Page  00000001 DEVELOPMENT OF AN ANTHROPOMORPHIC FLUTIST ROBOT WF-3RIV Atsuo Takanishil)2) Manabu Maedal)2) 697a1207 1) Department of Mechanical Engineering, School of Science and Engineering 2) Humanoid Research Laboratory, Advanced Research Institute for Science and Engineering Waseda University, 3-4-1 Okubo, Shinjuku-ku, Tokyo 169-8555, Japan Abstract The purpose of this study is to clarify the mechanism involved in human flute playing from an engineering perspective. The authors developed an Anthropomorphic Flutist Robot WF3RIV(Waseda Flutist No.3 Refined IV), which reproduces the functions of human organs: a respiratory system, a playing attitude control mechanism, fingers, a mouth, a throat, a tongue, etc. WF3RIV was able to play Mozart's " Flute Quartets KV 298" accompanied by a MIDI tone generator module. This research is part of the "Humanoid Project" at Waseda University. 1 Introduction The "Humanoid Project" was begun at the Humanoid Research Laboratory(HUREL), Advanced Research Center for Science and Engineering, in 1992. In this project, Humanoid, who is an anthropomorphic robot and interacts with humans is being developed for practical uses in the human living environment by the Fig. 1 Anthropomorphic Flutist Robot beginning of the 21st century. In order to accomplish this end, basic WF-3RIV research is being done on both the configuration and functions of the robot, the authors are doing research on anthropomorphic flutist robots as one of the research themes in the Humanoid Project. When humans play musical instruments, they seem to perform various expressions by a cooperative movement of their organs, however, there has been very little research which observes the mechanism considering the function of human organs to play musical instruments. Therefore, the authors chose flute playing and started to develop the Anthropomorphic Flutist Robot (Fig. 1), which simulates human motion in flute playing. The authors believe that this robot provides an quantitative explanation of human flute playing. This paper includes five sections. Section one presents the Humanoid Project and the purpose of this study,section two summarizes the Air Beam Parameters and the mechanism that produces sound in the flute, section three explains the basic design for each function of an Anthropomorphic Flutist Robot, and section four describes the realization of musical performance. 2 Human Flute Playing This robot is supposed to reproduce human organrw Air Beam Width. w ]: Air Beam Width functions on flute playing as closely as possible. This section summarizes human flute playing, and the t Air Beam Thickness mechanism that produces sound in a flute. the length control of an air column by the opening and shutting of flute keys and conditional control of the Fig. 2 The Air Beam Parameters airstream.

Page  00000002 2.2 The Air Beam Parameters. The airstream conditions as defined by Ando et al. are Lung Pt shown in Fig. 2. The air beam velocity, thickness and width Bellowphragm are parameters of an air beam. The air beam length, bias and angle are the parameters of the relative position between an air beam and the flute. The GAP indicates how much the lower lip should covers the embouchure hole. 3 Basic Design of An Anthropomorphic Flutist Robot This section discusses the basic design of each part of Y the Anthropomorphic Flutist Robot WF-3RIV (Waseda Linear Encoder Ball Screw with Flutist No.3 Refined IV). Linear Guide 3.1 Lung The authors believe that a range of the air beam DC Servomotor Tachogenerator velocity resonates along the length of the air column, and Fig. 3 Lung Mechanism that it is possible to blow equal temperament by controlling Sthe velocity within the range. The authors therefore S Lips utBal creaw developed the lung mechanism shown in Fig. 3. The Flute 1 | Linear.. \Bearing diaphragm was constructed by a bellowphragm which is a > piston and sylinder mechanism actuated by a DC p servomotor and a ball screw that can control the velocity of Xa an air beam that is directed into the embouchure hole by Balcrew controlling the path velocity of the diaphragm. SThis lung design has the same capacity as to the Lung DC Motor human lung. It is important for the