Environment, Robotics
Leave a comment

Our Time – Spatial instrument for manipulating the perception of time

uva_our_time_01

Our Time is the latest large-scale installation by United Visual Artists,  investigating the subjective experience of the passing of time – How long is a moment? At what rate does time actually flow? The work joins a series of kinetic sculptures that began with Momentum (2013), an installation designed as a ‘spatial instrument’ that revealed the relationship between expectation and perception when intersected with a physical space. Our Time was commissioned by MONA and presented as part of Dark Mofo, Hobart, Tasmania in June 2016.

The installation is defined by a physical environment where pendulums swing at a pace apparently unhindered by the laws of nature and where no single time measurement applies. The installation combines movement, light and sound as a multi-sensory, multi-dimensional canvas the visitor can enter. Pendulums swing – each to their own rhythm – as time flows through the grid. With light tracing the path and sound its echo, the passing of time becomes almost palpable.

↑ Video shows an early prototype pendulum device slowly changing its movement over time from natural gravity pull to disorder.

Our Time is comprised of 21 bespoke mechanical pendulums driven by a central control system. The array of pendulums forms a system which allows the team to create both synchronous and asynchronous behaviour, by slowly changing it over time from natural order to disorder. Each instrument is calibrated and monitored using a central control system so that each unit responds in exactly the same manner. The units are suspended so that the lowest point sits at 2.5m above floor level – out of reach of the viewer – and arranged so that adjacent pendulums almost come into contact at the maximum angle of swing (45 degrees).

↑ Early simulation/visualization of the proposed installation.

During the R&D process, different forms and techniques were explored to determine how to build and drive the mechanism. The final design consists of 21 pendulums each with a 2-axis gimbal system, individually driven by a large stepper motor and 3-stage planetary gearbox. Each axis is counterbalanced to ensure the mechanism is not fighting gravity but rather the inertia of the pendulum itself.

diagram

At the end of each pendulum’s 3m-long pole is a machined aluminium pendant that houses two independent light sources and a speaker driver. A bright downward pointing LED creates a spotlight while a speaker and ring of LED likewise project upwards reflecting off the disk and creating a more pronounced sense of directionality with each swing. The speaker and light source integrated into each pendulum bob c a direct, physical connection between sound, light and movement.

The LEDs are individually driven by a high-resolution controller to dim the lights very smoothly, which is particularly important in low-intensity settings. The motors are driven by a custom-built motion controller, running a real-time variant of Linux.

Each pendulum is embedded with its own control unit responsible for reading on-board sensors, maintaining the state of the pendulum, responding to commands from the master computer and generating the pulse train for the stepper motors.

↑ UVA’s D3 simulation in realtime, showing behaviour of individual pendulum.

The overall structure is then programmed from a central system allowing the team to sequence the complete, 21-pendulum grid as one canvas. From this sequencing interface, they can control the period, phase offset and amplitude of each pendulum as well as the lights and the sound being played back, hence all the installation’s individual elements can be tightly linked.

The software includes C for the main control loop, Assembly for the very low jitter pulse train generation and Python for the maintenance and monitoring scripts. The sounds are played back from a series of channels and sub-basses through a programme that responds to commands and inputs sent from our control centre via OSC.

For more more information on UVA and their amazing body of work, see the links below. Many thanks to the team at UVA for providing CAN with details/images and behind-the-scenes footage.

Project Page | United Visual Artists

pendulum2

uva_our_time_02

uva_our_time_05 uva_our_time_07 uva_our_time_06