Team Shakey Build Diary- Featherweight

For my As level resistant materials I am building a featherweight (mainly because they have a welder and free steel.). Though Since I only get one shot at building a featherweight I will be starting with a more ambitious robot of a 4 bar pneumatic Flipper. I have built quite a few smaller antweights so I have some experience except for the pneumatics.

I have picked up quite a few of the parts already:
600g CO2 tank
4oz CO2 Tank (a very small buffer)
4 Drill Motors (already locked the clutches)
Trevor Regulator
16bar 50mm Bore 80mm Stroke Pneumatic ram
Spektrum DX6i

I plan on running it with electronise 30A speed controllers, a 4cell lipo (14.4v) and a spektrum receiver (not the cheap hobbyking ones). The Ram is double Acting And I think I will use it that way despite the fact it uses more CO2.

The chassis will bemostly 8mm HDPE (on order) reinforced with steel and a steel flipper frame (bolted and welded). Some 75mm Robochallenge blue wheels for the drills and it should be good to go.

I have some pictures of the rough layout here:
http://i685.photobucket.com/albums/v..._aj/Robot2.jpg
http://i685.photobucket.com/albums/v..._aj/Robot1.jpg

This is a quick CAD of the flipper I am working on. The flipper it self has a tip travel of 240mm, with the ram at 16bar it should be okay for flipping.


The only difficulty at the moment is 16 bar fittings and trying to fit the 4OZ cylinder onto the system ( I will remove the pin valve eventually).
http://i685.photobucket.com/albums/v...lippercopy.jpg
Cheers,
Alex

This looks fantastic. It will be great to see a 4 bar flipper, their forwards and upwards motion is superior (in my opinion) to rear and front hinged weapons. I shall be observing carefully as progress is made!

Are you planning to power the front bars or the back bars ?

I'm planning on a 4-bar LP flipper :twisted:

Where did you get your main tank from?

I am planning to power the front bars so the ram can sit inside it and because it has more power extending then when retracting.

The CO2 bottle was from roaming robots if I remember correctly. 4 Bar flippers are very nice to watch I think, my inspiration came from the american super heavyweight named Ziggy.

You'll struggle to get a cheap 16bar valve, most will only go to 10.

Quote:

---

Originally Posted by blazerbotics

You'll struggle to get a cheap 16bar valve, most will only go to 10.

---

That is the component that is proving to be the hardest to find right now.

If anyone knows of any suitable 16 bar 5/2 valves it would be a great help, I don't really have enough experience to know exactly what to look for in a valve.

Until then there is a 10bar one lying around so I'll just regulate it to run off 10 bar until a 16 bar valve is found.

The Parker 'Viking Extreme' valves go to 16bar, RS sell them.

@16 bar, that ram uses 4.5 liter of gas in each action.

20oz bottle =600 grams of CO2 = 307 liter of gas= 65 actions. (rounded off to 50)

Maybe , if you're running out of weight, to consider to use a 12 or 9oz paintball bottle?

Ah thanks for that blazerbotics.

Also that is a lot more flips than I was expecting to get out of the bottle so I'll see about moving to a 12oz one that is lying around the house somewhere.

One small question, what ground clearance between the arena and the base of your chassis would be good? This is for running at the roaming robots type events so the arena gets quite damaged towards the end.

Cheers,
Alex

EDIT: What issues are there with valves and failsafing? I take it you just need a failsafe to keep the last known command on the channel the valve is on so it willnot fire when signal is lost?

Quote:

---

Originally Posted by Haywire

Also that is a lot more flips than I was expecting to get out of the bottle so I'll see about moving to a 12oz one that is lying around the house somewhere.

---

FP using Hannibalito III gets enough shots from a 12oz bottle. So, why not?

Quote:

---

One small question, what ground clearance between the arena and the base of your chassis would be good? This is for running at the roaming robots type events so the arena gets quite damaged towards the end.

---

Each to his own in this case, but I prefer more grundclearance. Getting flipped is less annoying than get stuck on a toothpick and left for death by the opponents.

Quote:

---

What issues are there with valves and failsafing? I take it you just need a failsafe to keep the last known command on the channel the valve is on so it willnot fire when signal is lost?

---

A failsafe just should do what it says, making a fail situation safe. The ram in or out, who cares , as long it can't move in the failsaved situation.

10 bar isnt a bad option to start with. I think you will be surprised on how well that mech will work on 10 bar. Easy and cheap parts to get hold of and it will get you going. Get a good flow rate on a 10bar system and i think you will be more than happy with it. We were going to do the 16bar option with chuck but we are happy with how it performs and wont be going to 16bar.

Good luck with the build tho.

One of the reasons for the large cylinder was that I couldn't find a replacement valve for a paintball one unless I am missing some obvious solution?

For now I'll run it at 10 bar but build all the fittings to 16 bar so I can switchover when I can afford a high rated valve. The only components left to get are a dump vlave, PRV, piping and push fittings (which I think Norgren do 16bar varients of).

Thanks for all the help.

Also I like chuck it is a very nice robot!

You'll see an influx of unadapted paintball bottle users at the UK events.

The reason why the screw valves are so common, was the difficulty to find an on/off valve for the paintball bottles- standard equipped with a pin valve-. But that's no longer a reason.

Another reason is the refilling at events. Most event organisers have a big bottle refill hose. But no paintball refilling station.

That is easy to solve. If you want to test at home with CO2, you'll want a big source bottle and a filling station. Meaning , you just will have to undo the big bottle filling station, fit your own standard paintball filling station and fill your bottle.

I have started the main CAD of the robot so I can sort out the sizing of everything. There should be enough room inside for the rest of the pneumatics and electronics to sit once I get sizes.

