Simple robot suggests physical interlimb communication is essential for quadruped walking

TLDR

Quadrupeds exhibit versatile gait patterns that depend on speed, environment, and species, generated by limb coordination partly controlled by a central pattern generator, yet the mechanism underlying interlimb coordination remains unclear. The study aims to develop a simple quadruped robot to propose an unconventional CPG model for interlimb coordination. The authors built a minimalistic robot with four decoupled oscillators and local force feedback in each leg to implement the CPG. The robot adapts to changes in weight distribution and speed via local feedback, mimics real quadruped walking, and the results suggest that physical leg interactions are essential for interlimb coordination.

Abstract

Quadrupeds have versatile gait patterns, depending on the locomotion speed, environmental conditions and animal species. These locomotor patterns are generated via the coordination between limbs and are partly controlled by an intraspinal neural network called the central pattern generator (CPG). Although this forms the basis for current control paradigms of interlimb coordination, the mechanism responsible for interlimb coordination remains elusive. By using a minimalistic approach, we have developed a simple-structured quadruped robot, with the help of which we propose an unconventional CPG model that consists of four decoupled oscillators with only local force feedback in each leg. Our robot exhibits good adaptability to changes in weight distribution and walking speed simply by responding to local feedback, and it can mimic the walking patterns of actual quadrupeds. Our proposed CPG-based control method suggests that physical interaction between legs during movements is essential for interlimb coordination in quadruped walking.