Stability of Control Systems with Time-varying Sampling

For digital control systems comprising a linear digital controller and a continuous plant with time-varying sampling periods, some stability conditions of the nontrivial equilibrium of both linear and nonlinear digital control systems in the Lyapunov sense are obtained. The existing stability results are extended to general digital control systems consisting of nonlinear continuous plants and nonlinear digital controllers. Meanwhile, Langrange stability problem of nonlinear digital control systems with slowly varying exogenous input signal is studied, too. Langrange stability conditions are derived for such systems whether the quantization effects are considered or not.