Biomedical Engineering Reference
In-Depth Information
Figure 8.1 The FES-robot training experimental setup (a). The configuration of the FES
electrodes and EMG electrodes on a muscle (b). For color reference, see page 218.
FES/robot parts was an analog-digital card. The PC-based control platform had
three functions:
(1) to provide a programmed tracking task and guide a subject through visual
feedback;
(2) to control the FES and robot parts providing assistance during tracking; and
(3) to save data during training.
The FES part was a two-channel programmable voltage stimulator. In this
study, the outputs of a channel of the stimulator were square pulses with constant
amplitude of 100 V, inter-pulse interval at 25 ms (i.e., stimulation frequency of
40 Hz), and varied pulse width from 0-200
s. The robotic part of the FES-
Robot system had one-degree of freedom, i.e. wrist flexion and extension on the
horizontal plane, was designed and fabricated for assisting the wrist movements,
as illustrated in Figure 8.2(b) . A two-layer of aluminum plates were connected by
four aluminum pillars inside of a motor and torque sensor tower. The lower plate
was fixed to the base of the tower. The direct drive brushless AC servo motor was
fixed to the lower plate. The motor was connected to a torque sensor. The other
end of the torque sensor was connected to a manipulandum with an orthosis to
fix the palm. During the training, the palm of the paretic side of a subject was
placed into the orthosis on the manipulandum which could rotate with the motor;
and the wrist angle signals were measured via readings of the positions of the
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