Dimensionality of manifold is best explained at 2
The residual variance at dimension 2 reduces sharply and for dimensionality higher than 2, the residual variance drops very little only by 0.04 in beginning and then becomes almost constant. The robot has 2 degree of freedoms and this is best captured at dimensionality 2 in the scree plot.
The toplogy in 3-Dimension on zooming in looks like a TORUS which is what we actually expect.