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Yes people use the, for FP buffers, I think Jarvis does in metal beak for one. The problem with refilling them is the valve, it's a pin valve with a very odd thread so you'd need to swap the valve for some sort of twist valve with a usable output thread. There's no problem with actually refilling them though, sodas tram do this when you send the empty cylinders back anyway.
Still haven't got round to testing the regulator because I've just moved house- spent over 4hours at weekend moving only half the stuff in the garage! But I have been at metal workers (only 10mins away now!) working on my fw flipper, I'm thinking of 'Up' as a name if it's not taken. Basically I have cut and folded the Monocoque base/side armour from 2mm steel and made a flipper arm from 2 bits of angle welded together which I swear I didn't steal the idea for from Jamie! Also cut the hdpe bulkheads and made shafts for my ram and made use of there massive really slow pillar drill to drill some big holes.
Also got the record for largest tap sheared by hand at 16mm diameter!
I will try and get some pictures up tommorow.
instead of up why dont you call it up-chuck or up-lift
I hope you realise that if you call it 'Up' Max, you will have to attach a load of balloons to it :)
And a tear jerker back story.
squirrel :lol:
Can you mig weld hardox to mild steel as if it's all mild steel or does it need setting up differently?
Here is the folded base plate and armour:
http://i1261.photobucket.com/albums/...t/fb6ea20f.jpg
It's made from 2mm steel.
This is the central bulkheads made from 15mm hdpe with the flipper arm and ram attached:
http://i1261.photobucket.com/albums/...t/23914630.jpg
And here it is with the ram extended:
http://i1261.photobucket.com/albums/...t/a0c9966f.jpg
And here it is on the base plate:
http://i1261.photobucket.com/albums/...t/cc611f33.jpg
Yes, and even with reasonable results, but the weld itself won't even be close to the capacity of the Hardox.
For best results, you need to adhere strictly to the welding instructions of SSAB, and that will ask for a certain basic investment.
I myself find a combination of TIG welding Hardox to any other kind of steel with pure argon and 316ti wire easiest and affordable.
looking good :)
Tested the pneumatic system again- it went badly!
I had the system piped up and turned on the co2 from a paintball bottle, I had the nut on the regulator fully undone then I screwed it up, it was at 2 bar and I tried firing the ram but it didn't have enough power. So I turned the regulator nut a little bit more then the prv (10 bar) fired and all the co2 came out. On my pressure gauge it went further than it measures. The pvr was covered in frost and the bottle froze to the ground. There was a lot of pressure when the pvr went off.
Is my Trevor regulator Brocken?
What kind of forces so fw hydraulic crushers like cobalt have at the tip? And what about electric crushers rather than just grabbers?
I'm after the force at the tip rather than the pressure
Thanks!
in theory my crushers actuator produces 10000N pushing (electric) and with losses calculated it would be 7000N on the tip which equates to roughly 700kg on the tip
I think Kenny said that cobalts tip force was 2000kg, naturally hydraulics are going to produces far bigger numbers than electric but the downside is, the expensive parts needed etc
Bit more progress on flipper;http://i1261.photobucket.com/albums/...t/219138d7.jpg
And got Some pneumatics done:
http://i1261.photobucket.com/albums/...t/ed7ee907.jpg
Hi all,
Looking but the event at Guildford I don't think my flipper was very effective, it more turned people over rather than throwing them up, does anyone who saw it know what might be wrong?
the angle of the flipper arm looked quite high i would say reducing this will help so it makes robots run up it giving a better flip
What sort of size is the ram?
I think it is a 63mm bore and 125mm stroke but it doesn't use all the stroke.
I had a horizontal plate at the bottom of the flipper to get under people but I see what you mean about the slope. But even when I put a brick right up on the flipper arm it didn't go very far.
Quite a bit bigger than Jr then.
I just watched the video of it and it didn't look too bad, its not going to get the same sort of force as a FP flipper is but if its getting people over at least then thats a good sign. I noticed Jr had trouble flipping robots unless it was just under them and they were near to the ground. I think theres a video of my trying to right Jamie's MDF bot at Edinburgh and because of the unusual shape it was when it was upside down it couldn't get at it properly.
So maybe its just the limitation of the system? If not, test the setting on the reg as at the highest for your system and similarly for the PRV.
I'd just like to point out that I only had one drive motor working in that video and that's why the driving is terrible.
could be a flowrate issue
I think the regulator was set a bit low so I'll get a pressure gauge and test.