model to realize natural otor Ball acrew - and human-like musical performance; i.e., phrasing based on the limits of human vital capacity, effects of dynamic Fig. 4 Playing Attitude Control Mechanism range, etc. Therefore, the authors designed a lung whose vital capacity is 5.1 X 10-3 [m3], (which is as much as that of male adults). It is necessary for the robot not to cause a any perceptible time delay. The authors experimentally checked that the response time is within 50[ms] to reach the reference path velocity of the developed diaphragm, and then made the musical performance delay to be negligible by giving the reference in advance of the correct timing. 3.2 Fingers Flutes are held using three points holding, however, it is necessary to control accurately the relative position of the mouth to the embouchure hole, therefore, this robot has a playing attitude control mechanism, which fixes the flute on a holder and moves it. As shown in Fig. 4, this mechanism has 3 degrees of freedom. The X-axis has back-and-forth movement and the Z-axis up-and-down movement of the mouth. Theta shows the angle of an air beam to the embouchure hole. This mechanism achieves position control by a DC - " Oral Cavity Mouth Roller DC Servo Motor Upper Lip Lips.Z (Elastic Part) (Elastic Part) Lower Lip A iW B-/I 'ly i Lj_ A 1-1-'D~~orv-~ *-T'" T- n1 O -, s riiA - m ,C-LA Fig. 5 Mouth Model (Front View) Fig. 6 New Mouth Mechanism(Front View)

Page  00000003 Fig. 7 Throat Mechanism Tachogenerator DC Servomotor servomotor and a ball screw. The robot can control the position of the air beam by this mechanism, i.e. the length, angle, bias of the air Beam, and the GAP. These values are geometrically calculated from the values of the absolute coordinates of X, Y and Theta as measured by potentiometers. The fingers are mounted on the flute holder and are actuated by solenoids. 3.3 Mouth The authors made a mouth model based on human flute playing.(Fig. 5) There are two rollers on each side, and the elastic part is sandwiched between a roller and another. By the roll of the rollers, the elastic part is rolled out and back and, then mouth thickness is changed. In addition the rollers move along the direction of the mouth width-axis, thereby changing the mouth width. Predicated on this model, a new mouth mechanism which is based on this model is shown in Fig. 6 As for the mouth mechanism, a elastic part(rubber tube)is used for the lips, and two rollers sandwich the elastic part on each side. By the roll of the rollers, the elastic part is rolled out and back, which changes the mouth thickness. In addition the bearing part of the rollers itself moves along the mouth widthaxis, which changes the mouth width. These rollers are actuated by a DC servomotor on each side and, high and low rollers which turn opposite each other by a cogwheel. In order to prevent cogwheel backlash these rollers are tensed in one direction. 3.4 Throat The two types of vibrato are pith and intensity. Vibrato, - Coil Spring Linear Encoder Slide Table Mouth Roller Mechanism Flexible Shaft \ Fig.8 Tongue Mechanism in general, vibrato is a mix of both. As for the flute, the increase in air beam velocity causes not only an increase in pressure level, but also an increase in pitch. The cause of vibrato has been discussed by researchers for a long time. Galtner says that the throat is much more effective than the diaphragm is experimentally, the experiments being electric potential measurements of muscle and X-ray examinations. The authors adopted the method of the throat vibrato and developed the mechanism shown in Fig. 7. A rod actuated by a voice coil varies the value of the cross section area of the throat and effects the airstream. 3.5 Tongue The human tongue is in the oral cavity, and so it is very difficult to understand its movement. Therefore, the authors developed the tongue mechanism shown in Fig. 8, by considering the empirical explanations in methods. A rod fixed on the axis of rotation pushes the cam follower of the tongue, which is mounted on the slide table. This part converts rotation to linear movement. The rod and Fingers Flute Vibrato Mechanism Tonguing Mechanism g Variable Mouth Width Mechanism - Lung - Bellowpharagm Encoder Ball Screw 1ater MIDI Tone MIDITone Loud Speaker Generator Module Sequencer Fig. 9 Musical Performance System

