Research on Design and Control Method of Flexible Wing Ribs with Chordwise Variable Camber

To improve the continuous chordwise bending performance of morphing wings, this study proposes a rigid-flexible coupled wing rib structure and its control strategy. Initially, the optimal rigid-flexible hybrid configuration was optimized via the mean camber line parameterization and genetic algorithm. For the flexible segment, topology optimization was conducted using the load path method, followed by subspace-based shape-size alternating optimization; bionic "longbow" curved beams and 'S'-shaped substructures were adopted to enhance deformability. Biomimetic pneumatic muscles were used as actuators, and a fuzzy-adjusted PI sliding mode controller was designed to address the issue that traditional PI sliding mode controllers cannot achieve precise control under non-optimal parameters or when there is a significant difference in deformation targets. Experimental results show that when the flexible rib deflects by 15°, the three-rib wing box achieves a 30° deflection, with stresses within the allowable limit of 7075Al-T6 (540 MPa) and a deformation error of only 7.6%. For the 15° downward bending control, the adjustment time is 6.06 s, the steady-state error is 0.19°, and the overshoot is 1.8%. This study verifies the feasibility of the proposed rigid-flexible coupled structure and fuzzy PI-SMC, providing a technical reference for morphing aircraft.