FEATURE FOCUS Wild mouse in the funhouse Downloaded from http://asmedigitalcollection.asme.org/memagazineselect/article-pdf/122/08/52/6354466/me-2000-aug2.pdf by guest on 24 September 2021 Combining spinning-coaster thrills with interactive special effects, a new amusement ride blends several control systems as well. By Paul Sharke, Associate Editor

Controlling personalities may want to skip the ticket window for this ride. Any feeling of terror is partly the doing of sophisticated controls.

52 AUGUST 2000 MECHANICAL ENG INEERI NG LONG A SECT ION OF the Extenninator at Ke. n­ nator, French manufac turer Reverchon of Paris would nywood Amusement Park, riders in cars roll supply the roller coaster that eventually would take riders toward what park electrical director Bill Mar­ along the dark underground passages of the utility tunnel. venko calls the "infinite track mirror trick." Today, however, audiences depend on more than just :rhe track looks as though it's been gnawed roller coasters for their thrills. So Kennywood planned awayA by giant rats, which are loose in a subterranean utility the ride around a runaway-rat theme. For the animation, space, chewing their way out. A mirror perched trackside Kennywood brought in Jacksonville-based Sally Corp. reflects the scene of devastation back to the riders; the real The Exterminator combines a "wild mouse" coaster track remains safely intact beneath the cart. with the interactivity of a dark ride, said Sally Corp.'s Along another section, riders brace as fire and smoke eEO, John Wood. The old wild mouse ride was always from an industrial boiler threaten to consume them. The popular, but it has recently undergone a resurgence in rid­ effect is done partly with a fo g machine. ership. The typical wild mouse coaster sends four passen­ Downloaded from http://asmedigitalcollection.asme.org/memagazineselect/article-pdf/122/08/52/6354466/me-2000-aug2.pdf by guest on 24 September 2021 What brings the ride to life is not smoke and mirrors at gers in a single car through a series of hairpins and drops. all, but the careful orchestration of a myriad of inputs "The hairpin turn is really where it got its history," Wood said. "The ride looks innocuous. It looks like it would just be fun." Because the carts use offset turning wheels, the wild mouse "gives you the feeling at every turn that you're going to go off the edge," Wood said. "You go straight and the turning wheel is back about 18 inches. When you make that turn, there's no railing or anything around you. You 're asking, 'What's keeping me up?' " As if that's not enough, the E xterminator dropped a box over the wild mouse, Wood said, putting the whole thing in the dark. " Dark ride" is amusement­ maker parlan ce for funhouse­ style frights that pop into view unexpectedly. Wood sa id that such rides, which his company specializes in building, are quite

From the loading station, three passengers embark on their ascent up the first hill. At the top, the cart sophisticated in terms of the descends under the power of gravity alone with fin brakes and a PLC controlling its speed. audience participation level they can attain. and outputs by control sys tems behind the scenes. A "Our evolution of the dark ride has incorporated a combination of progranU1uble logic controllers, sound game component into the ride experience. Riders go on and automation controllers, and logic modules supervis­ a quest," Wood said, "and in order to participate in the es everything from directing the descent of the coaster quest they shoot at targets with fl ashlights or laser guns carts, to animating the figures and special effects, to initi­ or za ppers. Riders are scored as they go, either collec­ ating animation sequences. tively or individually." According to Marvenko, the Exterminator started op­ The Exterminator does not strive for that level of audi­ eratillg last year at the amusement park in West Miillin, ence participation. With the coaster and the animation, Pa., near Pittsburgh. As with any large-scale construction it doesn't need to. There's already plenty going on. But project, building the ride took the efforts of several ma­ Wood sa id that the sophistication of today's controls jor and minor contributors. Even more than on most demonstrates how technology is advancing the industry. projects, though, a great many finishing touches had to wait to adorn the ride until the coaster and the anima­ A RIDE ON THE WILD SIDE tion modules were bolted down. According to M arvenko, a trip aboard the Exterminator Ont!e Kennywood decided to introduce the new ride, it goes something like this: Before loading, riders form a brought in R&R Creative Amusem.ent Designs of Ana­ line along a queue-up ramp. They walk up and through heim, Calif., to create a theme, look, and story. Although a control room replete w ith a television anchor an­ no two anlUsement rides are alike, many share common el­ nouncing a city takeover by rats. Almost a thousand ements from different suppliers. In the case of the Extermi- lights blink randomly at the panel. Along the walls of the

