21m linear rail project holds no ‘fear’ for Hepcomotion

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A breathtaking display of art that appeared at the Tate Modern in London relies on a linear transmission and positioning system supplied by HepcoMotion. ‘Fearful Symmetry’ by Ruairi Glynn, a renowned artist who builds interactive kinetic installations, features an illuminated tetrahedron mounted to the world’s largest delta robot created the illusion of being ‘alive’ within the gallery’s vast darkened tanks. At an impressive 21m in length, the DLS4 linear rail from HepcoMotion allows the tetrahedron to traverse across space as it ‘interacted’ in real time with gallery visitors.

21m linear rail project holds no ‘fear’ for HepcomotionMr Glynn says: “When I first went to HepcoMotion I had little more than an animation. The delta robot was in construction and I had a rough idea of weight, but that’s all. I knew HepcoMotion offered the technology we needed, but was unsure of typical delivery time.”

Mr Glynn and his team needed to undertake testing before installing Fearful Symmetry at the Tate Modern, which meant HepcoMotion had just 4 weeks to supply the linear rail system, gearbox and mounting ancillaries.

My Glynn says: “Fortunately, they came through. The initial follow-up and appointment was quick, and the product was fully specified the next day, which was a big help in achieving the short lead-time.”

HepcoMotion’s off-the-shelf DLS4 system can save hours in design and specifying time. It comprises belt-driven linear modules, an AC motor/inverter package, and a range of compact planetary gearboxes for use with servo motors. Options include a cantilever axis with lightweight beam, plus couplings and connecting shafts for units used in parallel.

Aside from delivery and cost, other factors on Mr Glynn’s priority list included distance capability, speed of motion and quality of movement. Among the advanced features of the DLS4 is a steel-reinforced polyurethane belt for minimum stretch and high speed capability, as well as quiet, trouble-free operation from proven ‘V’ bearing technology.

Although capable of quicker, the motorised 21m linear rail facilitates 2m/sec traverse speed of the carbon fibre delta robot, which at 5m in height (fully extended) is thought to be the world’s largest.

An intense and visceral experience

Once installed within the subterranean tanks at the Tate Modern, Fearful Symmetry was commissioned and presented to the public for the first time as part of the Undercurrent arts programme in August 2012. Taking its title from William Blake’s poem ‘The Tyger’, the installation returns visitors to a primal state of hyper-awareness through advanced computer vision, robotics and interactive choreography, the sum of which created an intense and visceral experience for more than 10,000 visitors a day.

The glowing tetrahedron, made from electro-luminescent sheet, glides through the air suspended above people’s heads. As the only light source in the room, the tetrahedron acts as entertainer and guide to the space, dancing with the audience, and playfully encouraging them to become an active part of the performance. This is facilitated by an array of sensors that create a 3D map of the 30m diameter, 7m high space, relaying information to an on-board computer.

The project was sponsored and supported by Bartlett School of Architecture at University College London, the Centre for Robotics Research at King’s College London, and the Product Design Engineering Department at Middlesex University. Such was its success at the Tate Modern that Mr Glynn and his team are now in discussions with a renowned gallery in France about a subsequent display of Fearful Symmetry.

To find out more about linear transmission and positioning systems from HepcMotion, please visit

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