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SERVO Gripper Control Modes
The servo gripper operates in two distinct control modes: force mode
and
position mode. Force mode commands let you open or close the gripper
fingers
with a precise amount of force, but give you no control over position.
In
position mode, you can accurately position the gripper fingers but
you cannot
control the amount of force.
Executing a Force Mode Command
When a force mode command is executed, the servo gripper voltage increases
until the fingers are moving with the specified amount of force. The
motor
continues to operate at this voltage until the fingers contact an object
or a
hard stop limit.
Note: A force of 30% or greater is required when opening or closing
the
gripper fingers from a stationary position. This force is required
in
order to overcome the stiction of the fingers. For very fragile objects,
you can reduce the grip force once the fingers are in motion.
If there is nothing available to grip, the fingers move to the end
of their travel.
The specified force is maintained until another gripper command is
issued.
Executing a Position Mode Command
Position mode commands let you accurately set or read the position
of the
gripper fingers. In position mode, the gripper fingers move at maximum
gripper force until the feedback potentiometer detects that the fingers
are at
the specified location. At the commanded position, the gripper fingers
stop
moving and maintain their position.
Use position mode commands to improve the efficiency of your gripper
application. By precisely specifying how far apart the fingers should
open or
close for a particular task, you can reduce the time necessary to complete
the
operation.
Warning! Never use a positional gripper command to grip an object.
Position
commands are used to accurately position the gripper fingers and operate
at
maximum gripper force. When applied to an object, this force can damage
the
gripper motor and shorten the life of your gripper.