Rigging math

[DuckJordan]

I'm trying to keep my head in the game and keep my math right.

This is all for education purposes and not for an actual working event.

Say you have 4 points for a square truss rig. All points are dead hang to motor so no bridles. Wouldn't the load (leveled truss) be the same for each motor? or am I missing something from my memory.

Diagram of said load where X's are motors
X--X
| |
X--X

Square Box 24" truss at 10' lengths and corner block connections. Although not sure that would matter other than calculating how much flex would be inherent in the design.

 

[porkchop]

Exactly level, with uniformly distributed distributed load yes. But once you start dealing with cable picks and curtains and lighting battens it turns into an incalculable indeterminate system pretty fast.

 

[DuckJordan]

The system I'm designing is planned to be a 10-1 ratio no lights or curtains.

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[rsmentele]

as porkchop said, unit MUST be perfectly level!

 

[DuckJordan]

The hazards of it not being level is the unit having a wobble in a specific axis with two to three motors having the load while on is free correct? In the loads I'm describing its far from limits maybe 400 pounds split between the four

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[BillConnerFASTC]

Well, if one pick will support entire load with a reasonable design factor, it probably doesn't matter, but see the Sapsis video with a grid on several motors and load cells. What looks "level" is very far from it when dealing with chain motor control. Also, if I recall, an issue in several "super grid" failures. Put load cells on all picks, and make sure it's close to even before allowing anyone under, and don't move it overheads no matter what.

 

[DuckJordan]

That was the plan if this idea goes farther we currently own 8 load cells with more planning on being ordered

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