Millipedes suggest decentralized trunk–limb coordination control is essential for inter-limb coordination in many-legged locomotion

Abstract Many-legged arthropods, such as myriapods, exhibit coordinated stepping patterns during walking. Although they are known to use similar inter-limb coordination patterns across species, it remains elusive whether common control principles exist for many-legged locomotion. To address this issue, we observed millipede walking and found that subtle trunk-pitch bending, coordinated with leg movements, sometimes appears. Drawing inspiration from this finding, we hypothesized that inter-limb coordination in many-legged locomotion could be generated via trunk–limb coordination control. To test this hypothesis, we constructed a neuro-mechanical model of many-legged animals and proposed a simple trunk–limb coordination control based on local sensory feedback. In simulations, we verified that our model can reproduce the inter-limb coordination of many-legged arthropods with various leg numbers. We expect that our model will provide new insights into the control principles underlying many-legged locomotion.