17.07.25

When the US opera Blue arrived at the English National Opera, a dramatic backdrop was required to match the tenor of the production. A rotating set was precisely coordinated to accommodate the performers and synchronise with a background of abstract video projection.

Set in modern-day New York City, the opera Blue tells the story of a family cast asunder. A mother gives birth to a son, but amongst racial tension, family and friends within the black neighbourhood warn of the challenges he will face. The boy’s father, a policeman, is undaunted, but as the boy grows, the young man’s protest against inequality sets the father and son at odds. Tragically, the 16-year-old is shot and killed by a police officer at a protest, sending the family into anguish while giving lessons in hope and the importance of family.

Following a premier of Blue in the US in 2019 where it was performed at a host of venues, the opera came to London in 2023 for a production at the English National Opera, based at the London Coliseum. While the impressive building is the largest theatre in London’s West End, a special set developed for Blue’s production would play a crucial role in bringing the turmoil and emotion of the story to life.

The English National Opera commissioned creative construction company Scott Fleary for the ambitious project, based on a vertically rotating stage. The set would comprise a 7.6m diameter, vertically rotating drum, housing a 6m by 3m room. This backdrop would rotate between scenes, set in a portrait, landscape, or 45-degree angle. In one crucial scene, the set also had to rotate continuously during the performance.

To fit the tone of each scene, the motion of the drum also had to synchronise with projection-mapped video content of abstract New York City street life, adding to the dramatic backdrop.

Motion control for the rotating set

Assembled in two halves, the large drum weighing 10 tonnes was secured within a cradle, holding its position while allowing it to rotate. To drive the drum, the Scott Fleary design team, led by Project Manager Andrew Mitchel, specified a 4.5kW AC motor, coupled to a planetary gearbox with a 50:1 ratio. Connected to the motor shaft, a 1,000-tooth drive wheel would turn the drum’s central strut. To stabilise the drum, its outer struts would be guided by nylon rollers secured to the cradle.

Controlling the position of the drum was crucial, and to achieve automated synchronisation, Scott Fleary commissioned electronics and automation integration partner Iskudo.

“Between each scene, the drum was set into motion, and it had to stop at exactly the right point,” explains Andrew. “For the pivotal scene where the mother learns of the loss of her son, the backdrop was also required to continually rotate, emphasising the disarray she faced, before stopping at 90 degrees in perfect alignment with the stage.”

Tim Baarsch, who leads Iskudo, worked around Blue’s eight scenes to plan the motion and achieve the required angle of turn according to the specified time of each scene change, such as movement of 90 degrees over 38 seconds.

To achieve this, Tim selected a Trio Motion Technology MC6N-ECAT Motion Coordinator, providing high-speed EtherCAT communications to optimise motion control precision, supplied by GAPP Automation, a long-time Trio distributor. Tim programmed the controller using the TrioBASIC language. Although Trio controllers can be programmed with IEC languages, Tim favoured Trio’s high-level language command set for its ease and speed of development.

Precise and repeatable motion profiles

Calibration of the motion profiles for each scene required a speed ramp up and ramp down, especially important considering the weight of the drum and the extent of inertia, which could easily damage the set if not carefully controlled. The motor was also equipped with a breaking resistor to assist a controlled slow down, and precise tensioning between the motor and drive wheel provided dampening. Control was particularly tested during scenes where performers were positioned within the drum.

“The level of precision required to position the set exactly where we need it could only be achieved with a specialised motion controller, and the reason I work with Trio is that the controllers give repeatability as well as high precision,” says Tim.

To coordinate the motion with the projection of video imagery, the controller had to provide the media server with the drum’s precise position. This was achieved via the Trio controller’s serial communications port, set up to give angular position every tenth of a second. Using a compact conversion device, the serial communications data was translated into OSC (Open Sound Control), a format commonly used in media and theatre for control and synchronisation between automation and lighting, audio, and video systems.

“We couldn’t mount a typical sensor in the centre of the drum to give constant angular feedback because of the challenges of integrating a cabling solution with the rotating drum, so we had to use a limit switch and then make the calculations inside the MC6N controller,” explains Tim. “In the end, this method, which the flexibility of the Trio controller allowed, gave us the required precision in coordination between the video projection and drum position.”

To operate the motion of the set for each performance, Iskudo developed a 7” touchscreen system that a production crewmember could use on the theatre floor. With buttons corresponding with the drum’s motion moves required for each scene, the touchscreen device integrated with the Trio controller via its Ethernet port.

Reliable and seamless control

While building and testing the mechanical elements of the stage could take place at Scott Fleary’s facilities in nearby Streatham, commissioning the automation system including integration with the media server had to take place at the London Coliseum. With various productions ongoing, this meant the team only had a short timeframe to complete the set up.

Even after opening night, other operas were taking place throughout the week – or even on the same day – meaning that the set had to be wheeled away and then rapidly reinstalled, ready again for Blue’s next performance.

“Each night, we went through a brief homing process before each show to achieve the zero position, and from there, the operator took over with the touchscreen,” says Tim.

Opening in April 2023, Blue continued at the English National Opera for a two-month stretch, receiving wide acclaim. “The English National Opera were happy, and the production worked really well as an opera,” says Andrew.

ENDS