At the top of each hour, a proprietary controller sends a signal via RS-485 link to twin controllers, causing them to execute a motion profile program that drives each of two sculptures. A NEMA 34 stepper motor running in the open-loop mode in conjunction with a 15:1 right angle gearhead provides enough torque to drive the system. An open gear reduction of 5:1 between the gear-head output pinion and the slewing ring gear on the stage platen maintains a favorable inertia ratio between the rotating sculpture and the motor. This configuration allows the system to accelerate the sculptures at approximately 1 rev/sec2 to speeds in excess of 20 rpm when executing their motion profile. The completed rotary stage is repeatable to Ī2 degrees, with most of the position error due to backlash in the open gearing comprising the final stage of the drive train. The easy programmability of the ZETA system allowed for a dynamic and realistic motion profile.
Californiaís plan to mandate an electric vehicle market isnít the first such undertaking and certainly wonít be the last. But as the Golden State ratchets up for its next big step toward zero-emission vehicle status in 2018, it might be wise to consider a bit of history.