Dynamic modeling and optimal control of a twin rotor MIMO system

A dynamic model for the characterising of a one-degree-of-freedom (DOF) twin rotor MIMO system (TRMS) in hover is extracted using a black-box system identification technique. The behaviour of the TRMS in certain aspects resembles that of a helicopter. Hence, it is an interesting identification and control problem. Identification for a 1-DOF rigid-body, discrete-time linear model is presented. The extracted model is employed in the design of a feedback LQG compensator. This has a good tracking capability, but requires high control effort and has inadequate authority over residual vibration of the system. These problems are resolved by further augmenting the system with a command path prefilter. The combined feedforward and feedback compensator satisfies the performance objectives and obeys the actuator constraint.