Plucked strings are an exciting sound generation model for technical and timbral exploration. Mechatronic chordophones take advantage of this model and have been the focus of extensive research and exploration in musical robotics, often used as stand-alone instruments or as part of sound art installations. However, no existing chordophone designs have utilised the expressive potential of plucked strings to their full extent.In this paper, we introduce an expressive mechatronic mono-chord that serves as a prototyping platform for the construction of a polystring chordophone. This new chordophone has been developed to offer enhanced dynamic range, fast picking speeds, fast pitch shifter displacement, and additional expressive techniques compared to existing systems.

The continuous automatic calibration of musical robots is an important step toward enabling them to create accurate, reliable, and expressive performances. Several attempts have been made to achieve this using external laptops, single-board computers and off-the-shelf hardware, but these solutions have various drawbacks that preclude their use in many musical robotics contexts. This paper presents a new, custom-built embedded DSP system that is capable of up to 32 channels of high quality audio input and output, created to carry out musical information retrieval tasks on the sonic output of musical robots in real time while they are performing. The results of these analyses are continuously fed to musical robot control hardware in order to inform their performance. The design and construction of the circuit board is described, the Musical Information Retrieval (MIR)-based algorithms carried out by the board are outlined, the system's performance in representative applications are evaluated, and its various implications to the field of musical robotics and beyond are discussed. By integrating this system into new musical robots, the result is instruments that are able to `listen' to the audible results of their own actuations in real time, and continuously calibrate their actions to best represent the intentions of the programmed musical composition or live input.