A novel approach to stable zero dynamics of sampled-data models for nonlinear systems in backward triangle sample and hold case.

Highlights • An approximate sampled-data model for nonlinear systems with backward triangle sample and hold function is first derived. • Obtaining a novel expression and stable conditions of zero dynamics in the obtained sampled-data model. • Zero dynamics of the resulting model can be arbitrarily placed by selecting proper parameters from the stable conditions. • Nonlinear systems using those methods in this paper have better control performance. Abstract It is well known that a good approximate sampled-data model is very important in sampled-data controller design of nonlinear continuous-time system because the exact sampled-data model of nonlinear continuous-time system is often unavailable. It is also a truth that unstable zero dynamics of sampled-data model greatly limit the control performance of the system. This paper investigates the properties of approximate sampled-data model and its zero dynamics, which generated during the process of discretization with backward triangle sample and hold (BTSH). Further, a more accurate sampled-data model is obtained for nonlinear systems in BTSH case. The zero dynamics form and stable conditions are also derived. Finally, numerical examples are provided to better show the results developed in this paper. [ABSTRACT FROM AUTHOR]