  A vacuum lifter is widely used to hold and pick up large, heavy, and flat
objects. Conventionally, when using a vacuum lifter, a human worker watches the
state of a running vacuum lifter and adjusts the object's pose to maintain
balance. In this work, we propose using a dual-arm robot to replace the human
workers and develop planning and control methods for a dual-arm robot to raise
a heavy plate with the help of a vacuum lifter. The methods help the robot
determine its actions by considering the vacuum lifer's suction position and
suction force limits. The essence of the methods is two-fold. First, we build a
Manipulation State Graph (MSG) to store the weighted logical relations of
various plate contact states and robot/vacuum lifter configurations, and search
the graph to plan efficient and low-cost robot manipulation sequences. Second,
we develop a velocity-based impedance controller to coordinate the robot and
the vacuum lifter when lifting an object. With its help, a robot can follow the
vacuum lifter's motion and realize compliant robot-vacuum lifter collaboration.
The proposed planning and control methods are investigated using real-world
experiments. The results show that a robot can effectively and flexibly work
together with a vacuum lifter to manipulate large and heavy plate-like objects
with the methods' support.
