404 Ch81-I044963.fm Page 404 Tuesday, August 1, 2006 4:54 PM Ch81-I044963.fm Page 404 Tuesday, August 1, 2006 4:54 PM 404 (linear translation), we had a subject driving the simulator. The actuator intended for longitudinal movement restitution was powered by the above-described classic washout algorithm. This algorithm was computed on a control PC which received the acceleration of the simulated vehicle at 1.5kHz. The acceleration signal obtained during the subject's driving contains acceleration phases, deceleration and continuous accelerations phases. Following the processing of this acceleration by the washout algorithm, this acceleration is transformed into a desired position profile with a tendency to return to the neutral position during the continuous acceleration phase (fig 3). We noted in this one that with a PID corrector, the platform position exactly superposed the desired position. Washout algorithm has been implemented in a two-factor (Back of the seat x Motion base) repeated measure where the seat variable consists of two levels (Back of the seat tilt 'on' or 'off), whereas the magnitude of the platform motion consists of three levels (Without, Short, or Long longitudinal movement). All of these 2x3 experimental conditions, requires that the subjects drive the simulator for five minutes on average. In (Neimer et al. (2005)) we show that best performance is obtained by having a controlled combination of the back of the seat inclination 'On' and Short longitudinal platform displacement. Rotating the entire seat is not considered since it induces false cues. CONCLUSION The proposed driving simulator and the motion cueing algorithm have been used in various psychophysics experiments. Experiments consisted in exploring minimal displacements and subsequent inertial effect restitution to perform file queuing driving situations. Obtained results are presented in (Neimer et al. (2005)) and show the validity of the proposed concepts. Our future work will focus on the development of new control strategies for the platform, which will aim to favour driver control over the virtual vehicle's acceleration. Optimal coupling of visual, haptic and inertia effects restitution will be also investigated. REFERENCES Kheddar A. and Garrec Ph. (2002). Architectures de plates-formes mobiles pour simulateurs de conduite automobile. Appraisal Report, CRJIF. Reid L.D. and Grant P.R. (1991). Motion-base development package for NADS. Transportation Research Center of OHIO. Reymond G. and Kemeny A. (2000). Motion cueing in the Renault Driving Simulator. Vehicle System Dynamics 34:4, 249-259. Reymond G. and Kemeny A. and Droulez J. and Berthoz A. (2000). Contribution of motion platform to kinesthetic restitution in a driving simulator. Driving Simulation Conference. 33-55. Seigler I. and Kemeny A. (2001). Etude sur la pertinence de la restitution physique du mouvement en simulation de conduite en fonction des caracteristiques physiologiques et psycho-physiques de la perception du mouvement propre. Appraisal Report, LPPA. Mohellebi H. and Espie S. and Kheddar A. (2004). Adaptive haptic steering wheel for driving simulators. International Conference on Intelligent Robots and Systems. Neimer J. and Mohellebi H. and Espie S. and Kheddar A. (2005). Optimization of Linear Motion Base Dedicated to Normal Driving Conditions. Driving Simulation Conference. 405 Ch82-I044963.fm Page 405 Saturday, July 29, 2006 7:32 AM Ch82-I044963.fm Page 405 Saturday, July 29, 2006 7:32 AM 405 HIGH PERFORMANCE LOW COST STEREO PROJECTOR SYSTEM FOR VIRTUAL REALITY Heikki Kosola, Karri Palovuori Tampere university of Technology Institute of Electronics P.O.Box 692, 33101 Tampere, Finland ABSTRACT This paper describes a novel method for producing projected stereo images with very high quality and reduced cost. Using two standard LCD-projectors with an electro-mechanical shutter it is possible to produce a time division multiplexed stereo image pair with a very high refresh rate. All beneficial characteristics of the LCD-projectors like the spatial stability, good geometry and image sharpness are preserved. KEYWORDS Stereo projection, Virtual reality, LCD, Shutter INTRODUCTION Motion and position compensated stereographic visualization is an almost essential requirement for any virtual environment setup today. To produce projected stereographic image there are three main techniques available: autostereoscopic, passive stereo and active stereo. In the autostereoscopic display each pixel is divided to subpixels. Each subpixel has its own spatial sector where it can be seen. Spectator's eyes see different set of subpixels and stereoscopic information can be