  The objective of this paper is to present a systematic review of existing
sensor-based control methodologies for applications that involve direct
interaction between humans and robots, in the form of either physical
collaboration or safe coexistence. To this end, we first introduce the basic
formulation of the sensor-servo problem, then present the most common
approaches: vision-based, touch-based, audio-based, and distance-based control.
Afterwards, we discuss and formalize the methods that integrate heterogeneous
sensors at the control level. The surveyed body of literature is classified
according to the type of sensor, to the way multiple measurements are combined,
and to the target objectives and applications. Finally, we discuss open
problems, potential applications, and future research directions.
