UNDERSTANDING, DESIGNING & CONSTRUCTING ROBOTS & ROBOTIC SYSTEMS
■ BY VERN GRANER
PNEUMATICS IN ROBOTICS
THE PRESSURE'S ON!
In taking some of my own advice from last month's Robo Resolutions article,
this month we're going to try something new! Let’s dip our toe into some possibly unfamiliar waters as we explore the world of electronically controlled
pneumatic actuators for hobby robotic and animatronic mechanisms.
PLUMBING THE DEPTHS
In the world of experimental and
hobby robotics, servo motors and
solenoids tend to dominate the landscape. This is most likely due to the
simplicity of using a single power
source for all the functions (
movement, computing, sensors, etc.).
However, in commercial automation and industrial assembly lines,
many of the moving systems rely on
compressed air and air-powered actuators of various types (Figure 1) to
do the work. One of the interesting
things you'll discover when you start
to play with the components of a
pneumatic system is that what you're
actually doing is plumbing!
Subsequently, you get to explore a
whole new set of schematic symbols
and terminology. To help you get
started, I've included a link to some
■ Figure 1. Examples of typical
common pneumatic symbology in
the Resources section.
THE BASIC PARTS OF A
Since there are plenty of great
resources on the Internet to get you
going with pneumatics, in this article
I'm only going to give a quick
overview of the basic parts you will
need in order to start experimenting
with pneumatics for your next robotic
■ Figure 2. A 1.5 gallon workbench
portable air compressor. This unit
features much quieter operation
than most typical "pancake" type
Compressor: (Figure 2) When
using pneumatics, you need a ready
supply of compressed gas. This is typically provided by an air compressor.
Though many of the pneumatic systems incorporated into "battling"
robots use high-pressure CO systems
(for both strength and portability), I
wanted to have a non-exhaustible air
source that didn't require me to get
tanks refilled. For my experimentation, I purchased a 1.5 gallon, 150 psi
■ Figure 3. An air pressure regulator.
PLEASE NOTE: A flow regulator is
not the same thing as a pressure
regulator! A flow regulator simply
limits the speed the air may pass
through the device and does NOT
limit pressure! Be sure to read the
description carefully before making
a purchase so you don't end up with
the wrong part!
February 2009 81