Bot-thoven: A Musical Robot Performer
From Honda’s theremin playing robot (Tsujino, Okuno, & Mizumoto, 2014) to the robot used in Nigel Stanford’s music video “Automatica,” a numerous number of instrument-playing robots have been created in the past. While instrument playing robots demonstrate impressive accuracy in hitting correct pitches or performing in perfect rhythm, these robots lack performing with musical expression that one would find through a human performer (Kemper & Barton, 2018). Human performers use techniques such as dynamics - difference in volume levels - and articulation - difference in the clarity of sound - in order to convey various musical emotions to the listener. By working with a partner in the Computer Systems Lab, we propose to develop a robot which can read sheet music and perform with musical techniques like that of a human performer.
We have chosen the xylophone to serve as the instrument for our project. Research shows that the strength at which a xylophone key is struck conveys different emotional responses for a listener (Chau & Horner, 2016). The six emotional categories which showed the strongest effects due to differing strengths was calm, mysterious, comic, angry, scary, and sad, with softer strokes especially conveying comical emotions while harder strokes conveyed mysterious and angry feelings.
Research shows two possible ways to vary the strength at which a xylophone key is struck on a robotic instrument. One is through time varying torque as used by drum-playing robots when achieving a diverse drum stroke pallet (Gopinath & Weinberg, 2016). Regarding the xylophone mallet as a rod and the pivot point where the mallet is controlled by the servo as a fulcrum creates a time varying torque resulting in a diverse range of applicable forces for an instrument playing robot. A second option is through changing a servo’s rotation degrees per second (Oh & Park, 2013). By changing the rotation degrees per second on a servo, a mallet-servo system can strike a key at different velocities, resulting in an instrument playing robot to perform at various dynamics.
Creating a musical instrument-playing robot will allow anyone to listen to a personalized live performance at any time or location. The robot will be able to perform any given repertoire with musical expression like a human performer as long as the sheet music is printed for the program to read. While our project currently focuses on a single instrument - a xylophone, our work on how to have robotic instruments play with dynamics and musical techniques has the potential to be applied for a variety of instruments. The expansion of our research to various instruments will give listeners even more freedom in personalization. In addition, music has been shown to help dementia and Alzheimer’s patients in helping regain memory loss. Our technology has the potential to be used in the field of music therapy - where Bot-thoven can be set up in nursing homes to help residents use the power of music for positive recovery.
The first objective is to create a working servo-mallet system which is able to strike the xylophone key at various dynamics. By achieving this goal, our project would have achieved the aspect of performing on an instrument with musical expression like a human performer. After completing one successful servo-mallet system, we will be able to quickly duplicate the model to create the necessary amount needed for the entire xylophone.
Another objective is to create a working program which is able to take the music input data and create an output conveying details on the appropriate pitch, length, and musical expression (ex: dynamic level). By achieving this goal, we will be able to send data for the Arduino board to use when telling the servo-mallet system at which strength to strike the key.
After completing our project, we plan on setting...Read more »