A Low-Noise Guitar Robot Featuring a New Class of Silent Actuators

This paper presents the development of the automatic string-plucking system of a guitar robot, which was designed to generate music without machine noise. The soft robotics approach led to the development of a novel silent actuator that utilizes soft elastomeric cones as cushioning to prevent impact noise. We present the method to design the elastomeric cone based on nonlinear finite element analysis. The silent feature of the silent actuator was confirmed by a noise test comparing the silent actuator with the conventional ones. We also present a new design of the robot fingers, which is quiet and capable of hurdling the string in the returning stroke. To enrich the music dynamics, loudness variation was created by simple open-loop control. As a sample performance test, an accompaniment music of the song “Five Hundred Miles” was played in front of an audience for their opinions. Lastly, in a speed test, the results showed that the speed limit of the plucking fingers can reach 720 PPM. A video of the robot playing “Five Hundred Miles” can be found in: https://www.youtube.com/watch?time_continue=3&v=dwdimrP6M2U.