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General Misc => Misc => Topic started by: siempre.aprendiendo on November 29, 2008, 12:43:08 PM

Title: Math help needed
Post by: siempre.aprendiendo on November 29, 2008, 12:43:08 PM

I'm trying to create an "IR radar" to detect objects. But I have this math problem to get the position (polar or rectangular coordinate) of the detected object,

how I could calculate the "a2" yellow angle, knowing "a1", "AX-S1 head size" and "IR distance to X,Y"?

(http://www.roboticchallenge.com/images/otras/objet.png) (http://www.roboticchallenge.com/images/otras/objet.png)

Title: Re: Math help needed
Post by: ArcMan on November 29, 2008, 02:52:41 PM

Do the lines "AX-S1 head size" and "IR distance to X,Y" always form a right angle?

Title: Re: Math help needed
Post by: siempre.aprendiendo on November 29, 2008, 03:12:53 PM

Yes, always. It's a IR sensor.

Well, a multiple IR sensor, it has 3 IR, left, right and front. The graphic shows an example with the right IR.

Title: Re: Math help needed
Post by: ArcMan on November 29, 2008, 07:31:01 PM

OK.  Then...

a2 = a1 + (tan^-1(("IR distance X,Y") / ("AX-S1 head size")))

Title: Re: Math help needed
Post by: siempre.aprendiendo on November 30, 2008, 03:13:09 AM

Thank you very much, ArcMan!

By the way... do you know a good book/article/tutorial about to "recover" ("remember") this kind of lost math knowledge (trigonometry, coordinate system) related to robotics?

Title: Re: Math help needed
Post by: ArcMan on November 30, 2008, 08:45:35 AM

I have to say that I'm a big fan of the "for dummies" books.  So "Geometry for Dummies" is what you would need.  I recently wanted a refresher in calculus and differential equations.  I cracked open my college texts, but that was just alot more than I needed.  The "Calculus for Dummies" book was just what I needed.

Title: Re: Math help needed
Post by: siempre.aprendiendo on November 30, 2008, 09:04:33 AM

Thanks, ArcMan

I am reading "Intermediate Statistics For Dummies" and it's pretty good. I will add "Geometry for Dummies" to my collection :)

Title: Re: Math help needed
Post by: ArcMan on November 30, 2008, 09:29:08 AM

Oops.  I meant "Trigonometry for Dummies".

Title: Re: Math help needed
Post by: Admin on December 02, 2008, 04:26:35 AM

I'm really starting to like the new recommended posts links at the bottom of every thread - it found the exact post on robot math I wanted to link here:
http://www.societyofrobots.com/robotforum/index.php?topic=3908.0