Outline of Research Activities(all)

Annual Report 1996
Annual Report 1998　Annual Report 1997　Annual Report 1996

CONTENTS
　［Message］　［Outline of Research Activities］　［International Cooperative Activities］　［Statistical Trends in Recent Years］　［Organization of MEL(1997)］　［List of Publications(1996)］　Back to [Main Research Areas]

Outline of Research Activities
　［Material Science and Technology］　［Bioenginering］　［Information and Systems Science］　［Advanced Machine Technology］　［Energy and Environmental Technology］　［Manufacturing Technology］　［Robotics］　［List of Publications(1996)］

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Materials Science and Technology
Any enquiries regarding this project should be directed to e-mail: kiso0@mel.go.jp

　　Materials science plays an important role in the development of almost all advanced technologies. Materials science research at MEL covers a wide range of work related to the synthesis of new materials and coatings and their characterization under various conditions.
　　Some current research topics are described below．

Materials Properties
　　The Materials Properties Division concentrates on mechanical characterization of fracture and other damage in advanced structural materials such as composites, engineering ceramics, and functionally gradient materials.
　　Fracture mechanics and electron micro-fractography have been used to investigate fracture toughness and fatigue crack growth resistance in both titanium aluminide TiAl and intermetallic Ti₃Al compound matrix composites with continuous fibres.⁸⁾ New ideas about the toughening of ceramics by the incorporation of a ductile metal phase have been developed and used to improve fracture toughness. These ideas have also been applied to functionally gradient materials.
　　Work has been done on the characterization of materials at cryogenic temperatures of 4.2K under high magnetic fields (up to 6T). Tests have also been done towards understanding the fracture mechanics of both metallic and polymer matrix composites, including superconductors, both with and without a magnetic field.⁵⁾ Nondestructive testing using a SQUID to qualitatively evaluate fatigue damage or defects has also been investigated.
　　Work has been done on computer simulation techniques to predict materials behavior at the atomic level, together with advanced research on smart structures in which the aim is to integrate materials properties, structures, and information in order to ultimately incorporate decision-making and learning properties into material and structural systems.

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Fig.2-1 Basic concept of the smart structural system

Materials Design
　　Work in the Materials Design Division centres on the improvement of microstructure and properties, and the design of new metallic materials such as intermetallic compounds, titanium alloys for biomedical applications, superplastic single phase stainless steels, and nicklel-base superalloys.
　　For example, homogenisation of the micro-structure of intermetallic TiAl binary, tertiary, and quertiary alloys has been investigated using rheocasting in which the solidifying alloy is vigorously agitated by a stirrer rotating at between 900 and 4200 rpm, under an argon blanket. Extremely refined microstructure was formed in rheocast Ti-44at%Al alloys. The tensile strength of these alloys when rheocast at 42OOrpm were typically 538MPa at 1173K and 439MPa at 1273K, while these cast without stirring were only 363MPa at 1173K and 389MPa at 1273K, as shown in the figure. ¹⁰⁾
　　The elongation to failure of a single phase stainless steel (SUS3O4) exceeded 300%, and superplasticity originated after recrystallisation.

fig

Fig.2-2 Relation between tensile strength at 1273k and elongation at room temperature

Tribology
　　The Tribology Division concentrates on gaining understanding of the physico-chemical phenomena that occur at sliding surfaces, and their effects on the tribological performance of a range of materials in various environments.
　　Triboemission phenomena and the formation of friction polymers in advanced materials have been investigated. The emission of electrons, ions, and photons from sliding surfaces has been successfully measured in-situ. ^{7,15,7,24,29)}
　　An EHL film tester and friction and wear tester equipped with an environmental chamber have been developed for work on tribological problems associated with the use of environmentally friendly refrigerants such as HFC-134a. Chemical and physical phenomena associated with the refrigerants have been investigated. ^14,19)
　　New lubricants containing siloxane and both hydrocarbon and flourocarbon chains have been developed which have excellent characteristics when used with bronze and iron. Friction is markedly decreased when they are added to base engine oil.
　　Solid, multi-phase oxide lubricants have been developed firing BaZrO3 + Cr2O3 and BaO + Cr2O3 mixtures. Barium chromates such as BaCrO₄, BaCr₂O₄ and BaCrO₃ are formed which give rise to low friction and wear characteristics in air over a wide temperature range from room temperature to 1000℃. ²⁰⁾

fig

Fig.3-1 Friction and wear of A1₂0₃/A1₂0₃ pairs lubricated by BaCrO₄ at room temperature and 1000℃

　　Surface modification is one of the most useful techniques for optimising the tribological properties of materials. We have developed a new laser/plasma hybrid spraying (LPHS) method for surface modification, and the surface layers produced by this method are superior to these produced by normal plasma spraying techniques. The tribology of diamond-like carbon films have been investigated and they has been found to have ultra-low friction coefficients of about 0.05 in dry air. ^27,31)

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Fig.3-2 Friction and wear of Triballoy films produced by LPHS and LPPS (Low pressure plasma deposition)

　　The catastrophic slip that occurs in geological faults and causes earthquakes may be thought of as a tribological phenomenon. Prediction of earthquakes is of great interest in Japan and elsewhere, and precursory seismic electromagnetic phenomena have recently been attracting considerable interest in this regard.³³⁾ Laboratory experiments³²⁾ and field observations near Tsukuba are in progress in attempts to detect the transient electric currents associated with rock and crustal failure, towards developing an earthquake prediction system.

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Fig.3-3 Earth-current measurement system to detect seismic electric signal

List of Publications(1996)
Materials Science and Technology

1) K. Kanazawa, H. Kubota, K. Nakamura and K. Hirano, Fracture Toughness and Fatigue Crack Growth Characteristics of Aluminum Alloy Die Castings, Trans. JSME 62-594 (Feb. 1996), pp.379～386
2) T. Shimizu and T. Sano, Penalty Method Contact-Friction Algorithm and Expression of Tools by B-Spline Function-Penalty Method Contact Argorithm and Rigid Plastic FEM I, J. of JSTP 37-421 (Feb. 1996), pp.225～230
3) K. Nakayama, T. Dekura and T. Kobayashi, Effects of Additives on Friction, Wear and Iron Fluoridew Formation Under Perfluoropolyether Fluid Lubrication in Vacuum and Various Atmospheres Containing Oxygen, Wear 192 (Mar.1996), pp. 178～185
4) A. Bhattacyaraya, T. Singh, A. K. Tripathi, V. K. Verma and K. Nakayama, Wear and Friction Studies on Silicon Nitride Bearing Balls Using S-Containing Potential Lubricant Additives, Indian j. of Eng. & Mater. Sci. 3 (Apr.1996), pp. 70～72
5) T. Suzuki and K. Hirano, Fatigue Crack Growth Characteristics of Austenitic Stainless Steel at Cryogenic Temperature Under High-Magnetic Field, Fatigue '96 (May 1996), pp. 405～410
6) K. Hirano and M. Vivensang, Fatigue Failure Mechanism of Advanced 2-Dimensional C/C Composites, Fatigue'96 (May 1996), pp. 1681～1686
7) K. Nakayama, Tribocharging and Friction in Insulators in Ambient Air, Wear 194 (Jun. 1996), pp. 185～189
8) K. Hirano, K. Etoh and M. Kikuchi, Fracture Toughness of Unidirectional Fiber Reinforced Titanium Alloy and Titanium Intermetallic Matix Composites, Localized Damage IV-Conzputer-Aided Assessment and Control - (Jun. 1996), pp. 409～416
9) K. Sekine, Y. Zhong, A. uzuka and K. Nonaka, A Theoretical Analysis of magnetic Force Acting on magnetic in the Immediate Vicinity of Surface Flaws, Proc. First US-JAPAN Symp. on Adovances in NDT, Hawai, USA, ed, by ASNT(Jun. 1996), pp. 396～401
10) K. Ichikawa and Y. Kinoshita, Refinement of Microstructures and Improvement of Mechanical Properties in Intermetallic TiAl Alloys by Rheocasting, Mater. Trans., JIM 37-6 (Jun. 1996), pp.1311～1318
11) T. Shimizu, T. Sano, S. Mochizuki and M. Fuchizawa, A Debinding Method Using Supercritical C0₂ on MIM Process, Proc. of the World Congress on Powder Metallurgy and Particulate Mater. 19 (Jun. 1996), pp. 207～212
12) K. Hirano and M. Vivensang, Evaluation of Damage Tolerant Behavior for Advanced C/C Composites, Proc. of Asian Pacific Conf. on Fracture and Strength '96 (Jul. 1996), pp. 149～154
13) Y. Saotome, Y. Nakazawa, Y. Yokoyama and T. Aoki, Disassembling and Selective Materials Recovering Process of Vacuum-Aided Recycling Systems Technology of Ecofactory, Proc. 4th Int. Cong. on Environmentally Conscious Design and Manuf. (Jul. 1996), pp.389～396
14) M. Akei, K. Mizuhara, T. Taki and T. Yamamoto, Evaluation of Film-Forming Capability of Refrigeration Lubricants in Pressurized Refrigerant Atmosphere, Wear 196 (Aug.1996), pp.180～187
15) K. Nakayama and H. Hashimoto, Triboemission, Tribochemical Reaction, and Friction and Wear in Ceramics Under Various N-butane Gas Pressures, Tribology Int. 29-5 (Aug.1996), pp. 385～393
16) Y. Saotome, Y. Nakazawa and Y.Yokoyama, Vacuum Aided Recycling Systems Technology as a Restoration Systems Technology of Ecofactory, Vacuum 47-6-8 (Aug.1996), pp. 833～836
17) K. Nakayama and H. Hashimoto, Triboemission of Charged Particles and Friction During Wear of Solids in the Atmosphere, Proc. Int. Tribology Conf. Yokohama 1995,(Aug 1996), pp. 79～84
18) K. Mizuhara and S. Jahanmir, Characterization of Oxides Formed on Silicon Nitride Surfaces During Higt Temperature Friction Tests, Proc. Int. Tribology Conf. Yokohama 1995, (Aug.1996), pp. 439～443
19) K. Mizuhara, M. Akei, T. Taki, K. Kawahara, T. Nishizawa, K. Sawai, N. Masuda and E. Usui, Evaluation of Physical Properties of Lubricants with Alternative Refrigerants, Proc. Int. Tribology Conf. Yokohama 1995, (Aug.1996), pp. 881～886
20) K. Umeda, Y. Enomoto and A. Tanaka, Development of Multi-Oxide Solid Lubricants Usable from Room Temperature up to 1000℃ in Air, Proc. Int. Tribology Conf. Yokohama 1995, (Aug.1996), pp.1181～1186
21) Y. Hibi, Y. Enomoto, K. Kikuchi, H. Ogiso and N. Shikata, Effective Mirror-Like Machining of Silicon Based Ceramics by Excimer Laser Assisted Chemical Machining, Proc. Int. Tribology Conf. Yokohama 1995, (Aug.1996), pp.1731～1736
22) T. Shimizu, T. Sano, S. Mochizuki and M. Fuchizawa, Supercritical C0₂ Debinding Method in MIM Process-Debinding Condition and Process in Supercritical Debinding, J. of the Soc. of Powder and Powder Metallurgy, 41-8 (Aug.1996), pp.1188～1192
23) K. Nakayama and T. Kobayashi, Effect of Dissolved Oxygen on the Formation of Iron Fluoride, Friction and Wear in an Iron/Iron Frictional System under Perfluoropolyether Fluid Lubrication, Wear 198 (Oct.1996), pp.52～57
24) K. Nakayama and H. Ikeda, Triboemission Characteristics of Electrons During Wear of Amorphous Carbon and Hydrogenated Amorphous Carbon Films in a Dry Air Atmosphere, Wear 198 (Oct. 1996), pp. 71～76
25) F. Tamai and K. Hirano, Characteristics of Static and Fatigue Strength of Alumina Ceramic, Joints JSME Int. J. 39-4 (Oct. 1996), pp.613～619
26) K. Hanada, Y. Murakoshi, H. Negishi and T. Sano, Microstructures and Mechanical Properties of A1-Li/SiCp Composite Produced by Extrusion Processing, J. of Mater. and Processing Tech. 63 (Nov.1996), pp. 405～410
27) A. Tanaka, K. Mizuhara, I. Umeda, M. Ko, S. Kim, S. Shin and S. Lee, Friction and Wear of Diamond-like Carbon Films Produced by Plasma Assisted CVD Technique, Proc. Int. Diamond Symp. (Nov. 1996), pp.139～144
28) K. Umeda, A. Tanaka and S. Takatsu, Tribological Properties of Sintered Diamonds with WC-Co Matrix, Proc. Int. Diamond Symp. Seoul 1996, (Nov. 1996), pp. 222～226
29) K. Nakayama, Triboemission and Wear of Hydrogenated Carbon Films, Mat. Res. Soc. Symp. Proc. 409 Materials Research Soc. (1996), pp. 391～396
30) Y. Kimura, M. Tanaka and Y. Enomoto, Tribology Research in Japan －　A State-of-the Art Report －, Imech E, Proc. Instn. Mech. Engrs, 210(1996), pp. 159～172
31) Y. Enomoto, S. Miyake and S. Yazu, Friction and Wear of Synthetic Diamond with and without N+ Implantation and CVD Diamond Coating in Air, Water and Methanol, Tribology Leteers 2 (1996), pp. 241～246
32) Y. Enomoto, H. Hashimoto and K. Kikuchi, Measurements of Transient Electric Current Associated with Indentation Fracture and Deformation of Brittle Solids, Phil. Mag. 74-5 (1996), pp. 1299～1310
33) Y. Enomoto, Notes on Generation and Propagation of Seismic Transient Electric Signals "A Critical Review of VAN", Sir J. Lighthill ed. World Sci. Singapore(1996), pp. 324～331

