FIGURE 6. Ken Maxon's robot, Sojourner.
mine, Jim Hill. Jim was a parts manager for a Chrysler
dealership in West Covina, CA and built his robot entirely by
using hand tools; the only power tool he used was a 120
VAC drill. I had long admired Jim’s creation and used it as
the cover photograph (shown in Figure 4) for a Popular
Mechanics story I wrote on home-built robots back in 1984.
Jim concentrated on both form and function in creating
Charlie. All the metal was cut by a hacksaw and then filed
smooth. The complex movements of the arms and claws
were accomplished by 12 VDC electric car seat motors
within the robot’s body, and the rotary motion delivered to
the different linear actuators was done by flexible shafts.
The arm’s joints used surplus aircraft flap actuators that
acted like human muscles.
Jim is shown in Figure 5 beside Charlie in a photo
by Roger Ressmeyer. Jim’s robot was not a simple,
servo-driven tabletop robot and was so heavy that he
needed a trailer to bring it down to my house in Long
Beach, CA, for the photographs. I have frequently used his
robot as an example of how virtually anybody with a
FIGURE 8. Parts being machined.
Robots: Form or Function?
FIGURE 7. Rocker bogey suspension.
mechanical bent and basic hand tools can build a
great robot. Charlie is an early example of a fine robot
exhibiting both great aesthetical form and function in
Ken Maxon’s Robots
Jumping to the present, the robot that started the
series of comments on the Seattle Robotics Society’s
list I mentioned earlier was Ken Maxon’s Sojourner
shown in Figure 6. It is quite obvious that this robot is
probably second to none in overall aesthetics (at least
from a machinist’s point of view), and that includes any
factory-built machine. Ken named it Sojourner; not
necessarily to copy the name of the first NASA Mars-roving
robot, but an appropriate name for a great robot that
uses the NASA JPL-designed six-wheel rocker-bogey
system. This suspension is shown being tried out in Figure
7. The few finished parts lying on the table in Figure 8
illustrates just how much machining was required in the
FIGURE 9. Ken’s electronics workshop.