A high-order extended state observer-enhanced controller is proposed to address the problem of velocity and altitude tracking for a hypersonic flight vehicle with strong nonlinearity, parameter uncertainty, and external disturbance. First, the feedback linearization-based control is introduced as the baseline controller, and the nonlinear multi-input/multi-output system is transformed into two integral-chain single-input/single-output systems. And then, the lumped disturbance is extended as a new system state to represent the total effect of the unknown part of nonlinearity, parameter uncertainties, and external disturbances. Consequently, a high-order extended state observer is proposed to estimate all the states of the extended system for each channel of the longitudinal dynamics. With the compensation of the estimated disturbance, a high-order extended state observer-enhance control is investigated to improve the control tracking performance and robustness. Moreover, all the control parameters are associated with the bandwidth, and the stability of the closed-loop system is analyzed. Due to the concise form of the proposed enhanced controller, all of the vehicle information except for the system outputs is not necessary to be obtained. Therefore, a simplification of the control system framework could be accomplished, which reveals an enormous potential in the engineering practice. Simulation results demonstrate the high effectivity and strong robustness of the proposed method for the hypersonic flight vehicle compared with the other controllers.
High-order extended state observer-enhanced control for a hypersonic flight vehicle with parameter uncertainty and external disturbance
2015
Article (Journal)
English