Bioengineering
Any enquiries regarding this project should be directed to e-mail: kiso0@mel.go.jp

　　Bioengineering is concerned with the application of engineering to the biological sciences and medicine. Research in this field at MEL aims to improve our basic knowledge of living beings and apply that knowledge to the development of health care systems. An advanced understanding of biomechanics is a prerequisite for successful research in bioengineering. MEL's research includes the following topics:
1) The biomechanics of bone and muscle
2) Biocompatibility evaluation techniques
3) Development of advanced biomaterials for artificial bones and joints
4) Motor mechanisms for molecular machines
5) Artificial heart development
6) Optical tomography
7) Non-invasive measurement of brain function
8) Novel MRI/S techniques
9) Development of laser ablation techniques for hard tissue
10) Studies for computer aided surgery
　　Some of these are described below.

Advanced biomaterials for artificial bones and joints
　　Ti-6A1-4V alloy is often used for prosthetic implants, but the vanadium and aluminum in this alloy can have unfortunate toxic effects. New titanium alloys which retain the strength of Ti 6A1-4V without the toxicity are under development and twelve of these have been tested for tensile strength, cyto-compatibility, and Ti solubility in hydrochloric acid. The tests showed that tensile properties are better with tin as an alloying material than with zirconium. Ti-155n-4Nb-2Ta-0.2Pd alloy has better tensile strength than Ti 6A1-4V. Cyto-compatibility tests showed that Ti-l5Zr-4Nb-4Ta-0.2Pd alloy has improved compatibility, and in solubility tests the concentration of dissolved titanium from Ti-Zr, Ti-Zr-Pd, and Ti-Sn-Pd series alloys was found to be about two orders of magnitude less than that from Ti-6A1-4V. Optimum compositions for the new titanium alloys were found to be Ti-l5Zr-4Nb-4Ta-0.2Pd and Ti-155n-4Nb-2Ta-0.2Pd. ^34,37,39,44)

fig

Fig.4-1 A water droplet moves when 1-octanol is added to one side of the droplet.

Motor mechanisms for molecular machines
　　A new phenomenon which has potential for application to drive mechanisms was investigated. When a water droplet of volume about 30 μl is placed on a polytetrafluoroethylene substrate in n-octane and a line of the surfactant 1-octanol drawn to one side of the droplet, the droplet moves along the 1-octanol line as shown in the above figure. The driving force arises from the difference in interfacial tension produced by the concentration difference between front and rear of the droplet.

Artificial heart
　　A centrifugal blood pump incorporating rotor suspension using rare earth permanent magnets and a ceramic mono-pivot bearing is under development for application as an implantable artificial heart⁴⁰⁾. A recently developed model (figure below) has an impeller 50 mm in diameter and has sufficient output (output pressure: 100 mmHg with a flow rate of 5 1/mm at 1,900 rpm) and total efficiency (greater than 10%) for use in this application. Secondary flow patterns in the blood pump have been determined using flow visualization with tracer particles and a high speed video camera³⁶⁾.

fig

Fig.4-2 A newly developed mono-pivot magnetic-suspension blood pump for an implantable artificial heart.

Optical tomography
　　Optical tomographic imaging using near infrared light has potential as a non-invasive measurement technique for determining the oxygenation state of living tissues. However, light is strongly scattered by tissue, and an understanding of photon migration in living organisms is necessary.^4l,42,45) We have developed computer codes to simulate photon migration and have also developed a new algorithm for optical tomography based on inverse techniques.^35,38) Experimental results using a solid phantom simulating a living body have shown the usefulness of the new algorithm (figure below).

fig

Fig.5-1 Image of an absorbing cylinder embedded in a scattering cylindrical phantom obtained using optical tomography with the new reconstruction algorithm.

Fig.5-2 Metabolic MR Images of (a) the brain and (b) the foot muscle of a rat.

Novel MRI/S techniques
　　Magnetic Resonance Imaging and Spectroscopy (MRJ/S) can measure the concentration of nuclei such as hydrogen and phosphoric acid in biological tissues, and gives images of their two-and/or three-dimensional distribution. We have developed several novel MRJ/S techniques including: fast three-dimensional T2 weighted imaging with high S/N ratio, and two dimensional diffusion/perfusion imaging with chemical selection. These techniques are useful as diagnostic techniques in medicine and biology (figure at the left bottom).

Computer aided surgery
　　Computer Aided Surgery (CAS) is an expanding technology in surgical treatment. Some CAS applications, e.g., non-rigid registration, virtual reality for manipulation of soft organs, and surgical robots, require mathematical models of tissue behavior. However, the mechanical behavior of soft organs under modest interaction has not been intensively studied. We have investigated the uniaxial, unconfined compression of swine brain tissue in-vitro for three loading velocities ranging over five orders of magnitude⁴³⁾. We could find no linear region in the stress-strain characteristic from which a meaningful elastic modulus might be determined. The strong rate dependence of the stress-strain characteristic prohibits the use of the standard biphasic model. We therefore proposed the use of a single-phase, non-linear, viscoelastic model based on the strain energy function, written in the form of a convolution integral with coefficients expressed as a Prony series. Our model is in good agreement with experimental results as shown in the figure below.

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Fig.5-3 Stress-strain curves: i) experimental results (solid lines), ii) curves computed using our new model (broken lines).

List of Publications(1996)
Bioengineering

34) S. Rao, T. Ushida, T. Tateishi, Y. Okazaki and S. Asao, Effect of Ti, Al, and V Ions on the Relative Growth Rate of Fibroblasts (L929) and Osteoblasts (MC3T3-E1) Cells, Bio-Medical Mater. & Eng. 6 (Jan. 1996), pp.79～86
35) I. Oda, H. Eda, Y. Tsunasawa, M. Takada, Y. Yamada, G. Nishimura and M. Tamura, Optical Tomography by the Temporally Extrapolated Absorbance Method, Appl. Opt. 35-1 (Jan. 1996), pp. 169～175
36) T. Ikeda, T. Yamane, T. Orita and T. Tateishi, A Quantitative Visualization Study of Flow in a Scaled-up Model of a Centrifugal Blood Pump, Artif Organs 20-2 (Feb. 1996), pp. 132～138
37) Y. Okazaki, Y. Ito, A. Ito and T. Tateishi, New Titanium Alloys to be Considered for Medical Implants, ASTM Standard Technical Publication 1272 (Mar.1996), pp.45～59
38) M. R. Jones, M. Q. Brewster and Y. Yamada, Application of a Genetic Algorithm to the Optical Characterization of Propellant Smoke, J. Thermophysics and Heat Transfer 10-2 (Apr.1996), pp. 372～377
39) Y. Okazaki, Y. Ito and T. Tateishi, Effects of Heat Treatment on Mechanical Properties and Corrosion Fatigue Strength in Physiological Saline Solution of New Titanium Alloys for Medical Implants, Mater. Trans., JIM 37-4 (Apr. 1996), pp.843～849
40) T. Yamane, T. Ikeda, T. Orita and T. Tateishi, Fluid Dynamics of Turbo Pumps for Artificial Hearts, Mater. Sci. & Eng. C4 (Jun. 1996), pp.99～106
41) S. Kumar, K. Mitra and Y. Yamada, Hyperbolic Damped-Wave Models for Transient Light-Pulse Propagation in Scattering Media, Appl. Opt. 35-19 (Jul. 1996),pp. 3372～3378
42) M. R. Jones and Y. Yamada, Determination of the Asymmetry Parameter and Scattering Coefficient of Turbid Media from Spatially Resolved Reflectance Measurements, Proc. of OSA, Trends in Optics and Photonics on Advances in Optical Imaging and Photon Migration II (Jul. 1996), pp. 379～382
43) K. Chinzei and K. Miller, Compression of Swine Brain Tissue; Experiment in Vitro, J. Mech. Eng. Lab. 50-4 (Jul. 1996), pp.106～115
44) Y. Okazaki, Y. Ito, K. Kyo and T. Tateishi, Corrosion Resistance and Corrosion Fatigue Strength of New Titanium Alloys for Medical Implants without V and Al, Mater. Sci. & Eng. A213 (Aug. 1996), pp.138～147
45) Y. Yamada and Y. Hasegawa, Time-Dependent FEM Analysis of Photon Migration in Biological Tissues, JSME Int. J. B 39-4 (Oct.1996), pp. 754～761
46) Y. Yamada, H. Ishiguro, M. Yamashita, T. Tanaka, M. Takeuchi and H. Kawamura, Rise of Tissue Temperature Induced by Reduced Blood Perfusion Caused by External Pressure, Adv. in Exp. Med. and Biol., 388 (Oct.1996),pp. 391～397
47) K. Hyodo and K. Homma, Neurotransmitter Levels in a Rat Brain Subject to Magnetic Resonance Imaging, Proc. Int. Workshop on Brainware 96 (Dec.1996), pp. 90～92

Information and Systems Science
Any enquiries regarding this project should be directed to e-mail: butsuri0@mel.go.jp

　　 The efficient transfer of information is a key technology in the complex systems upon which the success of modern society depends, and information technology is therefore of great importance. Work in this field at MEL includes development of optical information processing techniques to improve on electronic methods, work on instrumentation and control systems for use in difficult environments (eg space), and investigations into object-oriented machine design software and distributed control theory for complex systems. Some of the main topics are introduced below.

