A Pneumatic Sensor-Equipped Hexapod Landing Gear and Gripper System for Gentle Drone Contact with Building Envelopes and Energy Assets

Drones are increasingly used for inspection tasks in modern construction, yet their utility is constrained by the inability to safely land on or interact with fragile surfaces. This paper presents a tactile-sensing, pneumatically actuated hexapod system that enables drones to make controlled, adaptive contact with delicate construction materials—such as glass curtain walls, solar panels, lightweight cladding, and green roof systems—without causing damage. The proposed system integrates six biomimetic soft feet with embedded tactile sensor arrays, allowing drones to perceive contact forces and surface textures in real time. A closed-loop control system modulates pneumatic pressure through dual-chamber actuators, providing both landing impact damping and object manipulation capabilities. Experimental validation demonstrated a 68% reduction in impact force compared to rigid landing gear, with peak contact pressures of only 15 kPa—well below damage thresholds for sensitive materials. The system can securely grasp and manipulate objects up to 1.2 kg with 93% reliability, while integrated capacitive pressure sensors and strain gauges enable material assessment through contact. Beyond enabling safe landings, tactile feedback supports on-contact diagnostics, including detection of subsurface defects invisible to visual inspection. This technology transforms drones from distance-limited visual inspection tools into comprehensive assessment platforms capable of physical interaction, extending application domains in construction inspection while reducing energy consumption by eliminating the need for continuous hovering during detailed inspections.