  Despite the advances made in artificial intelligence, software agents, and
robotics, there is little we see today that we can truly call a fully
autonomous system. We conjecture that the main inhibitor for advancing autonomy
is lack of trust. Trusted autonomy is the scientific and engineering field to
establish the foundations and ground work for developing trusted autonomous
systems (robotics and software agents) that can be used in our daily life, and
can be integrated with humans seamlessly, naturally and efficiently.
  In this paper, we review this literature to reveal opportunities for
researchers and practitioners to work on topics that can create a leap forward
in advancing the field of trusted autonomy. We focus the paper on the `trust'
component as the uniting technology between humans and machines. Our inquiry
into this topic revolves around three sub-topics: (1) reviewing and positioning
the trust modelling literature for the purpose of trusted autonomy; (2)
reviewing a critical subset of sensor technologies that allow a machine to
sense human states; and (3) distilling some critical questions for advancing
the field of trusted autonomy. The inquiry is augmented with conceptual models
that we propose along the way by recompiling and reshaping the literature into
forms that enables trusted autonomous systems to become a reality. The paper
offers a vision for a Trusted Cyborg Swarm, an extension of our previous
Cognitive Cyber Symbiosis concept, whereby humans and machines meld together in
a harmonious, seamless, and coordinated manner.
