  For some years now, the use of social, anthropomorphic robots in various
situations has been on the rise. These are robots developed to interact with
humans and are equipped with corresponding extremities. They already support
human users in various industries, such as retail, gastronomy, hotels,
education and healthcare. During such Human-Robot Interaction (HRI) scenarios,
physical touch plays a central role in the various applications of social
robots as interactive non-verbal behaviour is a key factor in making the
interaction more natural. Shaking hands is a simple, natural interaction used
commonly in many social contexts and is seen as a symbol of greeting, farewell
and congratulations. In this paper, we take a look at the existing state of
Human-Robot Handshaking research, categorise the works based on their focus
areas, draw out the major findings of these areas while analysing their
pitfalls. We mainly see that some form of synchronisation exists during the
different phases of the interaction. In addition to this, we also find that
additional factors like gaze, voice facial expressions etc. can affect the
perception of a robotic handshake and that internal factors like personality
and mood can affect the way in which handshaking behaviours are executed by
humans. Based on the findings and insights, we finally discuss possible ways
forward for research on such physically interactive behaviours.
