Multivariable Control System Design for the Robust control of Twin Rotor MIMO System using Quantitative Feedback Theory

This paper focuses on design of multivariable controller for twin rotor MIMO system (TRMS), a two input two output system with large plant uncertainty using quantitative feedback theory (QFT) methodology. The various QFT based controller for TRMS, reported earlier, consider two approaches; cross coupling effects are neglected in one of them while the other approach employs a decoupler to take into account of the coupling effects. The objective of this paper is to propose a QFT based diagonal robust controller by using the multivariable structure of the TRMS, so that the need for a separate decoupling is completely avoided. Thus the main advantage of this strategy is that the design procedure is made simpler to meet the time domain tracking specifications and robust stability requirement in positioning the pitch and yaw angles of the TRMS.