MEC HANI C AL E NG INEERING AU G U ST 2000 53 28-foot building hang maps depicting West Miffiin's util­ onto scrim, bounce among the breaker's three giant elec­ ity underground. The effects sequence repeats at inter­ trodes. Frayed cables hang helter-skelter, obviously the vals of about 20 minutes, Marvenko said. work of furry Luddites. After riders enter the loading station, which extends The cart then descends, climbs, rounds a bend, and along the coaster track for about 50 feet, they climb into comes upon a giant ra t arm, M arvenko said. The arm cars by groups of fo ur. The roller coaster uses seven in­ lowers in front of the oncoming cart, surely ready to dependent cars in all. The load station, serving as a por­ sweep it off the track. At the last moment, the track falls tal to the underworl d, plays up this effect with ro ots away and the occupants slip benea th the rat's surly grasp. overhea d , red lightin g (fo r the sake of safety), and, In the next scene, an animated exterminator in orange down-track, where the ca rs enter the tunnel, a giant, coveralls stands ready to fire a gun loaded with what pas­ slow-moving exhaust fa n powered by a small motor. sengers know can only be high-strength rat poison. This Once loaded, the cart makes its one and only powered is also where the track disappears in the mirror trick. Downloaded from http://asmedigitalcollection.asme.org/memagazineselect/article-pdf/122/08/52/6354466/me-2000-aug2.pdf by guest on 24 September 2021 climb to the top of the first hill. From there, the cart will The cart speeds on to a darkened room. As it starts ne­ freewheel, with only brakes controlling its descent. gotiating the serpentine section of track, a patented lock­ The first scene is the electric room, where the 10,000- ing mechanism releases the cart body from the chassis. pound shell of an Alstom circuit breaker (for which Ken­ Up until this time, the cart body has been locked to the nywood paid $30,000) shows sure signs of trouble. Elec­ rolling chassis to ensure safe passage th ro ugh the upper tric arcs , the result of a digital video image projecting drops. Now fre e to spin, the cart body and its four occu-

A proximity sensor, positioned after the coaster and animation went in, begins the action sequence for this figure just as the riders come upon it.

54 AUGUST 2000 M EC H AN ICAL ENG INEERI G pants begin winding one way or another while the chas­ the cars as they enter the zones, the PLC knows the ap­ sis chases the hairpins. A rotation cam between body and proximate whereabouts of as many as six cars at once. chassis controls spin speed, but each trip through is dif­ N ine d o uble pneumati c fin brakes are distributed ferent because the direction of spin can reverse and its around the trac k circuit, one for every zone, he said. At ro tati onal rate depends on w hether the ca rt holds four each location, two lengths of angle, each 2 meters long, portlies or three slims. Still spinning, cart and passengers bac k up against air bladders. Actuated by air pressure fol­ enter the maw of the boiler. lowing a PLC signal, the angles force opposing strips of Alive after escaping the fire and smoke of the boiler, the brass toward each other. The soft metal provides wear passe ngers continue spinning as they ride over a series of surfaces that rub along the sides of corresponding metal camelbacks-small hills-that dissipate the coaster's en­ fin s projecting from the cart undersides. ergy before it returns to the loading area. The coaster PLC keeps all the ac tive carts under surveil­

