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DumHed
Experienced Roboteer
Joined: 29 Jun 2004
Posts: 1219
Location: Sydney
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Well, I've now rebuilt two of the smaller rams, possibly to be used for the flipper.
I drilled out the air feed and exit holes so the rams can operate much faster, and cleaned all the old gunk out - to be replaced with new gunk!
I also pulled apart a dual solenoid valve from a gas stove / oven, which I think I might be able to use to control the air flow.
The valves give about 8mm diameter of flow, and they're setup as two valves in series as a double safety thing for the gas supply. By adding another fitting in the middle I end up with an "in" solenoid to fire the ram, and an "out" solenoid to empty it again, all in one pretty light alloy casing.
The actual solenoids are 110v, but the coil sections are removable so I can wind my own and fit them to the casing very easily to get 12v operation.
If these can take the pressure they should flow very well, and will make controlling the ram very simple. _________________
The Engine Whisperer
- fixer of things
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Tue Jan 04, 2005 9:03 pm |
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DumHed
Experienced Roboteer
Joined: 29 Jun 2004
Posts: 1219
Location: Sydney
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Today the chassis was commenced!
It's all square steel tube, the same as used on ROFLChopter, but will be welded rather than held together with alloy corner pieces (partly for weight saving, partly for strength, and partly because of all the funny angles involved)
At the moment the drive system is looking like it'll be a single 300w scooter motor, with a belt drive pulley on it, driving a wide roller style wheel made out of 4 red wheels. The pulley on the wheel is one I found in some old photocopier bits, which happens to fit the scooter belt.
If that doesn't work out I have a backup plan for a chain drive setup using much larger wheels, but that will be a fair bit heavier.
Power will either come from a couple of 12v NiMh packs, or more likely from a couple of drill packs to begin with. I think the electrical load will be quite small with only one motor, and a very simple drive train.
The pneumatics will be controlled either by servos directly, or by something faster like car central locking actuators (they're also mega cheap).
For the front steering I'll probably start with servos, but they'll have some strain relief so they don't strip gears under high load.
I found some really nice 12v actuators from Silvia air con controls, but they're too slow for what I want (very light and powerful though, with feedback switches, etc)
The main center part of the chassis will be wider than I'd originally planned, which allows for trying out different drive setups, and makes it easier to fit in other weapons.
I now have a plan for a very modular weapon system where I can install either the flipper, a hammer - by swapping the actual weapon and just connecting the ram up to it, or a crusher, which will use the much fatter ram and a different weapon linkage.
I can also use different pressure sources, and will be able to easily install either the CO2 tank, a fire extinguisher tank, or twin extinguishers for more air supply and two separate outputs.
I'm also moving more towards making the front wheel outriggers shorter, which will make the bot easier to flip sideways, but will make it a lot easier for me to make it self righting, which may prove useful _________________
The Engine Whisperer
- fixer of things
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Sun Jan 09, 2005 2:54 am |
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