Exteroceptive sensors determine the measurements of objects relative to a robot's frame of reference. These sensors are categorized as a proximity sensors.
Proximity sensors enable a robot to tell when it is near an object. These sensors keep the robot from colliding with other objects. They can also be used to measure distance from the robot to another object.
There are three main types of exteroceptive sensors.
- Contact Sensors: Contact sensors are typically simple mechanical switches that send a signal when physical contact is made. Contact sensors are used to detect the positive contact between two mating parts and/or to measure the interaction forces and torques which appear while the robot manipulator conducts part mating operations. Another type of contact sensors are tactile sensors. These measure a multitude of parameters of the touched object surface.
- Range Sensors: Range sensors measure the distance to objects in their operation area. A range sensor can also be a distance detection devices that provides a simple binary signal when a particular threshold is detected. Range sensors are used for robot navigation, obstacle avoidance, or to recover the third dimension for monocular vision. Range sensors are based on one of the two principles: time-of-flight and triangulation
- Vision Sensors: Robot vision is a complex sensing process. It involves extracting, characterizing and interpreting information from images in order to identify or describe objects in environment.