The waseda flutist robot No. 4 refined IV: enhancing the sound clarity and the articulation between notes by improving the design of the lips and tonguing mechanisms

As a result from our research, the Waseda Flutist Robot is able of playing the flute nearly similar to an intermediate level flutist. In order to enhance the expressiveness of its performance, we are focusing our research on improving the mechanical design of the simulated organs as well as implementing automated algorithms for the generation of expressive music performance. In a previous research, we have developed a human-like vocal cord to improve the production of vibrato. In this paper, we are presenting the newest version of the flutist robot; where the lips, oral cavity and tonguing mechanisms were improved. Such improvements were proposed to effectively control the attack time and double tonguing. The attack time is useful to produce clear sounds and the double tonguing is an important articulation that helps players to produce shaped notes and smooth transitions between notes. The lips mechanism is composed by 3-DOFs which enables the accurate control of the air stream parameters (width, thickness and angle). The lips of the robot were designed more human-like by using a thermoplastic rubber (septon). The oral cavity was designed similar to the human one also made by septon. Inside the oral cavity, an improved tonguing mechanism was designed (1-DOF) to reproduce better the double tonguing technique. A set of experiments were performed to analyze the improvements on the dynamical properties of the sound while playing the flute.