  In this paper, we present a planner for a master dual-arm robot to manipulate
tethered tools with an assistant dual-arm robot's help. The assistant robot
provides assistance to the master robot by manipulating the tool cable and
avoiding collisions. The provided assistance allows the master robot to perform
tool placements on the robot workspace table to regrasp the tool, which would
typically fail since the tool cable tension may change the tool positions. It
also allows the master robot to perform tool handovers, which would normally
cause entanglements or collisions with the cable and the environment without
the assistance. Simulations and real-world experiments are performed to
validate the proposed planner.
