water cut, so we are hoping the rest will go together pretty smoothly...

[daveimi]

The angle that the hydrualic nipper sits at looks as though it would just skip along the top of an opponent once clamped, as opposed to puncture it.