Hi,
I noticed that when I press B button, it changes C value and when I press C button, it changes B value. I am in world frame.
Please see the attached screenshots.
Why is it happening? Pressing B should reflect in B not in C value .
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Thanks
Hi,
I noticed that when I press B button, it changes C value and when I press C button, it changes B value. I am in world frame.
Please see the attached screenshots.
Why is it happening? Pressing B should reflect in B not in C value .
-
Thanks
This is purely speculation on my part, but I'm guessing that your tool isn't perfectly perpendicular with the axis about which you're trying to rotate the tool AND normal to the other two axes. In other words, if the tool is not perfectly lined up with the Z axis, rotating around Y will inherently force some rotation about X.
Just a spitball though, so it could be something else. Good luck!
The tool is not perfectly lined up with the Z axis
No its not. The tool is lined up with Z axis. Do you want me to put a picture of the setup or anything else to verify this?
That is ok.
May be You search for 'Problems regarding Euler Angle' or 'Ambiguous Euler Angle'.
In short: It is possible to reach one specific position with different rotations.
It is possible to reach one specific position with different rotations.
I know that but the doubt was "when I am trying to change B why it is reflecting on C on in B"
Because there are the mathematical transformations between your fingertip on for example 'B+', the movement, and the display of the angles.
And these transformations are ambiguous, so the programmers have to make decisions in the transformations for the one or the other or a complete different rotation order.
In fact that confusion happens if one of the angles is nearly 0, 90, or 180 degrees.
Try it when all angles are roundabout 30 degrees.
No its not. The tool is lined up with Z axis. Do you want me to put a picture of the setup or anything else to verify this?
No picture necessary. If you say it is, then I have no reason not to believe you. Weird, however, that my quote was edited to make it seem like an unconditional statement rather than a purely subjective one, and upon that you offered "proof" that what I "said" was false.
Full disclosure:
In other words, if the tool is not perfectly lined up with the Z axis, rotating around Y will inherently force some rotation about X.
Oh well. I hope you find a solution.
The ABC angles of a point in space represent a sequence of three Euler rotations (in the case of KUKAs, sequence Rz, Ry, Rx) to achieve that orientation starting from the orientation of the currently active $BASE value.
This means that, at any given TCP orientation in space that does not perfectly match the active $BASE, rotating around one axis does not result in a $POS_ACT value that only changes around that axis. And since Euler rotations can achieve a given orientation through many different angle combinations, the solution space is deliberately limited to +/-180 in A and C, and +/-90 in B. There is additional disambiguation using the S and T elements of an E6POS structure, but that's a bit beyond the scope of this conversation.