Nonregressivity in switched linear circuits and mechanical systems

We analyze several examples of switched linear circuits and a switched spring–mass system to illustrate the physical manifestations of regressivity and nonregressivity for discrete and continuous time systems as well as hybrid discrete/continuous systems from a time scales perspective. These examples highlight the role that nonregressivity plays in modeling and applications, and they point out a fascinating dichotomy between purely continuous systems and discrete, continuous, or hybrid systems. We conclude with a physically realizable null space criterion for inducing nonregressivity.