i.) The three types of feature that are possible to be used to
recognize pen drive are :
a.) Proximity
b.) 3D Vision
c.) Color
ii.) a.) For determining the nearness or farness of the object
placed proximity sensor is used. It will help to send a signal to
arm to increase/decrease the distance and get closer to the pen
drive.
b.) 3D vision helps in determining the x,y,z dimensions of the
object. By it, the end effector will place itself
Also, the orientation of the object is known by its co-ordinates by
which the arm will rotate corresponding to what is required.
c.) The Colour of the object is determined by photosensor by which
the system is able to distinguish between objects and also on the
way on how to lift the object.
iii.) 
ud wo M Camera Robot Arm Pen Drive Figure Q2a Robot pick and place with camera...