Page  00000004 32Bit Personal Computer Sound Blaster MIDI Driver START for Windows Open MIDI Input Device Op MIDI Callback START Function Setup Setup LOAD Robot Control Data Open Performance Data Performance MIDI In Start Start Start Playin MIDI Message... Handler Process Timing Clock Performance (Fid D namic Playin Process Control No End-flag On? or ROBOT Emergency? Yes Performance Stop MIDI In I Performance Stop & Reset | q | Stop Require CloseMIIlnputDeiCltose Device Close MIDI Input Device - -----eice Close END) J I END Sequencer Start Playing START Tiaiag Clock Performance Process 2END Sequence data MID! Tone Generator Module the cam follower are pressed into each other by a spring so they will not become separate, even in a high path velocity; therefore, there is no backlash and they stick together. An elastic part(Oil Jelly) is set on the tip of the tongue and it sticks to the mouth slit in order to shut the airstream. This mechanism is actuated by a DC servomotor, which is separated from the tongue mechanism because it is noisy. Movement is transmitted by a flexible shaft. The maximum cycle of continuous tonguing is about 27[ms]. The robot, therefore, is able to play a sixteenth note at a tempo of 550 quarter notes per minutes. This is about twice as fast as human playing. 4 Musical Performance System of WF-3RIV Fig. 9 gives an outline of the robot system of WF3RIV. As described in section three, the robot system consists of: a respiratory system (including a lung), a playing attitude control mechanism, fingers, a mouth mechanism, a throat mechanism, a tonguing mechanism, as well as a personal computer for robot control and a MIDI tone generator module accompaniment system. communications among a MIDI sequencer (Sequencer), a Fig. 10 Flowchart of Control Process The synchronized accompaniment is realized by MIDI Driver for Windows (MDW) and a personal computer for robot control (PC). The Sequencer controls a MIDI tone generator module and manages the time information of the music. The MDW receives the start and stop messages and the timing clock, and generates the start and stop messages and the timing clock, and sends these to the PC. The PC receives the interrupt message, and if the message is start, stop or timing clock, then the PC processes the sequence data of robot performance and control the robot hardware. A rough flowchart of this control process is shown in Fig. 10. An Anthropomorphic Flutist Robot WF-3RIV could reproduce human flute playing and could also realized the musical performance, Mozart's KV 298. Acknowledgments This study was done as part of the project: Humanoid at HUREL (HUmanoid REsearch Laboratory), Advanced Research Institute for Science and Engineering, Waseda University. The authors would like to thank ATR, NAMCO Ltd., and YASKAWA ELECTRIC Corp., for their cooperation in this project. The authors would also like to thank MURAMATSU Inc., NSK Ltd., YAMAHA CORPORATION and professional flutist Mr. Kunimitsu Wakamatsu for their assistance in developing the anthropomorphic flutist robot in this study. References Stevens, R. S., "Vibrato," Artistic FLUTE Technique and Study, Highland Music Co., pp. 41-44, 1967. Stvens, R. S., "Articulation," Artistic FLUTE Technique and Study, Highland Music Co., pp. 44-48, 1967. Ando, Y., "Drive Conditions of a Flute and their Influences upon Sound Pressure Level and Fundamental Frequency of Generated Tone (An Experimental Study of Flute I)," The Journal of the Acoustical Society of Japan (in Japanese), Vol. 26, No. 6, pp. 253-260, 1970. Altes, H., Methode pour Flute, 1er Partie, (Japanese translation and commentary, Uemura, Y., Sinfonia Inc., pp. 44, 1978.) Guyton, A. C., M.D., Physiology of the Human Body, (Japanese translation, Aikawa, S., Ito, H. et al., Physiology of the Human Body, Hirokawa Publishing Co., pp. 245-261, 1982.) Gartner, J., Das Vibrato unter besonderer Berucksichtigung der Verhaltnisse bei Flotisten, 2nd ed. Gustav Bosse Verlag Regensburg, 1980. (Japanese translation, Ishihara, T., Das Vibrato bei Flotisten, Sinfonia Inc., pp. 79 -170, 1983.)