Abstract: For the problem of large time-delay and great inertia in the process control field,a new nonlinear PI controller is proposed which can compensate the time-delay features by an aperiodic sampling unit,speed up the adjustment process and reduce the overshoot by a nonlinear PI controller.The simulation of the aperiodic sampling unit and nonlinear unit is realized by the S-Function of MATLAB.Simulation results demonstrate that the new nonlinear PI controller has less overshoot and faster response.In the case of the model-process mismatch,it also has a good performance and robust stability.

Key words: aperiodic sampling, nonlinear, PI controller, simulation