Simscape V-Belt Pulley Network

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Felix Schönig
Felix Schönig on 17 Sep 2020
I am trying to model a pulley network with several pulleys, inertias, and so on. First I modeled it with "ideal" pulleys without slip. Then later I got some data about cable type, wrap angles and so on. I changed the belt pulley blocks to V-belt, adjusted the number of V's (to 7) and the sheave angle (39°). Then, nothing worked anymore. On some changed the pulleys would just be stuck and not turn at all (or just with a radial velocity of 1e-142 rad/s), on some tries the solver just told me to go home and canceled the simulation attempt.
I tried breaking it down, and here I am with the most basic pulley system and it´s not working:
Pulley settings are identical, other tabs in the pulley settings are untouched:
I am getting these errors:
=== Simulation (Elapsed: 1 sec) ===
Warning:The model may not give enough information to make it possible to solve for values of some of its variables. Specific advice is given below.
all components and nodal across variables involved
Cannot solve for one or more variables:
'Pulley_1.A.v' (Velocity)
'Pulley_1.B.v' (Velocity)
'Pulley_1.rel_velocity' (Pulley-belt relative velocity)
'Pulley_2.A.v' (Velocity)
'Pulley_2.B.v' (Velocity)
'Pulley_2.rel_velocity' (Pulley-belt relative velocity)
'Tensioner_1.C.v' (Velocity)
'Tensioner_1.Damper.C.v' (Velocity)
'Tensioner_1.Damper.R.v' (Velocity)
'Tensioner_1.R.v' (Velocity)
'Tensioner_1.Spring.C.v' (Velocity)
'Tensioner_1.Spring.R.v' (Velocity)
'Tensioner_2.C.v' (Velocity)
'Tensioner_2.Damper.C.v' (Velocity)
'Tensioner_2.Damper.R.v' (Velocity)
'Tensioner_2.R.v' (Velocity)
'Tensioner_2.Spring.C.v' (Velocity)
'Tensioner_2.Spring.R.v' (Velocity)
Problems possible for transient initialization, as well as stepsize control for transient solve, due to equations (including nonlinear equations) of one or more components:
all components involved
'untitled/Pulley 1'
Equation locations are:
'C:\Program Files\MATLAB\R2020a\toolbox\physmod\sdl\sdl\+sdl\+couplings\belt_pulley.sscp' (no line number info)
'C:\Program Files\MATLAB\R2020a\toolbox\physmod\sdl\sdl\+sdl\+couplings\belt_pulley.sscp' (no line number info)
'untitled/Pulley 2'
Equation locations are:
'C:\Program Files\MATLAB\R2020a\toolbox\physmod\sdl\sdl\+sdl\+couplings\belt_pulley.sscp' (no line number info)
'C:\Program Files\MATLAB\R2020a\toolbox\physmod\sdl\sdl\+sdl\+couplings\belt_pulley.sscp' (no line number info)
'untitled/Tensioner 1/Damper'
Equation locations are:
'C:\Program Files\MATLAB\R2020a\toolbox\physmod\simscape\library\m\+foundation\+mechanical\+translational\branch.ssc' (line 23)
'C:\Program Files\MATLAB\R2020a\toolbox\physmod\simscape\library\m\+foundation\+mechanical\+translational\damper.ssc' (line 17)
'untitled/Tensioner 1/Spring'
Equation locations are:
'C:\Program Files\MATLAB\R2020a\toolbox\physmod\simscape\library\m\+foundation\+mechanical\+translational\spring.ssc' (line 21)
'C:\Program Files\MATLAB\R2020a\toolbox\physmod\simscape\library\m\+foundation\+mechanical\+translational\spring.ssc' (line 22)
'untitled/Tensioner 2/Damper'
Equation locations are:
'C:\Program Files\MATLAB\R2020a\toolbox\physmod\simscape\library\m\+foundation\+mechanical\+translational\branch.ssc' (line 23)
'C:\Program Files\MATLAB\R2020a\toolbox\physmod\simscape\library\m\+foundation\+mechanical\+translational\damper.ssc' (line 17)
'untitled/Tensioner 2/Spring'
Equation locations are:
'C:\Program Files\MATLAB\R2020a\toolbox\physmod\simscape\library\m\+foundation\+mechanical\+translational\spring.ssc' (line 21)
'C:\Program Files\MATLAB\R2020a\toolbox\physmod\simscape\library\m\+foundation\+mechanical\+translational\spring.ssc' (line 22)
Warning:The model may not give enough information to make it possible to solve for values of some of its variables. Specific advice is given below.
all components and nodal across variables involved
Cannot solve for one or more variables:
'Pulley_1.A.v' (Velocity)
'Pulley_1.B.v' (Velocity)
'Pulley_1.rel_velocity' (Pulley-belt relative velocity)
'Pulley_2.A.v' (Velocity)
'Pulley_2.B.v' (Velocity)
'Pulley_2.rel_velocity' (Pulley-belt relative velocity)
'Tensioner_1.C.v' (Velocity)
'Tensioner_1.Damper.C.v' (Velocity)
'Tensioner_1.Damper.R.v' (Velocity)
'Tensioner_1.R.v' (Velocity)
'Tensioner_1.Spring.C.v' (Velocity)
'Tensioner_1.Spring.R.v' (Velocity)
'Tensioner_2.C.v' (Velocity)
'Tensioner_2.Damper.C.v' (Velocity)
'Tensioner_2.Damper.R.v' (Velocity)
'Tensioner_2.R.v' (Velocity)
'Tensioner_2.Spring.C.v' (Velocity)
'Tensioner_2.Spring.R.v' (Velocity)
Error:An error occurred while running the simulation and the simulation was terminated
Caused by:
Solver encountered an error while simulating model 'untitled' at time 0 and cannot continue. Please check the model for errors.
Solver could not solve the system of algebraic equations because a singular iteration matrix was encountered. Consider providing more accurate initial conditions. If the problem persists, check the model structure and values of parameters.
The tensioners are spring/damper systems with 5000 N/m and 500 N/(m/s).
Can anyone help me? I am on this for hours, and it must be so simple. I really should quit engineering and do something less depressing...

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