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IEEE International Workshop on robotics in Alpe-Adria-Danube Region (RAAD)

作者： J.K. Tar I.J. Rudas J.F. Bitó K.R. Kozłowski C. Pozna John von Neumann Faculty of Informatics buda University Budapest Hungary Chair of Control and Systems Engineering Poznan University of Technology Poznan Poland Design and Robotics Department University Transilvania of Brasov Brasov Romania

The “Model Reference Adaptive Control (MRAC)” is a popular approach from the early nineties to our days. Its basic idea is the application of proper feedback that makes the behavior of the controlled system identical to that of the “reference model” that normally is simple enough to control. The idea has many particular variants with the common feature that they are designed by the use of Lyapunov's 2 nd (“direct”) method that normally applies a quadratic Lyapunov function constructed of the tracking error and further additional terms. Though this approach normally guarantees global asymptotic stability, its use can entail complicated tuning that may have disadvantages whenever very fast applications are needed. In this paper an alternative problem tackling, the application of “Robust Fixed Point Transformations (RFPT)” in the MRAC technique is recommended. This approach applies strongly saturated, multiplicative nonlinear terms causing a kind of “deformation” of the input of the available imprecise system model. Instead parameter tuning that is typical in the traditional MRAC it operates with a simple convergence guaranteed only within a local basin of attraction. This technique can well compensate the simultaneous consequences of modeling errors and external disturbances that normally can “fob” the more traditional, tuning based approaches. As a potential application paradigm the novel MRAC control of a “cart - beam - hamper” system is considered. The conclusions of the paper are illustrated by simulation results.

关键词： Adaptive control MIMO Lyapunov method Motion control Programmable control Intelligent robots systems engineering and theory Control systems Control system synthesis Asymptotic stability

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Learning compliance control of robot manipulators in contact with the unknown environment

Learning compliance control of robot manipulators in contact...

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IEEE International Conference on Automation Science and engineering (CASE)

作者： Yanan Li Chenguang Yang Shuzhi Sam Ge Social Robotics Laboratory Interactive Digital Media Institute and NUS Graduate School of Integrative Sciences and Engineering National University of Singapore Singapore Department of Bioengineering Imperial College London London UK Institute of Intelligent Systems University of Electronic Science and Technology Chengdu China

ISBN: (纸本)9781424454471

In this paper, a control mechanism is presented to improve the compliance performance of the robot manipulator when it is in contact with the unknown environment. This mechanism guarantees that the dynamics of the whole system follows a target impedance model so that the desired compliance performance is obtained. In particular, under the assumption that the dynamics is periodic, a learning law is developed to estimate the unknown dynamics parameters. Besides, the proposed systematic learning control does not require the accurate force measurement. Its performance and robustness are discussed in details by the rigorous analysis. At last, the validity of the proposed method is verified by simulation.

关键词： Impedance Manipulator dynamics Force Control design Force measurement

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Spread spectrum for compressed sensing techniques in magnetic resonance imaging

Spread spectrum for compressed sensing techniques in magneti...

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IEEE International Symposium on Biomedical Imaging

作者： Y. Wiaux G. Puy R. Gruetter J.-Ph. Thiran D. Van De Ville P. Vandergheynst Department of Radiology and Medical Informatics University of Geneva Geneva Switzerland Institute of Electrical Engineering Ecole Polytechnique Fédérale de Lausanne Lausanne Switzerland Ecole Polytechnique Federale de Lausanne Lausanne VD CH Institute of the Physics of Biological Systems Ecole Polytechnique Fédérale de Lausanne Lausanne Switzerland Institute of Bioengineering Ecole Polytechnique Fédérale de Lausanne Lausanne Switzerland

