Control of Poly-Articular Chain Trajectory Using Temporal Sequence of Its Joints Displacements

Abstract

This paper discusses on the role of joint temporal sequence while moving a two-dimensional arm from an initial position to targets into the fingertip workspace in humans. For this purpose, we proposed a general monotonic model of joint asymmetric displacement. Optimization consisted in minimizing least square dis-placement of either fingertip or arm centre of mass from arm initial position to four targets located into fin-gertip workspace, i.e. contralaterally and ipsilaterally. Except for 60° ipsilateral target, results of the simula-tion presented in all cases temporal sequences of the shoulder, the elbow and the wrist. We concluded that primary function of proximal-to-distal or distal-to-proximal joint sequence is to flatten the trajectory of the fingertip or body centre of mass.