When we want to detect an object in the
path of a robot, we have a number of schemes available to us. Let us start with
detecting the closest object and then move on to detecting objects that are
further away. A switch that closes when
an object comes up against it is an effective way to detect a collision. The
problem is that we have to actually run into something before we get a signal
and running into things may not be the best thing to do for a number of
reasons, not least of which is the lack of elegance. An additional problem is
that this is a rather ineffective way of letting us know that we have moved too
close to an object because this technique does not tell us anything about the
object the robot ran into other than it was strong enough to actuate the
switch. This is not ideal for any automation scenario, especially not lab experiments that deal with delicate objects.
The object might have been a little stone
or it might have been a boulder the size of house. Increasing the number of
micro switches tells us a bit more about the direction from which the collision
came but tells us nothing about the object itself. In general, micro-switches
cannot detect the size of an object even if we had a lot of them. However, it
should be appreciated that knowing the size of the object is often not
important to what we are trying to do.
