Mobile manipulation of humanoids-real-time control based on manipulability and stability

A real-time control method for a humanoid in mobile manipulation, doing tasks with its arms while moving, is proposed. The arm tips always follow their desired position with external force applied by impedance control, for carrying out a given task with the arms. An evaluation function consisting of not only stability but also arm manipulability-both are important for mobile manipulation-is defined; the humanoid controls its body and legs so that this evaluation may be optimal. As a result, the humanoid autonomously steps or keeps standing, coordinating with the arm tips motion. The effectiveness and usefulness of the proposed method are ascertained by computer simulations on a humanoid of human-size and experiments using a small experimental robot.