Main Content

Troubleshoot Overconstrained and Conflicting Degrees of Freedom

Analyzing and counting the driveline degrees of freedom (DoFs) are essential to fixing one type of simulation error. For more information, see Driveline Degrees of Freedom.

To run successfully, your driveline simulation must have a positive number of independent DoFs, from the start to the end of the simulation. Furthermore, the model DoFs must not conflict with each other.

If you encounter a simulation error where the driveline cannot move, check whether the number NDoF of independent DoFs is positive, and whether the DoFs do not conflict with each other.

Checking the Number of DoFs

If NDoF is not positive:

  • Remove one or more constraining blocks, such as Gears, Clutches or clutch-like elements, and Mechanical Rotational References.

  • Remove one or more Ideal Angular Velocity Source blocks.

Try one or both of these steps repeatedly until you locate the origin or origins of the simulation failure and make NDoF positive.

Checking the Consistency of DoFs

Consider also whether two or more DoFs are in conflict. For example, check whether two velocity sources are trying to move a single DoF in two different ways. Such a configuration creates a motion conflict and leads to a simulation error.