Robotic Finger Hardware and Controls Design for Dynamic Piano Playing

Abstract

Robotic manipulators have traditionally been designed with the industrial world in mind. High degrees of freedom (DOF) robotic hands are starting to enable a new section of tasks like grasping unfamiliar objects with complex shapes, in-hand re-orientation, and even solving Rubik's cubes. This work explores a new kind of task: playing piano. Unlike most common robotic hand objectives, playing piano requires much higher accelerations and control over velocity rather than position. Proper velocity control allows us to play the piano like professionals, with different music dynamics, allowing us to play soft and hard depending on the emotion of the notes being played. To understand the critical factors, constraints, and next steps to creating a full robotic hand for dynamic piano playing, I designed and built several one degree of freedom fingers capable of the high accelerations and velocity control needed for playing the piano using actuators that are appropriately sized for a 10+ DOF robotic hand. With this setup, I was able to consistently play individual notes within 1dB of their respective desired output volume, ranging from -25dB to -4dB, at song speeds of up to 129 beats per minute (BPM). This range is equivalent to playing pianissimo (very quiet) to fortissimo (very loud).