Human-humanoid physical interaction realizing force following and task fulfillment

The authors describe the control methods used for a humanoid's compliant behavior following human force and motions while fulfilling given tasks under various constraint conditions during Physical InterFerence (PIF) with a human. PIF is a form of physical interaction viewed from the robot's point of view. In cases of PIF occurrence, PIF Adapting Behaviors for attenuating physical influences caused by PIF on both a human body and a robots' task are required. First, a base control method for compliantly following PIF by coordinating multiple joints of the arms and trunk is presented. By utilizing this method, PIF force produced on several areas of the robot's entire body is efficiently reduced. Next, the control methods for fulfilling given tasks, as well as following PIF at the same time, are proposed. In these methods, the idea is incorporated that if the utilization of redundancy is needed for task fulfillment or constraint conditions and attributes of the given task are changed, the role of each joint needs to change as well. Adapting to the diversity of task attributes and also the necessity of utilizing redundancy, the proposed control methods enable the robots to realize both force following and task fulfillment at the same time. Finally, from the evaluation of the experiments, it was confirmed that the proposed methods realize a humanoid's capability of compliantly adapting to human motions while fulfilling tasks by efficiently utilizing redundancy.