Bumpless Transfer Control Design of Continuous Integral Sliding Mode Switching Controller for Turbofan Aeroengine

In this paper, a bumpless transfer control design of robust tracking control is proposed to avoid large jumps in fuel flow for turbofan aeroengine speed control system. The control design is divided into two parts: one part is the linear feedback control (LFC) which meets the requirement of bumpless indices, and the other part is the continuous sliding mode control (CSMC). First, the LFC design considering the nominal system without the disturbance and uncertainty is proposed, and the linear feedback coefficients satisfy the bumpless indices. Then, a robust integral sliding mode (RISM) design is proposed, in which the uncertain linear switched system satisfies the given H-infinity robust performance index and can resist the unmatched uncertainty. Consequently, the CSMC ensures that the RISM surface can be reached from the initial time instant. By composing the CSMC with the LFC, the control design achieves the robust trajectory tracking and the suppression of the control signal bumps during switching. Finally, the proposed bumpless transfer control design was applied to a turbofan aeroengine model, and the effectiveness was verified.