Analytical Inverse Kinematics of Anthropomorphic Movements for 7-DOF Humanoid Manipulators

Abstract

To obtain anthropomorphic arm postures for a given end-effector position and orientation, a new inverse kinematics method is proposed for seven degrees of freedom (DOF) humanoid manipulators base on the characteristics of human arm postures. The wrist position is determined by the end-effector position and orientation, and then the redundancy resolution of human arm is solved using the elbow twist angle, which is determined by the minimum potential energy measure. Furthermore, the analytical formulation of the inverse kinematics for humanoid manipulators is derived. The results of simulations and experiments prove the similarity with human arm postures and the continuity of the solutions. Finally, the instability of this method is analyzed based on the dexterity of humanoid manipulators, which shows that the humanoid manipulator is singular when the elbow twist angle suddenly changes. Due to the analytical formulation, this method is efficient for the real time control of humanoid manipulators.