Could you make a crude speed controller by having a circuit with a variable resister, a capacititor then one side of a relay and a small battery (3v) then to the other side of the relay attach the motor. Then use a servo to control the variable resistor and have a simular setup for reverse?
I know it wouldn't be the best but would it work?
You could do. That is how some of the really old RC cars used to work, and also how th 4WD's worked before they made an interface for it (Look up Hypno-disc's build diaries)
Right I am thinking of rebuilding my flipper with a fatter shorter ram.
I am thinking of a 100mm bore 80mm stoke running at 10bar.
To keep it as compact as possible I want to make it my self by using a piece of aluminium tube then having a piece of 20mm hdpe as end caps. I plan on drilling holes in the corners of the hdpe and using threaded bar to hold the end caps together with the tube in between.
Then make a aluminium plunger and then weld a peice of aluminium rod to the plunger.
Would this work? What thicknesses would I need? How would I get a good seal between the pipe and the end caps and between the plunger and tube?
Thanks,
Max
first off i have no experience in this area but i would have a feeling that precision is very critical both for safty and to make the ram actually work. the best and easiest way to do so is using computer controlled machines with CAD models
like I say i might be wrong ....... dont let this stump your ambitions though :D
I'm doing something similar but to keep it simple I bought a cheap cylinder off ebay like this one:
http://www.ebay.co.uk/itm/Single-Rod-63 ... 569wt_1142
It can be disassembled easily, will use the same endcaps and piston and manufacture a new cylinder bore and piston shaft. The endcap I will fit a 1/2'' fitting to it for max flow.
Max
Buy a second hand low pressure ram and stick to the pressure ratings, it will be powerful enough for a feather.
100mm bore by 80 stroke is the same as the ram on Meggamouse so if you did build one properly it would be way overpowered, and use too much gas. I cannot recommend you build your own, if you have to ask the question, you will not have the skills.
Trevor
I've found it hard to find a commercial ram with big enough ports (12mm) and ideally I want a smaller second port as well, commercial rams also seem to be very big and heavy considering the shortness of the stroke.
I also feel I lack the knowledge of how to build a ram, not necessarily the skills. Anyone can build anything with a good set of instructions and the right tools.
i think the right tools is the pharse to think about
Could you use a small botbitz controller (10amp) to an automotive relay so the relay turns on and off rapidly so you can vary the speed of a car fan motor cheaply? Could it also be used for a heavyweight motor (with a bigger relay)
the relay would weld together
What if I used a solid state relay
Its probably just as cheap to use a battleswitch-relay setup that is proven to work.
I am trying to charge 2 12v 7.2ah sla batteries, but my charger has other ideas!
For one it says battery low voltage, which the manual says means I have input the wrong number of cells but I haven't. When I measured the voltage with a multi meter it says it's 14v so defiantly not too low.
The other says circuit break, but there defiantly isn't a break in the connectors as its the same setup for both batteries, however when I measure the voltage of that battery it says it's only 4v rather than 12v.
Adam anyone help?
If a SLA is showing 4v then its knackerd. They should only show 14volts when charging, what charger are you using?
Yep 4volts is bad and the charger will just cut out. Your only chance is to tell the charger its a 4cell nicd and charging just to get the volts up,then go to 5 cells then 6 etc untill the voltage is around 12v, then go back to SLA charging. Might work it has for me in the past but the ah might not be what it should be.
As I am rebuilding my flipper I wondered if I should make it front hinged?
But I don't see how it would be effective as you wouldn't get much movement at the front so wouldn't send a robot very far?
What are the advantages of front hinged over rear hinged?
Awesome self right from a front hinged, that's reason enough surely?!
Much easier to aim your attacks. With a rear hinged, unless you're driving forwards, the robot could go more or less anywhere. With a front hinged you can deliberately send a robot somewhere, i.e., the pit, oota, etc.
It might not be so spectacular but I have always thought they're more controlled and strategic than rears. Think of Firestorm's success, and Envy's success! And Mute's general coolness. Andx2 the smooth self-righting. :P
If you design it well getting other robots to sit high enough on the arm for them to topple shouldn't be much of a problem.
Edit: and if nothing else, you'll be praised (at least in my book) for doing something a little different with a pneumatic system.
You have to have a good drive system for a front hinged, drills or similar are no good. Keep the wedge angle as low as possible.