Magnetically Actuated Lamina Emergent Mechanism for Bimodal Crawling and Flipping Locomotion

Abstract

Magnetically actuated elastomeric soft robots are capable of untethered multimodal locomotion due to their ability to adapt to environments. However, they are usually fabricated with soft materials and suffer from structural instabilities under external loads. We designed a multilayer lamina emergent mechanism (LEM) that is capable of crawling and flipping due to its highly coupled kinematics that enables the simplification of multiple joint control. Each LEM layer is designed as a parallelogram linkage that couples four legs arranged in a staggered manner, giving rise to an alternative tetrapod crawling gait with just two degrees of freedom under the influence of a changing magnetic field. The mechanism is capable of controlled flipping without the need for additional actuators or structural components. The mechanism can crawl at a speed of ∼4.5 mm/s (0.1125 body length/s) when actuated at a frequency of 1.0 Hz. It can flip at a speed of ∼60.4 mm/s (1.5 body length/s) when actuated at a frequency of 0.5 Hz. We demonstrated the potential benefits of multimodal locomotion, where the mechanism can flip to travel faster and overcome obstacles, and crawl for more controlled navigation.