Optical Engineering
　　We have developed a new interferometer with a synthesised scatter plate for testing mirror surface shape. The scatter plate uses a computer-generated rotationally symmetric binary random pattern. New versions of the plate are easier to make than before and produce high contrast fringes.
　　In phase-shifting interferometers, non-sinusoidal fringe profiles and linearity errors in the phase shifter give rise to systematic errors. Several different types of error-compensating algorithm which have different degrees of immunity to fringe distortion and phase shift errors have been derived.
　　We have also developed approximate analytic methods for describing multiple light scattering in fluctuating random media. Simple closed-form expressions have been derived for the statistically-averaged spectral density of the scattered light, giving an intuitive insight into the physical picture of the phenomena involved.

fig

Fig.6-1 Figure Interferogram with an electron beam fablicated scatter plate.

Advanced control technologies in aerospace
　　A large, space-borne telescope can be conceived with segmented mirrors positioned by reaction actuators to attain sub-micron accuracy.
　　Optical servo-systems, which use light as both control signal and power source, overcome many problems associated with electromagnetic interference. PLZT bimorphs can attain large stroke and sub-micron positioning.
　　Micro-gravity two-phase fluid flows are investigated using a drop shaft and airplane.
　　Stratospheric airships have potential as observation and communications-relay platforms and fly at altitudes of 20km (where winds are relatively weak), powered by solar energy or surface-to-air microwave transmissions.

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Fig.6-2 Prototype stratospheric airship.

An algebraic constraint solver
　　An algebraic constraint solver named NUTS (Non-linear Utilities System) has been developed to handle the algebraic equality and inequality constraints which appear in design problems. NUTS is capable of both symbolic and numerical computation. NUTS manipulates a given algebraic constraint set symbolically, and transforms it into a simpler constraint set which is completely equivalent. This helps the designer gain insight into the underlying relationships among design parameters.
　　NUTS calculates numerical real solutions to a given algebraic constraint set with completeness and soundness. That is, all numerical real solutions are computed within a defined margin of error, and all the invalid solutions are excluded. In the case of an under-constrained problem where an infinite number of solutions exist, NUTS computes several numerical real solutions as examples.

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Fig.7-1 Algebraic constraint network solved by NUTS.

Vehicle lateral control using machine vision
　　Since automatic vehicle driving systems are a possible solution to road traffic problems, active research is in progress in the USA, Europe, and Japan. MEL has been involved in the field for 20 years, and current interests are in control using lane markings detected by machine vision.
　　In our approach, it is not necessary to detect all lane markings simultaneously in order to determine the vehicle path. Instead, markings on each side of the lane are detected in discrete fashion to produce two series of sampled points from which the optimal path of the vehicle is determined, taking into account requirements for stability, safety, and comfort. The optimal path is approximated by a cubic curve to provide the vehicle with lateral control. The system uses two-dimensional information on lane markings and is robust in that control is not seriously affected if some points are missing. Experiments with an indoor robot have aided development of the image processing and control algorithm. The picture shows indoor experiments in lateral control.

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Fig.7-2 Lateral control of a vision-based indoor robot.

Adaptive finite element methods
　　The finite element method (FEM) is now widely used in industry. However there are still serious practical problems on FE mesh generation and its appropriate control, which is an important factor on the quality of FEM solution. Adaptive finite element methods, in which quantitative control of FE errors is achieved automatically by finite element mesh regeneration based on a-posteriori error estimation, were proposed in our division some years ago. We applied these methods to optimal design, metal forming, and elastic contact. A five-year research project entitled : "Adaptive mesh generation methods for 3-D finite element analysis" is currently in its third year at MEL. We have extended the a-posteriori error estimation scheme and some of the mesh control schemes to three-dimensions this year. More research is necessary on the computational efficiency of the adaptive process.

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Fig.7-3 h-adaptive mesh refinement.

List of Publications(1996)
Information and Systems Science

48) T. Shirai and T. Asakura, Multiple Light Scattering from Spatially Random Media under the Second-order Born Approximation, Opt. Commun. /Full-length Article 123-1, 2, 3 (Jan. 1996), pp. 234～249
49) T. Shirai and T. Asakura, Spectral Changes of Light and Scattering Phenomena, Opt. Rev. 3-1 (Jan. 1996), pp. 1～10
50) T. Murata, H. Kurokawa, Y. Tomita and S. Kokaji, Self-Assembly Method for Mechanical Structure, Proc. Int. Symp. Artificial Life & Robotics (Feb. 1996), pp. 55～58
51) T. Shirai, Correlation-Induced Spectral Changes in Laser Light Scattering, Proc. Photon Tech. Workshop (Mar. 1996),L25
52) K. Tenjimbayashi, M. Kawazoe, A. K. Nirala, K. Matsuda, C. Shakher and A. Ishizaka, Phase Conjugate Interferometry for Testing a Parabolic Mirror, Proc. Photon Tech. Workshop (Mar. 1996) L26
53) A. Tezuka, 2D Mesh Generation Scheme for Adaptive Remeshing Process in FEM, JSME Int. J. 39-2A (Apr. 1996), pp. 204～215
54) M. Misawa, N. Ichikawa and M. Kawaji, Gravity Effects on Bubble Detachment in Shear Flow, Proc. 2nd European Symp. Fluids in Space (Apr. 1996), pp. 501～508
55) I. Hukui, Tissue Preparation for Reconstruction of Large-scale 3-D Structures Using a Scanning Electron Microscope, J. Microscopy Oxford 182, Pt2 (May 1996), pp. 95～101
56) M. Onda and M. L. Ford, Efforts Toward Achieving an Unmanned, High-altitude LTA Platform, Proc. 2nd Int. Airborne Remote Sensing Conf. and Exhibition (Jun. 1996) pp.I- 654～663
57) S. Tsugawa, M. Aoki, A. Hosaka and K. Seki, A Survey of Present IVHS Activities in Japan, 13th World Cong. of IFAC (Jul. 1996), pp.147～152
58) S. Kato and S. Tsugawa, Obstacle Detection by Extended Slit-Ray Projection and its Application to Mobile Robots, Proc. Jpn. USA Symp. on Flexible Automation (Jul. 1996), pp. 569～576
59) M. L. Ford and M. Onda, General Applications of the Stratospheric, Unmanned Airship, Proc. Int. Airship Convention and Exibition (Jul. 1996), pp.12- 1～ 8
60) M. L. Ford and M. Onda, Powering of High-altitude LTA's by Surface-to-air Microwave Transmissions, Proc. Unmanned Vehicle Systems Int. (AUVSI) Conf. (Jul. 1996), pp. 363～372
61) K. Matsuuchi, Y. Eguchi, N. Yamamura, T. Adachi, M. Onda and M. L. Ford, Aerodynamic Considerations for a High-altitude, Long-endurance LTA Platform, Proc. 2nd Int. Airship Conf. (Jul. 1996), pp.35～43
62) H. Kurokawa, Constrained Steering Law of Pyramid Type CMGs and Ground Tests, Proc. AIAA Guidance Navigation and Control Conf. AIAA 96-3790 (Jul. 1996), P.9
63) N. Ichikawa, M. Misawa, K. Kawasaki, S. Muramatsu, T. Tada, M. Koyama and T. S. Morita, Interface Dynamics of Capillary Flow in a Tube and Effects of Gravity-Jitter under Low-Gravity Conditions Using a MU-300 Airplane, AIChE Symp. Ser. No.310 (Aug.1996), pp. 186～194
64) K. Hibino, D. Farrant, B. Ward and B. Oreb, Effective Wavelength Tuning of a Phase-shifted Ronchi Test for Optimum Dynamic Range, Proc. 1996 Int. Workshop on Interferometry (Aug. 1996), pp. 77～78
65) K. Hibino, B. F. Oreb, D. I. Farrant and K. G. Larkin, Phase Shifting Algorithms for Nonsinusoidal Signals Compensating Nonlinear Phase Shift Errors and Their Susceptibility to Random Noise, Proc. 17th Cong. Int. Commission for Opt. SPIE 2778 (Aug. 1996), pp. 235～236
66) T. Shirai and E. Wolf, Coherence Filters and some of their Uses, Proc. 17th Cong. Int. Commission for Opt. SPIE 2778 (Aug. 1996), pp. 371～372
67) T. Shirai and T. Asakura, Spectral Changes of Light Produced by Multiple Scattering from Space-time Fluctuating Random Media Under the Born Approximation, Opt. Rev. 3-5 (Sep. 1996), pp. 324～334
68) S. Kato, K. Tomita and S. Tsugawa, Visual Navigation Along Reference Lines and Collision Avoidance for Autnomous Vehicles, Proc. 1996 IEEE Intelligent Vehicles Symp. (Sep. 1996), p.385
69) S. Kokaji, S. Murata, H. Kurokawa and, K. Tomita, Clock Synchronization Mechanisms for a Distributed Autonomous System, J. Robotics & Mechatronics 8-5 (Oct. 1996), pp. 427～434
70) K. Tomita, S. Murata, E. Yoshida, H. Kurokawa and S. Kokaji, Reconfiguration Method for a Distributed Mechanical System, Distributed Autonomous Robotic Systems 2 Springer-Verlag (Oct. 1996), pp. 17～25
71) Il-Y. Kim (Winter Institute) and A. Tezuka, Optimal Shape Design by Adaptive FEM with B-spline Description, Proc. of KSME Int. Session on Dynamic, Systems and Design (Nov. 1996), pp. 150～157
72) E. Yoshida, T. Arai, M. Yamamoto, J. Ota and D. Kurabayashi, Evaluating the Efficiency of Local and Global Communication in Distributed Mobile Robotic Systems, Proc. IEEE/RSJ Int. Conf. Intelligent Robot & Systems (Nov.1996), pp. 1661～1666
73) K. Tenjimbayashi, Large Deformation Measurement Using ESPI, Proc. SPIE 2888 (Nov. 1996), pp. 126～133
74) S. Imamura, Re-organization of Object Oriented Systems to Adapt to Specification Changes, Proc. of IMSA '96 (Dec.1996), p.103

Advanced Machine Technology
Any enquiries regarding this project should be directed to e-mail: kyoku0@mel.go.jp

　　Advanced Mechanical Technologies are essential not just for development of the field of Mechanical Engineering itself, but also for progress in almost every other field of industrial engineering and science.
　　Research in the Department of Advanced Machinery, carried out in close cooperation with other departments in the laboratory, aims to develop these technologies and includes work in the following areas:
　　1)Investigations into the basic properties of mechanical components and machines, with a view to creating completely new designs and mechanisms. This work includes the development of mechanisms for micromachines, and the design of high precision mechanical components.
　　2)Development of new processing methods and technologies for measurement and evaluation of processing results. Here, we are working on ion-beam and hybrid processing techniques, and methods for nondestructive testing and process evaluation.
　　3)General improvements in mechanical devices and systems. This includes work towards improving safety and reliability (for example ; predictive maintenance), and sound and vibration control.
　　Some specific projects are described in more detail below.

Understanding rolling fatigue initiation
　　We have used acoustic emission (AE) techniques, originally developed at MEL for predicting the failure of rolling components, to gain a better understanding of rolling contact fatigue in rolling bearings. Rolling contact fatigue tests are monitored using AF techniques. When emissions reach a set level at any position on a test piece, the test is automatically shut down. AE techniques enable location of the emission source, and so the test piece is cut at each source location and the cross section examined under a scanning electron microscope. We have discovered cracks, initiated by inclusions, which propagate inside the metal parallel to the surface.

fig

Fig.8-1 Crack initiated from an inclusion below the surface.

