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Author Topic: accelerometer/gyro combination for balancing robot  (Read 3932 times)

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Offline CanElecTopic starter

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accelerometer/gyro combination for balancing robot
« on: January 21, 2009, 01:12:29 PM »
I am trying to make a balancing robot. I am looking for accelerometers and gyros on this website:

accelerometers: http://www.robotshop.ca/sensors-accelerometers.html
gyros: http://www.robotshop.ca/sensors-gyroscopes.html

How many axes do I need for the accelerometer and gyro? There are single, dual and triple axis versions of each.

Also, there is a g rating. How many g's would I need for a balancing robot?

Thanks!

Offline pomprocker

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Re: accelerometer/gyro combination for balancing robot
« Reply #1 on: January 21, 2009, 01:21:58 PM »
David Anderson's nBot is a great one to look at for what was done

Offline TrickyNekro

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Re: accelerometer/gyro combination for balancing robot
« Reply #2 on: January 21, 2009, 01:25:46 PM »
Only one axis is good....
Placing is tricky... have to be in the middle of the wheels for best effect....
And you need an accelerometer to cancel drift....
Are you sure, you don't want to go with a simple distance meter.... I know gyros are better but....
It's a little bit hitting your head in a wall.... :P
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P.S. I've been inactive for almost a year... Don't give promises but I'll try to complete my tutorials. I'll let you know when..

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Offline Geir

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Re: accelerometer/gyro combination for balancing robot
« Reply #3 on: January 22, 2009, 02:03:06 AM »
Have any one tryed building one that can drive around? Whit a distance sensor. I've seen balancing ones on youtube, but I've never seen one that moves.
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Offline TrickyNekro

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Re: accelerometer/gyro combination for balancing robot
« Reply #4 on: January 22, 2009, 04:20:59 AM »
Well, I have... It's only how you can embed maths like PID in your program...
The guy who build it also has build a racing Sim (cool stuff!!!)....
But there are many others...
I don't know how to help you further, sorry... :P
For whom the interrupts toll...


P.S. I've been inactive for almost a year... Don't give promises but I'll try to complete my tutorials. I'll let you know when..

Cheers!

Offline CanElecTopic starter

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Re: accelerometer/gyro combination for balancing robot
« Reply #5 on: January 22, 2009, 10:13:15 AM »
So I will need a one axis accelerometer and a one axis gyro? Also the gyros have a degree/second rating. Is this important?

Offline CanElecTopic starter

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Re: accelerometer/gyro combination for balancing robot
« Reply #6 on: January 23, 2009, 01:12:10 AM »
I noticed that there is a g-rating for these. How many g's do I need? Also what is a good degree/second rating for the gyros?

I want to place my order but without knowing these two pieces of information, I don't know which ones to choose.

Offline cosminprund

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Re: accelerometer/gyro combination for balancing robot
« Reply #7 on: January 23, 2009, 03:36:17 AM »
Can you get some information on how little variation in acceleration/rotation can the accelerometer/gyro measure? How often can you get a reading?

I don't think you need an 5g accelerometer because I imagine an balancing robot is falling as a rock by the time it registers 1g so 5g might be waaay over the top - this is why I believe resolution is the more intereasting parameter.

The same is probably true for the gyro: resolution and sampling rate might be more important then total number of degrees per second. Here's my reasoning: If the bot has just registered 300 degrees rotation in one second it's probably nose-down in the dirt, too late to do anything! On the other hand if the gyro allows 1kHz sampling rate, then you can get 1000 samples per second and the 300 degrees per second translate to 0.3 degrees per millisecond.

Some time in the (very) distant future I'd like to build an balancing robot myself, this is why I'm interested in anything about balancing.

 


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