Working in the wings: Automation ensures effects are precise, safe and repeatable
For those in the live entertainment industry, putting on a successful show is all about creating an immersive experience. Whether watching a West End play or a spectacular Las Vegas stage show, the audience must not have their suspension of belief broken, least of all by the behind-the-scenes mechanisms helping to create the illusions.
From flying performers and moving scenery to bringing large-scale puppets to life, the systems of wires and pulleys making it all happen should be neither seen nor heard. Traditionally, these systems would have been manually operated. But today, stage automation engineers use electrical, hydraulic or pneumatic power to create precise, safe and – all importantly – repeatable stage effects.
Alec Gass, manufacturing manager of automation firm Stage Technologies, says the work is both challenging and exciting. Projects he has been involved with range from making giant diamond chandeliers appear in a casino atrium to producing overhead trolley systems to traverse and suspend a giant blue suede shoe for an Elvis Presley-themed show in Vegas.
The firm’s sister company, Delstar Engineering, which designs, manufactures and installs stage engineering and rigging equipment, has similarly worked on a
range of projects, from creating a flying car for Chitty Chitty Bang Bang to a fully functional glass elevator for Charlie and the Chocolate Factory – stage productions in both cases.
“It is a varied industry,” says Gass. “Out of my peers who studied with me for a mechanical engineering degree, I use by far the most of the disciplines we learnt in my daily job – mechanics, electro-mechanics, basic control theory, pneumatics and stress analysis. The opportunity to use the different disciplines is huge.”
Since the firm’s inception in 1994, Stage Technologies has provided theatre automation to a range of clients, large and small. It offers off-the-shelf products – including touchscreen operating panels for clients with smaller budgets, such as school theatres – up to bespoke automation equipment and software made and developed in-house for films and spectacles such as those of Cirque du Soleil. It also offers a complete turnkey service, from installation to training operators and commissioning.
Projects, says Gass, can range from offering just a single-axis control to move one element, such as a high-speed winch, to the refit of an entire theatre’s moving equipment. “It can be stage lifts, scenery bars overhead and rotating stages, but our customers are more frequently coming to us with far more interesting and challenging requirements,” he says.
Transports of delight: Audiences cheered the glass elevator in the Charlie production
One example is the work by Stage Technologies for the world première of the Charlie and the Chocolate Factory stage production at London’s Theatre Royal Drury Lane. Stage Technologies and Delstar together supplied a massive, 75-axis automation system comprising counterweight assist winches, floor tracks, trucks, sliders and supplementary motors, stage engineering and hydraulics.
The technical expectations of Charlie were huge, because of both the challenges of installing the complex show in a 200-year-old venue, and the precision required by the creative team’s vision. While the main system of counterweights, floor tracks and sliders was reasonably conventional and did not pose particular challenges, says Delstar, the bespoke elements of the show required extra focus.
One such element was the glass elevator ridden by Willy Wonka and Charlie. A robot arm was commissioned to lift the elevator safely and seamlessly from below stage and fly it over the orchestra pit, while compensating for any tilting or rotation using two electrical actuators. The arm included two large, proportionally controlled hydraulic rams to create an elbow mechanism. A hydraulic, ram-driven telescoping tower was used to lift the arm and elevator out of the basement, and an electrically driven rotate slew was mounted on top to rotate the arm mechanism.
The arm and its lifting tower had to be robust, as they were required not only to move the elevator with actors standing inside, but also to position it under the stage for storage when not in use.
Essentially a live prototype, the elevator had to be refined throughout the technical period. This, says Delstar, was because the hydraulic pumps and control had been installed in the theatre’s basement before the stage floor being built and before the delivery of the arm and elevator.
Patrick Molony, the show’s production manager, says: “The glass elevator proved to be a more difficult project than any of us had understood. After many hours of work, Stage Technologies and Delstar produced results that finished the show brilliantly and got cheers every night.”
As the industry progresses, the theatres are looking for bigger, better and more complex stage effects, says Gass. This trend has often led to Stage Technologies creating a new product line or software to meet the requirements of the client.
For example, Chitty Chitty Bang Bang was the first show in London’s West End to display the technical capabilities of the firm’s three-dimensional automation plotting software, Pathway. In subsequent years, Pathway has evolved into a more advanced Visual Creator software. This software can plot paths, maps or profiles as ‘Visual Creator actions’ and allow operators to change cues, such as speed, or even reverse a cue. These can be previewed on screen, enabling the proposed moves to be enhanced before they are executed on stage.
Creating the effect of a one-tonne flying car was a challenge, says Delstar, with the car mechanism alone taking three months of development and testing. The Pathway software’s functionality was extended to allow for additional pitch, yaw and rotate elements, enabling the car to perform 360º turns while tilting and panning.
