 Abstract—This research develops a Pneumatic Actuated Seating System (PASS), a new human-machine interaction tool to aid in chair design. The seating system is powered by thirty six designed intelligent pneumatic actuators. Three attributes are proposed for chair design namely shape, stiffness and damping characteristics. These facilitate investigation of chair shapes from spring and damping effect for seat and backrest surface. The proposed attributes will quantify the relationship between human styles of seating with the developed seating system. This research tool will be used as experimental apparatus for chair design in the area of customized and specialized seating. The system design, instrument and sitting tests are presented. Three subject sitting tests were done to evaluate the current system and confirm the function ability for further optimization technique in selecting the best parameters. I. INTRODUCTION hairs have been one of the important tools in human daily activities while sitting position is considered the most frequent body posture in industrialized countries. Chairs were developed to reduce the physical strain on the body [1]. However, bad seating and poor chair design may lead to pathological degeneration of the vertebrae discs, backache [1] and risk of pressure ulcers from the soft tissue stress and strain [2]. Various studies previously carried out on sitting postures and shapes of chairs resulted in many different points of view in designing them. Some of the researchers (M. Vergara et al [3] and M. Langsfeld et al [4]) claimed that mobility of lumbar spine is important in improving comfort by locating the lumbar spine curvature on chairs properly. On the other hand, R. H. M. Goosens et al [5] reported that the inclination angles of backrest and seat are among important design criteria. S. M. Reichel [6] focused attention on shear force, defined as a force parallel to a surface which relates to the chair design. Goosens, then developed an instrument that Manuscript received February 1, 2010. This research was supported by a Grant-in-Aid for Scientific Research on Priority Area (No. 438) “Intelligent Actuators for Multi-Degrees-of-Freedom Mechatronics (16078209)” from the Ministry of Education, Culture, Sports, Science and Technology of Japan. A.A.M.F. would like to acknowledge Ministry of Higher Education (MOHE) and Universiti Teknologi Malaysia (UTM) for the scholarship awarded. Ahmad `Athif Mohd Faudzi, is with Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan. He is also a lecturer in Universiti Teknologi Malaysia (UTM), Malaysia. (e-mail: athif@act.sys.okayama-u.ac.jp/ athif@fke.utm.my). Koichi Suzumori is with Graduate School of Natural Science and Technology, Okayama University, Okayama, Japan. (Phone: 81-86-251- 8158 ; fax: 81-86-251-8158; e-mail: suzumori@act.sys.okayama-u.ac.jp). Shuichi Wakimoto is with Research Core for Interdisciplinary Sciences, Okayama University, Okayama, Japan (e-mail: wakimoto@act.sys. okayama-u.ac.jp). can measure the total forces on the body-supporting surface [7] and a biomechanical model which reduces shear forces in passive seating [5]. The development of advanced sensing and evaluation techniques has made it possible to understand the relationship between seating comfort and objective measurements of the human body-seat interface [8]. Several other research tools were also developed to focus on specific target of users. For instance, an adjustable seating rig was used to create 3D shape of a static lounge chair which was targeted for use by elderly in institutions. J. M. Holden et al [9] used questionnaires to evaluate the comfort which was more on chair shapes lacking of other attributes. In 1993, N. Yamazaki et al presented an experimental chair with backrest and seats which made use of ten and six actuator bars respectively to study suitable chair characteristics [10]. Comfortable distribution of cushions in automobile backseat was analyzed which relates to hip and lumbar flexion. However the system applies mechanical spring in the design that have limitation of mechanical tuning. The backrest and seat unit also have static value in vertical line as the unit is connected in bar type actuator. Other researches that have been reported by D. M. Brienza et al [11] applied a research tool that allows for control of surface shape using CASS, a computer-aided seating system based from force control feedbacks to prevent pressure sores. Stepper motors were chosen as position actuators. The study which is devoted only on seat panel has main challenges on performance of the motor which is largely dependent on the indexing and drive circuit. This paper presents the continuation of the previous work [12, 13] to develop an experimental apparatus namely Pneumatic Actuated Seating System (PASS) that will be used to aid in designing chairs. Compared to previous literatures, this research proposed several attributes in chair design taking consideration of the previous literatures and apply different sensing and actuation methodology using physical human machine interaction. This concept is shown in Fig. 1 where the previously developed intelligent actuator will be used as the interface for bilateral physical information exchange for receiving and sending data. Improved ergonomics shapes resulting from suitable spring and damping characteristics will position the lumbar curve perfectly and allows minimum back muscle activity [14]. Three attributes of shapes, spring and damping are proposed to aid in chair design by physical interaction with the user. These three characteristics are achieved using the designed pneumatic actuator as sensors and actuators for the system. Development of Pneumatic Actuated Seating System to Aid Chair Design Ahmad `Athif Mohd Faudzi, Member, IEEE, Koichi Suzumori, Member, IEEE and Shuichi Wakimoto C 2010 IEEE/ASME International Conference on Advanced Intelligent Mechatronics Montréal, Canada, July 6-9, 2010 978-1-4244-8030-2/10/$26.00 ©2010 IEEE 1035