  With the advancements in human-robot interaction (HRI), robots are now
capable of operating in close proximity and engaging in physical interactions
with humans (pHRI). Likewise, contact-based pHRI is becoming increasingly
common as robots are equipped with a range of sensors to perceive human
motions. Despite the presence of surveys exploring various aspects of HRI and
pHRI, there is presently a gap in comprehensive studies that collect, organize
and relate developments across all aspects of contact-based pHRI. It has become
challenging to gain a comprehensive understanding of the current state of the
field, thoroughly analyze the aspects that have been covered, and identify
areas needing further attention. Hence, the present survey. While it includes
key developments in pHRI, a particular focus is placed on contact-based
interaction, which has numerous applications in industrial, rehabilitation and
medical robotics. Across the literature, a common denominator is the importance
to establish a safe, compliant and human intention-oriented interaction. This
endeavour encompasses aspects of perception, planning and control, and how they
work together to enhance safety and reliability. Notably, the survey highlights
the application of data-driven techniques: backed by a growing body of
literature demonstrating their effectiveness, approaches like reinforcement
learning and learning from demonstration have become key to improving robot
perception and decision-making within complex and uncertain pHRI scenarios. As
the field is yet in its early stage, these observations may help guide future
developments and steer research towards the responsible integration of
physically interactive robots into workplaces, public spaces, and elements of
private life.
