ergoCub 1.0 S/N:000 – `r_thumb_add` loose joint

[SimoneMic]

Robot Name 🤖

ergoCub 1.0 S/N:000

Request/Failure description

The joint is loose and doesn't stay fixed in place. The motor is not actuated.

Detailed context

Additional context

Probably, during the various calibrations and turn-offs, the thumb collides with the upper-leg cover and it got damaged.

How does it affect you?

No response

[sgiraz]

Hi @SimoneMic,

From the picture posted above It seems that a pin is coming out:

Additionally, please keep in mind that we are already aware of the necessity to replace the right forearm with a new one in order to solve many other problems.

@GiacomoVassallo13 could you take a look at it?

cc @fbiggi @AntonioConsilvio

[fbiggi]

replacement of part code 16674 A1 gluing with Loctite 648 engine MAXON_B7E7C938897D replacement of the 2x6 pin on the support C_028_P_004 with screw m 2x8 + washer m2 + nut m2 movement test performed compliant recovery time 2.5 hours

@AntonioConsilvio @sgiraz @maggia80 @Fabrizio69

[sgiraz]

Well done @fbiggi!

@SimoneMic waiting for your feedback.

[maggia80]

the connector of the FAP of the thumb is damaged:

this is due to the male connector that is damaged as well:

we should pay extreme attention to these cables/connectors during the insertion. If they are damaged we should replace them.

I guess the MMA of the right palm is damaged. We should verify it and replace it.

[SimoneMic]

The adduction seems fine now, but there is another loose pin that doesn't keep the rest of the finger stiff:

Also I think that there's a missing spacer like this one (which was on the ground today):

[EhsanRanjbari]

Ciao @AntonioConsilvio, What is the latest situation with the thumb? Is it possible to fix it anytime soon? (I reserved the robot today from 11 a.m. and I need the right hand to do some experiments), thanks

[AntonioConsilvio]

Hi @EhsanRanjbari @SimoneMic, The phalange of the right thumb is broken:

This is how it should be

As you can see in this photo, the part of the phalanx where the hole was to connect the phalanx to the pivot is broken.

So we should replace this phalange with a new one.

For now, I have removed the joint from calibration.

cc @maggia80 @sgiraz @Fabrizio69 @fiorisi @GiulioRomualdi @lrapetti

[GiacomoVassallo13]

Hi. The broken component cod 16624.A3 hands thumb medial phalanx, hase been replaced. For this operation the finger was separated from the forearm.All the dowel pins were replaced and the new ones glued with Loctite648. The joint has been rewired due to disassembly of the thumb finger. To rewire the joint it was necessary to separate the forearm from the robot, because the sheath had detached from the support from the side of the pulley. The joint was tested with jogger set up before the arm was reattached.

cc: @Fabrizio69 @sgiraz @AntonioConsilvio

[AntonioConsilvio]

Hi, After replacing the damaged phalanx by @GiacomoVassallo13, I solved the electronic problems (see comment) by replacing the MMA board and some wires.

Following these interventions, only one problem remains, namely that the thumb_add is able to close (0-->90), but not to reopen (90-->0).

The problem seems to be caused by the mechanism which, following the interventions described in this comment, has become very hard.

But it has been tested with the jogger and the mechanism works correctly, but with yarpmotorgui it does not.

cc @maggia80 @sgiraz @Fabrizio69

[sgiraz]

Hi @SimoneMic,

Can you confirm that the joint involved in this issue is now working correctly?

If yes, I would close this issue.

[SimoneMic]

Yep! The joint moves from the motorgui, and is not loose anymore.

Thanks