A small soft-bodied crawling robot with electromagnetic legs and neural control for locomotion on various metal terrains

Soft-bodied crawling animals (like caterpillars and inchworms) exploit their active soft bodies with passive adapt-ability to achieve efficient locomotion and move on multiple terrains. While several research studies have used this principle for robot development, most existing caterpillar/inchworm-inspired soft robots can still crawl on specific terrain (flat, inner, or outer pipes). To advance state-of-the-art soft robotic technology, we propose here a small soft-bodied crawling robot with electromagnetic legs and passive body adaptation. The robot is driven by neural central pattern generator (CPG)-based control. Due to the combination of its actively con-tractable/extendable body, passively adaptable interconnected body joints, and electromagnetic legs, the robot can successfully crawl on a variety of metal terrains, including a flat surface, step, slope, confined space, and an inner (concave surface) and outer (convex surface) pipe in both horizontal and vertical directions. Additionally, it can be steered to navigate through a cluttered environment with obstacles. Using the CPG-based control method, the robot's locomotion speed can be simply regulated by changing a single CPG-frequency control param-eter. This small soft robot has the potential to be employed as a robotic system for inner and outer pipe inspection and confined space exploration in the oil and gas industry.