Expressive Robotic Guitars: Developments in Musical Robotics for Chordophones

Abstract

This article provides a history of robotic guitars and bass guitars as well as a discussion of the design, construction, and evaluation of two new robotic chordophones, with a focus on different techniques to extend the expressivity of robotic guitars. Swivel and MechBass, two new robots we built, are discussed. Construction techniques likely to interest other musical roboticists are included. These robots use a variety of techniques, both new and inspired by prior work, to afford composers and performers the ability to precisely control pitch and string-picking parameters. Both new robots are evaluated to test their precision, repeatability, and speed. The article closes with a discussion of the compositional and performative implications of such levels of control, and how it might affect humans who wish to interface with the systems.

Designing Mechatronic Musical Instruments: The Guitar

“…The simplest means by which a pick may be moved across the string to cause it to vibrate is the solenoid-based approach. Here, a guitar pick is affixed to one or more solenoid actuators (exemplified by the picking system on Jason Long's Robotic Taishogoto [11]) or DC motor actuators (exemplified by GuitarBot and by the Authors' Swivel 2 [12]). Upon actuation, the actuators displace the pick and drag it across the string.…”

“…Many prior mechatronic chordophones use a simple solenoid actuator to which some vibration damping material, such as felt or foam, has been attached. Systems such as GuitarBot and many others (such as those described in [12]) mount the damper near the picker in a fixed position. While this allows for the string to be damped, a more rapid damping action can be achieved with a larger damper with multiple effectors.…”

Beyond the Keyboard and Sequencer: Strategies for Interaction between Parametrically-­Dense Motion Sensing Devices and Robotic Musical Instruments

“…In essence, the musical robot is mapped to respond to typical MIDI keyboard com-mands. While this system is widespread and applied to many systems both simple and rela-tively complicated (exemplified in and (Focke, 2011) and (Singer et al, 2004)), it fails to ac-count for the current trend in increasing para-metric density on contemporary musical ro-bots (Murphy et al, 2015). As musical robots gain more parameters, the number of relevant MIDI commands falls short.…”

An Inclusive Musical Mechatronics Course

“…1), that now has over 700,000 YouTube hits (for example [16]), the modular 6 string guitar Swivel 2 ( Fig. 2) [17], the integrated mechatronic guitar StrumBot [18] (Fig. 3), and a number of other mechatronic instruments detailed in [19][20].…”