Abstract:

Dynamics of high-performance aircraft are highly nonlinear, time-varying and strongly coupled. Conventional control designs are based on the assumption that the system works at a specific operating point and described by linear perturbation equations. In addition, the longitudinal motion is assumed to be independent of lateral motion. Therefore the equations can be decoupled and treated independently. The objective of this work is to develop a new sliding mode control (SMC) designs for the nonlinear flight model with actuator dynamics. The key feature of the scheme is that prior knowledge of uncertainties of both the upper bound and matched condition is not required. The controller consists of a nominal controller and an adaptive sliding controller. The proposed SMC technique is applied to a nonlinear 6-DOF flight dynamics model. Simulations demonstrate robustness and accurate tracking in the presence of system uncertainties.

Key words: nonlinear systems, adaptive control, sliding control, flight control