Decoupled Fuzzy Sliding-Mode Control of a Nonlinear Aeroelastic Structure

A decoupled fuzzy sliding-mode control for an aeroelastic system is derived. This aeroelastic dynamic system describes the nonlinear plunge and pitch motions of a wing section, using a single trailing-edge flap as the control input. The decoupled fuzzy sliding-mode control design method is proposed to simultaneously control both the plunge and pitch motions of the aeroelastic system. In this design, a decoupled sliding surface is developed to include all the information of the plunge and pitch motions. By the decoupled sliding surface, the plunge and pitch motions can be driven to zeros simultaneously with single control input. The proposed decoupled fuzzy sliding-mode control comprises two fuzzy inference systems. The slope of the decoupled sliding surface is tuned by a fuzzy inference system to govern the simultaneous control of the plunge and pitch motions with small convergence time. Then the behavior of the plunge and pitch motions is regulated by a fuzzy sliding-mode control system to achieve favorable control performance. A comparison between the adaptive control, fuzzy sliding-mode control and the proposed decoupled fuzzy sliding-mode control for an aeroelastic system is developed. The simulation results verify that the proposed decoupled fuzzy sliding-mode control can achieve favorable control responses for both the plunge and pitch motions.