Mechanical Systems

Modeling Complete Drive Systems

PLECS provides a Mechanical Domain with a comprehensive component library for translational and rotational motion. Included in the library are non-linear blocks for modeling clutches, backlash, hard stops and stick-slip friction. Combined with the electrical and control domains, the mechanical components facilitate the modeling and simulation of complete drive systems such as servomechanisms and electric powertrains for vehicle applications.

Below is an example developed to investigate and mitigate low speed drivetrain oscillation in electric vehicles.

Ideal Clutches and Inelastic Collisions

Analogous to its ideal electrical switches, PLECS features an ideal mechanical clutch that engages and disengages instantaneously. While engaged it makes a  rigid connection between its flanges and while disengaged it transmits zero force (or torque).

PLECS permits connecting an ideal clutch between two bodies and engaging it while the bodies rotate at different speeds. PLECS treats such an event as a perfectly inelastic collision and calculates the common speed after collision based on the conservation law of angular momentum.

This approach not only applies to clutches, but also to the modeling of backlash typically found in coupling elements and gear trains.