This is built for 100mm blue wheels and they will have some guards on but I haven't done them yet.

The majority of this is 8mm HDPE. The Angle Iron down the centre for the flipper should lend it ridgidity.

How do you plan to join 8mm on edge to the base-plate?

It will probably be a mix of brackets and screws to help support it. My main Concern is if it will flex too much If I am hit on the side so I might add some triangle supports at 90 degrees to the wall. I have worked out that the entire chassis will be made out of 10 bits of HDPE with 5 forming the CAD and the other 5 for the front and top.

I don't look forwards to finding out how it does against axes. I don't intend on putting this against spinners though. :)

how are you mounting your ram?

Quote:

---

Originally Posted by Hard Time

how are you mounting your ram?

---

The ram (When I get aournd to CADing it) will be mounted at the back with a pivot sitting underneath the CO2 tank so it can pivot on a vertical plane. It will be connected by a bar on the front two bars from a mount, which is basically a nut that screws onto the end of the ram welded to another pivot. My only worry is if the bar on the front will withstand the force of the ram or whether it would bend.

Then I have to be careful piping into the ram otherwise it might be caught in the ram which I can't imagine ending well. :P

Also the angle Iron is on order So I can begin building the flipper frame soon so there is something to look at other than CAD.

I got the main shape done and I quite like the look of it. I think it is fairly interesting even if it isn't the most effective. I will be putting some kind of guard around the front wheels at some point.

I'm waiting on some wheels befor eI cad them in so i know the exact details of the dimensions.

Are they 100mm wheels, 'cause there's a model of them on the 3D Warehouse.

That is a bit more interesting than your bog-standard box. It actually reminds me of a cross between Mortis and Vercingetorix/Comengetorix, not that that's a bad thing :)

Unless you need more specific dimensions, the 100mm Blue wheels are...well...100mm diameter and 30mm wide. Tyre thickness I'd say is probably around the 5mm-7mm mark, then it's the black plastic hub.

Thanks for the info. No more work on the feather as the CAD file is unaccessible right now but I sorted out one of my ants. It needed it after the last event.

A quick C+P from Robotwars 101:
Here is the final version of Stanley Ready for print. It has a servo hold ontop so it can self right/maybe do a bit of lifting/flipping.

http://i685.photobucket.com/albums/v...ingchassis.jpg

And because 8WD wasn't enough I upped the anti to 12WD.
http://i685.photobucket.com/albums/v...nleywheels.jpg

The order has been placed (Along with some wheels for Formic and Flint).

This should address a lot of issues I found at the last event. Somehow the new chassis is lighter than the old one even though this has more things on it. So I used the spare weight to add a selfrighter, bigger wheels and more armour. It is also very wide about 120mm wide but short so it still fits in the cube, this is to make it harder to avoid the scoop and give more controlled turning and to help reduce the likelyhood of spinners catching the side *cough*Combatant*cough*. :lol:

Some progress on the featherweight, the design is completed so I am starting to actually build the thing now. I will be making wooden templates for the armour plates so I can cut new ones easily if they get damaged.

http://i685.photobucket.com/albums/v...j/IMG_2107.jpg
http://i685.photobucket.com/albums/v...j/IMG_2108.jpg

that buffer tank looks a bit on the small size for the ram. try and squeeze in a larger bottle or double up.

yeah i would second that, looks small

You're probaly right. I think there are some 9oz and 12oz around the house somewhere so I will see what room is like when I am done and try to wedge a larger buffer tank in.

good progress tho, whats the dimensions of the base plate?

The base plate is (including the side bits) 480mm wide and 425mm long. It is on the large side i think but it should still be okay as I can't compact it down without changing the flipper design.

Cut out most the plates and am starting to refine the edges so they fit together nicely.

Looking good.

I'm sure it's been said, but looks a bit like a Ziggy / Mortis cross, should be good!

Edit: As long as it can do this.

http://www.youtube.com/watch?v=4ofH34HezHE

and that is why i like 4 bar flippers

such power in them, insted of chucking something oota, they push it :)

can they self right though?

Ziggy is actually the inspiration for the feather I am building. Been hooked on that robot since watching a few videos of it, insanely powerful!

Self righting is a worry of mine but if all else fails it could be solved like I did with my antweight in my profile picture, adding random bits to it until it does. :P

Biohazard self-righted with its four-bar lifter back at Robot Wars 1996 so it is possible to self-right. It will depend on the different lengths of the lifting bars and the available travel though.

Biohazard was more of a lifter though than a flipper, and it only just made it over.

I tried looking for a decent video of that a while back but couldn't find one.

I think I have it on Video somewhere......

At 9:10 in this video

http://www.youtube.com/watch?v=ldih_n9H ... ideo_title

Ah sweet! Someone has put the whole lot up, cheers.

The throw on biohazard is very different to the throw on Ziggy (and my planned one) if you compare the videos the back of Ziggys flippers stays almost in line with the top while biohazard's comes up out the robot

http://www.youtube.com/watch?v=t0Gox-hiZzM

Some progress on the feather, I didn't manage to get pictures of the work I did on the flipper today but it progressing quickly.
http://i685.photobucket.com/albums/v...IMG_2191-1.jpg
http://i685.photobucket.com/albums/v...IMG_2190-1.jpg
http://i685.photobucket.com/albums/v...j/IMG_2188.jpg
http://i685.photobucket.com/albums/v...j/IMG_2187.jpg
http://i685.photobucket.com/albums/v...IMG_2186-1.jpg

And the team ready for tomorrows Antweight world series, Stanley is looking a bit wonky at the front but it should do the job.
http://i685.photobucket.com/albums/v...SDC11542-1.jpg