  The presence and coexistence of human operators and collaborative robots in
shop-floor environments raises the need for assigning tasks to either operators
or robots, or both. Depending on task characteristics, operator capabilities
and the involved robot functionalities, it is of the utmost importance to
design strategies allowing for the concurrent and/or sequential allocation of
tasks related to object manipulation and assembly. In this paper, we extend the
\textsc{FlexHRC} framework presented in \cite{darvish2018flexible} to allow a
human operator to interact with multiple, heterogeneous robots at the same time
in order to jointly carry out a given task. The extended \textsc{FlexHRC}
framework leverages a concurrent and sequential task representation framework
to allocate tasks to either operators or robots as part of a dynamic
collaboration process. In particular, we focus on a use case related to the
inspection of product defects, which involves a human operator, a dual-arm
Baxter manipulator from Rethink Robotics and a Kuka youBot mobile manipulator.
