Limit cycle oscillation suppression of an airfoil based on sliding mode control law

Limit cycle oscillation happens in airfoil systems with freeplay nonlinearity within a specific velocity range. Because the traditional linear control law’s limit cycle suppression effect is typically insignificant and its robustness is insufficient, a corresponding nonlinear control law must be designed in order to improve the system’s control effect and robustness. According to this article, the limit cycle speed range is optimized between 11.4−16.9 m/s and 12.9−19.2 m/s. The linear quadratic regulartor (LQR) control law is created for the 2D airfoil aeroelastic system with freeplay nonlinearity. At the same time, the sliding mode control law (SMC) is designed for the 2D airfoil aeroelastic system with freeplay nonlinearity above, it shows that the speed range of the limit cycle is optimized from 11.4−16.9 m/s to 29.4−39.3 m/s. The result of the calculating example shows that the SMC law is better than that of LQR for nonlinear systems in this paper.