A Bio-Inspired Quadruped Robot with a Global Compliant Spine

A compliant spine of one-piece elastic material is designed to replace the rigid trunk of a quadruped robot to improve motion coordination among the four legs and postural stability of the trunk. Based on deformation mechanism of elastic material and discretized pseudo rigid body, the shape and dimensions of the compliant spine are designed, and the stress-strain distributions of three different spines are analyzed comparatively. The biologically-inspired central pattern generator is modeled to produce position trajectories for the active joints of the quadruped robot. The effects of the compliant spine on walking of the quadruped robot are evaluated via dynamic simulations. The results show the compliant spine can improve the coordination and postural stability positively. The physical robot is built and can walk compliantly and perform multiple movements.