Into the Soft Machine
This chapter traces the evolution of “soft machines” and inflatable robotics in the work of artist Chico MacMurtrie/Amorphic Robot Works (ARW). These kinetic machines, which take various forms and scales, explore the underlying essence of movement and transformation in organic and non-organic bodies. The artist recounts his creative journey as well as the technological and material aspects that enable the soft machines to change shape in relation to internal air pressure acting on multiple inflatable tubes, behaving like both muscles and bones. Early performances involving latex skins led to inflatable sculptures powered by inflatable “muscles.” More recent sculptures are conceived as a modular or “molecular” system, comprising webs of interconnected, inflatable members with hundreds of operable joints. The process of constant reinvention and refinement is reflected in the increasing sophistication of the couplings of the inflatable members and of light-weight, minimal-control systems. Interaction between machines and humans has been an ongoing pursuit of the soft machines, which are increasingly designed to interact with each other on the basis of air exchange. Ultimately the goal is to imbue the machines with a capacity for supple gesture and expression.
Introduction: Body and Movement
The essence of the body, for me, lies in movement. Rather than static form, I am interested in changing positions, expressions, and gestures. Making kinetic sculpture allows me to explore these dynamics of the body. My work is based on a long-running fascination with living organisms and the technological entities with which we surround ourselves.
While ARW’s output over our first decade comprised largely metal machines and robotic sculptures defined by structure, more recently I have focused on developing “soft machines” based on inflatable components. I will trace my creative and technical journey from an early interest in supple forms, toward rigid machines, and back into more sophisticated soft robotics. I will devote the most space to this most recent and current phase, where I continue to concentrate my efforts today.
An Echo of the Living Body
This in turn led to another tantalizing discovery: the empty latex skin, buffeted by ambient air currents, suggested the possibility of an autonomous form. I envisioned artificially reanimating that form and imbuing it with life of its own. To animate these skins, I began putting mechanical structure inside them, and experimenting with cast rubber air muscles to animate them. Although the rubber components imbued the forms with a softer presence, I focused on hard mechanisms, leading to a decade’s worth of kinetic machines in which structure became increasingly prominent.
ARW’s technology has evolved over the years from repurposed circuit boards and early machine languages to complex servo control systems, vision systems, and dual redundant ladder logic systems. Frequently we have invented tools and techniques simultaneously with the development of the sculpture itself. By 1992, collaborator Geo Homsy had introduced the first multi-channeled, MIDI-controllable computer. By 1994, MIDI hardware designer “Stock” Bart Plum, Engineer Frank Hausman and Artists Brian Kane and Marc9 were programming full performances of movement and sounds with midi software.
Experiments in Locomotion and Interaction
The inflatable mountain ranges from the Trigram opera reappeared, this time larger and imbued with percussive function. These soft sculptural elements had an ability to transform the performance area as the audience moved around it. The internal hydroelectric mechanisms were birthing the machine performers and elevating them at heights where the audience, no matter how large, could always view them. Comprising giant inflatable bladders of air driven by large valves that exhausted percussively, the mountain ranges sounded deep rhythms, evoking a mysterious life force within, while the other percussive machines would attempt to synchronize their rhythms in a primal gesture of connection (Several dozen percussive robots from this period have been refurbished and reunited to form The Robotic Church, a site-specific installation and performance series that debuted in 2013 in our Brooklyn studio.).
In 2004, Richard Castelli curated ARW’s retrospective exhibition in Lille, France, set within a massive exhibition on Robotics. An elaborate vision system tracked the audience, allowing them to move in front of the machines to bring out one of their pre-memorized qualities. Keeping 250 machines and mechanisms alive and working for over 3 months was an epic finale to our work with hard machines, but it spurred me toward another approach. My metallic machines were not well suited to interact physically and safely with humans, which was an increasingly important goal. I dreamed of doing yoga with robots, or embracing them, rather than only directing and observing them. This desire for physical, expressive interaction suggested an entirely different kind of machine body, one more supple and forgiving.
I began a conceptual and technical shift toward lightweight materials and inflatable technology. In some ways I was building upon previous inflatable machines or components, like the inflatable muscles of Inverting Woman or the inflatable mountains of Amorphic Landscape. But instead of using inflatable machines as accessories to a larger machine or installation, I wanted to make stand-alone soft machines.
Supple Gesture and Soft Media
Gesture and surface expression, for me, is one of the most fascinating capacities of the body, and one of the most exciting potential areas of synthesis of art and robotics. There is a vast amount of expressive power and topological change contained in routine human motions. To rest one’s face in one’s hand, for example, is to let the face muscles relax and let the skin slide gently over them. The malleable, forgiving nature of flesh inspired my next generation of machines. In terms of materials, the path forward lay in high-tensile fabrics. We needed a fabric strong enough to hold forced air at high pressures in complex and organic shapes and to support the mass of the inflated sculpture.
