A robotic rehabilitation system for cooperative motor training: A preliminary study in a balance seesaw task

A new robotic rehabilitation system for the upper limb is developed to provide a cooperative motor task executing by a pair of trainees/patients toward neuro-rehabilitation including human-human physical interactions. A balance seesaw task was created as an example of a cooperative motor task for enhancing and maintaining training/learning motivation, in which a pair of humans operates two handles of the robotic system and controls the angle of a bar according to the computer graphics on a display so that a ball falls from the bar into a right-to-left moving box. A set of preliminary tests was carried out by six pairs with four healthy subjects under the different four task conditions on dynamic properties of the bar and robotic handles. The results demonstrated that they unconsciously and skillfully regulated the angle of the bar to fall the ball within the period between 8 s to 10 s from the start time. Next, three types of visual or/and motor assistance by the system were designed based on the observed strategies for the target task. Experimental results showed that all types of assistance were worked to succeed the target task, whereas the lack of visual information (i.e., only motor assistance) tended to decay the operational feeling of a trainee/patient in cooperative movements.