Analysis of the Interaction Torque on the Arm Based on Via-Point Movement

To produce a desired movement, the human motor control system must regular the interaction torque generated owing to the multi-joint structure of the body. In this study, the trajectories of human movements were evaluated considering the interaction torque generated through the elbow and shoulder joints. Measurement experiments were conducted, in which the participants performed movements corresponding to a three-point task, and the results indicated that the interaction torque is correlated with certain characteristics of the trajectories of the arm movements. Moreover, the contribution of the interaction torque in realizing the task differs in the cases of dominant and non-dominant hands. In addition, through a simulation, the interaction torque of simulated trajectories was modulated to examine the corresponding effect on the arm movements. For a point-to-point movement, certain characteristics of the actual movements were reproduced in the simulated trajectories. However, for a three-point movement, the characteristics of the simulated trajectories were only partially similar to those of the measured trajectories. The findings indicate that the interaction torque notably influences the motor control, and the tuning of the interaction torque is more complex than the other criteria of motor control