Robust attitude decentralized tracking control for a 3-DOF helicopter with unknown input time-delay

Robust attitude decentralized tracking control problem for a 3-DOF helicopter is investigated. The model of the 3DOF helicopter is described as a MIMO strict-feedback form system with unknown parameters, bounded disturbances, nonlinear uncertain coupling effects and unknown input-delay. A new design method based on signal compensation technique and backstepping strategy is proposed. Based on the signal compensation method, at each backstepping design step, a robust controller consists of a nominal controller and a robust compensator. Robust practical tracking stability condition is derived in terms of linear matrix inequalities (LMIs). Experimental results demonstrate the effectiveness of the proposed control strategy.