lance. If a cart starts gaining on the one ahead of it, the Downloaded from http://asmedigitalcollection.asme.org/memagazineselect/article-pdf/122/08/52/6354466/me-2000-aug2.pdf by guest on 24 September 2021 THREE-PART CONTROL PLC claps the appropriate fin brake to slow it, he said. If Bringing the Exterminator up to speed was a matter of a cart does not pass a sensor w ithin a certain period of controlling the coaster, controlling the animation, and time, the PLC assumes it is dead on the tracks and stops controlling the inter­ the car trailing it. The actio n b etween the sequ ence repeats until two independent sys­ all ac tive carts are tems, Marvenko said. safely stilled. Unlike the anima­ Altho u gh m any tion, w hi c h Sally amusem ent rides use Corp. built in accor­ PLCs by other manu­ dan ce w ith R &R 's facturers, R everchon original custom de­ elected to use a sign, the coaster du­ Si em ens controller plica tes a prototype partly because of its ride that R everchon ability to m eet Cen­ firs t made in 1986, of elec (th e Europea n whi ch 35 copies have Committee for Elec­ since been sold. trotechnical Standard­ According to Vin­ ization) Level 4 safety cent Pic Paris, R ever­ directives, he sa id. chon's U.s. represen­ " The ride is fitted tative in Jupiter, Fla ., with two computers the company makes A lock on the underbody holds carriage and chassis as one along upper reaches of the track. In that check each oth- lower sections, the lock releases and the carriage spins wildly through a series of hairpin turns. its spinning coaster in er," he added. only one version. The same version can be carted from Unlike the controls for the coaster, the animation aspects fai r to fair as a portable ride or fixed in place to act alone of the ride-the rat arm motion, the exterminators, the or, in Kennywood's case, as the core around which other sm oky boiler room- require that the action sequence be amusements such as dark rides are built. synchronized to an audio trac k. "Typically, we won't do "The track is not modular," Pic Paris said, "and we are much with PLCs," said Sally Corp.'s Wood. For anima­ trying to keep it as is. Any modification of the trac k rep­ tronics, synchronizing audio and action is the primary resents a huge amount of engineering hours." Standard­ task. "PLCs are obviously a scripted technique, program­ izing the track helps R everchon m eet the conformity as­ ming a series of activities that take place one after the oth­ sessments of such organiza tions as Bureau Veritas of er, sometimes related to time, but not always," Wood said. Courbevoie, France, and TUV Suddeutschland of Mu­ "Time synchronization is critical when it comes to mov­ nich, which test and control the integrity of both sys­ ing a mouth at the right sequence, or having characters ap­ tems and welds, he sa id. pear more lifelike," Wood said. Sally Corp. programmers Standardiza tion holds true for controls, too, at least in code mostly by way of a clock track or by way of analog how R everchon engineers address them. "The controls FSK (frequency shift keying), in which a signal is encoded approach is the same for all the spinning coasters we have or decoded on a separate track of the disk, tape, or digital manufac tured and delivered," he said, although specific chip, and synchronized with the audio program. components of the system have changed over the years as "When you are sitting there trying to manipulate what manufac turers have introduced new produ cts. is, in essence, an electronic puppet, then you've got to The coaster uses a blocking system to keep successive play the soundtrac k on one hand, while you're manipu­ carts spaced safely apart, Pic Paris said. A series of prox­ lating the character on the other, and putting all that in­ imity senso rs set at intervals along the track se nse cart formation on some storage vehicle," Wood said. presence, reporting back to a Siem ens PLC. The sensors T he success of a ride like th e Exterminator depends divide th e track into zones. By detecting the presence of grea tly on putting the audience in the scene, Wood ex-

MECH A ICA L ENG I NEERI G AUGUST 2000 55 plained. Action is directed troubleshooting because at the riders as carts swing walkie-talkies or video moni­ by individual animations. tors are unnecessary. On the "We want the action to ap­ other hand, "some operators pear as though it's happen­ like to tour people through ing because of the rider's their control Mecca." For presence. We're shooting them, central control is the fog on people, in the case of way to go. "Disney is certain­ the Exterminator, which ly one of those," he said. adds to the sensation of the The ride designers origi­ experience," Wood said. nally planned on triggering

