The i-Limb Hand is the world’s first
commercially available bionic hand which allows the wearer to change the grip
with a simple gesture. This prosthetic hand has individually powered fingers
and thumb, with a choice of grips. Inside of the molded forearm are two
electrodes that respond to muscular signals in the remaining limb. Sending a
signal to one electrode opens the hand, while sending signals to the other closes
the hand. This process of using gestures to change the grip is called gesture
control.
Computer science is heavily
involved when it comes to getting the i-Limb to actually move. The i-Limb Hand
has up to four different muscle triggers. The users are able to assign a grip
to move the device to a certain, commonly used position. These muscle triggers
include
1) “Hold open”: using open signal for set period of time
1) “Hold open”: using open signal for set period of time
2) “Double
impulse”: two quick open signals after hand is fully open
3)"Triple
impulse”: three quick open signals after hand is fully open
4)“Co-contraction”: contracting
both the open and close muscles simultaneously
When the user uses these muscle
triggers, the muscle signals are picked up by the electrodes, and sent to a
microprocessor, which is an integrated circuit that contains all the functions
of a central processing unit (CPU) of a computer. The microprocessor then
instructs the limb to open and close.
Aside from gesture control, the
i-Limb can also be controlled using the app. The user can open the app to
access up to 24 quick grips. The i-limb is programmed to change its position
once a new grip is selected. When the user activates any of these grips using
the app, the i-limb will then move to the grip that has been assigned to it
through the algorithm. As you can see, the i-limb can either take inputs from
the user’s muscular triggers, or through the app. The i-limb uses a
microprocessor to process the request, which then executes the action.
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