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Humanoid robots can pick up objects, run, and even play sports (to a limited degree), but can they master the rhythm of a drum kit? Thanks to new research, they sort of can.
Robot Drummer is a humanoid robot avatar capable of “expressive, high-precision drumming”, scientists at the Politecnico di Milano said in a new study uploaded July 15 to the preprint ArXiv database.
This was a concept that was spontaneously conceived over coffee by co-authors Asaf Ali Shahid and Loris Roveda, they told Tech Explore.
“We were discussing how humanoid robots have become increasingly capable at a wide range of tasks, but rarely engage in creative and expressive domains,” Ali Shahid said. “That raised a fascinating question: what if a humanoid robot could take on a creative role, like performing music? Drumming seemed like a perfect frontier, as it’s rhythmic, physical, and requires rapid coordination across limbs.”
Robot Drummer isn’t a robot itself; rather, it’s a simulation that uses the G1 Unitree robot as a model to build a system that a future humanoid robot could eventually use. The 3-D visualised G1 robot plays a color-coded drum kit.
In a video published on YouTube, Robot Drummer is shown mimicking the drum beats to two well-known songs. There’s something a little off about the sound — perhaps to make the drumming more accessible to the ear. Its rendition of “In the end”, by Linkin Park sounds just off the rhythm, while its attempt at “Roxanne” by the Police sounds more matched to the rest of the arrangement.
Related: Robots awkwardly race, fight and flop around in China’s first World Humanoid Robot Games
Learning to play any musical instrument, particularly the drums, presents a unique challenge, the researchers said in the study. It is a multifaceted task that needs split-second timing, rapid contacts, and the combined coordination of hands and feet — all of which needs to be sustained for several minutes.
Trial and error was the basis for Robot Drummer’s learning, with the researchers employing reinforcement learning (RL), a type of artificial intelligence (AI) machine learning process in which an agent learns to make decisions by interacting with its environment.
The agent is rewarded or punished for its actions with a mathematical signal, and it’s often a positive number that signifies a correct action. The aim is to earn more rewards by finding the optimal policy. For Robot Drummer, each song was represented as a chain of precisely timed “contact events,” according to the researchers, which informed the robot what drum strikes were needed and where.
Learned behaviours, the researchers noted, included specific drumming strategies, such as cross-arm strikes and adaptive stick assignments (using a drum stick for a particular sound). This, the researchers said, demonstrated the potential of reinforcement learning for robots in creative domains such as music.
The researchers said that Robot Drummer was put through extensive experiments with over 30 popular songs across pop, rock, metal, and jazz.
