  Periodic event-triggered control (PETC) evaluates the triggering rule
periodically and is well-suited for implementation on digital platforms. This
paper investigates PETC design for nonlinear systems affected by external
disturbances under the impulsive system formulation. Sufficient conditions are
provided to ensure the input-to-state stability of the resulting closed-loop
system for the state feedback and the observer-based output feedback
configurations separately. For each configuration, the sampling period and the
triggering functions are provided explicitly. Sufficient conditions in the form
of linear matrix inequalities are provided for the PETC design of incrementally
quadratic nonlinear systems. Two examples are given to illustrate the
effectiveness of the proposed method.
