On-line human motion transition and control for humanoid upper body manipulation

This paper represents the method to manipulate the objects with the upper body of a humanoid robot by capturing human motions in real-time. To control the upper body of a humanoid robot and make it behave as a human does, we define several virtual spring-damper elements between the humanoid robot and the human. The resultant motions given by the virtual forces of the elements lead the humanoid robot to move as the human acts. We employ the forward dynamics formulation to represent the dynamics model of humanoid upper body as an articulated body system with those virtual spring-damper elements for obtaining the resultant motions. Due to considering the whole dynamics of upper body, it is easy to resolve the ill-posedness or singularity of inverse kinematics problem and to involve external forces. The present method may be of use in teaching a humanoid robot working skills or detailed motions of a human. For validating the proposed method, we transited human motions to a humanoid robot using a motion capture system and controlled the robot to grasp an object passed by a person simultaneously.