You might recall the rather lengthy article that I wrote last month on the design of the Toy Story Mania attractions. In that article I dissected the attraction from some operator screens and in the end we found out that much of the ride was built on Siemens integrated Programmable Logic Controller (PLC) technology.
Siemens has been in the PLC space for some time, along with the likes of GE and Allen Bradley to name a couple of other big players.
A PLC is basically a small, special built computer that reads a variety of sensors (speed, temperature, humidity, etc.) and then makes 'logical' decisions based on those inputs in real time. They are used throughout the manufacturing, building control and now even in cars.
A programmer programs boundary conditions, control conditions, exception handling (what to do when a process can't be kept in control),etc. to control a process, or a set of processes. Then the PLC's are usually connected on a larger bus network to a set of master control systems that display, log and allow remote control of those processes.
For instance, when I was in college I worked for our campus power plant which used PLC's in two very typical arrangements. One was in the power plant itself: controlling everything you could think of from the scale the trucks drove over coming and leaving the plant to the high pressure steam coming out of the boilers and going into the turbines, just to name a few.
Likewise, when I worked there we were in the process of converting all of our campus buildings to use an integrated PLC based system from Johnson Controls to control the building environment: temp, humidity, air flow, set back, etc. Which we could bring up on a set of computers in our office to ensure a buildings HVAC plant was running at efficiency.
So why bring all this up again? Well, it's a very important area for people in Imagineering that's why! All of the rides you and I love are really all real time systems, many of them based on manufacturing techniques that were invented at the height of the industrial revolution and then re-purposed. Think of all the rides that are somehow inspired by Henry Ford's production line for instance.
In those days of course, there were no computers, so the logic in the system was human. But we humans are notoriously slow and not always the most sequential thinkers, especially when it comes to high speed processes.
We tend to get distracted, emotional, etc. when things start to happen. Just think of Lucy and Ethel in that famous chocolate assembly line skit!
Of course Disney is not only in the entertainment business: first and foremost (like us in the military) they are in the safety business. Safety always comes first (and security usually a very close second). If people aren't safe, the entertainment factor doesn't matter.
So that's a long lead up to say that this short blurb at Design News shares what Imagineering has been up to from a safety perspective on their new ride control systems.
It seems according to the article and Imagineer Jody Gerstner that for years Disney has been building their own custom (and now probably expensive) safety control system, but doing it in hardware. That system has been standalone, but I bet it's been in use in a general sense for sometime.
With Toy Story Mania and Imagineering's partnership with Siemens they apparently had the opportunity to do some experimenting. It appears they were able to do all that custom hardware function now in one tiny, little software controlled PLC controller from Siemens.
That little box has only 1.4 megs of RAM, but it can monitor and control 1024 digital inputs/outputs (i.e. on/off logic) and 256 analog channels. The truly amazing thing is that it can do all that monitoring AND make a decision in SUB-MICRO-SECOND time, like really tiny fractions of a micro-second.
So we can thank all those really smart Imagineers for keeping us safe for all these years with the custom built stuff. Disney has a phenomenal safety record after all.
And with tomorrow's design, it just might be a small little box tucked in a dark corner that saves that teenager's butt next to you when he steps off the platform and in milliseconds the whole ride comes to a screeching halt.
Walt would be amazed. . .
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2 comments:
Excellent post! Another good example of pre-PLC is with the Matterhorn in Disneyland. Originally the only control was the dispatch interval controlled by ride operators. Gravity was the only other factor which was effected by the weight of the ride vehicle. More loaded cars would travel faster than empty ones. Failure to have enough experience would cause the operator to dispatch them too close together causing mid-ride collisions. Later, they installed very early versions of PLC into the attraction along with idler wheels which would be used to speed up slow vehicles or slow down faster ones - so they all go about the same rate. Most people do not realize that this is all done with optical sensors and a crude form of PLC which causes the electric motor to affect each vehicles rate of decent.
Yeah I was always amazed by the Matterhorn and how the guys at Arrow took all of that into account.
Certainly the track wasn't the only major obstacle when they built Space Mountain either. Without some kind of integrated safety system other than the gravity and dispatch system on the Mattherhorn, the ride would have either unsafe for more than one vehicle at a time effectively thrashing the ride capacity. And we all know that even today it's not a REAL people mover.
I have to admit that I like the idler wheel in places where it works. It's a lot smoother than the typical air breaks on more modern coasters, which always seem to be pretty harsh to me. Safe yes, but harsh.
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