Robot Mechanisms and Mechanical Devices Illustrated - Profe Saul

288 Chapter 11 Proprioceptive and Environmental Sensing Mechanisms and Devices
Figure 11-18 Vertical flexible
post bumper suspension
that uses one of these layouts can be used with no hard centering system
by using the “limit switch as hard stop” concept discussed previously.
The bumper is sprung so that its relaxed position is just off the contacts
of three or more switches. This system is simple and effective for smaller
robots and a very similar layout is used on the popular Rug Warrior
robot.
For larger designs, where the flexible post would need to be too big,
compression springs can be used instead. A clever designer may even be
able to size a single-compression spring layout that would be simple
indeed. The system can be designed to use the springs in their relaxed
state as springy posts, or, for larger forces, the springs can be slightly
compressed, held by internal cables, to increase their centering force and
make their default position more repeatable.