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Spockie-Tech
Site Admin
Joined: 31 May 2004
Posts: 3160
Location: Melbourne, Australia
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I mentioned this at the just happened meeting.. But I'll put it in writing here as well for the benefit of all
Most of the newcomers being Engineer/Hackerspace type guys, I recognise and appreicate your interest in developing a prototype for a future "Holographic Control System", and the desire to use an Arduino or other Microcontroller wherever possible..
Quite simply. *Don't.
As Jake said, Invent as few wheels as possible.
It might seem technically boring to use off-the-shelf standard RC gear, but, the fact is, its (relatively) standardised, its reliable, its simple, its proven, and these days, its even cheap ! (It didnt used to be B.H. (Before HobbyKing) ).
For the first few events, you will be dealing with *plenty of newcomer issues (mainly mechanical), probably a few electrical (ESC, Batteries), and most importantly, you have to learn to drive skillfully..
You wont do well at any of these if you are *also debugging your custom prototype control system.
A combat robot is an *incredibly hostile environment for prototype electronics to live in..
Sagging battery voltages (limited battery capacity thanks to weight), inductive current surges of *hundreds of amps rushing through sparking and stalled motor brushes and coils, (creating RF interference like you wouldnt believe)
Metal fragments, swarf, rubber and dust flying around (look inside a bot after an event, you would think they have been 4WDing in the desert)
and regular G-Force shocks that are almost inconceivably violent to most newcomers. Imagine throwing a 13Kg sledgehammer moving at 20-30kph (another bot) at the box your project is mounted in, or even better, a hit from a spinning bar doing several hundred Kph.
Shock Forces in the *thousands of G arent uncommon. I have seen through hole components torn right off circuit boards and chips ripped out of machine-pin sockets just from impacts.
Its just not a place you want to be trying to test and develop a concoction of beta code, inter-board connectors and custom components.
If you believe you have an idea that will confer a *serious benefit over the standard control system, by all means develop and test it outside the arena, then add it to the 'bot *After the bots electro/mech systems are debugged and proven.
Sitting still, twitching, or having poor control in the arena, is an invitation to have your bots face (and other parts) ripped off.. You want the simplest, most reliable control system you can find to start with..
Assuming of course, that your goal is to enter the arena with a reasoanble chance of winning or surviving a match or two _________________ Great minds discuss ideas. Average minds discuss events. Small minds discuss people
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Mon Sep 21, 2015 2:55 pm |
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Spockie-Tech
Site Admin
Joined: 31 May 2004
Posts: 3160
Location: Melbourne, Australia
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Tank style control just means left-stick = left motor drive, right stick = right motor drive. so both forward = forward, both back = reverse, opposite = turn etc.
With Elevon mixing, Elevator forward = both motors forward, elevator back = both motors backwards, and any "aileron" input (x, side to side) stick movement adjusts the balance between left and right channels. so full left aileron (x on the stick) = left motor full speed one way, right motor the other way, with the reverse for full right stick.
So, you get exactly the same amount of motor control, with the ability to spin on the spot, do gradual turns etc, with the same maneuverability..
The only difference is that when mixing, its all controller by the one X/Y stick, instead of two sticks Y-only.
Most people learn to drive with the mixed right-side single-stick control, probably 80-90% of drivers drive this way. This leaves the left stick (throttle/Rudder) for activating weapon motors or articulated arms etc.
a few (mainly those with RC Car experience) prefer wheel/trigger radios.
A little known emergency hack is you can use a non-mixed TX setup as if it was mixed, merely by holding the radio at 45-degrees., so when you push "forward" (relative to you) on the stick, you are actually taking both channels 1(y)+2(x) forward by means of actually pushing the stick diagonally (relative to the TX body). It doesnt work very well, since the X/Y springs make it feel weird and difficult to go *straight forward, but it works in a pinch. _________________ Great minds discuss ideas. Average minds discuss events. Small minds discuss people
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Mon Sep 21, 2015 5:07 pm |
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