Cybernetic Human HRP-4C: A humanoid robot with human-like proportions Shuuji KAJITA, Kenji KANEKO, Fumio KANEIRO, Kensuke HARADA, Mitsuharu MORISAWA, Shin’ichiro NAKAOKA, Kanako MIURA, Kiyoshi FUJIWARA, Ee Sian NEO, Isao HARA, Kazuhito YOKOI, Hirohisa HIRUKAWA Abstract Cybernetic human HRP-4C is a humanoid robot whose body dimensions were designed to match the average Japanese young female. In this paper, we ex- plain the aim of the development, realization of human-like shape and dimensions, research to realize human-like motion and interactions using speech recognition. 1 Introduction Cybernetics studies the dynamics of information as a common principle of com- plex systems which have goals or purposes. The systems can be machines, animals or a social systems, therefore, cybernetics is multidiciplinary from its nature. Since Norbert Wiener advocated the concept in his book in 1948[1], the term has widely spreaded into academic and pop culture. At present, cybernetics has diverged into robotics, control theory, artificial intelligence and many other research fields, how- ever, the original unified concept has not yet lost its glory. Robotics is one of the biggest streams that branched out from cybernetics, and its goal is to create a useful system by combining mechanical devices with information technology. From a practical point of view, a robot does not have to be humanoid; nevertheless we believe the concept of cybernetics can justify the research of hu- manoid robots for it can be an effective hub of multidiciplinary research. WABOT-1, the world first humanoid robot developed by Kato and his colleagues in 1973[2], was built as an integrated system having two arms, two legs, a voice Shuuji Kajita, Kenji Kaneko, Fumio Kanehiro, Kensuke Harada, Mitsuharu Morisawa, Shin’ichiro Nakaoka, Kanako Miura, Kiyoshi Fujiwara, Ee Sian Neo, Isao Hara, Kazuhito Yokoi, Hirohisa Hirukawa AIST, 1-1-1 Umezono, Tukuba, Ibaraki, Japan e-mail: {s.kajita,k.kaneko,f- kanehiro,kensuke.harada,m.morisawa,s.nakaoka,kanako.miura,k-fujiwara,rio.neo,isao- hara,Kazuhito.Yokoi,hiro.hirukawa}@aist.go.jp 1 2 Kajita, Kaneko, Kanehiro, Harada, Morisawa, Nakaoka, Miura, Fujiwara et al. recognition system etc. Later, their group developed a piano playing humanoid, WABOT-2 in 1985[3] In the early 1990s, Brooks and his colleague started to build humanoid robots as physical embodiment of artificial intelligence[4]. Research activities in ATR[5] and the RobotCub project[6] can be considered to have the same intention, namely humanoid robotics for cognitive science. Since the breakthrough on biped walking done by Hirai et al.[7], many research projects on biped humanoid robots were conducted. Research was carried on gen- eration of walking motion[8], jogging and running [9, 10], efficient walking[11], human-like walking[12], dynamic whole body balance control[13] and so forth. There also exists research working on facial expression of humanoid robots [14, 15, 16, 17]. These works target social communication and interaction, which is another aspect of cybernetics. In AIST, we have been developing a series of humanoid robots[19, 20]. Cyber- netic human HRP-4C is our latest development, which is a humanoid robot designed to have body dimensions close to average Japanese young female(Fig.1, Table 1). This paper explains the goal of our project and introduce the developed robot sys- tem. Fig. 1 Cybernetic human HRP-4C Cybernetic Human HRP-4C: A humanoid robot with human-like proportions 3 Table 1 Principal specifications of HRP-4C Height 1,580 [mm] Weight(with batteries) 43 [kg] Total DOF 42 DOF Face 8 DOF Neck 3 DOF Arm 6 DOF × 2 Hand 2 DOF × 2 Waist 3 DOF Leg 6 DOF × 2 CPUs Motion controller Intel Pentium M 1.6GHz Speech recognition VIA C7 1.0GHz Sensors Body Posture sensor Sole 6-axies force sensor × 2 Batteries NiMH 2 Aim of the development 2.1 User Centered Robot Open Architecture Fig. 2 User Centered Robot Open Architecture (UCROA) HRP-4C was developed in the User Centered Robot Open Architecture (UCROA) Project which is one of the projects under the AIST Industrial Transformation Re- search Initiative, a 3-year industry-academia joint project implemented by AIST from the fiscal year of 2006. The goal of the UCROA is to show society that it is pos- 4 Kajita, Kaneko, Kanehiro, Harada, Morisawa, Nakaoka, Miura, Fujiwara et al. sible to develop robot products that meet the specifications required by users com- bining reusable core technologies and developing prototype next-generation robots which can be used in practice by 2010 and for which the market is expected to be large. Three prototype robots were developed in the project (Fig.2). 