The development of a mobile humanoid robot with varying joint stiffness waist

A mobile humanoid robot named YIREN has been developed as a platform for the research on intelligent robotics. The robot consists of 23 degrees of freedom (DOF), including the mobile platform, waist, torso, arms, neck and head, and it has two peculiarities: a waist mechanism that could adjust the mechanical compliance suitably and a mobile platform which is an omni-directional mobile robot with orthogonal-wheel assemblies. The design was mainly focused on two essential requirements of safety and mobility. This study aimed at realizing passive compliance of the mobile humanoid robot by its waist, and developing its autonomous navigation ability by its mobile platform. This paper presented a waist mechanism that could vary the joint stiffness. The influence of this waist on the compliant characteristics and the stability of the whole body were studied. The mobile humanoid robot that employs this waist is appropriate for the human-robot cooperative tasks, because it can realize safety motion by performing the waist and varying the joint stiffness while is operating.