Sliding Mode Control Applied for Flutter Suppression of a Nonlinear Aero-elastic System

This paper presents a Sliding Mode Control (SMC) system for the stabilization of an Aero-Servo-Elastic (ASE) system with structural nonlinearities at subsonic flight speed. For this research, a 2 DOF aero-elastic model of a wing section developed. For the aim of control, a single control surface associated with SMC technique is used. This control system suppresses flutter as well as the vibration level in sub-critical and postflutter speeds. For state-space representation of the model, the measured pitch angle, plunge displacement and their derivatives are allocated as state vector, andcontrol surface deflection as input command. For a given initial state conditions, two modes of open loop and closed loop control system are carried out. It is shown that the open loop system with a nonlinear structure in subsonic regimes is unstable with Limit Cycle Oscillations (LCOs). However, the closed loop system is asymptotically stable and converges to the origin. Therefore, the proposed approach has a good performance for suppressing flutter and LCOs, as well as short time response compared to other nonlinear methods such as State Dependence Riccati Equation or so-called SDRE method.

کلیدواژه ها:

Flutter ، Limit Cycle Oscillation (LCO) ، Sliding Mode Control (SMC) ، Regular Form Approach (RFA)