Micro-lathe development
　　A lathe that is much smaller than conventional lathes has been developed. This micro lathe comprises an X-Y stage driven by laminated piezoactuators, a main shaft driven by a micromotor, and a tool post. The micro-lathe measures 32.0 mm in length, 25.0 mm in depth, and 30.5 mm in height. It weighs 100 g and power consumption of the main shaft drive is approximately 1.5 W. The dimensions are approximately 1/50 of those of a conventional lathe, the weight is 5000 to 10000 times smaller, and the power consumption reduced by a factor of 500 to 1000.
　　A brass rod of 2.0 mm in diameter was cut on the micro-lathe. The surface roughness in the feed direction was Rmax 1.5 microns, and the roundness 2.5 microns. This cutting accuracy is equal to or better than that of a conventional lathe.
　　By using very small machine tools, production systems for small components and mechanical devices will become considerably smaller with concomitant savings in space and energy consumption.⁹⁵⁾

fig

Fig.8-2 The micro-lathe.

Scanning probe microscope (5PM) investigatiori of single ion tracks
　　The Nanotechnology Division has proposed a new concept in which three dimensional nanoscale mechanical devices are fabricated by single ion implantation. A feasibility study of the concept is in progress and the mechanism by which tracks are created by single ions in highly oriented pyrolytic graphite (HOPG) has been investigated using a scanning force microscope. The graphite was implanted with 3.1MeV Si, Cu, As, Sr, Ag, and Au ions at a dose of 1.9x10¹¹ cm^-2. The microscope detected tracks on the graphite surface with an increased coefficient of friction, i.e. ion impact changes the frictional force in a nanometer-sized area. We found that the probability of track creation varied widely between 0.2 and 0.54 depending on the ion species. This new result contrasts sharply with previous works where the probability was reported to he almost unity.
　　In order to understand our results better, we calculated the probabilities of knock-on atom generation by nuclear collision and found a strong correlation between the probabilities of knock-on atom production and ion track creation. We conclude that it is indeed a nuclear collision process which is responsible for ion track creation. This work shows the potential of single-ion beam processing for application to the production of nanoscale mechanical devices.⁹⁰⁾

fig

Fig.9-1 Relationship between the observed probability of ion track creation and atomic number of the incident ion, together with the calculated probability of knock-on atom generation and electronic stopping power as a function of atomic number of the incident ion.

　●: Observed probability of ion track creation
　○: Calculated probability of knock-on atom generation
　・: Electronic stopping power

Smart structures for active noise control
　　Work is in progress to develop novel active noise control systems for sound fields carried by three-dimensional structures. This project began with the introduction of a new parameter : the “acoustic power mode", initially intended for application to flat planar structures, and obtained by grouping structural vibration modes in order of acoustic radiation efficiency. The parameter allows the noisiest modes to be targeted for suppression, and will theoretically make it possible to guarantee that overall suppression in the spectrum of interest will be optimum. A new type of distributed parameter sensor using a PVDF film with an optimized shape has been developed, which gives an output voltage proportional to the acoustic power mode amplitude, together with a compact actuator incorporating PZT ceramic stacks and steel columns which is capable of applying bending moments. Because the structure condition may change with time, an adaptive controller which minimises sensor output using DSP techniques with a filtered-x LMS algorithm has also been devised.
　　This project is one stage in the development of smart structures incorporating distributed parameter sensors, bending moment actuators, and adaptive control algorithms. Although the development of smart structures initially began with work on large space structures, we anticipate these ideas will find new application in achieving a quiet everyday nvironments. ^{75,77,78,80,86,94)}

fig

Fig.9-2 Smart sensors and bending moment-type actuators for active noise control.

List of Publications(1996)
Advanced Machine Technology

75) S. D. Snyder, N. Tanaka and Y. Kikushima, The Use of Optimally Shaped Piezo-electric Film Sensors in the Active Control of Free Field Structural Radiation, Part2 Feedback Control, ASME J. Vibration & Acoustics 118-1 (Jan. 1996), pp. 112～121
76) K. Yamanaka, UFM Observation of Lattice Defects in Highly Oriented Pyrolytic Graphite, Thin Solid Films 273 (Jan. 1996), pp.116～121
77) N. Tanaka, S. D. Snyder and C. H. Hansen, Vorticity Characteristics of the Vibrational Intensity Field in an Actively Controlled Thin Plate, J. Acoustical Soc. Am. 99-2 (Feb.1996), pp. 942～953
78) N. Tanaka, Vibrational and Acoustic Power Flow of an Actively Controlled Thin Plate, Noise Control Eng. J. 44-1 (Feb. 1996), pp. 23～33
79) Y. Ando, J. Ino, K. Ozaki, Y. Ishikawa and T. Kitahara, Friction and Pull-off Force on Silicon Surface Modified by FIB, Proc. IEEE Micro Electro Mechanical Systems (Feb. 1996), pp. 349～353
80) N. Tanaka, Y. Kikushima, M. Kuroda and D. Snyder, Active Control of Acoustic Power Radiated from a Vibrating Planar Structure Using Smart Sensors (Acoustic Power Suppression Using Adaptive Feed-forward Control), JSME Int. J. Series C 39-1 (Mar. 1996), pp. 49～57
81) H. Mizutani and Y. Ishikawa, Power Loss of Long Addendum Spur Gears, VDI-Bericht 1230 (Apr. 1996), pp. 83～95
82) H. Cho, H. Sato, M. Takemoto, A. Sato and K. Yamanaka, Surface Acoustic Wave Velocity and Attenuation Dispersion Measurement by Phase Velocity Scanning of Laser Interference Fringes, Jpn. J. Appl. Phys. 35 Part 1-5B (May1996), pp. 3062～3065
83) H. Sato, H. Cho, H. Nishino, H. Ogiso and K. Yamanaka, Evaluation of Surface Defects Using Surface Acoustic Waves Generated by Phase Velocity Scanning of Laser Interference Fringes, Jpn. J. Appl. Phys. 35 Part 1-5B (May 1996), pp. 3066～3069
84) Y. Hoshi, H. Yoshida, K. Yamanaka and Y. Usui, Time Delay in Laser-Guided Discharge at Low Air Pressure, IEEE Trans. Plasma Science 24 - 3 (Jun. 1996), pp. 1137～1146
85) K. Yamanaka and S. Nakano, Ultrasonic Atomic Force Microscope with Overtone Excitation of Cantilever, Jpn. J. Appl. Phys. 35 Part 1-6B (Jun. 1996), pp. 3787～3792
86) N. Tanaka, Y. Kikushima and M. Kuroda, Vortex Power Flow and Its Influence on the Acoustic Field, Proc. 4th Int. Congress on Sound & Vibration (Jun. 1996), pp. 785～792
87) M. Kuroda, M. Nakai and N. Tanaka, Chaotic Vibration in a Forced Vibratory System with an Asymmetric Restoring Force, Proc. 4th Int. Congress on Sound & Vibration (Jun. 1996), pp. 1029～1037
88) M. Kuroda, M. Nakai, T. Hikawa and Y. Matsuki, Bifurcations and Chaos in a Forced Vibratory System with an Asymmetric Piecewise Linear-Restoring Force, Proc. 6th Conf. on Nonlinear Vibrations, Stability, and Dynamics of Structures (Jun. 1996), pp. 56～57
89) Y. Hoshi, H. Yoshida, K. Yamanaka and Y. Usui, Time Delay in Laser-Guided Discharge at Low Air Pressure, IEEE Transactions on Plasma Science 24-3 (Jun. 1996), pp. 1137～1146
90) H. Ogiso, S. Nakano, H. Tokumoto and K. Yamanaka, Friction Change Induced by Single MeV Ion Impact Measured by Scanning Probe Microscope, Mat. Res. Soc. Symp. Proc. 396 (Jun. 1996), pp. 667～672
91) M. Kuroda, Y. Kikushima and N. Tanaka, Chaotic Vibration in a Forced Vibratory System with a Piecewise Linear Restoring Force, Proc. Third Int. Conf. Motion & Vibration Control 1-6 (Sep. 1996), pp. 93～98
92) H. Ogawa, Y. Ishikawa, T. Kitahara and S. Kaneko, Tensile Testing of Microfabricated Thin Films, Proc. 5th Int. Conf. on Micro Electro, Mechanical Systems and Components (Sep. 1996), pp. 229～234
93) K. Yamanaka, H. Takano, E. Tomita and M. Fujihira, Lateral Force Modulation Atomic Force Microscopy of Langmuir-Blodgett Film in Water, Jpn. J. Appl. Phys. 35 1-10 (Oct. 1996), pp.5421～5425
94) N. Tanaka, S. D. Snyder and C. H. Hansen, Distributed Parameter Model Filtering Using Smart Sensors, ASME, J. Vibration & Acoustics 118 (Oct. 1996), pp. 630～640
95) T. Kitahara, Y. Ishikawa, T. Terada, N. Nakajima and K. Furuta, Development of Micro-Lathe, Proc. 2nd Int. Micro machine Symp. (Oct. 1996), pp. 59～67
96) H. Ogawa, Y. Ishikawa, T. Kitahara and S. Kaneko, Measurements of Stress-strain Diagrams of Thin Films by a Developed Tensile Machine, Proc. SPIE's 1996 Symp. on Micro-machining and Micro-fabrication, Micro-lithography and Metrology in Micro-machining II (Oct. 1996), pp. 272～279
97) K. Kondo, Study on Wave Drives (2nd Report) Design of Involute Tooth Profiles, Trans. of JSME 62-603 (Nov. 1996), pp. 4363～4368
98) M. Kuroda, M. Nakai, T. Hikawa and Y. Matsuki, Bifurcations of Higher Subharmonics and Chaos in a Forced Vibratory System with an Asymmetrical Pestoring Force, Trans. Jpn. Soc. Mech. Eng. Series C, 39-4 (Dec.1996), pp. 753～766

Energy and Environmental Technology
Any enquiries regarding this project should be directed to e-mail: energy0@mel.go.jp

　　In the Department of Energy Engineering, energy and environmental technologies have been developed under the auspices of large scale national research projects such as a new Sunshine Program and the Global Environmental Research Program. Of particular interest are : solar energy technology, hydrogen energy technology, eco energy city technology, wind energy technology, ceramic gas turbine technology, CO₂ fixation in the deep sea, life cycle analysis, and DeNOx technology. Fundamental research projects are also in progress for example : development of closed cycle MHD power generation systems, investigation of the thermal characteristics of a super critical fluid, high-tech plant factory surveys, and work on traffic noise reduction. Some of the main topics are briefly described below.

Thermal analysis of Si photovoltaic Substrate
　　The effect of RF (Radio Frequency) heating on molten silicon flow in FZ (Floating Zone) crystal growth processing has been studied experimentally and numerically. Experimentally, flow patterns have been determined using X-ray techniques to monitor the movement of 0.5mm Zirconia-cored tracer particles which have a quartz coating. Numerical techniques have been used in the investigation to calculate the flow of molten silicon in various configurations. The numerical code is based on the finite difference scheme and includes 3rd order upwind for calculation of convective terms, ADI for time integration, and SOR for Poissons equations.

