Whole-Body Modeling and Hierarchical Control of a Humanoid Robot Based on Dual Quaternion Algebra

This paper presents the whole-body modeling and hierarchical control of a humanoid robot. Both forward kinematics and first order differential kinematics are obtained using dual quaternion algebra, whereas the hierarchical control uses the null space of the whole-body Jacobian to execute tasks with lower priority without affecting higher-priority tasks. The proposed technique is evaluated in a realistic simulation by using a humanoid robot with twenty degrees of freedom in a task consisting of three hierarchical levels, namely balance control, servo-visual control and manipulation. The results show that the hierarchy is respected at all times and the robot is stable during the whole task.