Designing and Building Expressive Robotic Guitars

This paper provides a history of robotic guitars and bass guitars as well as a discussion of the design, construction, and evaluation of two new robotic instruments. Throughout the paper, a focus is made on different techniques to extend the expressivity of robotic guitars. Swivel and MechBass, two new robots, are built and discussed. Construction techniques of likely interest to other musical roboticists are included. These robots use a variety of techniques, both new and inspired by prior work, to afford composers and performers with the ability to precisely control pitch and plucking parameters. Both new robots are evaluated to test their precision, repeatability, and speed. The paper 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.