Simscape™ Driveline™ software shares the limitations of Simscape software concerning Simulink® features and tools. For Simscape limitations, see Limitations (Simscape).
Simscape Driveline software also has additional limitations of its own.
If you use the Variable Ratio Transmission block in your model, you might make your simulation slower or less accurate, depending on where the variable ratio comes from. A physical signal input defines the variable ratio as a function of time.
If this time function is defined autonomously, independently of the dynamics of the physical system, the variable ratio is not a simulation problem.
If this time function is defined in terms of feedback from the physical system itself, the variable ratio makes the physical-mathematical model into an Index-2 differential-algebraic equation (DAE) system. Its solution requires two differentiations of constraints and results in simulation warnings or errors.
To avoid this problem, do one of the following:
Remove the Variable Ratio Transmission blocks that use physical system feedback to define their variable ratios.
Delay the feedback signal, so that the feedback is no longer instantaneous.