"We have developed some the animation sequences Downloaded from http://asmedigitalcollection.asme.org/memagazineselect/article-pdf/122/08/52/6354466/me-2000-aug2.pdf by guest on 24 September 2021 techniques that allow for from photocells that detect­ localized, solid-state con­ ed the passing carts, Mar­ trol, as opposed to a cen­ venko said. But the park tralized scheme," he said. had tried photocells previ­ "We have little control box­ A rat's nest? No , just a show of what it takes to bring giant rats to life ously, he said, with limited in the Exterminator: primarily air hoses and electrical wiring. es that house what we call a success because dirt and mini-SAM-or sound and automation controller-and dust would debilitate them. Using them in the dark of on that card there is the ability to store up to four min­ the new ride was questionable as well. utes of audio." The card holds a small amplifier as well, The designers decided instead to use proximity sensors. along with an animation controller. A sensor, detecting a These could have been wired directly into the individual cart, starts the show and the sequence, he said. The Ex­ animation controllers, Marvenko said. That approach, terminator consists of a number of short shows in the however, would make it difficult to locate the sensors to middle of one big show, he added. fire the effects at the right times. A process of trial and Any of the rides that Sally Corp. has worked on could error, determining the right moment to start an event have used central control. It's more a matter of the individ­ occurs only after the animation is in place and the carts are ual park operator's tastes, Wood said. Local control assists riding the rails, he said. "We didn't know how fast the cars business, he said. Where possible, R&R confines the bidding on animation and ef­ fects to just a few companies. Construction of the amusements is strati­ fied, too. "As small as the business is, there are people who specialize in bigger anima­ tion and those who concentrate on smaller stuff," he said. "But there is no standard to bid against as there is in laying concrete, for instance." R&R is very much aware of what is tech­ nically feasible when it sets about to design Downloaded from http://asmedigitalcollection.asme.org/memagazineselect/article-pdf/122/08/52/6354466/me-2000-aug2.pdf by guest on 24 September 2021 a ride. But technical details are left to the animatronics makers. Take the exterminator figures, for example. "The designers created the location and the approximate poses of the figures," said Sally Corp.'s Wood. "We then translated that into life-size drawings of those poses." Sally Corp. engineers assemble frames for the exterminator figures. Plastic on stainless From the drawings, Sally Corp. engineers steel holds up better than conventional steel frames would in the fog of the dark ride . created frames of stainless steel because the would move. At the beginning of the ride they go slow and figures would feel fog. Then the engineers encapsulate in some places they go fast. If I were to put a photocell 50 the frames in vacuum-formed plastic, Wood said. "Inside feet away from the trick, it might trigger at the wrong time. this body form are the actuators that turn a head, tilt a I might be playing with that forever," he said. head, move a mouth, move an arm," he said. For most The trial-and-error process ended up adding sensors that animation, Sally Corp. uses pneumatic actuation because were beyond the capabilities of the original controllers, it is cleaner than hydraulics and less costly than motors. Marvenko said. T he designers considered several ways of "The animation schedule is rypically dictated by the accommodating the extra controls inputs. One way was to simply go to a larger master controller. Another way was to use several micro-PLCs. A third way, suggested by a salesman at Scott Electric of Greensburg, Pa., which supplied the original controls, was to use five logic modules from Siemens. Logic modules offered I/O for less cost than did the other approaches.

HEY, DUMMY, MOVE YOUR ARM A long time passed between the stirrings of the big idea and the final sequencing of ani­ mation, the last nailing down of scenery, and the first welcoming aboard of a paying thrillseeker. Along the way, however, the artistic themes that initiated the project never strayed far from center. Themed-adventure designers Richard Bastrup and Richard Fer­ Two animatronic exterminators audition outdoors at Kennywood Amusement Park before going below to slaughter vermin. Sally Corp . supplied four such figures for the ride. rin, who own R&R, were among the first people Kennywood approached with its idea for the Exter­ show action required-what's the most realistic action minator. They are usually among the last to sign off on a that we should be able to get for the budget. We then use ride as well. Mter developing initial concepts for the Exter­ industrially rated techniques activated by digital or ana­ minator, R&R designed art, logos, and characters, then log signals," Wood said. produced all the audio and video elements. Still, for all the technology that ride-builders have "We call ourselves art directors," Bastrup said. "We available today, Wood relies on a simpler equation. work closely with the project architect and all the manu­ "Technology does not typically drive the amusement facturers," he said. park field; it complements it," he sai.d. "Fun and enter­ Project timelines in the industry run from 7 to 18 tainment drive the amusement park. People don't care months, with a year being most common, Bastrup said. whether you have cams and cogs for moving your ani­ Designing themed adventures is very much a specialty mation or sophisticated controls-as long as it's fun." •

M EC HA N I AL ENG INEERI NG AUGUST 2000 57