FP HW Tips

[m2xt]

FP HW Tips

Mario,

I have no problem in getting the ball valve open before the ram fully strokes. Also, its not just about valve operating times, its also about restrictions which serve to slug the gas flow from the buffer to the ram. You have far more restrictions in solenoid valve installations than in ball valve solutions. Having tried both methods its a no brainer as far as I am concerned. Design your ball valve system right and I believe it will out perform multiple solenoid valve designs.

[beast]

FP HW Tips

its not getting the ram up i have truble with its getting it back down quick
thats why i left a spring in our hydralic ram to pull it back down, but another 2kg of weight and i im giving up with bungy lol

but either system should work good enough

[maddox]

FP HW Tips

Im not convinced that the added low pressure set up in the robot is an advantage.

The most ideal solution is to use a fully custom build balanced valve. Or get the QEV -Bufferram- working.

Chad, multiple burkerts just require a nicely designed manifold. Or can be connected to each other with off the shelf hydraulic parts.

(Message edited by maddox on May 07, 200

[m2xt]

FP HW Tips

Mario, I totally agree that the LP side is a pain but at the time I wanted the ultimate performance that I could achieve using my own tools. Not only that, but it is variable pressure from 10 to 50 bar controlled from the Tx so I had both a LP flipper and a HP flipper and everything in between. Shame it drove like a sack of spuds and the flipper kept breaking open the back of the bot. The only other design I have tried that came close was a design based on the impact ram principle but that was inherently unsafe and let down by a poor build.

[maddox]

FP HW Tips

Paul, I can achive the variable pressure as well, nothing difficult to it, just requiring a servo to adjust a setting. But I didnt use it before, because it defeats the KISS idea.

Also, something I learned , flow and pressure , as well ramsize arent everything. In Hannibalito1 I tried several flipper arm leverages and lengths, and its a huge difference, even with minimal changes.

But my own guidelines.
Buffertank volume 3* ram volume
1 Burkert is good for a 70mm bore ram
2 Burkerts are good for 100mm bore
and 140mm bore needs 4 burkerts.

Flipperarm at least 5 times stroke. Point of impact depending on force on the ram, but leverage so that at least 5 times the weight of the to be trown opponent is available on the point.

[m2xt]

FP HW Tips

Mario, a servo to adjust a setting - a setting of what? KISS is fine but if we all kept to that we would all still have mobility motors and fire alarm batteries!

1. My guidlines are 2* ram volume, 3* ram volume only gives an extra 12% final pressure and that is when its too late to do much good and does not always justify the extra weight.

2. Its all about gas flow and far less about pressure

3. A bigger ram is of little good if it is not matched by a corresponding increase in gas flow.

4. Use the Hassocks hog flipper calculator for designing the flipper arm.

[woody]

FP HW Tips

The ram opening speed reduces as the load / leverage increases and the fill time - flow - Kv or Cv versus the required flipper TIP speed also reduces.

Optimizing all the variables is key in getting an effective flipper.

[Mouldy]

FP HW Tips

i think mario might have come up with the same idea as me paul,

Using a burket as a regulator with a pressure switch on the buffer tank its fed by- closing the burket when it reaches a set pressure..

I havnt attempted it yet, but i remember the pressure switch i bought from you YEARS ago had a screw in it to adjust the pressure setting- i planned to exstend this screw, put a gear on the end and have it engage with a servo to ajust the pressure setting while the machine is in the arena- By calibrating it on the bench with a pressure guage and putting markings on the TX it should be possible to have a close measure to pressure via the remote throttle.

Abit of subject but id be quite interested to know how you solved that with the picaxe system you use?

Chad- i would also suggest the hassocks hog flipper calculator for maximising the effectiveness of your machine.

[leorcc]

FP HW Tips

That is exactly what we are thinking about doing in the new axe setup of Obsidian Dave, the pressure switch is already in place. We will use a set pressure though, not variable as Mario suggested with the servo. Setting it before the event/match is good enough.

[wazio]

FP HW Tips

http://www.valvepros.com/av-files/sharpe/series_76.pdfhttp://www.valvepros.com/av-files/sharpe/series_76.pdf set up 4

[maddox]

FP HW Tips

@ paul
The Hassocks Hog flipper calculator is pure theory.
What I use as guidelines is what I learned over 7 years of Robot wars pneumatics.

Its all about juggling weight/size/benefits.
I aim for the 3 times ram volume, but wont cry for it if it is 2.2 times.
I try for a 1 to 1.5 bore/stroke ram, but wont hesitate to divert from that aim if other lay outs give me a better total power to weight ratio.

@ Dave, Youre not far from what I have in mind. But there are some details. Please allow me to keep them for me.

[wazio]

FP HW Tips

after 15min o CAD I have the first view of what the HW may look like.. ish

http://i79.photobucket.com/albums/j147/wazio/hw1.jpghttp://i79.photobucket.com/albums/j147/wazio/hw1.jpg

http://i79.photobucket.com/albums/j147/wazio/hw2.jpghttp://i79.photobucket.com/albums/j147/wazio/hw2.jpg

6 wheel drive, 6-8diax6 cylinder. 2 2.5lb c02 tanks, Li-p Batt, probably mag motor drive of some sort... All that stuff will come later... If the thing even gets built.

[maddox]

FP HW Tips

http://www.bugs.nl/media/album/view.php?&path=L3J3L3R3ZW50ZTIwMDQvbmwtYm9yZ2UvRFN DRjAwNjQuSlBHhttp://www.bugs.nl/media/album/view....bmwtYm9yZ2UvRF NDRjAwNjQuSlBH

This tiny Dutch machine is waiting to get finished. But what is in there. A 5.5 ram with 5 stroke fed by 3 burkerts. Those are below the buffertank.
2 1.1kg bottles to feed the monster.
Drive is Bosch 750 and a 2 stage gearbox.

[m2xt]

FP HW Tips

Mario, not sure where you are coming from but the Hassocks Hog flipper calculator is a very useful modelling tool, modelling is used throughout everyday life so why not flippers. I like others who have used it have found it to be very good. Your 7 years of experience is personal to you whereas the calculator is freely available to all. Dont use it if you dont want to but equally dont knock something that others find useful. This thread is titled FP HW tips and the calculator is a great tip for builders trying to work out their fliiper geometry.

Dave, M2XT used an analogue output (2-20mA) pressure transmitter, this fed into a comparitor (PICAXE) where the pressure was compared to that of a signal direct from a Rx. The ouput of the comparitor was used to drive a HP solenoid valve which opened to pressurise the buffer tanks at a controlled rate until the desired pressure was reached when it then closes again.

[maddox]

FP HW Tips

Paul, if it reads that I ment that the Hassocks Hog flipper calulator is bad or so, sorry.
I just ment that there can be a big difference between predicted results and the real world results.
But as you say, modeling can be a great help to avoid wrong designs.