Online modification of reaching control policy in response to asymmetrical changes in target shape

Details

Supervisors

Lefèvre, Philippe

Faculty

Ecole polytechnique de Louvain

Degree label

Master [120] : ingénieur civil mécanicien, à finalité spécialisée

Abstract

For the past 20 years, more and more studies have had their focus on the forward-reaching movements. There have been studies on the size of the target, its structure, the presence of obstacles on the way, the control policy used, theories on optimal feedback control models etc. In this thesis, we looked at the change in target shape in an asymmetrical way and the impact on the control policy. To do so, participants had to perform a forward-reaching movement with their hand in order to reach a target located further ahead. That target, initially a wide rectangle centered with respect to the y-axis, could change into a narrower rectangle off-centered either to the left or to the right, or stay the same. A mechanical load could be applied on the hand during the movement as well. Both kinematics and muscular activities, collected with electromyography, were analyzed. We found significant differences between the trials where both perturbations were in opposite directions and the others, such as earlier and higher responses probably due to the urgency and the more complicated new task, longer reaching times that could be explained by a significant modification in the control policy in comparison to the other trials. We thus concluded that an asymmetrical change in the goal target indeed affects the control policy and the way the new task is handled.