Design of nonlinear PID controllers using system step response

Abstract This paper presents a computer-aided control engineering (CACE) environment for synthesis of nonlinear and time-varying PID controllers for use with systems that have highly nonlinear plants. The implemented CACE technique is based on a four-step systematic procedure. The nonlinear PID controller design methodology and the associated software allow the user to synthesize for robust nonlinear closed-loop feedback systems whose dynamic and static behaviours would satisfy a set of user-defined performance measures with a little sensitivity to the amplitude level of the excitation command as possible. The CACE environment performs a complete cycle of steps starting from plant description to time-domain modelling, linear system identification, controller synthesis, and design validation via digital simulation.