shown. The demand for unpractical number of subpixels and the required optics makes autostereoscopy an unthinkable solution for a large virtual reality display. The high cost of a stereo enabled CRT or DLP projector could be avoided by using passive methods to separate the images between the viewer's two eyes. Word 'passive' means that user is not wearing active shutter glasses to blank out the unwanted picture. Passive filters are used instead. Both images are projected simultaneously on the screen. Separation is done typically by different polarization of the two images. Both linear and circular polarization are used. Wavelength multiplexing is also used [1]. All of the projection techniques (CRT, DLP, LCD) could be used with passive stereo. Advantages of 406 Ch82-I044963.fm Page 406 Saturday, July 29, 2006 7:32 AM Ch82-I044963.fm Page 406 Saturday, July 29, 2006 7:32 AM 406 passive methods are the completely flickerfree image and lighter eyewear. All of the passive methods suffer from less than perfect channel separation. The most common active stereo approach is to use one CRT-projector per one display surface. Images for user's both eyes are shown sequentially. Shutter glasses are used to select the correct image for each eye. The speed of the phosphor material on the CRT is a compromise between a flickerfree image and an adequate response time. Problems arise especially in stereographic presentations where the CRT is forced to display two (or more) different images sequentially at a high rate. The previous image leaks to the next one so that the channel separation cannot be perfect. A flickerfree visual experience requires at least 75Hz refresh rate per eye at ordinaiy range of image brightnesses. As the brightness increases, the required image refresh rate rises up to and possibly beyond 500 Hz [2]! LCD-projectors and displays use a completely different image reproduction method. A constant light source is modulated by a liquid crystal panel. The typical response time of an lcd-panel is 20 - 40 ms. This is just enough to show animated graphics at 30 - 50 frames per second but it is way too slow for time division multiplexing required for shutter glasses. One major advantage of the LCD-projectors is the light output, which is significantly higher than in their CRT counterparts. Also the prices of LCD- projectors are very competitive compared to CRT-projectors with adequate light output. As mentioned above, the LCD-panel can not switch the image fast enough so the switching must be performed externally. This paper introduces a method where the light output of each individual projector is controlled by an external shutter disc. Shutter glasses, worn by the user, select which eye is allowed to see the image of the currently active projector. THEORY OF OPERATION The operation principle is simple and elegant. Both eyes have their own projector. The projector modulates its ligh source with the appropriate image and the external shutter switches the picture on and off to the screen. The inherent slowness of the LCD-panel poses no obstacle to a stereographic projection. In our construction the shutter is common for both projectors. Nevertheless, it is possible to use two separate shutters which give more flexibility to projector mounting. The LCD-projector The nature of the LCD-projector makes it very attractive to be used with an external shutter. Individual pixels maintain their states over the whole frame period. The external shutter could - but it does not have to - be synchronized with the projector or with the graphics generating computer. In a fast moving scene the unsynchronized image might bring out a 'tearing effect' where the image splits to horizontally unaligned upper and lower portions. If the projector updates its LCD-panels directly with the incoming RGB-signal it would be useful to use the vertical synchronization pulse to control the shutter motor. It would remove the tearing problem and give a constant response time from a graphics drawing to the screen. Both of these are desired aspects in a simulation environment. For comparison, the DLP projectors offer a slightly better contrast and light output as their LCD counterparts. The DLP technology also enables sequential stereo by itself it still have its limitations. Currently commercial DLP-stereo enabled projectors have frame rates limited to 60Hz per eye which is quite low for high bright images. [3] [4] The electro-mechanical shutter In our system, a mechanical shutter does the switching between the two images forming the stereo image pair. The shutter is disc shaped and positioned in very front of the projectors. The disc rotation 407 