A New Analytical Approach for Set-point Weighted 2DOF-PID Controller Design for Integrating Plus Time-Delay Processes: An Experimental Study
Sudipta Chakraborty, Jiwanjot Singh, Asim Kumar Naskar, Sandip Ghosh
Abstract
In many industrial processes, e.g. temperature and level control, chemical reactors can be classified as a variant of integrating plus time-delay system. Controlling these processes is a difficult task due to open-loop instability, which consists of time-delay and unbounded output for bounded input. 1DOF PID control always leads to a large overshoot in set-point tracking for IPTD processes. In a 2DOF PID structure, tuning the set-point weights and the controller parameters is important to achieve good tracking and disturbance rejection properties. But tuning the set-point weights and the parameters of the cascade-feedback controller together is a difficult task. Usually, predetermined values for set-points are chosen, and a controller design is followed. In the present work, an alternative simple approach to obtain controller parameters along with set-point weights is presented which are tuned to yield good tracking and load–disturbance rejection. Explicit controller parameters for different classes of integrating processes are obtained using gain-margin, phase-margin, and inverse plant model which can also be used for controller auto-tuning. To validate the effectiveness of the proposed controller, simulation comparisons with some recently developed methods are included. Moreover, the experimental validation of the proposed controller on a temperature control plant is also presented.