Yasuhiro Ohyama

Tokyo University of Technology, Edo, Tōkyō, Japan

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Publications (79)22.2 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: This paper describes a structure and soft finger model of digital hand for real-time dexterous manipulation. From investigations of human dexterous manipulation by using high speed camera, the structure and skin conditions of digital hand are defined. To evaluate our model, bar spinning as dexterous manipulation is adopted. Comparing manipulations with human hand and digital hand, we discuss its effectiveness and problems of our model.
    03/2014;
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    ABSTRACT: This research proposes an effective vertical clustering strategy of 3D data in an elliptical helical shape based on 2D geometry. The clustering object is an elliptical cross-sectioned metal pipe which is been bended in to an elliptical helical shape which is used in wearable muscle support designing for welfare industry. The aim of this proposed method is to maximize the vertical clustering (vertical partitioning) ability of surface data in order to run the product evaluation process addressed in research [2]. The experiment results prove that the proposed method outperforms the existing threshold no of clusters that preserves the vertical shape than applying the conventional 3D data. This research also proposes a new product testing strategy that provides the flexibility in computer aided testing by not restricting the sequence depending measurements which apply weight on measuring process. The clustering algorithms used for the experiments in this research are self-organizing map (SOM) and K-medoids.
    02/2014;
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    ABSTRACT: This research proposes a computation approach to address the evaluation of end product machining accuracy in elliptical surfaced helical pipe bending using 6dof parallel manipulator as a pipe bender. The target end product is wearable metal muscle supporters used in build-to-order welfare product manufacturing. This paper proposes a product testing model that mainly corrects the surface direction estimation errors of existing least squares ellipse fittings, followed by arc length and central angle evaluations. This post-machining modelling requires combination of reverse rotations and translations to a specific location before accuracy evaluation takes place, i.e. the reverse comparing to pre-machining product modelling. This specific location not only allows us to compute surface direction but also the amount of excessive surface twisting as a rotation angle about a specified axis, i.e. quantification of surface torsion. At first we experimented three ellipse fitting methods such as, two least-squares fitting methods with Bookstein constraint and Trace constraint, and one non- linear least squares method using Gauss-Newton algorithm. From fitting results, we found that using Trace constraint is more reliable and designed a correction filter for surface torsion observation. Finally we apply 2D total least squares line fitting method with a rectification filter for surface direction detection.
    02/2014;
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    ABSTRACT: We propose affective image classification on dimensional affective groups against conventional discrete affective groups which does not cover all three emotional vectors. This approach serves as affective group identification phase of a full emotion estimation model from affective pictures. The known emotional vector values Valence, Arousal and Dominance of IAPS photo set for all subjects are categorized into nine affective groups using few well known clustering algorithms and the clusters are evaluated by using photo description. The texture and histogram based graphical features of photographs without borders within the SOM based affective groups are evaluated by using the pattern recognition tools of neural network to identify the affective groups where the inputs originated. The test results proved that the gray scale is suitable for high valence or high arousal groups, edges and corners are suitable for high valence groups and blue histogram is useful in high arousal groups. Single or logical combination of these trained networks can be used for affective group recognition in high arousal or valence group. High dominance groups are under development.
    03/2013;
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    ABSTRACT: In this research, a classification method for human touching behaviors to haptic therapy robot is proposed. It is difficult to apply explicit discrete representation for human touch behaviors such as “slap”, “pat” due to the existence of intermediate touch behavioral patterns. Therefore a new classification approach for human touch behaviors using Self Organizing Map (SOM) is proposed, using its ability to classify the nearby data in to a group. Further in this research the axis of out put maps are defined to be meaningful by specifying the initial placement of the input data during the training process.
    Industrial Electronics Society, IECON 2013 - 39th Annual Conference of the IEEE; 01/2013
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    ABSTRACT: This paper describes dexterous manipulation of the digital hand we have developed, whose structure is based on human hand. The purpose of the development is to investigate good shape design for anyone to make use of it easily, the technology transfer in man hand and the novel operation of robot hand. To do this, it is necessary to examine the force distribution generating on a contact point between hand and object. We have developed the estimation systems; one is the dynamics simulation space that has the collision calculation function. The other is the shape inspection of hand with a high-speed camera which is able to record the dexterous hand motion. As a dexterous manipulation, bar spinnings by the digital hand are examined.
