STAGE TECHNOLOGY
74 AUDITORIA 2019 VOLUME ONE
In addition to the new wagon system, all
the over-stage and under-stage machinery was
fitted with SYB 3.0, the latest stage controller
from Bosch Rexroth. A decentralized system
architecture was added, with a central collision
controller developed for the project. This
equipment is aware of the exact position of
the turntable wagons and ensures that the
vertical movement of under-stage machinery
is coordinated with the horizontal movements
of the stage wagons. The system is designed to
prevent dangerous movements that could lead
to collisions between wagons and elevators.
Dress rehearsal
The installation closed the theater for 12 weeks.
“While this is a relatively long break between
seasons, it is still a very short time to implement
a completely new system and make sure it
works,” says Martin Johannes Trumpf, project
manager for stage technology at Bosch Rexroth.
To make the most of the available time, Bosch
Rexroth decided to have a dress rehearsal. The
turntable system was built at the company’s
factory in Lohr am Main, Germany, to test the
various components and ensure everything
worked smoothly. This gave the company a high
degree of confidence that the system would work
first time when it was installed in the theater.
“All our projects are custom, so every solution
is unique and has its own challenges,” says
Trumpf. “The major challenge of this project
was ensuring the accurate movement of a freely
wheeled set of wagons with electronic guidance,
safely synchronized with the vertical strokes of
the stage elevators. Fortunately, we have built up
a lot of experience over the years that allows us
to deal with unexpected challenges. In any case
Bosch Rexroth is a safe bet and a reliable partner
in any challenge or situation.”
The show goes on
The new system was successfully installed in
2018, ready for the new season’s performances.
“Audiences at the theater have since been
entertained and amazed by the performances
of the actors and the sets enabled by the new
turntable in many exciting shows and ballet
choreographies,” says Trumpf. n
www.boschrexroth.com
The wagons are moved by 12 drive units –
four on the smaller wagon and eight on the larger
one. These units can be controlled separately and
can also turn independently, enabling the wagons
to be moved in any direction. Each drive unit is
about 1m2 (10.8ft2) and is mounted on the steel
structure of the turntable wagon. On each unit,
a pair of servomotors is connected to the drive
wheels. These servomotors can be used to either
move the wagon in a specified direction or rotate
to a new direction.
Inductive sensors
The wagons were designed so that they sit flush
with the stage floor. A consequence of that is that
they have to be positioned extremely accurately
to fit exactly over the under-stage machinery, so
they don’t hit anything when moving. With a
tolerance of less than 5mm, the inductive
guidance system had to be incredibly accurate.
One of the requirements of the project was
to keep the theater floor closed with no gaps,
which meant that mechanical guide rails were
not an option. In addition, the intersections of
movements in X and Y directions had to work
extremely reliably without mechanical guidance.
In response to these challenges, Bosch Rexroth
worked with the Swedish stage engineering
company Visual Act to develop a fully electronic,
contactless solution that uses a series of inductive
sensors to detect passive metal guiding strips
fitted flush with the theater’s wooden floor. The
inductive sensors detect the exact position of the
wagon in relation to these strips, so the wagons
can be positioned accurately on the stage.
Additional RFID sensors are incorporated in
the stage floor to confirm that the wagon is in
the correct position, providing an extra level of
redundancy and safety when moving the sets up
or down between the stage and the trap room.
Above: The turntable wagon
in motion, with its sensor
strips and sensors clearly
visible underneath
Top left: There are four drive
units on each of the stage
wagons and eight on the
turntable wagon
Below: All the over-stage and
under-stage machinery can
be controlled through SYB 3.0,
which also features a specially
designed collision controller
/www.boschrexroth.com