Servocontrol Theater

Putting motion into art requires a different approach to motion control than typical machine-tool applications. Although hardware elements such as actuators, servomotors, and controllers are similar, the approach to motion in artistic endeavors is typically quite different. In contrast to industrial applications, artistic motions are often only roughly defined while the art piece or lifelike creature is being designed. The artist then experiments to make the motions look natural and bring them to “life.”

Industrial applications are usually characterized by motion tasks that are precisely repetitive and optimized for throughput. But some mechanized art is pure fantasy, with motions based solely on artistic whim. An art piece’s movements begin with an engineer or programmer commissioning the control loops and homing routines, and verifying the available motion dynamics. The various artwork shown in the accompanying images was commissioned using Window-based software called QuickControl. It is used to test and embed the control parameters, start-up and homing routines, and communications parameters into nonvolatile memory embedded into the controllers.

The development of the artistic motion methods depends on where and how the art will be used. Amusement parks and museums use hardware that will “carry the show” without much human interaction. In contrast, the motion-film industry depends on the real-time interpretation of “puppet masters” interacting with the actors to meet the artistic vision of the director. These different approaches require different motion-system architectures and communications protocols.

Amusement-park designs use a specialized stage controller to store and play both the sounds that will be used and the motion and lighting information in coordinated data sets called tracks. The stage controllers are usually configured through a laptop by the engineer/artist to match the motions to the desired timing. Overall motion design is often guided by sound tracks which provide the show tempo.