In Mech-Viz, the Euler angle convention of the robot is shown in the figure below, what do the marks ’ and ‘’ used with the Y and the X mean?

Z-> Y’-> X’’ is the sequence of the axes for three rotations. The mark ’ is used to distinguish the reference frame after a rotation from the reference frame before a rotation.

Y’ is the Y-axis of the mobile frame after the second rotation.

X’’ is the X-axis of the mobile frame after the third rotation.

The video below shows how the three rotations are performed:

https://www.youtube.com/watch?v=N7AVc5yYX-k