Robotic Consistency

As the debut performance for Swivel 2, Robotic Consistinency served as testbed for the instrument in a performance setting. The piece (whose setup is shown in Figure 9.3) was performed at Wellington City Gallery in Wellington, New Zealand on November 25, 2013. After presenting the motivations for the creation of the performance piece, the piece’s technical aspects and compositional elements are detailed. Finally, the outcomes of the performance are discussed.

Robotic Consistency was conceived of as a piece to go toward answering the question of what a performance would be like wherein a human performer attempts to emulate a musical robot’s actions. Such a piece would serve to contrast the means by which a human and robot achieve similar musical outcomes. Additionally, it was hoped that the mechanical precision and actuator motions of the robot would highlight the human performer’s fluid, silent actions. To address these objectives, a composition containing “call-and-response” elements between robot and human was created.

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Figure 9.3: Robotic Consistencyon stage at Wellington City Gallery. Visible is Swivel

2, the host computer, and the performer’s acoustic guitar.

Other pieces focusing on human/robot performance place the robot in a different po- sition than in Robotic Consistency, either placing it in the role of respondant or as an equal “collaborator” with a human performer. In Ajay Kapur’s Digital Sankirna, for example, the human perfomer serves as the master, creating musical gestures that are elaborated upon by arrays of mechatronic actuators [24]. Composer Jeff Aaron Bryant, in [42], describes similar compositions: sensor-equipped human dancers perform actions that trigger robot actions. Similarly, in [27] and subsequent work, robot builder Gil Weinberg creates collaborative improvisation contexts for humans and robots. In Robotic Consistency, by contrast, the human responds to musical gestures created by the robot: as the robot creates difficult-to-play patterns, the human must attempt to emulate them. Artist Tomie Hahn’s Pikapika served as inspiration to this work: in a 2011 performance of Pikapika, Hahn responds in part to a musical robot’s actions1.

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MIXING BOARD + PA COMPUTER WITH _DAW

USB TO MIDI ADAPTER USB 2.0 AUDIO INPUT

INTERFACE SWIVEL 2 (SIX MODULES) GUITAR WITH PIEZO PICKUP 6 2

Figure 9.4: _{Signal flow forRobotic Consistency.}

To direct the human instrumentalist to suitably engage with the robot, textual instruc- tions are provided to performers (in a manner similar to those used by, among others, LaMonte Young in hisComposition #5 1960 [76]). The instructions direct the performer to copy the robot’s actions during a segment of the piece:

For the first three and a half minutes, sit still next to the robot onstage. Then, with an ordinary guitar and slide, attempt to emulated the actions of the robot’s fretter, damper, and picker. Continue this for three minutes; after three minutes of emulation, remain still for the rest of the piece.

Technically, the piece consists of the Swivel 2 slide guitar robot (presented in Chap- ter 3) connected to a host PC, as shown in Figure 9.4. A human performer plays a pickup-equipped acoustic guitar. The signals from both Swivel and the acoustic guitar are amplified and, if necessary, processed by the host PC prior to being sent to the performance venue’s public address system.

Robotic Consisency contains five sections, of which the human/robot interaction is one: the sections, arranged in ABCDA’ form, are illustrated in Figure 9.5. The piece begins with an introduction of the robot: the fretter arms on each of Swivel’s modules slide up and down the length of the modules’ strings. After a brief melodic interlude that serves as a cue to the human performer to begin playing at its completion, the human/robot interaction section begins. During this section, the robot’s fretters move along prede- fined curves along the strings, pausing after each phrase; during the pauses, the human performer attempts to copy the slide gesture to the best of his or her abilities. After the human/robot interaction section,Robotic Consistency features an exhibition of Swivel’s expressive parameters: the fretters settle lightly upon the strings, bouncing slightly and producing rhythmic atonal sounds. The piece concludes with final section of slide events up and down the robot’s strings: where Section A consisted of serial slides (where each

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A

B

C

D

$·

1 2 3 4 5 6 7 8 9 10

Time (minutes)

Sequential slides: each module executes a slide

event; halfway through the event, the next

module begins

Human/robot call and response: Swivel 2 plays a slide pattern on one

of its string modules. In response, a performer attempts to emulate the

slide on an acoustic guitar

Bounce: fretters are

tapped against strings

Parallel slides: each module executes slide

events in unison.

Figure 9.5: _{A timeline of the sections inRobotic Consistency.}

string’s slide event began halfway through the previous module’s slide), section A’ con- sists of parallel slides: all fretters slide at the same rate and direction up and down the strings2.

Robotic Consistency serves as a general exhibition of many of Swivel 2’s capabilities. During the performance, the robot was found to be easy to deploy and configure in spite of its large number of actuators. Compositionally, though, the low-level interactions required to program musical gestures was found to be quite time-consuming. To address this, parametric encodings for the musical robots were developed, a number of which are described in Chapter 7. Further, to play chromatically, manual precise positioning of the fretter arms was required: as the arms required pitchbend input, specific 14-bit pitchbend numbers corresponding to each desired pitch had to be found. It is from this tedious task that the idea of a self-tuning scheme for Swivel 2 emerged (a system described in Chapter 6).