First featherweight robot questions

[Ekushiru3]

Hi everyone. I am planning to build a featherweight pneumatic flipper robot and I got some question.
I plan it go in 1 Mpa(145 psi) in the 80mm bore 80mm stroke ram, do you think it work?
I can't find any ram can operate upper 1 Mpa, I think a self made ram is too dangerous for a people who first time build this kind of robot.
What regulator you usually use? I can't find a regulator can input 30 Mpa and output 1 Mpa
I do not know why using a motor from a drill, I can buy a motor with gearbox having the same performance. Is the gearbox in the drill more durable?
I think a flipper robot may be too complicated as a first robot, what kind of robot do you suggest as a first robot?
I would like to attend the RoboChallenge 2016 if the robot can complete.

[typhoon_driver]

Welcome to the club!

I'll leave the pneumatic questions to others with experience in the topics.

To answer your other question, we use drills because they are easy to get a hold of, cheap and give an ideal speed output. They are tried and tested and we know they work. If you have another idea then by all means post a link and we can advise.

A flipper can be complex or simple. A lot of people start with a rammer as you get a good feel for the rules and experience your first event with a fairly simple machine. That's not to say that a more complex machine isn't possible. Just depends on your experience.

[Ekushiru3]

Thank you. I will try the motors I can get, I have ordered some. I may build a rammer or something if I can't solve the pneumatic problem untill march first. I have got a piece of 20mm HDPE for structure as many people do.

[Garfie489]

http://ranglebox.com/

If you want some high power, pre built stuff then you can order from here. They do Motors which are bigger than Drills with a prebuilt gearbox and also ESCs which again should be more than what youll ever need in a feather.

Just an alternative should you decide you want to buy something which can then be reused into a more combat focused machine afterwards - many championship robots do still run on drills however, so its not urgent to buy anything above whats considered starter (just worth being aware of)

[Ekushiru3]

Thank you all, I will not come to attend the RoboChallenge 2016 because of some funding problem, I may attend it next year. So that I have whole year learning and building my robot. Please everyone exhibitions in now and future.

[maddox10]

Pneumatics in feathers.

Using standard low pressure pneumatics is possible, but it's a heavy and large way to build. Can you give us the size and weight of your ram?

Most succesfull pneumatic featherweights use a CO2 paintball bottle for gas storage. This because they are easy to aquire and are perfect in the rules.
But there are machines that use a 12 or 24V "car tyre inflator" compressor.
Regulating CO2 from the paintball bottle.
2 main options if you're not an experienced engineer/pneumatics user.
Paintball regulator or Trevor regulator.
Trevors are custom regulators for RW, quite a few in use, but not easy to aquire.

Adapting a small industrial regulator is possible, but again, heavy and large.

[Ekushiru3]

Thank you replying. I have viewed some paintball regulator and I think the AG1 paintball regulator from Rap4 is good.
The ram I plan to use is 63mm bore and 50mm stroke. (I don't know why it is 63mm), operating at 1 Mpa.
I also wonder that the flipper force should be just upper opponent weight or much higher? The force according to my calculation the ram ouput is 3117N and the flipper as a lever it is 623N at the tip.
CO2 I know it can only up to 7Mpa but High Pressure Air can up to 30Mpa, why people choose CO2 but not HPA?
By the way, I found there's light build in the receiver and ESC, when I close the switch they will light up. Do I need a extra light to indicate the robot has powered up?

[Shakey]

People choose CO2 because there is a pressure limit for fighting robots in pneumatics. CO2 is just about liquid at this limit so you get he same force but a much greater volume of gas meaning more actuations.

HPA under the rules doesn't really offer any proper advantages but with the disadvantage of far less flips.

[maddox10]

The rules give us a maximum gas pressure of 1000psi/70bar/7 MPa.

For a storagebottle of the same size CO2 stores about 300%+ more gas. This because CO2 becomes liquid and densifies 10fold @ 5.5MPA at 20°C.

The disadvantage is that CO2 needs a lot of energy to go from liquid to gas.