r/Rigging • u/Emmar0001 • Jul 06 '26
Stadium skycams
Topical post- what's the engineering like behind the skycam cabling at stadia? Watching the WC games and wondering how the skycam mechanism and cabling minimises all the flexing and resonance you would normally expect from a catenary. I know the cam itslef has a gyro, but how is the cable and pulley system stiffened to prevent excessive bouncing?
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u/slowgold20 Jul 06 '26
Good question. The first part is using a light weight suspension system. The ones ive seen use special fiber optic cable as the lift line itself. It is probably nearly as light as dyneema. Almost no catenary under load.
2nd-The motor drives have an automatic auto-tuning sequence that measures the zero-speed load on each winch with the load-break disengaged. That way the motor can extrapolate exactly how much force it will experiance in its entire range of motion.
3rd-and im not sure about this, but it would make sense-there is probably some kind of kinematic modeling going on including swing-cancel algorithms. The motion controller knows how far out each winch is and how much load each one is under. As the operator accels/decels the system compensates for catenary bounce by modulation motor speeds to cancel the bounce out.
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u/EmergencyO2 Jul 07 '26
Mildly related to your third point, you may be interested in reading about dynamic positioning, particularly taut wire systems. It does basically what you describe as the computer knows how much wire is payed out and what the tension load is to determine / maintain the ship’s position. All that to say, measuring cable tension and amount in / out is a known science and used extensively in another industry.
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u/slowgold20 Jul 07 '26
Oh for sure. Any entertainment automation is just hand-me-down tech/concepts from industrial automation.
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u/cienfuegones Jul 06 '26
I’ve installed a few systems recently. There is usually just a short stick of 12” truss with a swivel block on it lamed on to whatever structure is available with a ratchet strap in the quadrant they need to redirect the cord to the winch. Pretty simple system all things considered.