Ch82-I044963.fm Page 407 Saturday, July 29, 2006 7:32 AM Ch82-I044963.fm Page 407 Saturday, July 29, 2006 7:32 AM 407 axis is fixed and in the middle of the line crossing both projectors output lenses. One half of the shutter needs to be transparent and another half opaque. To prevent simultaneous illumination of the screen, the opaque portion is extended by the width of the projected image at the shutter disc's plane. The extended opaque section decreases the optical efficiency somewhat from the theoretical maximum of 50%. The width of the extension has to be at least the width of the projected image at the shutter plane. Therefore it is wise to place the shutter as close to the projectors as possible. Increasing the radius of the disc decreases the angular width of the projector's image and therefore increases the optical efficiency. On the other hand, as the diameter of the shutter increases so does the induced audible noise, size of the installation and the alignment problems of the projected image. Figure 1 illustrates the geometry of the shutter disc. If the disc rotates in clockwise direction, the projector 2 would just start to show its image on the screen. Figure 1: The geometry of the shutter disc The shutter glasses The glasses we have been using in our tests and also in the constructed simulation environment are of the CrystalEYES II type. These glasses use an infrared link to get the synchronization signal from a controller. The custom infrared transmitter is controlled with a signal directly from the rotating disc. The phase locking between the electro-mechanical shutter and the shutter glasses is therefore very robust. Even if there is slight fluctuation in the rotational velocity of the disc, the glasses are switching at the precise moment. IMPLEMENTATION The construction of the prototype installation is based on two identical Canon LV-7105 LCD- dataprojector. These projectors are of a very common type with XGA resolution (1024 x 768) and about 1100 Ansi lumens of light output. The projectors are mounted inside a wooden enclosure. Without the possibility of the vertical lens shift on the projectors, there are a slight misalignment on the screen. As the position of the projectors obviously has to be slightly offset from each other (in our system they are vertically offset by 12 cm), if the projected images are adjusted for maximal overlap, the slight misalignment results from image keystoning. On a three-meter wide picture, the alignment error was about one to two pixels measured at the upper or lower edges of the image. In many applications, particularly in virtual reality, it is often not mandatory to project the images to overlap exactly as the graphics generating computer has to update the images constantly anyway and can easily incorporate the information of the factual, different image positions. The net result would be a change in the shape and size of the visualizable spatial space of the system. This might be beneficial or 408 Ch82-I044963.fm Page 408 Saturday, July 29, 2006 7:32 AM Ch82-I044963.fm Page 408 Saturday, July 29, 2006 7:32 AM 408 detrimental in theory, depending on the case, but in practical applications the difference would be neglectably small. Finally, by sacrificing the non-overlapping parts of the images and presenting them as black, even this small effect can be removed. The shutter disc is made of acrylic plastic sheet. The opaque areas are covered with metallic paint. The disc is balanced after coating to eliminate vibrations and noise. The diameter of the disc is 160 mm. The projected image covers a sector of 38 degrees from the disc. Therefore, the opaque sector is 218 degrees wide. So about 40% of the projectors light output is transferred to the screen. The attainable light output is comparable to a single DLP-projector stereo setup. [5] EXPERIMENTAL RESULTS The implemented prototype performs as expected. The use of the 100 Hz refresh rate per eye resulted in a completely flickerfree image. The disc type shutter is rotated by the brushless DC-motor that has offered reliable and maintenance free operation for thousands of hours. The projectors used in the prototype have an XGA resolution and 1100 ANSI lumens of light output. With a 3m width of projected image the overall brightness could be better but still is entirely comparable to a projected CRT image. All other characteristics like the sharpness, the spatial stability and the lack of flicker are superior when compared to the CRT counterpart. The constructed prototype has been applied to a person lift platform training simulator system. The simulator has been in everyday use for more than two years now, and