Singularity robust inverse kinematics for a humanoid robot with minimum energy configuration and self-collision avoidance

• Authors: Yuanwei Chua;Keng Peng Tee;Rui Yan
• Venue: Proceedings of the Workshop at SIGGRAPH Asia
• Year: 2012

A singularity robust inverse kinematics procedure with self-collision avoidance, is proposed for a 7 degree-of-freedom (DOF) robot arm, based on the minimization of energy consumption. The robot arm discussed here, is a fully revolute, redundant, open kinematic chain with two spherical joints located at the shoulder and the wrist, connected by a single revolute joint at the elbow. The extra degree of freedom allows the elbow to swivel freely about an axis from the wrist to the shoulder, given a fixed wrist position. Hence multiple solutions for the joint angles exist for each task specification. The optimal arm posture is the solution which requires the least consumption of energy, under joint limits constraint. Subsequently, the solution is passed through a self-collision avoidance module which detects whether robot segments are in close proximity with one another. Repulsive forces which are generated between nearby segments, alters the position of the end effector arm and/or the joint trajectories of the robot arm through prioritization. To complete the framework, the issue of kinematic singularity is handled using the concept of energy minimization.