#### Scheduling in Dual Gripper Robotic Cells for
Productivity Gains

**Abstract: **In many applications, robotic cells are
used in repetitive production of identical parts.
A robotic cell contains two or more robot-served machines.
The robot can have single or dual gripper.
The cycle time is the time to produce a part in the cell.
We consider single part-type problems.
Since all parts produced are identical, it is sufficient to determine the
sequence of moves performed by the robot. The
processing constraints define the cell to be a flowshop.
The objective is the minimization of the steady-state cycle time to
produce a part, or equivalently the maximization of the throughput rate.
The purpose of this paper is to study the problem of scheduling robot
moves in dual gripper robot cells functioning in a bufferless environment. We develop an analytical framework for studying dual gripper
robotic cells and examine the cycle time advantage (or productivity advantage)
of using a dual gripper rather than a single gripper robot.
It is shown that an *m-*machine dual gripper robot cell can have at
most double the productivity of its single gripper counterpart.
We also propose a practical heuristic algorithm to compare productivity
for given cell data. Computational
testing of the algorithm on realistic problem instances is also described.