the reliability of this new method of stereo projection has been field proven. CONCLUSION The described method for producing stereo projection was proven very functional. The major advantage of this method is the high stereo multiplexing rate. It is now possible to use sufficient rates without sacrificing any of the important properties of the projected image. Possible enhancements in the light output and/or resolution are simply achieved by selecting a proper type of LCD projectors. The stereo projector adjustments can be made even easier when both LCD projectors are located on the same optical axis. This could be done with full or semi-transparent mirrors. REFERENCES [1] Helmut Jorke, Markus Fritz, "Infitec - A new stereoscopic visualization tool by wavelength multiplex imaging", Infitec GmbH [2] Bridgeman, B. and Montegut, M. 1993. Faster flicker rate increases reading speed on CRTs. SPIE Vol.1913 Human Vision, Visual Processing, and Digital Display IV. PP. 134-145. [3] Christie Digital Systems, Inc. Web site: http://www.christiedigital.com/ [4] Ian McDowall, Mark Bolas, Dan Corr, Terry Schmidt, "Single and Multiple Viewer Stereo with DLP Projectors", Fakespace Labs, Christie Digital Systems [5] Barco nv. Web site: http://www.barco.com 409 Ch83-I044963.fm Page 409 Monday, August 7, 2006 11:30 AM Ch83-I044963.fm Page 409 Monday, August 7,2006 11:30 AM 409 ANALYTICAL AND EXPERIMENTAL MODELING OF INTRA-BODY COMMUNICATION CIRCUIT Y. Terauchi 1 , K. Hachisuka 1 , K. Sasaki 1 , Y. Kishi 1 , T. Hirota 1 , H. Hosaka 1 , K. Fujii 2 and K. Ito 3 1 Graduate School of Frontier Sciences, The University of Tokyo, Bunkyo-ku, Tokyo 113-8656, JAPAN " Graduate School of Science & Technology, Chiba University, Chiba-city, Chiba 263-8522, JAPAN 3 Research Center for Frontier Medical Engineering, Chiba University Chiba-city, Chiba 263-8522, JAPAN ABSTRACT Intra-body communication uses human body as the propagation medium. This may become a new wireless communication method for Personal Area Network (PAN) with less power consumption and higher communication security compared to conventional RF methods. A common analytical model of intra-body communication is a combination of capacitive coupling among the human body, electronic devices, and the environment. Experimental results suggest that there are optimal parameters for transmission. We assume that it is a combination of not only the capacitive couplings, but also of a radio wave transmission and of imbalances in the electrical impedances among the transmitter/receiver electrodes attached to the human body. KEYWORDS Personal Area Network, intra-body communication, analytical model, human body equivalent phantom, phase measurement INTRODUCTION Advancement of information technology has accelerated the spread of ever smaller and lighter information and communication devices such as mobile phones, PCs, and PDAs. It is common to see people carrying more than one of these devices. In the near future, the devices will most likely become wearable. Data and system resources can be shared by connecting multiple devices carried by a single person, similar to computers in offices connected by a LAN. This new type of network was proposed in Zimmerman (1995) as a Personal Area Network (PAN). 410 Ch83-I044963.fm Page 410 Monday, August 7, 2006 11:30 AM Ch83-I044963.fm Page 410 Monday, August 7,2006 11:30 AM 410 Intra-body communication, which uses human body as the propagation medium, is an alternative to conventional radio transmission for short-range wireless communication and proposed as the optimal method for PAN. Since the human body is an electrical conductor, intra-body communication may become a novel wireless communication method with less power consumption and higher communication security compared to conventional RF methods. Tt also allows a new communication mode of human friendly man-machine interface, because information is transmitted only when body contact is made. Three types of intra-body communication are shown in Figure 1. The circuit type and capacitive coupling type make a circuit with the surrounding environment, and are suited for communicating with devices that are not attached to the human body (e.g. electronic money, keyless entry system). Several research groups have already demonstrated intra-body communication devices of these types such as Handa, et al. (1997) and Matsushita, et al. (2000). The propagation type does not require external circuits and has more tolerance to external noise compared to the other two. It is suited for communication between devices attached to the body (e.g. PAN). Etectranugndic W«ne Simple current type Capacitive coupling type