Simple Internal Model-Based Robust Control Design for a Non-Minimum Phase Unmanned Aerial Vehicle

Abstract

Robust control has been successful in enabling flight stability and performance for UAVs. This paper presents a simple explainable robust control design for UAV platforms with non-minimum phase (NMP) zero characteristics in their model. The paper contributes to economic (simple) robust control design by addressing the NMP model’s characteristics via Internal Model Control (IMC) and its impact on the UAV pitch response performance. The proposed design is compared with a Parallel Feedback Control Design (PFCD) scheme for the same vehicle platform, for fair comparison. Simulation results illustrate the achievement of the proposed control designs for the UAV platform; only the pitch control is addressed. A by-product of this work is the interpretation of different ways of manipulating the non-minimum phase plant model, so-called ‘modelling for control’, to enable the simple controller design. The work in this paper underpins the simplicity and robustness of the IMC technique for the NMP UAV platform, which further supports the explainability of the control structure relative to performance.