More Motion Control News About Cirque du Soleil
We’ve received many comments on our motion-control story about Cirque du Soleil last month. One of the comments was from Stephen A. Sywak, PE Senior Mechanical Engineer at McLaren Engineering Group.
McLaren was responsible for the majority of the original design of the mechanical and structural stage elements for KA ( www.ka.com ) at the MGM Grand. Sywak figured greatly in the selection of the hydraulic and electric actuation and servo-control system.
The original motion-control system for KA was a closed-loop servo-controlled system,” says Sywak. “Not only was it closed loop with regard to position and velocity (as is common), but it also closed the loop on force—force measured by four specialty linear force transducers mounted to the ends of each of the four main hydraulic lift cylinders.” The sensors and their associated control electronics and logic, allowed balancing of forces between the close-coupled, adjacent lifting cylinder pairs stage left and stage right. They also served as secondary safety back-ups.
“Because of the high slenderness ratio of these cylinders, it is easy to understand that they can never be allowed to enter into a compressive condition,” explains Sywak. The cylinders normally carry about 75,000 pounds of tension, each. The control electronics were set to stop the movement of the “hammerhead” support structure carrying the Sand Cliff Deck if the tension in the sensors fell below a certain threshold. “They wouldn’t wait until the cylinders were at zero, or entering into compression; they would stop if they felt the trend towards zero was too great,” he says.
Other cool entertainment stories you might want to check out in this issue include a rapid prototyping story involving the popular video game Rock Band. We also have a story about Intel’s new processors, which are the first to include basic graphics capabilities that support high-definition, video playback, and casual 3D games. And don’t miss the Microsoft story about Natural User Interfaces and Project Natal, a code name for an Xbox 360 add-on that incorporates face, voice, gesture, and object recognition technology to give users a variety of ways to interact with the console, all without needing a controller.
Bruce
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McLaren was responsible for the majority of the original design of the mechanical and structural stage elements for KA ( www.ka.com ) at the MGM Grand. Sywak figured greatly in the selection of the hydraulic and electric actuation and servo-control system.
The original motion-control system for KA was a closed-loop servo-controlled system,” says Sywak. “Not only was it closed loop with regard to position and velocity (as is common), but it also closed the loop on force—force measured by four specialty linear force transducers mounted to the ends of each of the four main hydraulic lift cylinders.” The sensors and their associated control electronics and logic, allowed balancing of forces between the close-coupled, adjacent lifting cylinder pairs stage left and stage right. They also served as secondary safety back-ups.
“Because of the high slenderness ratio of these cylinders, it is easy to understand that they can never be allowed to enter into a compressive condition,” explains Sywak. The cylinders normally carry about 75,000 pounds of tension, each. The control electronics were set to stop the movement of the “hammerhead” support structure carrying the Sand Cliff Deck if the tension in the sensors fell below a certain threshold. “They wouldn’t wait until the cylinders were at zero, or entering into compression; they would stop if they felt the trend towards zero was too great,” he says.
Other cool entertainment stories you might want to check out in this issue include a rapid prototyping story involving the popular video game Rock Band. We also have a story about Intel’s new processors, which are the first to include basic graphics capabilities that support high-definition, video playback, and casual 3D games. And don’t miss the Microsoft story about Natural User Interfaces and Project Natal, a code name for an Xbox 360 add-on that incorporates face, voice, gesture, and object recognition technology to give users a variety of ways to interact with the console, all without needing a controller.
Bruce
Email Bruce
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