Internal Model Controller design for Non-linear System and Linear system with time delay

Abstract

The internal model control (IMC) technique is a widely popular technique due to its simplicity, ease of tuning and its ability to be transformed into the structure of proportional integral derivative (PID) controller. In this thesis, the drawbacks involved in the implementation of conventional IMC technique for the control of linear systems are discussed. The multimodel IMC approach is explained which involves the development of linear models around the equilibrium points of the nonlinear system. Subsequently, the multimodel system is extended for the control of time delayed linear systems, wherein Pade approximation is used for the approximation of time delay, then these models are multiplied by low pass filters to get the controllers which in turn will help with global command via fusion technique. The efficacy of the multimodel IMC technique is investigated for the position control of DC motor. The multimodel approach is interesting when dealing with nonlinear complex and with linear system having time delay. The simulation results are a testimony to the efficacy of the multimodel IMC technique. In this thesis, multi model controller developed will be described in different chapters; the first chapter will contain basic of Internal model control technique and its drawback, the second one will explain the multi model approach and its different types, then the chapter 3 will contain internal multi model controller design for the two different systems (i.e. non linear system and linear system with time delay) and finally the chapter 4 will contain the results obtained from the designed controller.