Propagation type Figure 1: Types of intra-body communication The authors aim to propose a new wireless communication method intended for PAN. This research focuses on clarifying an analytical model and the mechanism of intra-body communication of the propagation type. MODELING OF INTRA-BODY COMMUNICATION Electrical properties of the human body Electrical properties of the human body were measured to determine the most efficient frequency to send signals. Sine waves of 1 V p . p generated by a function generator (transmitter) were applied to two electrodes attached above the elbow. Two electrodes were also attached to the wrist of the same arm and an oscilloscope (receiver) was used to read the received signal strength. Figure 2 shows that maximum transmission gain is obtained around 10 MHz. For experiments, special care is taken for electrical isolation between the transmitter and the receiver, including the measurement devices. First, the signal ground is separated because a common ground between the transmitter and the receiver may act as a wired return path for the signal. Such paths would not exist in actual applications for intra-body communication. Using a common AC power line also exhibits a much stronger coupling than the capacitive coupling between the human body and 411 -60 -50 -40 -30 -20 -10 0 0 5 10 15 20 25 30 35 40 Frequency MHz niaG Bd Z b Z b Z c Z a Z a Z b Z b Z c Z a Z a Z b Z b Z b Z b Z c Z a Z a Z c Z a Z a Transmitter side electrode Receiver side electrode Arm (Phantom) Ch83-I044963.fm Page 411 Monday, August 7, 2006 11:30 AM Ch83-I044963.fm Page 411 Monday, August 7,2006 11:30 AM 411 surrounding environment. In order to minimize these undesired couplings, signal generator, amplifier, and oscilloscope are all battery-powered. Separate power supplies are used for the transmitter and the 0 -10 -20 3 -30 to -40 -50 -60 0 5 10 15 20 25 30 35 40 Frequency MHz Figure 2: Comparison of transmission gain with frequency In the experiments, a human equivalent phantom was also used. The conductivity and relative permittivity of the phantom was adjusted to the same value as the human body. Its size was 500 x 500 x 4500 mm , the average size of the human arm. Phantoms improve reproducibility of experiments. Its simple shape makes computer based calculations easier. Four-terminal circuit model In the kHz range, the effect of electromagnetic waves is considered negligible. A common analysis model of intra-body communication in such frequencies is a combination of capacitive coupling among the electrodes attached to the human body, the devices, and the environment. Figure 3 shows a four-terminal circuit model based on Hachisuka, et al. (2003) and Terauchi, et al. (2003). Transmitter side electrode Receiver side electrode Arm (Phantom) Figure 3: Four-electrode model Transmission gains calculated from this four-electrode model match the experimental results in the kHz range. It is calculated by the following equation. z a z c 7 7 [dB] (1) It can be seen from Eqn. 1 that the difference between the horizontal impedance element (Zj) and the diagonal impedance element (Z c ) has to be large to obtain a large gain. However, it can also be understood that the difference between the two elements becomes small as the distance between the transmitter and the receiver increases. Also, since the relative permittivity of the human muscle is more than 20,000 at 10 kHz, it is difficult to enlarge the difference between Zj and Z c . In this research, a similar four-terminal circuit model was investigated for a new form of transmission. 412 Figure 4: Two-electrode model -100 -90 -80 -70 -60 -50 -40 -30 -20 -10 0 0 50 100 150 200 250 300 350 Distance of electrodes [mm] ]Bd[ niaG Gain 2 Human 1 Human 2 -15.6 -21.1 -57.9 -71.8 -82.1 -17.7 -23.5 -43.1 -100 -90 -80 -70 -60 -50 -40 -30 -20 -10 0 0 50 100 150 200 250 300 350 Distance of electrodes [mm] ]Bd[ niaG Gain 2 Gain 4 b) Comparison of two-electrode model with four-electrode model Z d Z b Z c Z a Z a Z d Z b Z c Z a Z a Z d Z d Z b Z b Z c Z a Z a Z c Z a Z a a) Comparison of calculated gain with experimental results Arm (Phantom) Transmitter side electrode Receiver side electrode Ch83-I044963.fm Page 412 Monday, August 7, 2006 11:30 AM Ch83-I044963.fm Page 412 Monday, August 7,2006 11:30 AM 412 In the new model shown in Figure 4, only one electrode each from the transmitter and the receiver makes contact to the human body. This model is conventionally called the two-electrode model. Transmitter side electrode Receiver side electrode Arm (Phantom) Figure 4: Two-electrode model The transmission gain of this model is calculated by the following equation. Z c gain = 