  Large efforts have focused on ensuring that the controllers for mobile
service robots follow proxemics and other social rules to ensure both safe and
socially acceptable distance to pedestrians. Nonetheless, involuntary contact
may be unavoidable when the robot travels in crowded areas or when encountering
adversarial pedestrians. Freezing the robot in response to contact might be
detrimental to bystanders' safety and prevents it from achieving its task.
Unavoidable contacts must hence be controlled to ensure the safe and smooth
travelling of robots in pedestrian alleys. We present a force-limited and
obstacle avoidance controller integrated into a time-invariant dynamical system
(DS) in a closed-loop force controller that let the robot react instantaneously
to contact or to the sudden appearance of pedestrians. Mitigating the risk of
collision is done by modulating the velocity commands upon detecting a contact
and by absorbing part of the contact force through active compliant control
when the robot bumps inadvertently against a pedestrian. We evaluated our
method with a personal mobility robot -- Qolo -- showing contact mitigation
with passive and active compliance. We showed the robot able to overcome an
adversarial pedestrian within 9 N of the set limit contact force for speeds
under 1 m/s. Moreover, we evaluated integrated obstacle avoidance proving the
ability to advance without incurring any other collision.
