Modelling of the shoulder complex and application to the design of upper extremities for humanoid robots

Abstract

The classic industrial robot-arm does not need a shoulder in the anatomical sense: it is merely placed on a rotating trunk. The recent development of humanoid robots in which two arms must move laterally to a frame-trunk raises the question of integrating anthropomorphic shoulders. A rigorous analysis of the mobility of the so-called human shoulder complex is necessary in the design of robot shoulders. A kinematic model of the shoulder complex is discussed and its mobility derived. The consideration of a simple clavicle-based equivalent kinematic model has lead to highlight a serial nine d.o.f. anthropomorphic robot structure. By considering a fundamental kinematic model of a robot-arm including a clavicle-like link, it is shown how the elbow singularity can be limited to a restrictive zone of the reachable volume