The current work of ARW focuses on soft machines composed of high-tensile fabric tubular forms, air valves, and a variety of articulated or integrated joints. They are operated remotely by computer and fed from a concealed air compressor or blower or an on-board air storage vessel. Designed and built at increasingly large scales, these ephemeral bodies, either freestanding or suspended in mid-air, use air pressure/vacuum to inflate and deflate through various states of articulation. They exhibit the phenomena of gradual metamorphosis, growth, decay, and interaction. As works of sculpture they present a spectrum of form. Their in-between states are just as important to their poetic expression as the two end points of their metamorphosis.
The quiet metabolism of the machine—the increase and decrease of air in different modules—is usually performed at a slow pace, creating an alternate sense of time in the immediate vicinity. The gentle cycle of air exchange becomes a meditation on the flows of energy and constant movement that defines living organisms dependent on their environment. Sounds emanate from the machine as it changes shape, continuing ARW’s long fascination with rhythmic percussion in the robotic body. The machines slow down, pause, and accelerate only to pass out, exhausted. The search for expression involves the modulation of tempo, duration, pauses, and repetition. The rate of air intake and release becomes part of the character of each machine within the frame of a given performance.
The evolution of our soft machines corresponds to increasing technical and material sophistication. Two of the most important areas of ongoing refinement are the joint details and the high-tensile flexible material, itself. ARW’s relationship with Dyneema®, the manufacturer has been a mutually beneficial learning collaboration, over 10 years in the making. At each step along the way, as I visualize new ideas, the manufacturer, typically respond with new possibilities for more optimal, high-performance coatings and structural integrity suited to the needs of the project.
The chemistry of the finish helps the fabric endure the high levels of heat and pressure to which we subject it during the course of fabrication and exhibition. By modulating the degree of surface transparency and reflectivity, it also affects the visual performance of the sculpture. The woven fibers of the material are permanently altered by tensile forces, so that they reproduce the given form of the sculpture in response to pressure and vacuum. The material thus possesses a kind of memory.
Inflatable Muscle and Bone
In 2004 I began to design and build the Inflatable Bodies. I envisioned an inflatable machine that could perform live with a human performer on the basis of physical interaction. The two performers would be able to fully lift each other, hold each other in the air, and respond to each other’s gestures. The anatomy of the machine was composed purely of inflatable vessels. While the “bones” or limbs were shaped like tubes, the muscles took the form of more spherical bladders. Pairs of these inflatable muscles, glued into the inflatable bones, worked in opposite directions to push and pull the inflatable limbs into the desired position.
After some months of experimentation in the Inflatable Bodies, I had an opportunity to exhibit my first purely inflatable sculpture at the 2005 Elektrische Stadt Festival in Dresden, Germany. I arrived with my collaborator, Marc 9, with only a suitcase containing a roll of high-tensile fabric, a series of inflatable muscle devices, and a control system to animate an inflatable humanoid. The vast scale of the space—the hall of a former factory—called for a correspondingly large-scale installation. I responded by creating a suspended sculpture consisting of two long, conical, inflatable wings spanning over 30 feet. The inflatable muscles animated the movement of a series of humanoid limbs that merged into the center of the massive wing. I saw the “wings” as abstractions pushing my work toward dual-state metamorphic forms.
I decided to continue using the simple yet elegant metaphor of birds’ wings to further develop the soft machines, but to shift from individual forms to aggregated systems. This metaphor allowed for both abstraction and organic figuration, most importantly in the central kinetic device of inflating and deflating. The point was not to simulate the anatomical action of actual bird flight, but to probe deeper into the potentials of high-tensile fabric combined with inflatable muscles. ARW’s first multi-inflatable-sculpture installation was Sixteen Birds (2006), curated by Melentie Pandilovski, commissioned by and exhibited at Adelaide, at the Australian Experimental Art Foundation (AEAF). A central muscle controlled the movement of the wings of each simplified, V-shaped form. The utter simplicity of the concept took on a surprising lyrical power when aggregated across the flock.
The cycle of the wings not only reminded me of patterns in nature but also of the way man-made structures decay and collapse and return to nature. The image of the array of birds losing their volume appeared to me as a long collapsing vertebra. This aspect of the piece inspired the notion of Inflatable Architecture.
The initial form of the robotic sculpture is surprisingly simple. The car body shell conceals the existence of nearly 50 interdependent machines of varying aesthetic and functional purpose. As the sculpture opens and rises, these metal and inflatable machines give voice to varying modes of mobile abstraction, which develop throughout the growth and final “blooming” of the full, 20-m-tall work. The collision and negotiation between the organic and the inorganic aspects suggest narratives of entropy, domination, transformation, mortality, and strength.
Modular and Architectural Bodies
The IAB concept developed in two directions: one, abstract modular structures that evoke of the “inner body” of cells and molecules, where one finds a deeper geometry. And two, architectural-scaled constructions deployed in the urban realm. The sculptural form-finding process still unfolded through hand-made models and drawings. But the extreme technical precision required of the coupling and the angles required digital modeling and CNC fabrication techniques coordinated by the long-time collaborators Geo Homsy and Bill Washabaugh.
