Auto-tuning fractional-order fast terminal sliding mode control of a nonlinear aeroelastic system with uncertainty

Purpose This study aims to achieve the suppression of limit-cycle oscillations (LCOs) of a typical wing section by the robust sliding mode strategy based on fuzzy logic inference scheme (FLIS), finite time disturbance observer (FTDO) and fractional-order fast terminal sliding mode control (FOFTSMC) techniques. Design/methodology/approach To estimate extreme gust load disturbances to bolster the system’s robustness, the FTDO is designed. To enhance the adaptability to parameter uncertainties, a dynamic adjustment of the switching control gain through an FLIS is proposed. To enable finite-time stability and faster convergence of the system, an FOFTSMC is developed. Combined with the FTDO, FLIS and FOFTSMC techniques, a robust sliding mode method is proposed to achieve the suppression of LCOs. Findings An FLIS- and FTDO-based sliding mode method with the FOFTSMC technique is developed to achieve the suppression of LCOs under varying external loads and parameter conditions. And simulation results demonstrate the effectiveness of the proposed method. Originality/value No studies have yet incorporated fractional-order calculus into the terminal sliding mode control of the suppression of LCOs. Moreover, in the design of active suppression control laws for wing flutter, few studies have developed a finite-time designing framework. This study proposes a suppression scheme based on FTDO and FOFTSMC to address these issues and achieve satisfactory performance in the suppression of LCOs.