WE-Net Research
　　As a part of the development of hydrogen energy technology, we are developing fundamental technologies for clean and efficient power generation systems where the working fluid is heated internally by H₂-0₂ stoichiometric combustion. This type of system is expected to achieve 60% (HHV) of the maximum efficiency using steam as working fluid.
　　However, currently available basic H₂-0₂-Steam mixture combustion data are not sufficient and we are therefore in the process of gathering data on burning velocity, blow-off velocity, and the chemical reactions on the surface of the combustor, in order to determine the combustion characteristics. The figure shows laminar burning velocities for H2-O2, H₂-0₂-Ar and H₂-0₂-Steam gas mixtures. We found that the pressure dependencies in H₂-0₂-Steam mixtures are different from those in H₂-0₂mixtures.

fig

Fig.10-1 Laminar burning velocity of H₂-0₂ stoichiometric mixtures by chemical kinetic simulation.

　　We are also developing new technologies for combustion initiation and promotion using photochemical reactions which have potential for application in clean, efficient, combustion systems of the future. Ignition by excimer laser radiation is used in this work. Turbine system analysis, and overall analysis of the hydrogen energy system are also in progress for optimizing power generation and global energy systems.

Broad area energy network system (Eco-energy city project)
　　The broad energy network is an energy management system which is under development for efficient energy conservation and utilization. The concept makes use of advanced techniques for the recovery of waste heat from industrial processes using natural heat transfer media such as water, low loss energy transport in district heating schemes where heat is transferred efficiently from factories using chemical reactions or by the addition of surfactants, techniques for effective energy utilization by consumers, and optimization of overall energy system design. ^{100,101,106,107)}
　　Antifreeze proteins found in fish from the Antarctic Oceans are under investigation as additives for the storage and transportation of ice slurry in air conditioning systems. These proteins are adsorbed strongly onto the ice crystal surface by electro-static interaction between the polar protein residues and the crystal lattice. They inhibit crystal growth because non-polar groups appear on the outside of the adsorbed layer. This microscale Electro hydrodynamic (EHD) effect has been investigated using a Scanning Tunnelling Microscope to examine the crystal surfaces. The figure shows a 2Onm x 2Onm area of the surface of an ice crystal which is curved because of antifreeze protein adsorption.
　　The effects of ultrasonic vibration on the freezing point of supercooled water have been investigated towards developing methods for freezing point control in a cold energy storage system which uses ice slurry. Experimental results have shown that irradiation with ultrasound gives definite advantages.
　　The solubility of hydrogen in liquid phase methanol and methyl formate has been determined at pressures up to l5OOkPa and temperatures up to 140 degrees C, as part of work towards the development of more efficient liquid phase catalytic reactions.^{109,110,113,119)}
　　The use of surfactants for drag reduction in energy transportation systems is under investigation. Advanced heat exchangers which use practical surfactant solutions as the working fluid and have improved heat transfer coefficients at lower turbulence levels have been proposed.^103,105,112)

fig

Fig.11-1 Scanning Tunnelling Microscope surface profile of ice containing adsorbed Antifreeze Proteins (circles).

Wind energy technology
　　Variable speed operation of the experimental 16.5kW wind turbine WINDMEL-II has been investigated in order to reduce rotor component stresses and obtain longer lifetimes under strong wind gust conditions. Experiments have shown that peak stresses on the main rotor shaft are much smaller than when the turbine is operated at constant speed, and theoretical investigations confirmed that this was the flywheel effect due to a decrease in blade acceleration.⁹⁹⁾
　　The sound emission characteristics of the turbine have also been investigated in an attempt to reduce noise pollution. Experiments with two different types of blade confirmed that the noise depends on blade shape and the most strongly emitting region of the blade is the edge.

Ceramic gas turbine research
　　Boundary layer separation and reattachment on ceramic gas turbine blades has been investigated in a fundamental investigation aimed at improving turbine efficiency and robustness. Experiments with a turbine cascade showed that, in an impulse turbine, the overall pressure loss coefficient suddenly increases as Reynolds number falls due to an increase in flow separation. Impulse turbines are more robust against damage by foreign objects than reaction turbines, and so these experiments would be utilized to optimize the performance of ceramic turbine blades.

Emission control for internal combustion engines
　　A feasibility study on the development of a practical high-efficiency, low pollution LPG engine has been carried out. Part of the study included performance measurements on a dual fuel type LPG diesel engine and a lean burn type spark ignition LPG engine. The dual fuel engine was found to have good thermal efficiency and be very suitable for traditional engine applications. The lean burn engine was found to have very low NOx emission and can easily meet the long-term regulations which come into force in 1998. The picture shows a dual fuel LPG diesel powered vehicle that was developed in collaboration with companies involved in the project.

fig

Fig.12-1 Dual fuel LPG diesel engine powered delivery truck(prototype)

　　In attempts to achieve simultaneous reduction of NOx and particulate matter emissions from diesel engines, we have investigated the performance of Ag/Alumina catalytic converters operating with a trap oxidizer. The effects of reaction temperature, the hydrocarbons used as reduction agents, space velocity, and gas velocity on the reaction characteristics of the DeNOx catalyst were analyzed. The figure shows the effects of these parameters on the NOx reduction ratio.

fig

Fig.12-2 Effect of catalyst temperature and hydrocarbons used as the reduction agent on NO reduction ratio (conditions HG/NO ratio=3.1, 0₂conc.=2%, SV=3000hr^-1)

Closed Cycle MHD Power Generation
　　In closed cycle MHD (CCMHD) power generation, seed (alkali metal) vapor should be mixed uniformly with the working gas to promote non-equilibrium ionization in the MHD channel. We have developed a new seed injection system for the Fuji-15MWt blow down facility.¹¹⁵⁾ The seed injection system uses a two-fluid multi-hole nozzle to atomise liquid cesium into a high temperature (～2000K) high pressure (～0.4MPa) argon flow. The design and operating conditions of the seed injection system were determined from cold model experiments using air-water mixtures. This seed injection system has been used in power generation experiments with Fuji-1 and high enthalpy extraction (16.7%) and a large power output of 502kW were obtained simultaneously in RUN A4105. ¹¹⁶⁾

fig

Fig.12-3 Output power against seed fraction.

Tire/Road Noise Mechanisms
　　Road traffic noise is a serious environmental problem and is made up of three types of noise: engine noise, exhaust noise, and tire/road noise. Engine noise may be reduced by using an insulating sound-proof enclosure and exhaust noise is controllable by using an efficient attenuating muffler, but unfortunately these techniques cannot be applied to the reduction of tire/road noise. The noise generation mechanism is also not well understood. A drum facility in which part of the drum is located in an anechoic chamber has been developed for precise measurement of tire/road noise. The surface of the drum may be modified to simulate different road surfaces.
　　Several noise characteristics were investigated using the facility, and it was found that the noise level and the noise generation points depend greatly on the type of road surface.

fig

Fig.12-4 Tire/road noise measurement using the drum facility.

List of Publications(1996)
Energy and Environmental Technology

99) A. Sasamoto, H. Matsumiya, S. Kawamura and T. Ogawa, Comparison between Variable and Constant Rotor Speed Operation on WINDMEL- II, Proc. Energy Week '96 Conf. & Exhibition, (Jan. 1996), pp. 110～114
100) A. Yabe and T. Akiya, Advanced Heat Pumps and Their Economic Aspects - The Case for Super Heat Pump, Proc. lEA Heat Pump Center Workshop “Systems and Controls for Energy Efficiency” (May 1996), pp. 1～9
101) S. M. Kum, Y. Kawaguchi and J. Y. Seo, A Study on Heat Transfer Enhancement by Square Rod Array in Impinging Jet System, Heat Transfer-Japanese Research, 24 (2) (May 1996), pp. 193～207
102) J. Hama, S. Takahashi, H. Furutani and N. Iki, A Closed Gas Turbine System by using of Hydrogen-Oxygen Combustion, 11th Int. World Hydrogen Energy Conf. (Jun. 1996), pp. 1909～1913
103) Y. Kawaguchi, Y. Tawaraya, A. Yabe, K. Hishida and M. Maeda, Active Control of Turbulent Drag Reduction in Surfactant Solutions by Wall Heating, Proc. Symp. on Turbulent Modification and Drag Reduction (ASME) FED 237 (Jul. 1996), pp. 47～52
104) J. Shakal and S. Goto, Formation and Combustion of a Monodisperse Kerosene Droplet Cloud Under Microgravity, Drop Tower Days 1996 in Bremen (Jul. 1996), pp. 3-31～33
105) Y. Kawaguchi, Y. Tawaraya, A. Yabe, K. Hishida and M. Maeda, Turbulent Transport Mechanism in a Drag Reducing Flow with Surfactant Additive Investigated by Two Component LDV, Proc. 8th Int. Symp. on Application of Laser Techniques to Fluid Mechanics (Jul. 1996), pp. 29.4.1～29.4.7
106) A. Yabe, S. Terakado, J. P. Longtin, M.C. Hipwell and Chang-Lin Tien, Thermoelectric Characteristics of Microscale Thin Film Thermocouples, US.-Japan Joint Seminar on Molecular & Microscale Thermal Eng. (Aug. 1996), pp. 1～8
107) B. H. Kang and A. Yabe, Performance Analysis of a Metal-Hydride Heat Transformer for Waste Heat Recovery, Appl. Thermal Eng. 16, Nos8/9 (Aug 1996), pp. 677～690
108) J. Schmied Perger, S. Takahashi and H. Fujii, Improved RF Plasma Jet Generation of Singlet Delta Oxygen, Proc. 11th Symp. on Gas Flow and Chemical Lasers and High Power Laser Conf. (Aug.1996)
109) Q. Liu, F. Takemura and A. Yabe, Solubility and Diffusivity of Carbon Monoxide in Liquid Methanol, J. Chem. Eng. Data 41 (Sep.1996), pp. 589～592
110) F. Takemura, Q. Liu and A. Yabe, Effect of Density-Induced Natural Convection on the Absorption Process of Single Bubbles under a Plate, Chem. Eng. Sci. 51-20 (Sep.1996), pp.4551～4560
111) S. Goto, J. Shakal and H. Daigo, LPG Engine Research and Development in Japan, SAE Convergence 96, SAE Paper 96C052 (Oct. 1996), pp. 423～429
112) S. R. Park, H. K. Yoon and Y. Kawaguchi, Experimental Study of Turbulent Characteristics in Drag Reducing Channel Flow with 2D-LDV, Proc. 3rd KSME/JSME Thermal Eng. Conf. (Oct. 1996), pp. 221～226
113) Q. Liu, F. Takemura and A. Yabe, Transport Process of CO and H₂ Gases in Liquid Phase Methanol Synthesis and Reaction Rate, 4th Int. Symp. on Heat Transfer with Exhibition (Oct. 1996), pp. 760～765
114) N. Aya, H. Iwamoto and F. G. Shi, Generation of Zinc Compound Particles by Pulsed C0₂ Laser Irradiation, Proc. 15th Annual Conf. of the American Association for Aerosol Research (Oct. 1996), p.360
115) Y. Hasegawa, K. Tsukamoto, K. Tsuji, T. Furuya, K. Yoshikawa, H. Yamasaki and S. Shioda, Seed Fraction Measurement and Control in Fuji-1 Facility, Proc. 12th Int. Conf. on MHD Elec. Power Generation (Oct. 1996), pp. 632～640
116) Y. Okuno, T. Okamura, K. Yoshikawa, T. Suekane, K. Tsuji, K. Ohgaki, S. Kabashima, S. Shioda, H. Yamasaki, Y. Hasegawa, K. Matsutani, M. Tezuka, S. Ikeda and H. Mukai, Closed Cycle MHD Power Generation Experiments with Fuji-i Blow Down Facility, Proc. 12th Int. Conf. on MHD Elec. Power Generation (Oct. 1996), pp. 155～164
117) K. Seo, M. Shiraishi and M. Murakami, Temperature Oscillations of Working Gas Inside a Basic, an Orifice and a Double Inlet Pulse Tube Refrigerators, Advances in Cryogenic Eng. 41 (Dec.1996), pp. 1395～1402
118) M. Shiraishi, Y. Kim, K. Seo and M. Murakami, Start-up Behavior of Pulse Tube Refrigerator, Advances in Cryogenic Eng. 41 (Dec.1996), pp. 1455～1462
119) Q. Liu, F. Takemura and A. Yabe, Solubility of Hydrogen in Liquid Methanol and Methyl Formate at 200℃ to 1400℃, J. Chem. Eng. Data 41-5 (1996), pp.1141～1143

Manufacturing Technology
Any enquiries regarding this project should be directed to e-mail: seisan0@mel.go.jp

　　The Department of Manufacturing Systems is involved in research into several manufacturing technologies including: ecologically conscious manufacturing, hybrid machining, surface and interface technology, powder forming technology, production machines, and manufacturing information systems.
　　Some projects are introduced in detail below.

