Design of Multiloop Controller for Three Tank Process Using Cdm Techniques

Abstract

In this study the controller forthree tank multi loop system is designed using coefficient Diagram method. Coefficient Diagram Method is one of the polynomial methods in control design. The controller designed by using CDM technique is based on the coefficients of the characteristics polynomial of the closed loop system according to the convenient performance such as equivalent time constant, stability indices and stability limit. Contro ller is designed for the threetank process by using CDM Techniques;the simulation results show that the proposed control strategies have good set point tracking and better responsecapability. Most of the processes industry in power plants, refinery process, aircrafts and chemical industries are multivariable or multi-input multi-output (MIMO) and control of these MIMO processes are more complicated than SISO processes. The strategies are used to design a controller for the S ingle input and single output (SISO) process cannot be applied for Multi input and multi output (MI MO) process because of the more interaction between the two loops. The different methods have been presented in the literature for control (1) of MIMO process. Proportional -integral-derivative (PID) or Proportional-Integral (PI) based controllers are used very commonly to control three tank systems. Generalized synthesis method used to tuning the controller parameters. Generally the two types of control schemes are available to control the MIMO processes. The first control scheme or multiloop control scheme, where single loop controller are used to in the form of diagonal matrix is one.. The second scheme is a (3) multivariable controller known as the centralized controller. Matrix is not a diagonal one. In this paper, the Coefficient Diagram Method (CDM) can be used to design a controller for MIMO process. Now the CDM is well established approach to design a controller, which provides an outstanding time domain characteristics of closed loop systems. Basically the CDM is based on pole assignment, which can locate of the closed-loop system are used to obtained the predetermined values. Although it has been used to demonstrate the design based on CDM. It has some robustness and is possible to see that of the smooth response without oscillation in change in the model of the process exists.