Local Sensory Feedback Generates Various Wave Gaits in Multi-legged Robots via Embodied Sensorimotor Interaction.

According to the species and situations, multi-legged animals show three wave-like ipsilateral interlimb coordination. The swing leg movements propagate from posterior to anterior (direct-wave), from anterior to posterior (retrograde-wave), and in both directions with a source (source-wave). However, the gait generation mechanism is still unclear because of the complex interaction between neural control and dynamic body systems through sensory information (embodied sensorimotor interaction). Our previous study showed that local sensory feedback has a function to generate the three interlimb coordination observed in multi-legged animals using a simple model. In this study, to further understand the functional role of sensory feedback, we investigate the effect of the sensory feedback on a three-dimensional multi-legged robot model developed. The simulation result with the ten-legged dynamic robot model shows that the sensory feedback also generates various wave gaits in the robot due to the embodied sensorimotor interaction. The generated gaits are not predetermined but emerge in a decentralized manner. Parts of generated gaits are similar to direct and retrograde wave gaits. In addition, sink wave gait, in which the swing movements sink in the center of the robot, is also observed.