Development of Musculoskeletal Spine Structure with Variable Stiffness to Resist Force of Neck Muscles

Abstract

Human has a strong spine which can generate dynamic and flexible motion. We focus on its mechanisms and implement them to a robot spine of a musculoskeletal humanoid through hardware design. First, this paper describes methods to develop the robot spine which has both strength and flexibility. We separated 3 vertebra groups from the spine like a human and applied some machining methods to each group. Second, we show a human-like muscle arrangement of the spine including planar muscles. The planar muscles have larger surface and power than linear muscles designed with conventional methods. Therefore, the spine can keep its posture even if it receives force by a dynamic arm motion. Finally, we show a variable stiffness system of the spine to resist an impact by which the spine structure and muscles damage. We tested the system in the situation of whiplash injury which often occur in rear-end collision in a vehicle body.