Hi, I'm new. With the document "Coil Spring Simulation using CATIA DMU Kinematics", I have tested something that could be easier
My approach is to record frame by frame as in the document but with a macro that update automatically the product and increase the position of parts
I don't use DMU kinematics but i think we can do similarly
I use a constraint of distance between to parts and use it in parameter in the building of the spring
The macro is like this
Code
Sub CATMain()
'---- Début du script de résolution de l'objet : Product1
Dim productDocument1 As ProductDocument
Set productDocument1 = CATIA.ActiveDocument
Dim product1 As Product
Set product1 = productDocument1.Product
Dim constraints1 As Constraints
Set constraints1 = product1.Connections("CATIAConstraints")
Dim constraint1 As Constraint
Set constraint1 = constraints1.Item("Décalage.7") 'here you define the parameter to drive
'---- Fin du script de résolution
product1.Update
For X = 30 To 40 'here you set the extremes values of the movement
constraint1.Dimension.Value = X
product1.Update
Next
End Sub
I hop that could be useful 
sorry if my English is not really right, I m French (as you can see in the code 
)