1. Logistics support robot 2. Personal service robot 3. Cybernetic human For the logistics support robot, we developed a robotic system for warehouses. For the personal service robot, a small manipulator system to assist daily life of hand- icapped people was developed. The third subject of the UCROA is the cybernetic human, whose concept is explained in the next subsection. 2.2 Concept of Cybernetic human A humanoid robots attract many people, because of its human-like appearance and behavior. Although a robot with very human-like appearance is called an “android” in general, we coined a new term Cybernetic human to define a humanoid robot with the following features. 1. Have the appearance and shape of a human being 2. Can walk and move like a human being 3. Can interact with humans using speech recognition and so forth Such robots can be used in the entertainment industry, for example, exhibitions and fashion shows. It can be also used as a human simulator to evaluate devices for humans. As the successor of our previous humanoid robots HRP-2 and HRP-3[19, 20], we call our new humanoid robot HRP-4C, “C” stands for cybernetic human. 3 Realization of human-like shape and dimensions 3.1 Target specifications To determine the target shape and dimensions of HRP-4C, we used the anthropomet- ric database for Japanese population, which was measured and compiled by Kouchi et al.[18]. The database provides the dimensions of the following four different Japanese groups. 1. Young male: aged 19-27, average 20.5 years old, 110 samples 2. Young female: aged 19-27, average 20.2 years old, 107 samples 3. Aged male: aged 60-82, average 68.6 years old, 51 samples Cybernetic Human HRP-4C: A humanoid robot with human-like proportions 5 4. Aged female: aged 60-80, average 66.9 years old, 50 samples Considering the entertainment applications like fashion show, we picked the average young female data. Figure 3 shows part of the dimensions provided by the database. Upper arm circumference: 253 Forearm circumference: 228 Head breadth: 156 Chest circumference: 830 Waist circumference: 659 Head length: 181 Stature: 1586 Total head height: 231 Total Suprasternal height: 1281 Waist height: 993 Waist Cristal height: 944 Iliac spine height: 850 Trochanterion height: 801 Trochanterion Symphyseal height: 789 Lateral epicondyle height: 429 Thigh circumference: 543 [mm] Calf circumference: 351 Fig. 3 Anthropometric data of average young Japanese female [18] In the early stage of design, we explored the possible choice and arrangement of mechanical and electric devices by scaling up and down Fig.3 to have the stature between 145cm and 160cm. In our final design, HRP-4C is 158cm tall which is very close to the average of the young female, 158.6cm. 3.2 Joint configuration To obtain graceful motion of females, we asked a professional walking model to perform walking, turning, sitting on chair, and other motions. The positions of 86 markers attached to her body were captured by Vicon Motion Systems, a 3D optical motion capture device (Fig.4). This data was used to evaluate the different joint configurations proposed for HRP-4C structure. By calculating joint angles to realize the captured motion, the necessary movable range was estimated. In addition, we 6 Kajita, Kaneko, Kanehiro, Harada, Morisawa, Nakaoka, Miura, Fujiwara et al. Fig. 4 Motion capturing of professional walking model (Walking Studio Rei) estimated the motor power during biped walking to determine the appropriate leg joint configuration. (a) (b) z y x Fig. 5 Joint configuration of HRP-4C body (The head and hands are omitted) Figure 5 shows the joint configuration we finally decided on for HRP-4C. In this drawing, the joints for head and hands are omitted. It has the following characteristic compared with our former humanoid robots, HRP-2 and HRP-3. Cybernetic Human HRP-4C: A humanoid robot with human-like proportions 7 • Roll axes of waist and neck were added to realize human-like behavior (Fig.5 arrow (a)) • Slanted links of forearm and thigh to mimic human (Fig.5 arrow (b)) • Use of standard hip joint structure to realize natural waist line (For HRP-2 and HRP-3, we used cantilever type hip joint[19, 20]) 3.3 Design of the body mechanism Figure 6 shows the designed body mechanism of HRP-4C (right) and HRP-2 (left). By comparison, we see that HRP-4C realized much smaller chest and hip as well as slender extremities. To realize this body mechanism, we adopted the following technologies. • PCI-104 single board computer and peripheral boards for the whole body motion control • Distributed network motor drivers • Development of slim ankle mechanism For further details of the body mechanism and electronics, see our next report[21]. 1580 Design: Kawada Industries. Inc. Fig. 6 HRP-2 and mechanism of HRP-4C 8 Kajita, Kaneko, Kanehiro, Harada, Morisawa, Nakaoka, Miura, Fujiwara et al. 3.4 Design of appearance After the mechanical design of the leg part of HRP-4C was completed, we started to consider the design of appearance.