By building on the visual commonalities between what we build and what we are comprised of, the Inflatable Architectures make us aware of our actions and the symbioses in which we are embedded. The inflatable robotic structure of Inner Space is meant to be installed in a physically accessible location. When the work is at rest and deflated, it remains folded back on itself. As it inflates and extends (and it is capable of compressing in a taught state) in response to audience interaction, the articulated form takes various shapes, much like a living organism. The percussive sounds of the clicking valves, the air flow and crinkling sound of the extreme tightening of the skin of the tubes surrounding the audience, contribute to a sensory experience that draws the viewers in as spectators.
Inspired by the architecture of the human body on a molecular level, Chrysalis provides a direct, visceral experience of the minute geometric constructions that underlie all life forms. Programmed by Bill Bowen, Chrysalis responds to a visitor’s approach by opening one or a combination of several sections or by creating a portal that invites him or her inside. It also performs independently from the audience by drawing upon previously recorded software sequences. These sequences regulate the amount of air flowing in and out of the fabric tubes, creating a muscle-and-bone dynamic capable of expanding and retracting, lifting and lowering, and collapsing movements. In its transition from an organic to a geometric state, Chrysalis is best appreciated from inside of the sculpture. Here the audience faces their own biology on an inverted scale. Chrysalis, with its ever-changing geometry, manifests the hidden organic life that inspires and informs certain human-built systems.
Suspended from the ceiling so that they barely touch the floor, these hand-formed, levitating arches define an occupiable space with a fleeting architectural form. These soft machines signify a connection with the animate world of living matter and form. Their lightweight translucent skin catches the daylight, offering a view into their inner mechanisms. When inflated, the arches invite linear movement along their axis. This clear orientation gives way to an entirely different set of geometries as the air is allowed to escape the rigid fabric tubes. The crisp architectural forms yield gradually to a seemingly chaotic configuration that actually speaks of another, more organic order. The former arches coil inward to form spiraling strands reminiscent of DNA or complex molecules. These newly revealed, individual organic forms suggest a latent awakening or suspended chrysalis phase of life.
While not necessarily anthropomorphic, these various soft machines signify a connection with the animate world of living matter and form.
Future Soft Machines
The trajectory of the soft machines points toward increasingly close connections between the inflatable sculptural body, the human body, and the environment. The machines’ dependence on a constant energy supply reflects our own constant appetite for food and other resources. I am still motivated by the possibilities of physical machine-human interaction, reflecting both old and new modes of bodily connection, even in an age of increasing virtual interaction.
I am currently building soft machines that can physically interact with humans and their own inflatable environment. These newest machines are able to store their energy internally and use sensing technology to autonomously seek out air-refill machines that have been set up in the exhibition space, like refueling or nourishment stations. These larger architectural machines allow the mobile machines to temporarily dock and refuel while sensing the movement around them.
IAI is conceived as part of an ensemble of soft machines that subsist on air, the Inflatable Architectural Bodies of the Air Society. It becomes the infrastructure or architectural extension or atmosphere of the bodies of the soft humanoid robots that ply the space, searching for their next infusion of air. The various inflatable machines nourish and replenish each other’s air supply, with ensuing consequences for their physical form and movement.
In this scenario, a semi-autonomous tribe of humanoid robots wanders the space in search of sustenance. Their movements and behavior are driven by the need for survival, but also expressive of intention and the capacity for change. The Air Society is partly a metaphor for humans’ precarious relationship with our environment, and partly an experiment in human-machine relations.
Another project in the works is the Border Crossers, designed to challenge spatial boundaries. I have created the first of a flock of six machines. These soft machines initially grow upwards as if to gain a view of their surroundings, then cantilever over the boundary. Current planning of the project is to deploy them in a series of performances along different borders around the world. For example, along the U.S.-Mexico border, three of the machines would be placed on the Mexico side, and the other three on the U.S. side. Activated simultaneously, the six towers would cross the border from two sides, forming a white, semi-translucent archway. Border Crossers in turn could explore all manner of borders, from the political to the architectural and social.
From a technical point of view, these new prototypes are pushing the fabrication and assembly process to the next step. The increasingly elaborate networks of tubes will be assembled and joined in the lightest possible configuration, while reflecting the best structural combinations for fastening them to each other.
How does the soft machine fit into the future of robotics? And how does the artist contribute to a wider conversation about how advances in robotics and artificial intelligence will change our world, and who guides those changes? These are questions that drive my practice every day, and ones that will not be quickly resolved.
What is clear to me is that soft machines can go where other harder machines cannot because of their light weight and ability to change size and shape. They are becoming increasingly capable of expression and gesture as we learn to work with their air-driven physiology. Most of all, soft machines promise closer and more physical interaction between humans and machines. This proximity and even intimacy suggests a possible underlying compatibility or reciprocity, in which both machine and human retain a kind of agency.
Contributing writers: Gideon Fink Shapiro, Luise Kaunert