Inconsistent frames in the left/right thumb of ergoCubSN001/2 urdf

[giotherobot]

Hello, I have found some small inconsistencies in the frame definition of the thumbs in the urdf.

Right hand

Left hand

The inconsistencies are: 1) Wrt all the other fingers the thumb is the only one where the x axis is the one in the direction of the finger, instead all other fingers have the z axis in the direction of the finger; 2) Between the two hands, if the X axis is in the direction of the thumb, the right hand has the three frames oriented forward, backward, forward and the left hand backward, forward, forward; 3) There is a 90deg rotation of the first frame of the thumb wrt the other frames, around the X axis, that is not present in all other fingers.

cc @GiulioRomualdi

[mebbaid]

cc @ehsanRanjbari

[Nicogene]

Hi @giotherobot thanks for reporting the issue.

We will tackle it as soon as the new Program Increment starts (~ mid-May, cc @pattacini).

I can confirm that the urdf correctly represents how the frames are defined in the mech assembly

Left hand

Right hand

There is a 90deg rotation of the first frame of the thumb wrt the other frames, around the X axis, that is not present in all other fingers.

This is for sure a bug in the assembly.

Wrt all the other fingers the thumb is the only one where the x axis is the one in the direction of the finger, instead all other fingers have the z axis in the direction of the finger;

Between the two hands, if the X axis is in the direction of the thumb, the right hand has the three frames oriented forward, backward, forward and the left hand backward, forward, forward;

For these two latter points, I would cc @Lawproto that worked on this assembly