201og 10 Z a • "' + ^% "> ^% [dB] (2) The impedance of each element is calculated by FEMLAB (simulator software using the finite element method). Transmission gains are then calculated using Eqn. 2 and compared with experimental results. Tn Figure 5a, it can be seen that the calculated values and experimental values match well. Figure 5b shows that the gain of the new model is relatively higher than the previous four-electrode model and does not drop as the distance between the transmitter and receiver increases. If the human body is considered as a ground plane, the two-electrode circuit model may be similar to the behavior of rod antennas. However, this assumption requires further study. o -10 -20 „ -so m -40 r-so 8 -60 -70 -80 -90 -100 ; _ • -70Gain 2 • 80 Human 1 • -90 Human 2 ; *- I -i ] L | L | 1 ; ; ! 1 A i i 0 -10 -20 „ -3° m -40 c -50 § -60 -70 -80 -90 -100 100 150 200 250 Distance of electrodes [mm] 50 100 150 200 250 Distance of electrodes [mm] 300 350 a) Comparison of calculated gain with experimental results b) Comparison of two-electrode model with four-electrode model Figure 5: Comparison of transmission gain MEASUREMENT OF PHASE SHIFT The authors made a small transmitter with a size of 70 x 100 x 50 mm 3 for phase characteristics measurement of the four-terminal circuit. The signal from the transmitter is sent to the receiver to compare the phase difference between the original signal and the signal transmitted through the 413 0 0.2 0.4 0.6 0.8 1 1.2 1.4 0 90 180 270 360 Angle [deg] ].u.a[ rewoP 10AS 10BS 10CS 10DS -180 -135 -90 -45 0 45 90 135 180 0 90 180 270 360 Angle [deg] ]ged[ esahP 10AS 10BS 10CS 10DS c) Alignments of electrodes b) Comparison of phase shift with electrode ali g nments 0 10AS 10BS 10CS 10DS Transmitter Transmitter a) Comparison of signal power with electrode ali g nments Ch83-I044963.fm Page 413 Monday, August 7, 2006 11:30 AM Ch83-I044963.fm Page 413 Monday, August 7,2006 11:30 AM 413 phantom. To avoid unnecessary electrical coupling, optical fiber is used to send the synchronization signals. The distance between the transmitter and the receiver is 300 mm. 180 270 Angle [deg] 360 a) Comparison of signal power with electrode alignments Transmitter • • 10AS D • 10BS ; i 1 S10AS 10BS S10CS S10DS 90 180 270 Angle [deg] 360 b) Comparison of phase shift with electrode alignments Transmitter • • 10CS • • • S 10DS • c) Alignments of electrodes Figure 6: Measurement of phase shifts Figure 6 shows the result of the experiment at 10 MHz. As the transmitter rotates clockwise, signals were measured every 45 degrees for a total of 8 directions. Maximum transmission gain is attained when the two electrodes of the transmitter are aligned to the direction of the receiver (Figure 6a). Results show that the phase variation between the source signal and the received signal depends on the direction and arrangements of the electrodes (Figure 6b). If we assume that the four-terminal circuit model is correct, there should be a phase reversal when the electrodes of the transmitter are reversed. However, the measurements at 10 MHz show that the phase shift is only plus or minus 45 degrees. The results suggest that there are elements other than capacitive coupling. In the MHz range, the possibility of airborne radio wave transmission also remains (Fujii, et al. (2004)). TRANSMISSION PATH In the previous section, the path of transmission still remains unclear. There are three possible paths: (i) Inside the body (through muscles, blood etc.), (ii) Surface of the body (along the skin), and (iii) Airborne (radio wave transmission). An experiment in an electrical anechoic chamber was conducted in order to determine the path. A large conductor plate was placed between the transmitter and the receiver (Figure 7a). The walls of the chamber absorb all electromagnetic waves and there is no reflection so all airborne radio wave transmission is cutoff. The gap between the plate and phantom can be changed. The frequency of 10 MHz was chosen for the experiment. Figure 7b shows the experimental results with the signal strength calculated by FDTD method. There is only a slight difference between the signal strength measured when the gap is 10 mm and when there is no conductor plate. This suggests that the signal does not travel through the open space. As the gap closes, the received signal strength gradually decreases. When the gap is 0 mm, no signal is received. This suggests that the signal is not propagated inside the human body. This is may be explained by the fact that the relative permittivity at 10 MHz is about 150 for the muscle and over 250 [...]