Working principle of Proximity sensors
The output of the proximity sensors gives an indication of the presence of an object with in the vicinity job operation.
In robotics these sensors are used to generate information of object grasping and obstacle avoidance. This section deals with some of the important proximity sensors used in robotics.
Proximity sensor is a sensor, which senses the presence or absence of the object without having physical contact between the objects.
Inductive Proximity Sensors:
The ferromagnetic material brought close to this type of sensor results in change in position of the flux lines of the permanent magnet leading to change in inductance of the coil.
The induced current pulse in the coil with change in amplitude and shape is proportional to rate of change of flux line in magnet.
The proximity inductive sensor basically consists of a wound coil located in front of a permanent magnet encased inside a rugged housing. The lead from the coil, embedded in resin is connected to the display through a connector.
The effect of bringing the sensor in close proximity to a ferromagnetic material causes a change in the position of the flux lines of the permanent magnet.