An Inchworm-Inspired Fast-Moving Micro Flexible Robot for Autonomous Terrain-Adaptive Exploration

Abstract

Soft robots with motion sensing can achieve motion feedback and monitor environmental changes. Motion sensing significantly expands the potential applications of soft robots in exploration and other fields. This study investigates an inchworm-like miniature soft robot capable of rapid locomotion and autonomous terrain-adaptive exploration. The motion is enabled by two key innovations: (1) a piezoelectric driving body that harnesses the substantial expansion-contraction deformation through an enhanced geometric nonlinearity model, overcoming limitations of conventional small-deformation theories, and (2) the adhesive forces produced by electroadhesive pads. This robot can move rapidly on various substrates, reaching a maximum speed of 1.93 body lengths per second. Additionally, the robot exhibits excellent load-bearing capacity and robustness, capable of pushing a payload of 6.8 g (8.35 times its weight of 0.814 g) and resisting strong external forces. The robot shows environmental adaptability in different terrains, such as crawling on rough terrains (including sandpaper, Ra = 10.8 μm), passing through a circular pipe with an inner diameter of 92 mm, descending a 5 mm step, ascending slopes with a 28° inclination, and traversing narrow gaps with a height of 11.5 mm (0.38 times the robot's maximum body height). Furthermore, the integration of an inertial measurement unit (IMU) system provides the robot with motion sensing capabilities, facilitating real-time position detection and environmental mapping.