... International Symposium on Antennas and Propagation vol2, 100 5-1 008 Hachisuka K., Nakata A. , Takeda T., Shiba K., Sasaki K., Hosaka H and Itao K (2003) Development of wearable intra-body communication devices Sensors and Actuators A: Physical 105:1, 10 9-1 15 Handa T., Shoji S., Ike S., Takeda S and Sekiguchi T (1997) A Very Low-Power Consumption Wireless ECG Monitoring System Using Body as a Signal Transmission... Traditional industrial robots that have been used as general-purpose positioning devices are open chain mechanisms that generally have the links actuated in series These kinds of manipulators are more suitable for long reach and large workspace, but are inherently not very rigid and have poor dynamic performance at high speed and high dynamic loading under operating conditions Compared with open chain... Mae2 and Y Koseki3 'Department of System Innovation, Division of System Science and Applied Informatics, Graduate School of Engineering Science, Osaka University 1-3 Machikaneyama, Toyonaka, Osaka, 56 0-8 531, Japan "Department of Human and Artificial Intelligence Systems, Faculty of Engineering, University of Fukui 3 National Institute of Advanced Industrial Science and Technology ABSTRACT There has... http://www.microsoft.com/com/tech/ActiveX.asp Topi Maenpaa, Antti Tikanmaki, Jukka Riekki and Juha Roning (2004) A Distributed Architecture for Executing Complex Tasks with Multiple Robots, IEEE 2004 ICRA, International Conference on Robotics and Automation, Apr 26 - May 1, New Orleans, LA, USA 431 LINK LENGTH CONTROL USING DYNAMICS FOR PARALLEL MECHANISM WITH ADJUSTABLE LINK PARAMETERS W Tanaka1, T Arai1 , K Inoue1, T Takubo1,... Redundant Mechanism for Search and Rescue Tasks Proc 2003 IEEE/RSJ IROS, 288 9-2 895 421 MECHATRONICS DESIGN AND DEVELOPMENT TOWARDS A HEAVY-DUTY WATERHDRAULIC WELDING/CUTTING ROBOT Huapeng Wu, Heikki Handroos and Pekka Pessi Institute of Mechatronics and Virtual Engineering, Department of Mechanical Engineering, Lappeenranta University of Technology P.O.Box 20, FIN-53851 Lappeenranta, FINLAND ABSTRACT... machine Our idea is to cover each sub-workspace by a machine that has adjustable mechanical parameters There are some mechanical parameters which can be adjusted, such as base plate parameters, endeffector parameters and link parameters This paper discussed the parallel mechanism with adjustable 432 ' Stttr-workspace ? Sob-workspace 7') Sui p A whole required workspace : / Adjust Active rolary jvinl... desired transformation of the passive linear joints Their torques and acceleration are given to the forward dynamics equation to estimate the acceleration of the passive linear joints We also confirm whether the estimated acceleration of the passive linear joints is the same as the desired acceleration If the estimated acceleration is same as the desired acceleration, we can calculate the desired link length... combinational workspace Figure 2 : The 2-DOF planer rotaiy actuated parallel mechanism with adjustable link length link parameters, since the adjustable link parameters effects the overall workspace volume more than another parameters The link length of this parallel mechanism can be adjusted passively or actively A mechanism with actively adjusted link length is a kind of redundantly actuated mechanism... search balls is that they cannot move actively and cannot always be located as desired In order to cover this weak point, a large number of balls are scattered into rubble; that allows rapid and wide-area search It is difficult to search the entire area using only search balls Hence rescuers or rescue robots search the remaining area Such cooperation of search balls and rescuers/robots would be able... many balls will be an important issue ACKNOWLEDGEMENT This research was performed as a part of Special Project for Earthquake Disaster Mitigation in Urban Areas (in cooperation with International Rescue System Institute (IRS) and National Research Institute for Earth Science and Disaster Prevention (NIED)) RERERENCES Inoue K., et al (2005) 'Search Balls': Sensor Units for Searching Inside Rubble Advanced . Zj and Z c . In this research, a similar four-terminal circuit model was investigated for a new form of transmission. 412 Figure 4: Two-electrode model -1 00 -9 0 -8 0 -7 0 -6 0 -5 0 -4 0 -3 0 -2 0 -1 0 0 0. using the human body as a transmission channel. Proceedings of the 2004 International Symposium on Antennas and Propagation vol2, 100 5-1 008 Hachisuka K., Nakata A. , Takeda T., Shiba K., Sasaki. but contains some sensors for searching for disaster victims, such as cameras, and a radio transceiver in an impact-resistant outer shell. Many balls are thrown into rubble and fall down while repeatedly colliding;