ISBN: (纸本)9781424441259

Magnetic resonance imaging (MRI) probes signals through Fourier measurements. Accelerating the acquisition process is of major interest for various MRI applications. The recent theory of compressed sensing shows that sparse or compressible signals may be reconstructed from a small number of random measurements in a sensing basis incoherent with the sparsity basis. In this context, we advocate the use of a chirp modulation of MRI signals prior to probing an incomplete Fourier coverage, in the perspective of accelerating the acquisition process relative to a standard setting with complete coverage. We analyze the spread spectrum phenomenon related to the modulation and we prove its effectiveness in enhancing the overall quality of image reconstruction. We also study its impact at each scale of decomposition in a wavelet sparsity basis. Our preliminary results rely both on theoretical considerations related to the mutual coherence between the sparsity and sensing bases, as well as on numerical simulations from synthetic signals.

关键词： Spread spectrum communication Compressed sensing Magnetic resonance imaging Acceleration Image reconstruction Chirp modulation Probes Signal processing Image analysis Coherence

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Force field compensation can be learned without proprioceptive error

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World Congress on Medical Physics and Biomedical engineering: Neuroengineering, Neural systems, Rehabilitation and Prosthetics

作者： Melendez-Calderon, A. Masia, L. Casadio, M. Burdet, E. Department of Bioengineering Imperial College London United Kingdom Robotics Brain and Cognitive Sciences Italian Institute of Technology Italy Department of Informatics Systems and Telematics University of Genova Italy

ISBN: (纸本)9783642038884

Robotic devices able to train both reaching and manipulation, involving multiple degrees-of-freedom (DOF), are often large and complex. Could mechanically simpler devices be used to train people, by using only visual feedback and constraining the limb in one or more of the degrees of freedom during task performance? This study examines how this motion guidance influences motor learning in healthy subjects, when virtual kinematic error is provided as visual feedback. The results demonstrate that i) virtual learning is possible, though the learning pattern are slightly different than in learning with full proprioception error, and ii) the inverse model learned is similar in the two conditions. © 2009 Springer-Verlag.

关键词： Degrees of freedom (mechanics)

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Robotic wheelchair trajectory control considering user comfort

Robotic wheelchair trajectory control considering user comfo...

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5th International Conference on informatics in Control Automation and robotics, ICINCO 2008

作者： Solea, Razvan Nunes, Urbano Department of Electrical and Computer Engineering ISR - Institute of Systems and Robotics University of Coimbra Coimbra 3030-290 Portugal Department of Automation and Industrial Informatics Dunarea de Jos University of Galati Galati 800-008 Romania

ISBN: (纸本)9783642002700

This paper analyzes the comfort of wheelchair users when a sliding-mode trajectory-tracking controller is used. The transmission of the horizontal (fore-and-aft) vibration to the head-neck complex (HNC) in the seated human body may cause unacceptable discomfort and motion sickness. A double-inverted pendulum model with two degrees of freedom is considered as a model for the HNC. The user comfort is examined not only in the time domain (using the fourth power vibration dose value), but also in the frequency domain (using the cross-spectral density method). For measuring the acceleration of the wheelchair, along the trajectory, an inertial measurement unit was used. © 2009 Springer-Verlag Berlin Heidelberg.

关键词： Degrees of freedom (mechanics)

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On-chip fabrication and assembly of rotational microstructures

On-chip fabrication and assembly of rotational microstructur...

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2009 IEEE/RSJ International Conference on Intelligent Robots and systems

作者： Masaki Ito Masahiro Nakajima Hisataka Maruyama Toshio Fukuda Department of Micro Nano Systems Engineering University of Nagoya Nagoya Japan Department of Bioengineering and Robotics University of Tohoku Sendai Miyagi Japan

