Otto Bock SensorHand Speed 8E38-8 Manual page 33

Control Mode 4: VarioControl: One linear transducer
Opening
By speed and strength of the pull on the linear
transducer
Opening speed
Proportional
15 mm/s - 300 mm/s
Initial grip force
10 N
10 N
Control Mode 5: VarioDual
Requires: 2 electrodes
Control with two electrodes
With this control mode, the opening speed is determined by the strength and speed of the muscle contrac-
tion. The closing speed until the minimal grip force of approx. 10 N has been reached depends on the speed
of the muscle relaxation. The following or simultaneous muscle signal to the second electrode determines
the grip force.
FlexiGrip occurs when the repositioning force is higher than the present grip force. Once the object has
been repositioned, the SensorHand Speed reverts to the previous grip force.
Electrode 1:
Proportional. The speed and strength of the muscle tension determine the opening speed of
Opening:
the hand.
Proportional. The speed and amount of the muscle relaxation determine the closing speed of
Closing:
the hand. The grip force is approx. 10 N.
By very slow muscle relaxation to the electrode, the hand stops in an opened position.
Stopping:
Electrode 2:
Grasping: The level of the muscle signal to the second electrode determines the build-up of the grip
force. The maximal grip force is approx. 100 N.
Example 1: After opening the hand, the patient relaxes the muscle at any speed. The hand closes propor-
tionally to the speed of the muscle relaxation. The hand will grasp an object with minimal grip
force (10 N). FlexiGrip becomes active when a 20 N force is applied when moving an object
within the hand. Once the object has been repositioned, the SensorHand Speed reverts to
minimal grip force.
Example 2: After grasping as described in example 1, the hand shall grasp the object with a higher grip
force. Create a muscle signal to the second electrode. Proportionally, a grip force between
10 N and 100 N can be built up. If the object is slipping, the grip force increases up to 50%
Closing
By speed of release of the linear transducer
Closing speed
Proportional
15 mm/s - 300 mm/s
Auto-Grasp grip force increase
At low to moderate closing
speed
None
At moderate to high closing
speed
Up to 130 N
FlexiGrip function
At low to moderate closing
speed
Effective at 20 N
At moderate to high closing
speed
Effective at maximum grip force
Ottobock | 33