Processing technology for super lattice materials

(1) Bending and blanking of Ni₃Al ¹⁴¹⁾
　　The intermetallic compound Ni₃Al has high strength at room and elevated temperatures, the strength increasing with temperature. However, pure polycrystalline Ni₃Al has low ductility and is difficult to process because intergranular fracture takes place at an early stage during deformation.
　　The addition of small amounts of boron to Ni₃Al has a remarkable effect in improving the formability and machinability of the material. We have developed techniques to add boron locally from the surface of cast Ni₃Al by a thermal diffusion method, using a liquid containing B₂O₃.
　　Optimum diffusion conditions to improve bending properties were determined. Bending stress-strain curves are obtained from a 3-point bending test. The new process increased the bending limit of Ni₃Al sheets by 5 times after diffusion for 60min at ll73K. The springback angle also decreased by a factor of 10 when compared to cast Ni₃Al with 0.16wt% boron.
　　Crack initiation was suppressed in blanking by the addition of boron and the application of counter punch pressure. The thermal diffusion method also improved other blanking properties such as accuracy and the burr height of cut surfaces. In another investigation, we found that the addition of up to 0.08% boron to Ni₃Al during casting increased the life of blanking tools by a factor of 8.

fig

Fig.13-1 Bending stress-strain curve in Ni₃Al

Fig.13-2 Relation between burr height and methods of B addition in Ni₃Al

(2) Grinding of Nb₃AI
　　Nb₃Al is a difficult-to-machine material. Machiming or milling is almost impossible with this material. Grinding may propose a possible solution for machining this material.
　　We have experimentally investigated the grinding characteristics of Nb₃A1, using creep feed grinding and conventional pendulum grinding techniques. The composition of the Nb3Al specimen used in the experiment was: Nb: 94.1 wt%, and A1: 5.9 wt%, and its hardness was 52.3 HRC. The grinding wheels used were HA60F12V, and HA100 F12V.
　　In creep feed grinding, with a cutting depth of 0.125 mm and a table speed of 4 mm/s, the experiment could not be taken to completion because of the very high grinding force and large cracks and, grinding burns were observed on the material surface.
　　With conventional pendulum grinding, no work-piece burns or cracks were observed and there was no excessive load on the machine. With a cutting depth of 6μm and a table speed between 100 mm/s to 200 mm/s, the normal grinding force was 5-3.5 N/mm and the grinding force ratio (normal force/tangential force) was 2. The grinding ratio　(volume of wheel wear/work removal) was very small as 0.7.
　　It was found that Nb₃Al can be successfully machined by applying surface pendulum grinding with a small wheel depth of cut and higher table speed.

Manufacturing Database on World Wide Web
　　Experimental data on welding and machining accumulated at MEL during our research on manufacturing engineering are now available on a World Wide Web database. The database is one of the 26 public RIODBs (Research Information Open Data Base) available at http: //www.aist.go.jp/RIODB/manufacturing
　　The basic software architecture and consists of : man-machine interface, main processor, the welding database itself, a welding knowledge base, programs for doing the calculations, and a set of frequently asked questions (FAQs)
　　A sample menu page shows the objectives of the system and the various menu items. An introductory description of welding methods may be found under : "OUTLINE of Complex Arc Welding", a user guide is to be found under : "How to use this system", and detailed data on welding materials may be found under : "Search for welding data", where materials are selected by clicking with the mouse. Computations of the best welding wire to use and determination of the best welding process is available under : "Consultation of welding conditions" where the materials to be welded are input by the user in response to instructions from the system. The "Information" section shows systems updates and other messages from the server, and "FAQ" will be used to display a list of questions which have been put to MEL by users.
　　The database was made public in Jun.e 1996 and more than 12,000 requests had been successfully processed by the end of the year and users comments have also been collected. Another database on machining will be made available.

fig

Fig.14-1 Basic software architecture.

Fig.14-2 A sample menu page.

Machining
　　Diamond turning of rotationally non-symmetric fine surface figures by means of a fast tool servo
　　A new agile diamond turning system has been developed to generate precision surface figures. The system consists of a fast tool servo driven by a piezoelectric actuator on the tool slide of an ultra precision lathe, and is controlled by a dedicated PC independent of the normal numerical control system for the lathe. By controlling the depth-of-cut at a high update rate using the fast tool servo synchronized to the spindle rotation, the heights at all setpoints along the spiral tool path on the work-piece surface are defined so that arbitrary surface shapes can be generated, within some constraints. The constraints include: setpoint resolution, the angular segmentation and track pitch of the tool path, the nose radius of the tool, and the maximum travel of the fast tool servo. The tech nique is a single self-contained manufacturing process, capable of generating continuous height change and applicable to the machining of large areas-even on curved and inside surfaces.
　　Some machining tests were performed using OFHC and electrodeless-nickel plated aluminum alloy as work-pieces. Control data for the fast tool servo is generated from the surface figure which is defined in several different ways.
　　This technique has potential for application to the manufacture of some non-conventional optical components, precision mechanical components, and boundary layer control surfaces, as well as ornaments.

fig

Fig.15-1 System configuration.

Fig.15-2 Machined sample.

Micro-system configuration
　　Fabrication of three dimensional micro structures composed of ultra-fine particles.
　　Fabrication technology has been developed for the three-dimensional micro structures incorporating several different materials. The technology makes use of excimer laser ablation and an ultra-fine particle Jet Molding System (JMS). As shown in the figure, JMS may be applied to free forming, insert molding, and mask deposition. The technique allows the construction of micro-devices which contain both actuator and sensor materials (PZT) and electrodes (metal) - Examination by SEM, and measurement of the density and electrical properties of the structures showed good pattern transfer fidelity with deposited layers of adequate quality. The deposition rate of the PZT material was much faster than that attainable by other deposition methods, and PZT layers up to 40μm thick were successfully formed with the correct metal electrode structures.

fig

Fig.15-3 Concept of jet molding system.

List of Publications(1996)
Manufacturing Technology

120) M. Hattori, H. Noguchi, S. Ito, T. Suto and H. Inoue, Estimation of Thermal - Deformation in Machine Tools Using Neural Network Technique, J. Mater. Processing Tech. 56 (Jan. 1996), pp. 765～772
121) C. Meizer, M. Hattori and C. Tsutsui, Schleifmodusbeurteilung von Keramik als Beispiel fur Oberflachenmikrogeometrie - Charakterisierung, Vortraege:IX Int. Oberfllachenkolloquium (Jan. 1996), pp. 171～182
122) M. Hattori, H. Inoue and N. Nomura, Design Strategy for Ecologically Conscious Product, Proc. 3rd Int. Seminar on Life Cycle Eng. (Mar.1996), pp. 99～106
123) J. C. Fu, C. A. Troy and K. Mon, Chatter Classification by Entropy Functions and Morphological Processing in Cylindrical Traverse Grinding, Precision Eng. 18-2/3 (Apr. 1996), pp. 110～117
124) H. Takagi, K. Kikuchi, R. Maeda, T. R. Chung and T. Suga, Surface Activated Bonding of Silicon Wafers at Room Temperature, Appl. Phys. Letters (Apr. 1996), p.2222
125) T. Sano and K. Kawai, Activities of the JSTP Committee on Environmental Issues, J. Mater. Processing Tech. 59 (May 1996), pp. 183～185
126) T. Sano, Y. Murakoshi, H. Takagi, T. Homma, H. Takeishi and M. Mayuzumi, Characterization of Diamond-Dispersed Cu-Matrix Composite, Mater. Trans., JIM 37-5 (May 1996), pp. 1132～1137
127) N. Sawai, J. Song and H. Park, Automated Measurement Tool Wear Using an Image Processing System, Int. J. Jpn. Soc. for precision Eng. 30-2 (Jun. 1996), pp. 112～117
128) S. Jones, K. Mori and 0. Ryabov, Cutting Tool Sensor and Requirements for Reducing Process Variation, Proc. Jpn. / USA Symp. on Flexible Automation -1996-2 (Jul. 1996), pp. 991～998
129) Y. Ueno, K. Mori and N. Kasashima, An On-line Diagnostic Method to Predict the Spalling on a Ball Bearing, Proc. Jpn. / USA Symp. on Flexible Automation -1996-1 (Jul. 1996), pp. 449～542
130) K. Mori, N. Kasashima and H. Inoue, Teamworking Environment for Advanced Manufacturing (TEAM) - Conceptual System Design -, Proc. Jpn. / USA Symp. on Flexible Automation -1996-1 (Jul. 1996), pp. 661～664
131) K. Mori, N. Kasashima, T. Yoshioka and Y. Ueno, Prediction of Spalling on a Ball Bearing by Applying the Discrete Wavelet Transform to Vibration Signals, Wear 195 (Jul. 1996), pp. 162～168
132) 0. Ryabov, K. Mori and N. Kasashima, An In-process Direct Monitoring Method for Milling Tool Failures Using a Laser Sensor, Annals of the CIRP 45-1 (Aug. 1996), pp. 97～100
133) C. Lee, T. Itoh, R. Maeda and T. Suga, Micromachined Piezoelectric Force Sensors Based on Sol-gel Derived PZT and PNNZT Thin Films, Microsystem Technologies 96, Potsdam, Germany, (Sep.1996), pp. 357～362
134) C. Lee, T. Itoh, J. Chu, R. Maeda and T. Suga, Micromachined Piezoelectric PZT Force Sensors for Scanning Force Microscope, Proc. of 3rd Int. Symp. of Measurement Technology and Intelligent Instruments (Sep.1996), pp. 328～335
135) I. Goncharenko, K. Mori and N. Kasashima, Strategies to Develop a Telemonitoring Technology for Machine Tools Via the World Wide Web, Proc. 2nd Int. Conf. on the Design of Information Infrastructure Systems for Manufacturing (Sep.1996), pp. 14- 1～12
136) K. Masui, S. Chonan and Z. W. Jiang, Warp Control of a silicon-Wafer Slicer Cutting a Crystal Ingot, Proc. of Third Int. Conf. on Motion & Vibration Control (Sep. 1996), pp. 238～243
137) H. Takagi and R. Maeda, T. R. Chung and T. Suga, Silicon Wafer Direct Bonding at Room Temperature by the Surface Activation Method, Micro System Technologies 96, (Sep. 1996), p.319
138) S. Sugiyama, Y. Zhang, H. Ueno, M. Hosaka, T. Fujimoto, R. Maeda and T. Tanaka, A Compact SR Beam Line for Fabrication of High Aspect Ratio MEMS Micro Parts, Proc. MHS 1996, Nagoya, (Oct. 1996), pp. 79～84
139) K. Hanada, Y. Murakoshi, H. Negishi and T. Sano, Extrusion Processing of Aluminum-lithium/SiCp Composite Produced by Mechanical Milled Powders, Advanced Tech. of Plasticity 1 (Oct. 1996), pp. 255～258
140) T. Shimizu and T. Sano, Development of a 3D Metal Forming Simulator Using a Penalty Method Contact Algorithm and its Connecting with CAD System, Advanced Tech. of Plasticity 1 (Oct. 1996),pp. 385～388
141) S. Suto, M. Takahashi and T. Sano, Effect of Boron Addition on the Bending Properties of Intermetallic Ni₃Al Sheet, Advanced Tech. of Plasticity 2 (Oct. 1996), pp. 603～606
142) M. Takahashi, Y. Murakoshi, T. Sano and S. Fuchizawa, Blanking of an Amorphous Alloy by Ion Implanted P/M High Speed Punch, Advanced Tech. of Plasticity 2 (Oct. 1996), pp. 875～878
143) C. Lee, R. Maeda, T. Itoh and T. Suga, Development of Self-excited Force Sensing Piezoelectric PZT Microcantilevers for Dynamic SFM, Proc. of 3rd France-Japan / 1st Europe-Asia Congress on Mechatronics 1 (Oct. 1996), pp. 285～290
144) R. Maeda, K. Kikuchi, S. Matsumoto and S. Sugiyama, Mask Fabrication for Micro Three Dimensional Structuring by UV Laser and Xray, Proc. of 3rd France-Japan / 1st Europe-Asia Congress on Mechatronics 2 (Oct. 1996), pp. 546～550
145) H. Takagi, R. Maeda, T. R. Chung and T. Suga, Room Temperature Wafer Bonding in a Vacuum for Assembling Micro Parts, Proc. of 3rd France-Japan / 1st Europe-Asia Congress on Mechatronics (Oct. 1996), p.551
146) K. Hanada, Y. Murakoshi, H. Negishi and T. Sano, Microstructures and Mechanical Properties of Al-Li/Sicp Composite Produced by Extrusion Processing, J. Mater. Processing Tech. 63 (Nov.1966), pp.405～410
147) S. Miyazawa, H. Yoshida and Y. Murakoshi, Monitoring of Metal-Powder Diameter by Eddy-Current Sensor, J. Mater. Processing. Tech. 63 (Nov.1996) pp. 303～306
148) S. Ito, T. Yoshikawa, S. Miyazawa and K. Mon, Machinability of Ni₃Al-Based Intermetallic Compounds, J. Mater. Processing Tech. 63 (Nov.1966) pp. 181～186
149) Y. Okazaki, S. Sasaki and R. Murata, Micro-Dynamics of a Slide Mechanism Using Rolling Elements, Proc. ASPE 1996 Annual Meeting 14 (Nov. 1996), pp. 342～345
150) N. Ozawa, S. Kawabe and K. Mizuhara, The Effect of Circular Groove on Flatness Error of Metal Mirror Caused by Chucking Force, Proc. ASPE 1996 Annual Meeting 14 (Nov. 1996), pp. 243～246
151) N. Kasashima, C. Tsutsumi, K. Mori and C. Troy, Grinding Mode Classification of Ground Ceramics using 2-Dimensional Wavelet Transform, Proc. of 1996 IEEE Conf. on Emerging Tech. and Factory Automation 1 (Nov. 1996), pp.70～75
152) T. Shirai, K. Sibata, A. Takahashi, K. Mori, N. Kasashima and Y. Ueno, Method for Detecting Faults in FFUs Using SDP based on Audio Signal Analysis, Proc. of 1996 IEEE Conf. on Emerging Tech. & Factory Automation 1 (Nov. 1996), pp. 243～247
153) S. Sado and A. Iwata, Environmental Load Evaluation of Machinery Production Systems by Production Line Simulation, Proc. 2nd Int. Conf. on EcoBalance (Nov. 1996), pp. 441～446
154) R. Maeda, C. Lee, A. Schroth, T. Itoh and T. Suga, Development of Micromachined Force Sensors and Optical Mirror Actuators Based on Sol-gel Derived Ferroelectric Thin Films, IEDMS'96 Hsinchu Taiwan E4 (Dec. 1996), pp. 319～322
155) C. Lee, T. Itoh, J. Chu, R. Maeda and T. Suga, Microfabricated Piezoelectric Force Sensing PZT Cantilever Array for Multiprobe Scanning Force Microscope, IEDMS'96 Hsinchu Taiwan E4 (Dec. 1996), pp. 323～326

