Re: [rc-hackers] Strange shake of right hand

[Francesco N. <fra...@ii...>]

Dear Martin,

the wrist prono-supination backlash you noticed is indeed a (serious)
problem but it's a known issue which unfortunately will be fixed only in
later versions/upgrades of the robot.

Anyway, it is not the cause of the instability we have seen in the well
known "el cuatro" movie.

Can you please test the shoulder in the same way you tested the wrist?

Francesco

 

From: mar...@gm... [mailto:mar...@gm...] On Behalf Of Martin
Inderbitzin
Sent: Thursday, February 25, 2010 3:13 PM
To: Francesco Nori
Cc: Zenon Mathews; rob...@li...
Subject: Re: [rc-hackers] Strange shake of right hand

 

Hi Francesco,

Following your advice we made the calibration with the robotmotorgui and
tested the arm control. In the two videos u can see, that after the calib
the right arm is not the same 'stiff' on one joint...?

Do you think that this could be the problem...?
best, martin



On Tue, Feb 23, 2010 at 5:57 PM, Francesco Nori <fra...@ii...>
wrote:

Hi Zenon,

I think that the problem can be mechanical. Can you please check if you have
strange shoulder movements/backlash? The test should be as follows:

(1)    Calibrate the robot

(2)    Leave the robot in his home position

(3)    Try to move the left and right arm. Since the robot is position
controlled it should be very stiff.

Try to understand if there is any noticeable difference between the left and
right arm. Report me possible differences (possibly videos if you think they
are useful).

Cheers,

Francesco 

 

From: Zenon Mathews [mailto:zen...@gm...] 
Sent: Tuesday, February 23, 2010 5:04 PM
To: rob...@li...
Cc: Martin Inderbitzin
Subject: [rc-hackers] Strange shake of right hand

 

Hi Hackers,

Recently, we have been having a strange shaking of the right hand while
performing for example the ball reaching demo using the demoReach module.
The left hand doesn't seem to have this shake. Anyone had this or similar
before?

We have made two videos of the ball following using the right hand and the
left hand and is temporarily available at:
http://193.145.55.59/download/

thanks

Zenon

-- 
Zenon Mathews
PhD Student
Synthetic Perceptive Emotive Cognitive Systems Group
http://www.specs.upf.edu
Universitat Pompeu Fabra 
Barcelona Spain
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-- 
Martin Inderbitzin
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SPECS - Mixed Reality Laboratory
Universitat Pompeu Fabra
Roc Boronat 138
08018 Barcelona, Spain
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+34 935 421 393
mar...@up...
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