Robot Mechanisms and Mechanical Devices Illustrated - Profe Saul

220 Chapter 8 Pipe Crawlers and Other Special Cases
and this chapter will focus on the mobility systems required for unusual
environments and unusual methods for propulsion including external
pipe walking and snakes.
The pipe crawler mechanisms shown in the following figures give an
overview of the wide variety of methods of locomoting inside a pipe.
Choosing between one and the other must be based on the specific attributes
of the pipe and the material it transports, and if the robot has to work
in-situ or in a dry pipe. In addition to those shown in this book, there are
many other techniques and layouts for robots designed to move about in
pipes or tanks.
HORIZONTAL CRAWLERS
Moving along horizontal pipes is very similar to driving on level ground.
The crawler must still be able to steer to some degree because it must
negotiate corners in the pipes, but also because it must stay on the bottom
of the pipe or it may swerve up the walls and tip over. There are
many horizontal pipe crawlers on the market that use the four-wheeled
skid-steer principle, but tracked drives are also common. The wheels of
wheeled pipe crawlers are specially shaped to conform to the round
shape of the pipe walls, on tracked crawlers the treads are tilted for the
same reason. These vehicles’ suspension and locomotion systems are
frequently quite simple. Figures 8-1 and 8-2 show two examples.
Figure 8-1 Four-wheeled
horizontal pipe crawler