Misalignment - Flexible Coupling - Wrong Definition of a Variable

[murilloabs]

In misalignment.py, the variable 'fib' is incorrectly defined according to the reference paper.

We must swap the coordinate system using the Y and X axes to implement these calculations of Xia (2019), the reference adopted, on ROSS. So the representation becomes Z {Xia (2019)} = X {ROSS} and Y {Xia (2019)} = Y {ROSS}. This modification was done correctly in other parts of the code. However, I have found a mistake in the 'beta' definition.

According to Xia (2019), the tangent of 'beta' is defined as the fraction between the parallel misalignment in the Z and Y axes. So In ROSS 'beta' should be the arctan(Xmisalignment / Ymisalignment), which has not occurred. It was defined wrongly as arctan(Ymisalignment / Xmisalignment).

The pictures below show the 'beta' definition on the paper and the one presented in ROSS.

Definition in Xia(2019):

Definition of ROSS:

It's important to ensure that the other variables are correctly defined according to the reference paper and the changes needed.