Analysis of Movement Trajectories Focusing on the Interaction Torque in Arm Movements

Abstract

Human motor control system must tame interaction torque that is derived due to the multi-joint structure of the body to propose a desired movement. We attempted to evaluate the trajectories of human movements by focusing on the aspect of interaction torque on human arm movements produced with elbow and shoulder joints. As the results of the measurement experiment in which participants performed movements specified three-point as the task of the experiment, interaction torque relates some characteristics of the trajectories of arm movements and there is the difference of its contribution to achievement of the task between dominant and non-dominant hands. In the simulation experiment, interaction torque of simulated trajectories was distorted to assess the materiality of that on arm movements.

For a point-to-point movement, some characteristics of actual movements were reproduced in simulated trajectories. Meanwhile, for a three-points movement, the characteristics of simulated trajectories were partially similar to that of measured actual trajectories. We assumed that interaction torque was important for motor control whereas explicit tuning of interaction torque is bit circuity compared as other criteria of motor control.