28 | Ottobock
8E38=9, 8E39=9, 8E41=9
9.3 Control mode 3:
VarioControl
Control with 1 electrode or
1 linear transducer
With this control mode, the opening speed is determined by the strength and speed of the muscle
contraction. The closing speed and grip force depend on the reduction of muscle tension.
9.3.1 Control with 1 electrode
Opening:
Proportional. The opening speed is determined by the speed and strength of
the muscle contraction.
Closing:
Proportional. The closing speed is determined by the speed and strength of
the muscle relaxation.
Stopping:
By very slow muscle relaxation to the electrode; the MyoHand VariPlus Speed
stops in an opened position.
Example 1:
After opening the amputee slowly relaxes the muscle. Closing takes place pro-
portional to the decline of the electrode signal. The object is grasped with low
force.
Example 2:
After opening the amputee relaxes the muscle at maximum speed. The MyoHand
VariPlus Speed closes at maximum speed and begins to grasp an object with
maximum grip force (approx. 100 N).
Control
mode 3
OPEN
CLOSE
Indication
VarioControl Increasing electrode
signal through mus-
cle contraction
Declining electrode signal
through muscle relaxation
For amputees
with one strong
electrode signal or
tendancy to
co-contraction
Speed and strength
of muscle contraction
to the electrode
Grip force:
Proportional to the
decline of the electrode signal
After gripping once with maxi-
mum force, the EMG signal
required to OPEN the Hand
will be set to a higher value.
Opening the MyoHand VariPlus
Speed with unwanted electrode
signals is prevented.
Speed:
proportional
Adjustment regula-
tor A
Speed:
proportional
Adjustment regulator A
Display of the MyoSelect (757T13)
Adjustment regulator A is used to adjust the proportional speed
of the “OPENING / CLOSING” function and the speed of grip
force build-up.
Notice:
Always check the adjustments on the prosthesis and
adapt them to the amputee.