While complex stage effects have led Stage Technologies to develop new technology, it is often the practical considerations of working in the theatre, such as a lack of space or the need for low-noise solutions, that drive innovation.
To reduce the noise of its machinery, the Stage Technologies team developed the TipTow Point Hoist, a gearbox-less, multi-purpose, scenery-moving or performer-flying point hoist designed for use in theatres and television studios. The hoist’s motor and drum are directly coupled, to reduce noise and eliminate high-speed transmission components. This coupling also allows the hoist to be deployed with the drum positioned horizontally and the wire rope dropping directly off it, to avoid any noise generation from spooling over pulley sheaves. Achieving sub-50dB(A) noise levels at 1m away, the product has proven popular in the industry, particularly with live shows.
“Unlike in industry, where if you have a moving piece you want a big yellow light and a siren going off, the artistic directors and producers aren’t going to think much of that in their theatre,” says Gass. “It spoils the surprise if, before the big reveal of a moving piece coming into play, you hear a ‘click whirr’.”
One of the biggest practical considerations when operating automated machinery during live shows is safety. Gass and his team regularly work on projects that have traversing elements, with a trolley running high up in the roof above the stage on two tracks, travelling on either a curved or a straight path. The trolley will typically pick up three-phase electric power from busbars and collect its data wirelessly through a leaky feeder communication system. This consists of a coaxial cable run along tunnels, which emits and receives radio waves, functioning as an extended antenna, similar to those used in the London Underground.
“We often use a direct-drive traction wheel with one master-controlled traversing wheel and a number of slave drive wheels that refer to the feedback sensing from the master wheel,” says Gass. However, having a direct-drive wheel that relies on friction creates a risk of slip. “To counter this, we mount optical positioning sensors on the travelling trolley which detect a barcode strip that runs along the channel it is traversing. This then provides us with a linear position sensing within a millimetre or so,” he says.
When a performer is traversing high above the stage, the safety requirements are much higher. Starting with the lifting medium, whether it is a steel wire or synthetic rope, the team need to ensure a 10-to-one factor of safety. “There are stipulations on pulley size and design to make sure that the rope form is properly supported, and that we’re not wrapping them over too tight a radius,” says Gass.
Animal magic: The companies' projects include animating a King Kong puppet for an Australian play
The Stage Technologies team have become old hands at creating smooth-running and robust performer-flying systems, used not just in the theatre but also by touring rock and pop stars. Such artists include Pink and Taylor Swift.
For Swift, the equipment was used to fly a ‘Juliet balcony’ in which she floated over her fans. For safety, she was secured into the balcony, which was suspended with a four-way bridle system using four of Stage Technologies’ BigTow winches. These were controlled by AU:Tour drive cabinets – a flightcase-mounted, touring control rack that is operated via touch panels and can perform enhanced remote diagnostics using broadband connectivity.
“The winches were also built into trusses, so when they arrived at a new venue the crew could put truss-mounted equipment together and hoist it into the roof space. They would then run commissioning tests to verify the speed and capacity, and make sure the piece could cover the desired flight path, there were no obstructions and everything was running smoothly,” says Gass. Secondary load monitoring was also added to each of the axes, so they could verify the individual line loading and monitor whether any line was taking more weight than it should.
Another important factor is accurate positioning information of the performer or piece, and repeatability of the information, says Gass. Primarily, this is achieved with an absolute encoder on the servo motor that is moving the performer. In addition, a second encoder may be located separately on the equipment to verify the integrity of the primary encoder signal, and check they have not deviated from the intended path.
From West End theatres to US rock shows, the life of an automation engineer provides some special design challenges – perhaps none more so than adapting systems for installation in the theatres on cruise ships. With space on the ships being at a premium, reducing stage show staff through automation is desirable.
Cruise ships present a particular design challenge, says Gass. “Relative to the ship, gravity is consistent neither in direction nor magnitude. You don’t want to find the motion of the ocean causes suspended pieces of equipment to find each other in the night, so that in the morning the lighting rig is reduced to a pile of broken glass on stage.” To ensure the machinery can handle the movement and angles on the ships, the team must “factor g as being a bit higher than most would” says Gass.
Bizarre and extravagant requests are part and parcel of the job, from creating a giant mechanical tree of good fortune for a Las Vegas casino to animating a 6m tall, one-tonne King Kong puppet for an Australian theatre production. However, the team at Stage Technologies relish the challenge in making the seemingly impossible happen.
“We are regularly dealing with theatre companies or artistic types whose job it is to be imaginative and not be bogged down with the drudgeries of Newtonian physics or worry about whether something should be possible,” says Gass. “It is their job to be creative. Ours is to make it happen.”
