Improvement of PIO funnel control performance using future distance estimation

Abstract

PID funnel control, with time varying control gain strategy, is one of the effective control methods for nonlinear systems. This control strategy requires no system identification, and can ensure not only the transient response behavior but also the steady state error of the system using predefined arbitrary funnel boundaries. In general, the PID Funnel Controller (PID-FC) uses the vertical distance between norm of the error and its predefined funnel boundary including the vertical distance between norm of error derivative and funnel boundary of error derivative for computing the control signal. This paper presents the improvement of PID-FC performance using future distance (minimal distance) estimation. The efficiency of the conventional PID-FC and the modified PID-FC are compared. These regulators are applied for the velocity control of a water hydraulic servo motor system. The simulation results show that the future distance estimation can improve the efficiency of the PID-FC.