The microstructures are expected to be used as the components of on-chip single cell analysis system such as cell manipulation and measurement tools. In this paper, we propose the on-chip fabrication method of microstructures with minimum dimensions of 5 ¿m. The micro objects with arbitrary shape are fabricated by illumination of patterned UV-ray through the mask. The arbitrary shape objects are made of the photo-crosslinkable resin on the microchip under a microscope. The polymerized micro-objects, which we call as ¿Microtools¿, can be used for the single cell analysis. The microtools are fabricated at the desired place on the microchip in less than 1 second. Additionally, the microtools are manipulated by optical tweezers. By high-speed scanning of a single laser with galvanometer mirror, it is able to manipulate multiple points simultaneously. Using this technique, the rotational microstructure composed of the rotation axis and the microgear is assembled and rotated. We propose the two method of microstructure assembly. The assembled rotational microstructure is evaluated about the rotation speed depending on the laser power.

关键词： Fabrication Assembly Microstructure Shape System-on-a-chip Lighting Resins Microscopy Polymers High speed optical techniques

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Development of biodegradable scaffolds by leaching self-assembled magnetic sugar particles

Development of biodegradable scaffolds by leaching self-asse...

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20th Anniversary MHS 2009 and Micro-Nano Global COE - 2009 International Symposium on Micro-NanoMechatronics and Human Science

作者： Takamatsu, Ryo Oura, Hiroyuki Uchida, Tomoyuki Ikeda, Seiichi Ami, Fumihito Negoro, Makoto Hayakawa, Motoharu Takahashi, Ikuo Fukuda, Toshio Department of Micro-Nano Systems Engineering Nagoya University Nagoya 464-8603 Japan Department of Bioengineering and Robotics Tohoku University Sendai 980-8579 Japan Department of Neurological Surgery Fujita Health University Toyoake Aichi 470-1192 Japan Department of Neurological Surgery Anjo Kosei Hospital Anjo Aichi 446-8602 Japan

ISBN: (纸本)9781424450954

Technologies to develop scaffolds with controlled diameter and high porosity have great significance in tissue engineer ing. We have fabricated biodegradable 2D and 3D scaffol ds with ordered array of pores by casting polymer on self -assembled d-fructose (sugar) microspheres. First, ferrite mi croparticles were encapsulated in sugar spheres to make th em become magnetized. After sieving magnetic sugar partic les, those diameter-controlled particles were attracted by a magnet to form a self-assembled template for polymer cas ting. After removal of sugar particles, ordered array of po res were generated on the surface of sheet-like scaffolds. O rdered pores are also generated in 3D tubular scaffolds by using magnetic force and viscoelasticity of PVA solution. It was confirmed that MSPs leaching method makes it pos sible to make high porous scaffolds in spite of the thicknes s of scaffold and the porosity is homogeneous. Finally, the biocompatibility of the developed scaffold was confirmed by the viability of human umbilical vein endothelial cells. ©2009 IEEE.

关键词： Biocompatibility

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Experimental study on manipulator design for low collision impact force

Experimental study on manipulator design for low collision i...

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IEEE/ASME (AIM) International Conference on Advanced Intelligent Mechatronics

作者： Yusuke Sugahara Keigo Noha Kazuhiro Kosuge Jun'ichiro Ooga Hideichi Nakamoto Takashi Yoshimi Department of Bioengineering and Robotics University of Tohoku Sendai Japan Department of Bioengineering and Robotics University of Tohoku Japan Mechanical Systems Laboratory Corporate Research & Development Center Toshiba Corporation Kawasaki Japan Department of Electrical Engineering Shibaura Institute of Technology Tokyo Japan

This paper experimentally studies how the mechanism and system design of a manipulator affect the impact force when the manipulator collides with its environment. Although considerable safety-related research has been conducted, there has been no research comparing tendon-driven and direct-driven mechanisms. In this paper, from the perspective of impact force and impulse, two types of driving mechanisms are experimentally compared; a tendon-driven mechanism and a direct-driven mechanism. Also the effect of the absorber and the collision detection system are experimentally investigated. Finally, based on the knowledge obtained above, a single system design method of the manipulator to reduce the collision impact force is proposed and experimentally evaluated.

