Dual Actuator Wave-Like Navigator: An Untethered Soft Crawling Robot for Multisurface Locomotion

Abstract

Wave-based mechanisms inspired by traveling wave locomotion in animals have shown great potential use in robots to navigate unstructured environments. Herein, the dual actuator wave-like navigator (DAWN), a multisurface robot employing two actuated helical wave generators to produce continuous traveling waves on flexible link tracks enclosed in elastomer skins, is presented. These skins provide mechanical resilience, enhanced friction, and adaptability on uneven terrain. The robot demonstrates steering and controlled locomotion on flat surfaces, inclines, and declines. To characterize the robot, locomotion tests are performed on plywood, PMMA, and sand, achieving average linear speeds of 16.00, 15.76, and 1.63 mm s⁻¹, respectively. A key innovation is cyclic pneumatic actuation of the skins with actuation frequencies of 0.5 and 0.9 Hz, improving locomotion performance on sand to 2.22 and 2.70 mm s⁻¹. DAWN's capability to move on sand, grass, gravel, and wet soil is also demonstrated. Its modular design enables plug-and-play assembly of components including helical wave generators, flexible link tracks, and elastomer skins, allowing for easy maintenance, modification, and replacements. Potential applications include navigation in complex terrains for search and rescue, inspection, and environmental monitoring.