Page 30 - Concise Encyclopedia of Robotics

Attraction Gripper
To do its work properly, an assembly robot must have all the parts it
works with placed in exactly the correct locations. This ensures that the
robot can pick up each part in the assembly process, in turn, by moving
to the correct set of coordinates. There is little tolerance for error. In
some assembly systems, the various components are labeled with identi-
fying tags such as bar codes, so the robot can find each part by zeroing in
on the tag.
See also CARTESIAN COORDINATE GEOMETRY, CYLINDRICAL COORDINATE GEOMETRY, DEGREES
OF FREEDOM, POLAR COORDINATE GEOMETRY, ROBOT ARM, and SPHERICAL COORDINATE
GEOMETRY.
ATTRACTION GRIPPER
An attraction gripper is a robot end effector that grasps objects by means of
electrical or magnetic attraction. Generally, magnets are used; either per-
manent magnets or electromagnets will serve the purpose. Electromagnets
offer the advantage of being on/off controllable, so an object can be con-
veniently released without its having to be secured by some external
means. Permanent magnets, conversely, offer the advantage of a minimal
maintenance requirement.
Like the adhesive gripper, the attraction gripper is fundamentally simple.
There are two primary problems with this type of end effector. First, in
order for a magnetic attraction gripper to work, the object it grasps must
contain a ferromagnetic material such as iron or steel.Second,the magnetic
field produced by the end effector can permanently magnetize the objects
it handles. In some cases this is not a concern, but in other instances it
can cause trouble. Compare ADHESION GRIPPER.
ATTRACTIVE RADIAL FIELD
See POTENTIAL FIELD.
AUTOMATED GUIDED VEHICLE
An automated guided vehicle (AGV) is a robot cart that runs without a
driver. The cart has an electric engine and is guided by a magnetic field,
produced by a wire on or just beneath the floor (see the illustration).
Alternatively, an AGV can run on a set of rails. In automated systems,
AGVs are used to bring components to assembly lines. AGVs can also
serve as attendants in hospitals, bringing food and nonessential items to
patients, or as mechanical gophers to perform routine chores around the
home or office.
There has been some talk about making automobiles into AGVs that
follow wires embedded in the road pavement. This would take part of the
driver’s job away, letting computers steer the vehicle and adjust its speed.

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