Reference Manual Demo: AnyKinPointSurface File: AnyKinPointSurface.any kinematic analysis failes

#1

Hello everyone,

i would like to run the kinematic analysis in the AnyKinPointSurface.any file from the AnyBody Reference manual. Unfortunatly i get the following error message:

  1. Kinematics (Operation: Main.MyStudy.Kinematics):
    0.0) PreOperation (Operation: Main.MyStudy.Kinematics.PreOperation):
    0.0.0) InitialConditions (Operation: Main.MyStudy.InitialConditions):
    0.0.0) …Design variables have been updated.
    0.0.1) …Load-time positions have been re-established.
    ERROR(OBJ.MCH.KIN3) : D:/omar/D…s/A…2/C…s/AnyKinPointSurface.any(204) : MyStudy.InitialConditions : Kinematic analysis failed in time step 0 : Indefinite velocities
#2

Thanks for reporting this @omarel-edrissi. There seem to be some weird numerical issues here. If I just changed the starting guess slightly by altering the initial positions of rotating segments the solver seems to find a solution.

      AnySeg RotatingObject ={
        r0={0,0.0,0.0};
        Axes0 = RotMat(0.01,x); // <- add this line

This has no effect kinematic solution but only perturbs the starting guess. We will try to look into why this happens in the newest version of AnyBody…