A Robotic Generative Percussion Quartet

Abstract

This paper explores how a multi-agent system composed of small, simple Sphero BOLT robots can cooperatively compose and perform a generative percussion musical experience via physical interaction with frame drums and tambourines. The system generates music by, for the lead robot, selecting one of many pre-programmed patterns that represent conventional percussion music building blocks. Then, the other follower robots respond to the lead robot by selecting a complementary pattern. These patterns are performed using information from sensors located on the robots such as gyroscopes and motor encoders, and the robots keep time by following a global “metronome-clock”. During the live performance, human interaction is encouraged through playing a MIDI keyboard, which changes the robots' colors and movement patterns. Due to mechanical error, the robots often experience delays or inaccuracies in their paths. However, because of the generative nature of the music and the interesting rhythm choices that make up the patterns, the robots' errors are recycled into the musical experience as added complexity. Though the robots are unable to adapt to these errors, the errors are utilized to create and propagate unconventional rhythms that human quartets would find extremely difficult to coordinate.