Page 179 - Concise Encyclopedia of Robotics

JAW J
A jaw is a specialized robot gripper, consisting of individual parts that
can clamp down to hold an object, and open to let the object go free. The
device gets its name from its functional resemblance to the human jaw, or
to the jaws of various animals and insects.
A typical robotic jaw has two parts that are hinged at a common end.
One or both parts can move relative to the robot arm. Some jaws have
three or four movable parts that come together to grip an object,and dilate
to free it.
See also ROBOT GRIPPER.
JOIN
The term join is used in reference to a controller programming function
that allows a robot to resume a task where it left off, in the event of a dis-
ruption such as a power failure or accident. This feature is similar to,
although generally more sophisticated than, the capability of a computer
printer to start printing at the page where it left off, if the paper tray
becomes empty during a job and must be refilled.
An effective join program requires a nonvolatile memory, such as
random-access memory (RAM) with battery backup, to store information
concerning actions in the task that have already been performed,and those
that have yet to be performed. The present moment, or instant in time,
must be clearly known by the robot controller and updated at frequent
intervals (for example, a fraction of a second). This information is con-
stantly stored and refreshed in the nonvolatile RAM.
If there is a power interruption, accident, or other mishap, the robot is
programmed to go through a certain sequence to determine where and how
to begin again, based on the data stored in RAM. Along with the sequence
of previously executed movements and the movements yet to be performed
in a given task, additional information might be required, such as whether

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