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W. Reichenfelser, J Karner, M. Gföhler et al.:
"Feedback control of arm movements using Neuro-Muscular Electrical Stimulation (NMES) combined with a lockable, passive exoskeleton for gravity compensation.";
Frontiers in Neuroscience, 8 (2014), 1 - 16.

Within the European project MUNDUS, an assistive framework was developed for
the support of arm and hand functions during daily life activities in severely impaired
people. This contribution aims at designing a feedback control system for Neuro-Muscular
Electrical Stimulation (NMES) to enable reaching functions in people with no residual
voluntary control of the arm and shoulder due to high level spinal cord injury. NMES is
applied to the deltoids and the biceps muscles and integrated with a three degrees of
freedom (DoFs) passive exoskeleton, which partially compensates gravitational forces and
allows to lock each DOF. The user is able to choose the target hand position and to trigger
actions using an eyetracker system. The target position is selected by using the eyetracker
and determined by a marker-based tracking system using Microsoft Kinect. A central
controller, i.e., a finite state machine, issues a sequence of basic movement commands
to the real-time arm controller. The NMES control algorithm sequentially controls each
joint angle while locking the other DoFs. Daily activities, such as drinking, brushing hair,
pushing an alarm button, etc., can be supported by the system. The robust and easily
tunable control approach was evaluated with five healthy subjects during a drinking task.
Subjects were asked to remain passive and to allow NMES to induce the movements. In
all of them, the controller was able to perform the task, and a mean hand positioning error
of less than five centimeters was achieved. The average total time duration for moving the
hand from a rest position to a drinking cup, for moving the cup to the mouth and back, and
for finally returning the arm to the rest position was 71s

neuro-muscular electrical stimulation, neuroprosthetics, exoskeleton, feedback control, assistive technology, eye tracking

http://dx.doi.org/10.3389/fnins.2014.00262