Cartesian mechanisms have long been the mainstay of pick-and-
place operations. They are simple to design and easy to program.
Using linear actuators to move in X, Y and Z enables engineers
to map end-effector coordinates directly to actuator positions.
The velocity and acceleration of each axis are easy to
calculate, and single-feedback control loops can be used on each
axis. However, Cartesian mechanisms are not without limitations.
For one, they require a lot of space. And since two or three
actuators are stacked one atop the other, when one motor is
moving, the other motors are dead weight. Add the weight of the
power and control cables—not to mention the payload—and that’s a
lot of mass to move around. “You can only make a ballscrew move
so fast,” says Kevin Hull, senior applications engineer at
Yaskawa America Inc. “And Cartesian systems need support
structures, like linear bearings, that can take up a lot of
space. Today, engineers are trying to make things smaller,
faster, less expensive and more effic