Discussion: “A Simple Switching Control for Linear Systems to Assure Nonovershooting Step Responses” (Zhu, B., and Cai, K. Y., 2012, ASME J. Dyn. Syst. Meas., Control, 134, p. 034503)

This paper offers some comments on the article by Zhu and Cai (2012, “A Simple Switching Control for Linear Systems to Assure Nonovershooting Step Responses,” ASME J. Dyn. Syst. Meas., Control, 134, p. 034503). The authors offered a nonlinear switching scheme to obtain a nonovershooting step response from a linear plant, and motivated their method by showing that no linear Proportional-Integral-Derivative (PID) controller could achieve a nonovershooting response for a plant in the form of a triple integrator. In this paper, we show via an example that a linear state feedback controller in conjunction with a Luenberger observer can be found to achieve a nonovershooting response for a triple integrator.