Biomedical Engineering Reference
In-Depth Information
b
c
d
a
Figure 6.3
Platform to house the actuators (a) two levels actuator housing platform (b)
finger actuators (c) thumb actuator (d) thumb actuator support bar.
platforms can be slided back and forward and sideway along the tracks on the
base metal plate. Moreover, these poles can be rotated and elevated. The distance
and the horizontal level can be adjusted for better alignment between the hand and
the actuators. This flexible configuration of the hand function evaluation system
also supports set up for right or left hand training.
6.2.2.1 Actuators Platform
Each finger is assisted by one linear actuator and the actuators need to be aligned
with the finger movement path (
Figure 6.3
)
. A special platform was designed to
house the actuators. It has two levels and the actuators can be freely placed at
these levels. The advantage for this arrangement is that actuators can be placed
closer together to fit for smaller hand size or palm width. Instead of four actuators
placed side by side on the same level occupying wider space, two actuators for the
middle and ring fingers can be placed on the first level while another two actuators
for the index and last fingers can be placed on the second level. In addition, the
angular direction of the actuator can be adjusted to align with the direction of the
finger's flexion and extension to provide comfortable movement.
Two elongated rail bars are used to position the thumb actuator in two
different settings to support the two hand functions ie. palmar grasp and pinch, as
shown in
Figure 6.4
.
The actuator platform is placed vertically so that all fingers are
moving in horizontal level, reducing the gravity effects on the finger performance.
And the arm of the patient can be comfortably placed on the arm holder.
6.2.2.2 Connecting Fingers
The finger is connected to the hand rehabilitation robot using a button connection
(
Figure 6.5
)
. This is for easy attachment and detachment and act as a safety feature
to avoid excessive force applied to the finger. Patient can unbuckle their fingers at
anytime.
The 90 degree metal bars interconnect the fingers with the actuators. The metal
bar screwed tightly with the stroke tip of the linear actuator. A mounting at the
