Team Shakey Build Diary- Featherweight

[Shakey]

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:



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).

Cheers,
Alex

[Ellis]

Re: Team Shakey Build Diary- Featherweight

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!

[razerdave]

Re: Team Shakey Build Diary- Featherweight

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

[Laser]

Re: Team Shakey Build Diary- Featherweight

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

Where did you get your main tank from?

[Shakey]

Re: Team Shakey Build Diary- Featherweight

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.

[blazerbotics]

Re: Team Shakey Build Diary- Featherweight

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

[Shakey]

Re: Team Shakey Build Diary- Featherweight

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.

[blazerbotics]

Re: Team Shakey Build Diary- Featherweight

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

[maddox10]

Re: Team Shakey Build Diary- Featherweight

@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?

[Shakey]

Re: Team Shakey Build Diary- Featherweight

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?

[maddox10]

Re: Team Shakey Build Diary- Featherweight

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?

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.

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.

[swanaldo]

Re: Team Shakey Build Diary- Featherweight

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.

[Shakey]

Re: Team Shakey Build Diary- Featherweight

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!

[maddox10]

Re: Team Shakey Build Diary- Featherweight

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.

[Shakey]

Re: Team Shakey Build Diary- Featherweight

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.