An innovative reconfigurable shield-to-leg mechanism for UAVs in built cultural heritage inspection

This paper introduces a reconfigurable structural mechanism for unmanned aerial vehicles that transforms the same mechanical elements from propeller shields into adaptive landing legs. The concept is developed for drones operating in built cultural heritage sites, where safe navigation, stable landing on irregular surfaces, and non-intrusive inspection are critical. The mechanism can be reconfigured according to the flight phase: in flight, it forms a protective enclosure around the propellers to reduce the risk of collision with surrounding structures, while during landing it deploys into independently adjustable legs that adapt to the ground using real-time attitude feedback. The structural design of the drone is presented together with the kinematic and dynamic models of the reconfigurable mechanism. A prototype system was built and experimentally evaluated under controlled laboratory conditions and representative surface configurations. The results demonstrate the self-leveling and stabilization capability of the mechanism under the tested conditions, highlighting the potential of reconfigurable UAV mechanisms for future inspection and monitoring applications in constrained and sensitive cultural heritage environments. This study presents a unified shield-to-leg mechanism for morphing quadcopters. The functional performance of the mechanism in post-touchdown attitude leveling on uneven surfaces was validated using a ground-based physical prototype, while its dynamic stability and disturbance rejection were evaluated in numerical multi-body simulations.