DeNOC Based Dynamic Modelling of a Tree Type Humanoid Upper-body Robot with Fixed Base

Abstract

Better dynamic model of humanoid robots helps to study the dynamic interaction of coupled systems, stable locomotion, and the model-based controller design. The dynamic analysis of the tree-type robotic mechanism is complex due to the presence of higher degrees of freedom. This paper presents the forward and inverse dynamic analysis of a tree-type upper body humanoid robot with fixed base. The Newton-Euler (NE) formulation is used for determining the dynamic model. Decoupled Natural Orthogonal Complement (DeNOC) methodology is included in the dynamic modeling to couple the various branches of the tree-type upper body. Torques at various joints are analyzed. This paper also presents a method for deriving the inverse of the Generalized Inertia Matrix (GIM) in forward dynamics.