Passive mechanisms in flying insects and applications in bio-inspired flapping-wing micro air vehicles.

Insect flight systems exhibit intricate biomechanical adaptations enabling complex aerial manoeuvres. Their extraordinary flight capabilities, including sustained hovering, precise landing and agile manoeuvres, have secured insects' ecological dominance. This aerial proficiency persists despite neural constraints, with the nervous system allocating merely milligram-scale resources primarily for visual processing, which presents significant challenges in regulating dynamic flight control solely through active neuromuscular activation. Evolutionary innovations have addressed this biosystem paradox through synergistic integration of passive mechanisms that complement neural control. These biomechanical adaptations critically contribute to wing motion initiation and termination, flight stabilization and disturbance compensation in severe environments. This review synthesizes current research progress on passive mechanisms in insect flight systems, aiming to establish foundational knowledge frameworks and identify critical research gaps for future investigations while highlighting bio-inspired implications for flapping-wing micro air vehicles.