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RC Gyro's in Bots
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Spockie-Tech
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Joined: 31 May 2004
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Location: Melbourne, Australia


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quote:
Originally posted by Glen:
also looking at the safety checks, it mentions that your bot may go into a 'death spin' if it gets inverted with a gyro inside. NFI what that is.


A gyro is used by some competitors (especially on 2 wheel bots) to help improve the driveability by self-correcting the steering.

It basically a gadget from the RC world (originally used in helicopters) that goes between the receiver and the controller. It senses off-axis movement and if it senses the bot starting to veer sideways due to slippage (or whatever) that wasnt commanded by its servo inputs, then it modifies its servo output to the controller in the opposite direction by the amount required to bring the bot back into line.

I saw a demo of Voltronic sitting on a bench once, iff you swiveled the bot sideways without touching the sticks, the wheels spun in the opposite direction until you stopped moving it.

Supposedly they make quite a big improvement in control.

The only problem with them is that if you bot gets inverted, and the gyro isnt aware of that, then you create a positive feedback loop, where as soon as the bot starts to turn, the gyro thinks its in the wrong direction (since its now upside down), so it applies a corrective output, but of course, being upside down, its the wrong way around, so the turn gets worse, the gyro tries harder to pull it back into line, and so on, into the "gyro death spin" which you cant get out of.

So, to use a gyro in an invertible bot, you need an additional RC channel to either invert or disable the gyro's output when you are upside down.
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Post Sun Sep 05, 2004 1:27 am 
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Valen
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activating the flip input on the IBC would fix that wouldnt it?

we are thinking of putting one in Plan-B

Post Sun Sep 05, 2004 10:36 am 
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Nick
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Couldn't you invert or bypass the gyro with an inverting switch and some circuitry in the bot? Model plane gyros must be able to cope during inverted flight or they would crash 'n burn. I would love to try out a gyro but he lack of info on this and other gyro features has put me off so far.
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Post Sun Sep 05, 2004 10:44 am 
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Valen
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problem is you need to invert the pulseout time
change a 2ms pulse to a 1ms pulse
not that easy

i think the ibc's flip input would correct this however
cheapest gyro i saw was $60 or $80, i cant remember

i'm hoping that a gyro in Plan-B would allow us to do full speed rams forwards which would drasticly improve our wepons effectivness.

Post Sun Sep 05, 2004 11:09 am 
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NMO
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could you not have a mechanical solution to the problem where the gyro is attached to a peice of tube with a weight on the other side and a small axel going through the middle, the wieght would always want to be facing the ground so it would inver the gyro???

Just a thought.

Post Mon Sep 06, 2004 9:19 am 
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Nick
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That's an interesting solution - I would never have thought of it.

Jake - if you get a gyro, I'll have to fit a teleporter to hop out of your way Wink
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Post Mon Sep 06, 2004 10:12 am 
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prong
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well Nick if you install a teleporter i think i am going to need to install a high power cutting laser instead of my drill and a tractor beam to keep you from getting away and getting that bar spun up to speed! Laughing

Post Mon Sep 06, 2004 10:19 am 
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Nick
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Cool! and get 7 of 9 as your driver while you're at it please Very Happy
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Post Mon Sep 06, 2004 11:37 am 
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kkeerroo
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quote:
Originally posted by Nick:
Couldn't you invert or bypass the gyro with an inverting switch and some circuitry in the bot? Model plane gyros must be able to cope during inverted flight or they would crash 'n burn.

I have experimented with a gyro in Hellbringer 3 and yes it does help.
As for a "gyro death spin" this happens because when an invertable robot is flipped the steering is not actually reversed but the gyro is.
As for nick, when an aircraft is upside down both the steering and gyro are inverted.
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Post Mon Sep 06, 2004 7:11 pm 
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Brian



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I am trying to confuse myself. I have a two wheel robot with the IBC and a 2 channel car controller. I don't use the invert function on the IBC. When my bot is upside down the steering isn't reversed. And I think of forward as whatever way the bot goes when I tell it to go forward. I can see this as backwards on a 4 wheel bot. So does the flip reverse the throttle channel or the steering channel? If it reverses the throttle channel then the spin of death would still occur.? Rolling Eyes

Post Thu Sep 09, 2004 1:56 am 
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Ajax
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It is only the steering the is affected.
using the flip function of the IBC fix's the Gyro issue..

As KKeerroo said -


quote:

As for a "gyro death spin" this happens because when an invertable robot is flipped the steering is not actually reversed but the gyro is.


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Post Thu Sep 09, 2004 10:08 am 
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Eyce



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I've got a non-invertable bot lol, but I could use the help of a gyro... If I had enough weight left Embarassed .


The bot drives in a slight direction to the left Mad
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Post Fri Sep 10, 2004 6:45 pm 
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kkeerroo
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My gyro weighs about 25g.
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Post Fri Sep 10, 2004 6:50 pm 
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Eyce



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And From Memory from the last meet, shYte weight 12.99kg.... until It magically grew 1 gram Evil or Very Mad
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Post Fri Sep 10, 2004 6:57 pm 
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ffej
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Ahhh, one of the many advantages of owning a 6WD bot is that it just loves to go straight, without any fancy gyro, just uses good old friction Razz
(Well, the new version goes straight with no problems, the old version wouldnt go straight because the dodgey relay speed controller cut in each side at a differnet stick position . . . . The joys of propo Smile)
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Post Fri Sep 10, 2004 9:58 pm 
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