Expressively actuated percussion instruments and interfaces

Percussion instruments and interfaces can be extended by incorporating actuation with motors. While many prior designs have employed actuation to simply trigger notes, this work emphasizes the importance of the musician's gesture using expressively controlled actuators. This is achieved by implementing force-feedback control of the actuators. For example, the Haptic Drum essentially consists of a drum pad attached to a woofer. Every time that a drumstick strikes the drum pad, the woofer briefly pushes it upward again, adding energy to the motion of the drumstick. In this manner, the Haptic Drum enables musicians to play one-handed drum rolls at optionally superhuman speeds and with arbitrarily complex dynamics. Furthermore, because the musician and the drumstick are inside the feedback control loop, the musician can change the rate of the drum roll by modulating the stiffness of his or her muscles or changing the downward force applied to the drumstick. Conversely, borrowing on technology for remote surgery, expressively actuated percussion instruments can be designed using force-feedback teleoperation. Simply by recording the position of the master haptic device during teleoperation, generalized motor programs can be created for expressively playing percussion instruments. This technology was employed in the composition “When the Robots Get Loose."