Robotics
Any enquiries regarding this project should be directed to e-mail: robot0@mel.go.jp

　　The aim of robotics research at MEL is to develop advanced robotics technology using knowledge obtained by analyzing the way in which tasks are performed by living beings. Current work includes the engineering implementation of skills found in humans and animals such as dynamic walking and manipulation, micromanipulation, and behavior development by learning. The laboratory also does research on virtual reality, tele-robotics, and human friendly machines. A selection of robotics topics is introduced in more detail below.

Mobile robots with dynamic behavior
　　We have proposed a new method for achieving autonomy in mobile robots. We define robustness to the changing environment (Robust behavior) and various dynamic skills (Skill behavior) in terms of "Dynamic behavior modules", and aim to achieve autonomy in mobile robots by a non-hierarchic combination of these modules. A wheeled inverted pendulum type robot known as the "Variable structure type 4-wheeled robot" has been developed and used in experiments on rapid and smooth step negotiation.^157,174,196) We have recently succeeded in negotiating a step in as little as 2.0 seconds. Work using a biped walking robot "MELTRAN" ¹⁵⁸⁾ (a two-dimensional biped robot which can walk at several speeds and step widths and go up and down stairs), lead to theoretical studies of a three-dimensional biped. First results indicate that even fewer actuators are necessary to attain three-dimensional walking motion than used in the previous research.

fig

Fig.16-1 Step up movement of variable structure type 4-wheeled robot.

　　Non-holonomic robot systems, which have non-linear constraints formulated as non-integrable differential equations containing velocity or acceleration, have received increasing attention in recent years. By utilizing the dynamics of non-holonomic systems, robotic tasks involving more degrees of freedom than the number of control inputs can be realised. We are investigating control of a 3-degree-of-freedom planar manipulator with a passive joint, in which the motion of the free link has a non-holonomic constraint.^165,187) Trajectory planning and feedback stabilization of the manipulator have been successfully achieved by considering the motion of the center of percussion of the free link. We are also studying dynamic manipulation, aiming to control position and orientation of a planar object using a rotating arm with only 1 degree of freedom.

Model free robotics
　　We are developing dynamic robotic systems using the concept of "Model Free Robotics", which is a concept for robust adaptive control of robots with little or no direct sensing of the environment which may have unpredictable but bounded changes.
　　A vibration control system for a crane robot has been developed which uses wave control theory.175) Energy propagating as a wave in a multiple-pendulum system is absorbed using a controller which need not have a precise model of the system. The method has been demonstrated both by numerical simulation and by experiments using a triple-pendulum system.
　　A synchronous motor with 3-dimensional motion has been developed for application to shoulder joints. Only one actuator is necessary to achieve driven motion with three degrees of freedom.¹⁸¹⁾
　　A general framework for supporting skill discovery during the execution of robotic tasks has been developed. We define skill as a time-variable function which generates control information from sensory information so that skills cover dynamics as well as kinematics and statics. We approximated skill functions with polynomial expressions and reduced skill discovery to a combinatorial optimization of the polynomial coefficients. The technique was demonstrated using the visual servo problem of a robot baseball player catching a ball flying in 3D space.
　　A quadruped robot with coordinated leg function known as "MEL - HORSE" has been developed.^177,182) The fore- and rear legs of the robot have different functions in that the forelegs mainly support the body against gravity while the rear legs thrust the body forward. This configuration is effective for dynamic walking.

Integration of locomotion and manipulation
　　Integration of locomotion and manipulation requires that both locomotion and manipulation tasks be considered together during robot design so that the design, mechanics, control, and coordination of legs and arms are integrated together in the final robot.¹⁹¹⁾ The "Integrated Limb Mechanism" is a mechanism which may be used either as a leg or an arm. It usually works as a leg with a large force output for supporting the body of the machine, but sometimes transforms to an arm with faster motion than a leg in upper motion space.^170,190) A second prototype six-legged machine with integrated limb mechanisms and improved mechanical design, known as "MELMANTIS-2" was produced this year.

fig

Fig.17-1 MELMANTIS 2.

Whole arm manipulation
　　The "Whole Arm Manipulation" project aims to realize a mechanical system which has the manipulation capability of human arms. Integration of dexterous motion of the hand with widerange reach of the arm is in progress. A novel cooperative control technique which uses compliance control and force-tactile feedback was proposed and is now under investigaflon.^l6l,l66) In other work, a smart hand-arm mechanism integrated with a multi-processor system has been developed for experimental evaluation.

fig

Fig.17-2 Arm-mounted, four-fingered dexterous hand.

?Micro-manipulation
　　Micro-manipulation technology has potential for application to the assembly of miniature components into complete micro-machines, and in micro-scopic-surgery. A two fingered micro hand has been developed based on parallel mechanisms with six degrees of freedom, arranged in two layers.^189.192) Precise manipulation of micro objects has been achieved using teleoperation control and an auto-focusing microscope.
　　Macro-micro teleoperation is a technology for interfacing between macroscopic operator space and microscopic work space. Bilateral servo control methods have been evaluated with a view to providing macro-micro teleoperation with natural feedback of sensation to the operator.¹⁵⁹⁾ The maneuverability of teleoperation systems has been verified with force and position scaling using a dual-master, dual-slave arm system in which each arm has two degrees of freedom.

Virtual Reality
　　Virtual Reality is an important technology for the human-machine interface. A new Eye Movement Tracking Type Head Mounted Display (EMT-HMD) developed at MEL has a wide viewing angle but can also display high resolution images.188) This is achieved by combining a small, high resolution image displayed in the center of the operator's field of vision with a wide-angle, low resolution image displayed around the periphery. An image-capture system for use in real environments has been constructed and connected with an EMT-HMD. The system has been evaluated experimentally.

Tele-robotics
　　Tele-programming systems are an interesting application of virtual environment technology. In these systems, the discrepancy between the virtual world of the geometrical model and the real world can lead to unexpected awkward states during task execution. To cope with this problem, we define a task model as a network of contact states and robot-commands for the task as state-transition commands. When an error state is detected, a sequence of robot-commands for recovery is automatically generated using the task model network.¹⁸⁵⁾ We implemented this technique on a master-slave remote manipulation system and confirmed its operation using part-mating operations.

Human support technology
　　"Human Friendly Machines" are machines which are physiologically and psychologically "friendly" to human beings. A new type of stair lift for wheelchair users has been developed with the aim of providing a system which is both inexpensive and pracflcal.^169,172,180) The lift uses a "crawl type" mechanism in which there are three main parts : a traction guide, a drive guide, and the lift drive unit. The traction guide is a pair of parallel pipes mounted on the wall of the stairway, and the drive guide is a series of pipes set between the traction guide pipes. The drive unit travels along the traction guide on two rollers and is equipped with a disk driven by an electric motor. Four rollers are attached to the rim of the disk, and engage with the drive guide. The stair lift has many advantages in terms of economy and safety.^l97,l98)

fig

Fig.18-1 Crawl type stair lift (spiral type).

