Control of Twin Rotor MIMO System using Robust Generalized Dynamic Inversion

This paper presents the control design approach based on Robust Generalized Dynamic Inversion (RGDI) for the Twin Rotor Multi-input-multi-output System (TRMS). In RGDI control, constraint dynamics is formulated in the particular part, by prescribing the linear time varying constraint differential equation based on the attitude deviation function. The constraint dynamics encapsulates the control objectives and is inverted by using Moore-Penrose Generalized Inverse (MPGI) to generate the required control deflections for stable attitude tracking. The involved null control vector in the auxiliary part, is constructed by designing a proportionality gain matrix, which guarantees asymptotic stability of the body rate dynamics. The singularity problem due to non-square inversion is avoided by implementing dynamic scaling factor. To provide robustness, Sliding Mode term is integrated with GDI to make it RGDI, that will guarantee semi-global practically stable attitude tracking. Numerical simulations are conducted on TRMS simulator to demonstrate the performance of RGDI control under nominal and perturbed flight conditions.