    08/2012;
  • Jinhua She, Xin Xin, Yasuhiro Ohyama
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    ABSTRACT: This paper explains how to use an arm robot experiment system to teach sampled-data H∞ control theory. A design procedure is presented for a digital tracking control system for a continuous plant with structured uncertainties; the target is the positioning control of an arm robot. To guarantee the robust stability of the closed-loop system and provide the desired closed-loop performance, the design problem is first formulated as a sampled-data H∞ control problem, and is then transformed into an equivalent discrete-time H∞ control problem. Finally, linear matrix inequalities are used to obtain a reduced-order output-feedback controller and a static state-feedback controller. In a course, the design procedure is explained and practice is provided through simulations and experiments. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.
    IEEJ Transactions on Electrical and Electronic Engineering 11/2011; 6(6). · 0.34 Impact Factor
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    ABSTRACT: This paper considers the degree of freedom (DoF) in the modeling of the hand. Human hand dexterously manipulates objects. When the hand model in computer application will be developed, It is necessary to think about approximate DoF for the real DoF of the joint of hand mechanism. Especially, the approximated DoF is evaluated from a view of dexterously manipulation of human hand. We have developed a hand model which is used for design tool of the industrial production. It is evaluated on the approximate DoF from a view of dexterously manipulation.
    SICE Annual Conference (SICE), 2011 Proceedings of; 01/2011
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    ABSTRACT: This research focuses on the electric wheelchair controlled by Human Body Motion Interface (HBMI). HBMI uses the body motion which is caused by the voluntary motion. From our previous research, it has been confirmed that HBMI, which uses the center of weight on the pressure sensor attached on the backrest has the ability of an interface. However the problem has also remained. The velocities of each wheel have determined based on the error between initial and current position of center of weight. The error increases in the proportion to the inclination of the body. In some cases, the error doesn't increase due to the contact condition between body and backrest, even if the user leans own body. In this case, therefore, the user cannot control the wheelchair arbitrarily in spite of leaning his/her body. This paper shows the improvement to control wheelchair regardless of the amplitude of the error. I. INTRODUCTION
    01/2011;
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    ABSTRACT: This paper presents a force distribution measure­ ment system to investigate dexterous manipulation of hand. The purpose of this measurement is to find good shape designs not away from the hand easily when the object is dexterously manipulated by hand. To do this, it is necessary to examine the force distribution generating on a contact point between the hand and the object. We have developed the measurement systems; one is the dynamics simulation space that has the collision calculation function. The other is the shape inspection of hand with a high­ speed camera (2000fps) which is able to record the dexterous hand motion. It is used to evaluate hand manipulation, then the force distribution in the real manipulation is estimated. From the consideration, the simulation that realize the real manipulation is shown and disucussed. Index Terms-dexterous manipulation, hand model, dynamics space, force distribution, data glove
    01/2011;
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    ABSTRACT: This paper presents development of an evaluation system for easiness of manipulation of product shapes to design better product shapes. In developing the evaluation system, we concentrate mainly on manipulation which involves handling state such that even when the product is rotating it remains near the hand. The evaluation system consists of a glove type hand posture measuring instrument and physics simulation software environment in which a hand model moves in accordance with the pose of the hand wearing the glove. Observation of hand manipulation is also performed with a high-speed camera to analyze the motion and improve the evaluation system.
    01/2011;
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    ABSTRACT: This research focuses on the electric wheelchair controlled by Human Body Motion Interface (HBMI). HBMI uses the body motion which is caused by the voluntary motion. From our previous research, it has been confirmed that HBMI, which uses the center of weight on the pressure sensor attached on the backrest, has the ability of an interface. However the problem has also remained. The velocities of each wheel have determined based on the error between initial and current position of center of weight. When user tries to stop the wheelchair, user has to rigorously return the center of weight to the initial position. Therefore, if a slight error remains on the center of weight, the wheelchair is not able to stop exactly. This paper absorbs ambiguous human motion, and proposes the control scheme to prevent miss operation of wheelchair caused by slight variation of the center of weight.
    01/2011;
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    ABSTRACT: This paper describes an approach to estimate human hand posture using 3-dimensional range data. The approach employs an approximation of the human hand with a plane in the 3-dimensional space. While this approximation is not so precise for detail reconstruction of the hand shape, it is intended for tracking of the human hand in applications such as virtual reality applications, in which relatively low precision is acceptable.
    01/2011;
