Chapter 2 Fundamentals of Robotics 55
• General material handling and special payload handling and manipulation
• Meat packing
• Coating applications
• Assembly
• Injection molding
• Die casting
Spherical Configuration (Polar)
The spherical configuration, sometimes referred to as the polar config-
uration, resembles the action of the turret on a military tank. A pivot point
gives the robot its vertical movement, and a telescoping boom extends and
retracts to provide reach, Figure 2-37. Rotary movement occurs around an
axis perpendicular to the base. Figure 2-38 illustrates the work envelope
profile of a typical spherical configuration robot.
The spherical configuration generally provides a larger work envelope
than the Cartesian or cylindrical configurations. The design is simple and
provides good weight lifting capabilities. This configuration is suited to
applications where a small amount of vertical movement is adequate, such
as loading and unloading a punch press. Its disadvantages include reduced
mechanical rigidity and the need for a more sophisticated control system
than either the Cartesian or cylindrical configurations. The same problems
occur with inertia and accuracy in this configuration as they do in the
cylindrical configuration. Vertical movement is limited, as well.
Reach
Rot
a
ry
V
e
r
t
i
c
a
l
Figure 2-37. A pivot point enables the spherical confi guration robot to move vertically. It also can
rotate around a vertical axis.