Drum stroke variation using Variable Stiffness Actuators

Abstract

One interesting field of robotics technology is related to the entertainment industry. Performing a musical piece using a robot is a difficult task because music presents many features like melody, rhythm, tone, harmony and so on. Addressing these tasks with a robot is not trivial to implement. Most of approaches which related to this specific field lacks of quality to perform in front of human audience. Implementation of human-like motions can not be properly achieved with a conventional robot actuator. Consequently, we exploit a new type of actuator which simplifies the drawbacks of a conventional one. We used Variable Stiffness Actuator(VSA) instead of using conventional actuator. We can control position, force, and stiffness, simultaneously by using VSA. The most important novel feature is its controllable stiffness. When the stiffness of the actuator is changed, the characteristics of the actuator's response also changes. We implemented the specific stroke which is called "double stroke" using one of variable stiffness actuator. Although the double stroke is known as a special stroke which could be performed by human only, double stroke is successfully implemented by stiffness variation.

A generative physical model approach for enhancing the stroke palette for robotic drummers

“…Kim et. al have also modeled the dynamics of the interaction between the drumstick, drumhead and the fingers as a coupled mass-spring damper model and uses a variable stiffness actuator to realize the drum strokes in a robotic drummer [5]. Different ranges of stiffness that correspond to single and double strokes are also identified.…”

“…Furthermore, the dynamic level of the second hit in the double stroke is much lower than the first hit, which is very different from how a human will play a double stroke. Moreover, it will be hard to use the model presented in [5] to generate multiple bounce strokes. The work presented in this paper, do not suffer from such limitations as the force exerted by the finger on the stick can be modulated in such a way that the amplitude of hits remain consistent.…”

A Learning Method for Stiffness Control of a Drum Robot for Rebounding Double Strokes

“…Berdahl et al used a similar approach for a haptic drumstick robot [8]. Variable stiffness actuators have been used by Kim et al for successfully implementing the double stroke task with a single-joint robot [9]. They used an analytical linearized method for adjusting the stiffness of the actuators.…”