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    ABSTRACT: In this paper, a finger pose estimation method is presented. A direct use of fingers is useful in some applications which require handling of 3D position information. Our finger pose estimation method exploits anatomical constraints on finger motion and ring-shaped markers to achieve simple and practical measurements applicable to daily life situations. The use of anatomical constraints ensures that no exact placement of the markers is required.
    SICE Journal of Control, Measurement, and System Integration. 01/2011; 2(6):357-364.
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    ABSTRACT: Product design is an important process in industry whereas it has been usually performed based on aesthetics and static strength rather than on dynamical features of the product in use, or more specifically, in grasping. In this paper, dynamical analysis of grasping is to be discussed. Because it is difficult to deal with an actual hand dynamically interacting with an object, a hand model in dynamical simulation environment is used for the analysis. The hand model moves corresponding to a hand wearing a data glove. In the simulation, contact force vectors are calculated for each contact point between the hand model and the object to be grasped.
    SICE Annual Conference 2010, Proceedings of; 09/2010
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    ABSTRACT: This paper classified the body motion which is not distinguished when an electric wheelchair is operated by Human Body Motion Interface (HBMI). HBMI uses the body motion which is caused by the voluntary motion. This research focuses on the operation of an electric wheelchair as a practical application of HBMI. It has been confirmed that HBMI, which uses the center of weight on the pressure sensor attached on the backrest as the body motion index, has the ability of an interface. However the problem has also remained. The system cannot distinguish different body motion when the center of weight is the same position even if the subject takes the different body motion, because the pressure data converge on the one position which is the center of weight. We call such motion, whose center of weight is the same, “Confused motion”. The objective of this paper is to solve “Confused motion”. In this paper we classified “Confused motion” by using Self-Organizing Map (SOM). The result showed “Confused Motion” had been solved.
    Human System Interactions (HSI), 2010 3rd Conference on; 06/2010
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    ABSTRACT: This research studies the possibility of an intuitive interface for an electric wheelchair by using human body except hands. For this purpose, we focused on the human body motion which has relation to actions or behaviors. This motion comes from the human stabilization function for holding expectable collapsing caused by voluntary motion. Thus this motion is considered as one of the characteristics of human motions, and is linked to the intentions. Therefore, by applying this human body motion to the interface of an electric wheelchair, it is possible to operate the wheelchair without any complex motions or conscious motion. We call this interface as HBMI (Human Body Motion Interface). In this paper, We introduce the prototype by using HBMI, and show a classification of human body motion by using Self-Organizing Map (SOM).
    01/2010;
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    ABSTRACT: This paper describes evaluation of grasping-easiness from perspective of dynamics with hand model. Evaluation of grasping-easiness, which is degree of easiness to grasp an object, is an important factor because it is useful to design better industrial products. We have developed a system for evaluation of grasping-easiness, which consists of the dynamics simulation space and the data glove. This system and grasping-easiness will be discussed through experiments.
    01/2010;
  • [Show abstract] [Hide abstract]
    ABSTRACT: This research focuses on the electric wheelchair controlled by Human Body Motion Interface (HBMI). HBMI uses the body motion which is caused by the voluntary motion. From our previous research, it has been confirmed that HBMI, which uses the center of weight on the pressure sensor attached on the backrest, has the ability of an interface. However the problem has also remained. The velocities of each wheel have determined based on the error between initial and current position of center of weight. When user tries to stop the wheelchair, user has to rigorously return the center of weight to the initial position. Therefore, if a slight error remains, the wheelchair is not able to stop exactly. This paper estimates the stop intention from pressure distribution, and absorbs ambiguous human motion, and proposes the method to prevent miss operation of wheelchair caused by slight variation of the center of weight.
    01/2010;
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    ABSTRACT: This paper presents image-based finger pose measurement for hand user interface. The aim of this measurement technique is to make a better user interface enabling three dimensional operation by hand. The measurement technique uses stereo vision, and approximates the hand motion based on anatomical constraints. Distinctive feature of the measurement technique is usage of ring markers, which enable to determine the position and direction of the finger link where the marker put on. The appropriateness of the measurement technique is evaluated through experiments.
    01/2010;

Publication Stats

150 Citations
22.20 Total Impact Points

Institutions

  • 1–2011
    • Tokyo University of Technology
      • • School of Computer Science
      • • School of Bionics
      Edo, Tōkyō, Japan
  • 2010
    • Setsunan University
      Ōsaka, Ōsaka, Japan
  • 2008–2009
    • Tokyo Institute of Technology
      Edo, Tōkyō, Japan
    • Central South University
      Ch’ang-sha-shih, Hunan, China