关键词： Humans Actuators Manipulators Safety Service robots Orbital robotics Robot sensing systems Gears Hardware Force control

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Novel image analysis for trajectory of microtubules gliding on kinesins with Tip detection

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Journal of Biomechanical Science and engineering 2009年第3期4卷 404-414页

作者： Sugita, Shukei Sakamoto, Naoya Ohashi, Toshiro Sato, Masaaki Department of Biomedical Engineering Graduate School of Biomedical Engineering Tohoku University 6-6-01 Aramaki-aza-Aoba Aoba Sendai 980-8579 Japan VCAD System Research Program RIKEN 2-1 Hirosawa Wako 351-0198 Japan Department of Bioengineering and Robotics Graduate School of Engineering Tohoku University 6-6-01 Aramaki-aza-Aoba Aoba Sendai 980-8579 Japan Division of Human Mechanical Systems and Design Graduate School of Engineering Hokkaido University N13 W8 Kita Sapporo 060-8628 Japan

Control of the gliding directions of kinesin-driven microtubules (MTs) in vitro has good feasibility for the development of nano-scale transport systems. A requirement for the control of transporters in these systems includes detecting the positions of gliding MTs;however, no studies have reported on the monitoring of the positions of gliding MTs. Here, we suggest an algorithm to detect tip coordinates of gliding MTs by binarization, skeletonization, and filtration of fluorescent images of MTs. The algorithm was first applied to artificially drawn segments with given lengths (10-80 pixels), widths (1-10 pixels), and curvature radii (20-120 pixels) to verify the effect of the sizes of MTs on accuracy of tip coordinates extracted by the algorithm, and error was estimated by referring to the true coordinates. The estimated errors were as small as 2 pixels in the width and were not affected by the length and the curvature radius, indicating that our algorithm is useful to extract the tips of MTs. The algorithm was subsequently applied to images of gliding MTs. Since distances from the trajectories of the MTs to the centers of gravity of the MTs (3.7 ± 2.1 pixels) were significantly larger than those to the tips (1.9 ± 0.5 pixels), the use of the tips as representative points of gliding MTs was verified. A detection method using tips of MTs, as suggested in this study, may be a useful technique for monitoring each MT in nanoscale transport systems.

关键词： Pixels

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Self-help standing-up method based on quasi-static motion

Self-help standing-up method based on quasi-static motion

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IEEE International Conference on robotics and Biomimetics

作者： Takuro Hatsukari Shiho Kuroko Norihisa Miyake Jun'ichi Higuchi Ryushiro Kawazoe Yasuhisa Hirata Kazuhiro Kosuge Department of Development and Engineering Paramount Bed Company Limited Koutou Tokyo Japan Kumamoto Accessible Housing Institute Kumamoto Japan IT Systems Laboratories Fujitsu Laboratories Limited Nakahara Japan Department of Bioengineering and Robotics University of Tohoku Sendai Japan

When supporting standing-up motion, a caregiver takes advantage of gravity force to make sufficient momentum without bearing heavy burden. The physical abilities or decision-making abilities decrease for many of elderly people who need care. We propose a self-help standing-up method for such people. The method with quasi-static motion in which the acceleration is approximated to zero, so as to keep safety at the time of emergency, is preferable. However, the quasi-static motion gives heavy burden to a caregiver because it cannot make efficient use of inertia force by the help of gravity force. Compared to human assist, mechanical system can easily realize the quasi-static motion, since a mechanical system has an ability to hold a large force. However, a quasi-static motion trajectory has to be newly-developed because it is not well known. Therefore, we propose the mechanical system and a quasi-static method for supporting standing-up motion. As an example, the method using artificial upper body constraint, and fitted to physical characteristics of each patient have been proposed. This system is found to be the effectiveness.

关键词： Senior citizens Humans Insurance Costs Gravity Mechanical systems Laboratories Safety Accidents Robots

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