DH_Extractor

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algontijo
Posts: 2
Joined: 25 Apr 2018, 01:57

DH_Extractor

Post by algontijo » 25 Jun 2018, 01:25

Hi.

Anyone knows why DH_Extractor doesn't work with MTB_Robot?
It also doesn't work with robots that I've been making.
It seems the only problem is the parameter d.
The other parameters seems right to me.

Please help me.

Thanks

coppelia
Site Admin
Posts: 6800
Joined: 14 Dec 2012, 00:25

Re: DH_Extractor

Post by coppelia » 27 Jun 2018, 10:02

Hello,

not sure what you mean... what is d supposed to be in the MTB robot?

Cheers

algontijo
Posts: 2
Joined: 25 Apr 2018, 01:57

Re: DH_Extractor

Post by algontijo » 27 Jun 2018, 13:26

Hi.

The problem is in d parameter of DH Extractor.

"Between 'MTB_axis3' and 'MTB_axis4':
d=0.0000 <<--Here i think there should be a value diferent from zero
theta=0.0
a=0.0000
alpha=0.0"

In every other robot that i create this d parameter is also zero for any possible configuration.
In the list of models of non-mobile robots the only robot that the d parameter is also zero is the MTB robot,
That's why i think it's a similia situation i'm trying to understand.
There are any limitation on the DH Extractor program ?

Thanks for the reply. But i still need help.

coppelia
Site Admin
Posts: 6800
Joined: 14 Dec 2012, 00:25

Re: DH_Extractor

Post by coppelia » 28 Jun 2018, 13:34

As far as I can tell, all axes are parallel in the MTB robot. The two last axes, MTB_axis3 and MTB_axis4 are even coincident. From Wikipedia:
d: offset along previous z to the common normal
With parallel axes there is not one common normal, but an infinite amount of common normals. With coincident axes that normal does not even exist.

Cheers

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