G. Uday Bhaskar Babu

Fractional filter IMC-PID controller design for second order plus time delay processes

Abstract This article presents a simple method of designing a fractional filter PID controller for second order plus time delay (SOPTD) processes using internal model control (IMC) scheme. There has been limited number of tuning rules for SOPTD processes developed using direct synthesis method and IMC method. The proposed IMC-PID controller using fractional IMC filter results in a controller structure composed of PID controller cascaded with fractional filter. Simulations have been performed on several second order lag dominant and delay significant processes. Robustness checks are performed for variations in the process parameters and robustness analysis is carried out using sensitivity functions. The proposed controller results in an enhanced control performance for nominal process parameters and with parameter variations. In addition, the effect of measurement noise is also studied for set point tracking and load disturbance variations.

Fractional filter IMC-PID controller design for an unstable inverted pendulum system

In this article, a fractional filter internal model control (EMC) based proportional integral derivative (PID) controller is designed for controlling the unstable inverted pendulum system. The system is stabilized by using a compensatory function to cancel out the unstable poles and zeros in the model. Now, the controller is designed for the stabilized model producing a PID controller along with fractional filter. The simulations are performed for set point tracking and disturbance rejection with nominal process model and with perturbations. The results show an improvement in the control performance. Further, robustness analysis is done to check the stability of the closed loop system for parameter uncertainties.