Experimental measurement of fingerpad deformation during active manipulation of objects with an off-centered mass

This thesis explores object manipulation with precision grip. In particular, we observe the changes due to the addition of an off-centered mass, causing a torque. Different levels of torques are studied to emphasise variations due to the torque level. We also aim to observe the adaptation of the subjects by doing catch trials for which we change the torque condition. During the catches, we can see the adaptation of the subjects, being first influenced by their previous experience, before catching up to the current condition to handle properly the new load. Finally, we try to identify the signals responsible for this adaptation. We mainly look at the torque on the fingers and the strains on the fingertip. This last is our main point of interest, we try to prove that the information from the deformations of the fingertip is used by the central nervous system to identify the conditions of the object manipulation. These deformations could therefore initiate the adaptation of the subjects. This study aims to lead to a better understanding of the grip control that could be useful for patients’ rehabilitation, disease diagnosis, and even treatment.