The Design and Construction of an Expressive Mechatronic Chordophone

Mechatronic chordophones are stringed instruments that integrate mechanical components and electronics to make music. These instruments offer precise control over multiple sound parameters and expressive techniques for enhanced musical expression. There have been multiple successful mechatronic chordophone designs,from robotic slide guitars to bass guitar robots. Among these designs are plucked string and pitch shifting mechatronic chordophones, which make music by exciting the string with a picking mechanism and selecting musical notes with a pitch shifter mechanism. This configuration enables these systems to enhance their musical performance through pitch-based expressive techniques and micro tonal pitches. However, even if these instruments can achieve speeds and precision beyond the capabilities of a human performer, their expressive capabilities are limited. It is difficult for mechatronic chordophones to perform dynamic variations and expressive techniques,and the presence of extraneous noise usually interferes with their musical performance. Furthermore, it is still challenging for users to control such instruments. We have built two mechatronic chordophones. The first is Protochord, a mechatronic monochord prototype. We used this system as a platform for iterative design to develop new expressive mechatronic chordophone subsystems. The second is Azure Talos,a multi-string mechatronic chordophone designed to outperform other existing systems and to afford a wide array of parameters for musical expression. Our research has led to the development of novel mechatronic chordophone subsystems such as: a revolving picking mechanism with superior dynamic variation capabilities compared to that of other existing designs; a fast and precise robot arm pitch shifting mechanism that affords pitch-based expressive techniques; and an optical pickup that rejects extraneous noise. We have demonstrated the technical capabilities of these designs through quantitative evaluation processes, in many cases providing the first set of quantitative tests in the literature of these types of sub-assemblies and systems. A key aim is to provide standards and benchmarks in evaluation criteria which may be used in the development of new mechatronic chordophones. Finally, we developed strategies to assess Azure Talos' musical capabilities through standard guitar techniques, repertoire examples,and creative musical explorations.