Mechatronic instruments can create complex sounds that computers and digital instruments have yet to offer. As a specific example, we explore mechatronic chordophones, which use strings as a sound generator and offer a wide array of parametric affordances. The purpose of this work is to review recent approaches for chordophone design and construction, and present current, state-of-the-art devices. We explore multiple mechatronic frames and their components, and we analyze the challenges of building and interacting with these machines. Finally, we review software and hardware approaches that have been implemented to enhance these instruments and to bridge technical and creative restrictions.

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.