　　People suffering from lower limb paralysis are confined to bed or to a wheelchair, and this often causes problems with physiological stress, urinary dysfunction, and osteoporosis. We are developing an orthotic device to help these people walk, in a project entitled : "Ambulatory Apparatus with Weight Bearing Control". As the person walks, the device raises the sole of each supporting foot in turn using pneumatic actuators, making it easier to swing the other leg and facilitating walking over a level floor.
　　Lifting patients or handicapped people from a bed or the floor is heavy work for care givers. We are developing a power-assisted system for amplifying the input power of the person doing the lifting, and an elementary system with one degree of freedom has been developed using a Chebyshev link for vertical motion. The system provides stable amplification of the input power by 40 times and is suitable for heavy loads.

Human friendly robotics
　　A two-year feasibility study entitled "Friendly Network Robotics" began in April 1996 under the auspices of the Industrial Science and Technology Frontier Program. The project aims to develop technologies for making human friendly robots that can provide services to humans in homes, offices, hospitals etc. The research agenda includes : mechanisms for human friendly robotics, human-robot collaborative control methods, distributed intelligence technologies and - with future advances in communications technology in mind-network tele-robotics technologies. The Department of Robotics has made detailed investigations into the key technology of human friendly network robotics, which is one of the main technologies in network based robotics.

List of Publications(1996)
Robotics

156) K. Tani, Friction Models for a Mobile Machine Using Piezo Vibration, Proc. 4th Int. Workshop on Advanced Motion Control (Mar. 1996), pp. 717～722
157) 0. Matsumoto, S. Kajita and K. Tani, Dynamic Trajectory Control of a Variable Structure Type Four-Wheeled Robot to Pass Over Steps, Proc. 4th Int. Workshop on Advanced Motion Control (Mar. 1996), pp. 253～258
158) S. Kajita and K. Tani, Adaptive Gait Control of a Biped Robot Based on Real-time Sensing of the Ground Profile, Proc. IEEE Int. Conf. on Robotics & Automation (Apr.1996), pp. 570～577
159) H. Tokashiki, P. Akella, K. Kaneko, K. Komoriya and K. Tanie, Macro-Micro Teleoperated Systems with Sensory Integration, Proc. IEEE Int. Conf. on Robotics & Automation (Apr.1996), pp. 1687～1693
160) T. Shibata, K. Ohkawa and K. Tanie. Spontaneous Behavior of Robots for Cooperation-Emotionally Intelligent Robot System, Proc. IEEE Int. Conf. on Robotics & Automation (Apr. 1996), pp. 2426～2431
161) H. Maekawa, K. Tanie and K. Komoriya, Dynamic Grasping Force Control Using Tactile Feedback for Grasp of Multifingered Hand, Proc. IEEE Int. Conf. on Robotics & Automation (Apr. 1996), pp. 2462～2469
162) H. Zhang, K. Tanie and H. Maekawa, Dexterous Manipulation Planning by Grasp Transformation, Proc. IEEE Int. Conf. on Robotics & Automation (Apr. 1996), pp. 3055～3060
163) S. Hirose and H. Takeuchi, Study on Roller-Walk (Basic Characteristics and its Control), Proc. IEEE Int. Conf. on Robotics & Automation (Apr. 1996), pp. 3265～3270
164) H. Zhang, H. Maekawa and K. Tanie, Sensitivity Analysis and Experiments of Curvature Estimation Based on Rolling Contact, Proc. IEEE Int. Conf. on Robotics & Automation (Apr. 1996), pp. 3514～3519
165) H. Arai, Controllability of a 3-DOF Manipulator with a Passive Joint under a Nonholonomic Constraint, Proc. IEEE Int. Conf. on Robotics & Automation (Apr. 1996), pp. 3707～3713
166) H. Maekawa, K. Tanie and K. Komoriya, Tactile Sensor Based Grasp and Manipulation of an Object by a Multifingered Hand, Proc. IEEE Int. Conf. on Robotics & Automation (Apr.1996), Video Proc.
167) 0. Khatib, K. Yokoi, K. Chang, D. Ruspini, R. Holmberg, A. Casal and A. Baader, The Robotic Assistant, 1996 IEEE Robotics & Automation Conf. (Apr. 1996), Video Proc.
168) H. Adachi, N. Koyachi, T. Arai, K. Homma and K. Nishimura, Development of a Mobile Manipulator for Underground Excavation Task, Proc. 13th Int. Symp. on Automation & Robotics in Construction (Jun. 1996), pp.73～80
169) S. Hashino, Development of New Type Stair Lift for Wheelchair Users, Proc. Int. Symp. on Intelligent Robotics Systems (Jun. 1996), pp. 561～566
170) N. Koyachi, T. Arai, H. Adachi and A. Murakami, Mechanical Design of a Hexapod with Integrated Limb Mechanism: MELMANTIS, Proc. ASME-ISCIE Jpn.-U.S.A. Symp. On Flexible Automation (Jul. 1996), pp. 139～144
171) T. Arai, T. Tanikawa, J. P. Merlet and T. Sendai, Development of a New Parallel Manipulator with Fixed Linear Actuator, Proc. ASME-ISCIE Jpn.-US.A. Symp. On Flexible Automation (Jul. 1996), pp. 145～149
172) S. Hashino, Development of New Type Stair Lift for Wheelchair Users, Proc. ASME-ISCIE Jpn.- U.S.A Symp. on Flexible Automation (Jul. 1996), pp. 233～236
173) T. Yano, M. Murakami, T. Suwa and T. Yamamoto, Development of a Self-contained Scanning Type Suction Cups for the Self-contained Wall Climbing Robot, Proc. lASTED Int. Conf. on Robotics & Manufacturing (Aug. 1996), pp. 297～299
174) 0. Matsumoto, S. Kajita, K. Tani and K. Igura, Fast Passing Over Steps by a Variable Structure Type Four-wheeled Robot Considering the Collision in Landing, Proc. Second ECPD Int. Conf. on Advance Robotics, Intelligent Automation & Active Systems (Sep. 1996), pp. 356～361
175) M. Saigoh, N. Tanaka, A. Koumura and K. Tani, An Approach to Vibration Control of Multiple-Pendulum System by Wave Absorption, Proc. Third Int. Conf. MOVIC 3 (Sep. 1996), pp. 262～267
176) 0. Khatib, K. Yokoi, K. Chang, D. Ruspini, R. Holmberg, A. Casal and A. Baader, Force Strategies for Cooperative Tasks in Multiple Mobile Manipulation Systems, Robotic Research 7 (Sep. 1996), pp. 333～342
177) H. Takeuchi and K. Tani, Development of "MEL HORSE", Proc. Second ECPD Int. Conf. on Advanced Robotics, Intelligent Automation and Active Systems (Sep.1996), pp. 288～293
178) T. Yano, K. Suwa, K. Sakurada and M. Murakami, Development of a Wall Climbing Robot II with Scanning Type Suction Cups, Proc. Second ECPD Int. Conf. on Advanced Robotics, Intelligent Automation and Active Systems (Sep.1996), pp. 368～373
179) K. Homma, Feasibility Study of the Walking Wheelchair Concept, HUT Department of Machine Design Publication Series C nr. 282 (Oct. 1996), p.34
180) S. Hashino, Development of Crawl Type Stair Lift for Wheelchair Users, Proc. Int. Advanced Robotics Programme, Int. Workshop on Medical Robots (Oct. 1996), pp. 47～54
181) T. Yano, M. Kaneko and M. Sonoda, Position Control of a Developed Synchronous Motor with Three Degree of Freedom, Proc. 3rd Fr. -Jpn. Congress & 1st Europe-Asia Cong. on Mechatronics 2 (Oct. 1996) pp. 127～132
182) H. Takeuchi, Development of Leg-Functions Coordinated Robot "MEL HORSE", Proc. 3rd Fr. -Jpn. Congress & 1st Europe-Asia Congress on Mechatronics 2 (Oct. 1996), pp. 348～353
183) A. Agah and K. Tanie, Interactive Human-Robot Pole Balancing Utilizing Multiple Virtual Fuzzy Agents, Distributed Autonomous Robotic Systems 2 (H. Asama, T. Fukuda, T Arai and I. Endo eds.), Springer- Verlag Tokyo, (Oct. 1996), pp. 326～336
184) 0. Khatib, K. Yokoi, K. Chang, D. Ruspini, R. Holmberg and A. Casal, Decentralized Cooperation of Multiple Mobile Manipulators, Proc. 5th IEEE Int. Workshop on Robot & Human Communication (Nov. 1996), pp. 183～188
185) Y. J. Cho, T. Kotoku, K. Komoriya and K. Tanie, A Discrete Event Approach to the Automatic Command Generation in a Teleprogramming System, Proc. 5th IEEE Int. Workshop on Robot & Human Communication (Nov. 1996), pp. 238～243
186) A. Agah and K. Tanie, Human-Machine Interaction Through an Intelligent User Interface Based on Contention Architecture, Proc. 5th IEEE Int. Workshop on Robot & Human Communication (Nov. 1996), pp. 537～542
187) H. Arai, Position Control of a 3-DOF Manipulator with a Passive Joint under a Nonholonomic Constraint, Proc. IEEE/RSJ Int. Conf. on Intelligent, Robots & Systems (Nov. 1996), pp. 74～80
188) K. Iwamoto and K. Tanie, Bionocular Head Mounted Display with Eye Movement Tracking Function : Development of the Prototype and Its Application, Proc. IEEE/RSJ Int. Conf. on Intelligent Robots & Systems (Nov. 1996), pp. 354～359
189) T. Tanikawa, T. Arai and T. Masuda, Development of Micro Manipulation System with Two-Finger Micro Hand, Proc. IEEE/RSJ int. Conf. on Intelligent Robots & Systems (Nov. 1996), pp. 850～855
190) N. Koyachi, T. Arai, H. Adachi and A. Murakami, Design and Control of Hexapod with Integrated Limb Mechanism : MELMANTIS, Proc. IEEE/RSJ Int. Conf. on Intelligent Robots & Systems (Nov. 1996), pp. 877～882
191) T. Arai, Robots with Integrated Locomotion and Manipulation and Their Future, Proc. IEEE/RSJ Int. Conf. on Intelligent Robots & Systems (Nov. 1996), pp. 541～545
192) T. Arai, J. Herve and T. Tanikawa, Development of 3 DOF Micro Finger, Proc. IEEE/RSJ Int. Conf. on Intelligent Robots & Systems (Nov. 1996), pp. 981～987
193) 0. Khatib, K. Yokoi, K. Chang, D. Ruspini, R. Holmberg and A. Casal, Vehicle/Arm Coordination and Multiple Mobile Manipulator Decentralized Cooperation, Proc. IEEE/RSJ Int. Conf. on Intelligent Robots & Systems (Nov. 1996), pp. 546～553
194) H. Adachi, N. Koyachi, T. Arai and K. Nishimura, Control of a Manipulator Mounted on a Quadruped, Proc. IEEE/RSJ Int. Conf. on Intelligent Robots & Systems (Nov. 1996), pp. 883～888
195) 0. Khatib, K. Yokoi, K. Chang, D. Ruspini, R. Holmberg and A. Casal, Coordination and Decentralized Cooperation of Multiple Mobile Manipulator, J. Robotic Systems 13-11 (Nov. 1996), pp. 755～764
196) N. Shiroma, 0. Matsumoto, S. Kajita and K. Tani, Cooperative Behavior of a Wheeled Inverted Pendulum for Object Transportation, Proc. IEEE/RSJ Int. Conf. on Intelligent Robots & Systems (Nov. 1996) pp. 396～401
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