“…It can be used to make 2 M. DI BERNARDO, U. MONTANARO, J. M. OLM, S. SANTINI a PWL plant track asymptotically the states of a smooth or PWL reference model. As shown in the paper, a proof of asymptotic stability can be obtained in both cases under the assumption that the reference model is quadratically stable (Q-stable) [11], that is, it admits a common quadratic Lyapunov function when unforced. Indeed, when this is verified, it is possible to follow the steps of Landaus' passivity-based classical proof and recast the closed-loop error system as a feedback system.…”