Position control

Apply disturbing force 

kx = kv =

You can adjust the damping kv to 1.8 to give a response that does not overshoot.
But now apply a disturbance and see how 'soft' the control is.
Now try kx = 100 and kv = 50.  (Reset the disturbance to zero first.)
The block stops as though it has hit a rock.
Small disturbances have little effect - but of course a force of 1.2 Newton will overcome the motor and drive the block right off.