Exoskeletal meal assistance system (EMAS II) for progressive muscle dystrophy patient.

This paper introduces a 4-DOFs exoskeletal meal assistance system (EMAS II) for progressive muscle dystrophy patient. It is generally better for the patient to use his/her hands by himself in daily life because active works maintain level of residual functions, health and initiative of him/her. The EMAS II that has a new joystick-type user interface device and three-DOFs on a shoulder part is enhanced for an easier operation and more comfortable support on eating, as the succeeding model of the previous system that has two-DOFs on a shoulder. In order to control the 4-DOFs system by the simple user interface device, the EMAS II simulates upper limb motion patterns of a healthy person. The motion patterns are modeled by extracting correlations between the height of a user's wrist joint and that of the user's elbow joint at the table. Moreover, the EMAS II automatically brings user's hand up to his/her mouth or back to a table when he/she pushes a preset switch on the interface device. Therefore a user has only to control a position of his/her wrist to pick or scoop foods and then flip the switch to start automatic mode, while a height of the elbow joint is automatically controlled by the EMAS II itself. The results of experiments, where a healthy subject regarded as a muscle dystrophy patient eats a meal with EMAS II, show that the subject finished her meal in a natural way in 18 minutes 40 seconds which was within a recommended time of 30 minutes.