How Theme Parks Work

Control Systems

Control systems are one of the elements that differentiate theme parks from other forms of "live" entertainment. Sophisticated control systems are at the heart of Disney's animatronics, for instance. This is important enough to Disney has it employs its own proprietary systems for show control. However, with the power of the personal computer and am expanded marketplace, off-the-shelf solutions now exist that can do much the same thing.

Control systems can be divided into two flavors. One flavor likes to monitor events and provide oversight for the entire system. The other flavor likes to stick to the beat, so to speak. By synchronizing with the video, audio, or film elements of the show, the control system can trigger animation events, lighting, sound tracks, props, and so on, in time with the show. We call controllers in the 1st type Supervisors, and those of the 2nd type Show Controllers.

In the block diagram above, the Supervisor receives status messages, or fault messages, from the various types of equipment, including the Show Control unit. The Show Control unit sends synchronized, show-related commands to the various devices. Lights, figures, props, and video/audio are all controlled by the same device. Not all systems require separate units for show control and supervisor functions. Many systems are capable of running both kinds of applications at the same time.

Off-the-shelf show control systems are made by Alcorn McBride, Gilderfluke, and MediaMation. Each brand offers its own special way of handling controls. Most offer discrete and serial control, and some offer flash-card or hard-drive-based audio and video source devices that integrate well with their show control products. Some show controllers are capable of running multi-threaded applications, which allows for some unusual and flexible logic, as well as easy integration of supervisor and show control functions in the same unit.

The Digital Audio example on the previous page presented a MediaMatrix® screen with event status indicators on it. This was in effect a "soft" operator panel, presenting the state of the show to the operator through a graphical user interface. This was accomplished without requiring custom software to create the GUI, making it somewhat easier to maintain over the many years in which this system will likely be deployed. Through an Alcorn-McBride V16+ show control unit, the GUI was able to monitor the switches on an operator's control console (OCC) along with logic-filtered status signals from other controllers in the show. The audio processor's GUI receives these commands serially over a communications bus. Not only can the GUI be controlled through the show controller, but as one would expect, the DSP-based audio processor can also respond to such commands. In this manner, audio levels and signal routing can be controlled by a central show controller.

We'll explain this particular show, as it's controller performs a sophisticated task. The show has three rotating turntables, each carrying three automoabiles. This is a car show, where only one automobile is presented to the public at one time. To do this, each turntable has a special door which can be opened by the show control system. The task of the show controller is to command the rotatation of the turntables, and when the appropriate turntable is in the correct position, open the door. At the same time, lights and sound (but no dancing girls) are also controlled by the show controller, so that the entire show is carefully sychronized.

It takes time for the turntables to move, so the show controller has to figure out which cars are ready for a show, and make sure the start of the new show is in time with the end of the current show. For the times when a car needs to be washed or replaced, or when a turntable may be under maintenance, an operator panel can instruct the show controller to not show one or more cars. This information has to be accounted for during the show controllers operation of the show. To simplify this logic, multi-threaded routines are written to perform several logical processes at one time. When it is time to make a decision for starting a new show, the decision process looks at the state of other independent processes to make the decision. This operation can continue for up to 18 hours a day, 7 days a week. The show is fully automated and does not require human intervention until something goes wrong -- usually a mechanical failure in the turntables or turntable doors.

While sophisticated in application, this is a relatively simple system. More sophisticated systems utilize networks to allow many types of communication, including audio. Learn more at the Networks page.