Whole-body cooperative balanced motion generation for reaching

Abstract

This paper addresses a constructing method of a system that realizes whole body reaching motion of humanoids. Humanoids have many redundant DOFs for reaching, and even the base can be moved by making the robot step. Therefore there are infinite postures as solutions of final reaching posture, and there are also infinite solutions for reaching trajectory that realizes a final reaching posture. It is, however, difficult to find an appropriate solution because of the constraint of dynamical balance, relatively narrow movabIe range for each angle. We prepared basic postures heuristically, and a final reaching posture is generated by modifying one of them. This method enables to implement heuristics easily, such as, kneeling down is suitable for reaching near the ground. Methods that compose the reaching system, such as, basic posture selection, modification of posture for generating final reaching posture, balance compensation, footstep planning to realize desired feet position, and generation and execution of whole body motion to final reaching posture are described. Reaching to manually set position, and picking up a bat at various posture using visual information are shown as experiments to show the performance of the system.