Journal of Robotics and Mechatronics
Online ISSN : 1883-8049
Print ISSN : 0915-3942
ISSN-L : 0915-3942
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Regular Papers
  • Hitoshi Kino, Akihiro Kiyota, Takumi Inadomi, Tomonori Kato, Hiroyuki ...
    Type: Paper
    2019 Volume 31 Issue 5 Pages 647-656
    Published: October 20, 2019
    Released: October 20, 2019
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    In this study, we focus on a soft anisotropic gel actuator hybridized with nanosheet liquid crystal. This gel actuator is highly hydrophilic and can be operated underwater. Gel actuators can contract when heated and expand back to their original size when cooled down. It is anisotropic in the contraction direction, aligned with the orientation of the nanosheet liquid crystal. However, details of this step response property against the actuator undergoing thermal change have not been clarified. In this paper, we introduce a method to measure the step response using a square test sheet with a side length of 2–10 mm and thickness of 0.1–1.0 mm. This measurement was used to measure the heating and cooling step response. The obtained result was approximated using a first-order lag system to determine a steady-state value and time constant. In addition, the characteristics of steady-state value and time constant were clarified from the viewpoint of shapes such as specific surface area and thickness.

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  • Takafumi Matsumaru, Asyifa Imanda Septiana, Kazuki Horiuchi
    Type: Paper
    2019 Volume 31 Issue 5 Pages 657-670
    Published: October 20, 2019
    Released: October 20, 2019
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    In this paper, we introduce the three-dimensional aerial image interface, 3DAII. This interface reconstructs and aerially projects a three-dimensional object image, which can be simultaneously observed from various viewpoints or by multiple users with the naked eye. A pyramid reflector is used to reconstruct the object image, and a pair of parabolic mirrors is used to aerially project the image. A user can directly manipulate the three-dimensional object image by superimposing a user’s hand-finger or a rod on the image. A motion capture sensor detects the user’s hand-finger that manipulates the projected image, and the system immediately exhibits some reaction such as deformation, displacement, and discoloration of the object image, including sound effects. A performance test is executed to confirm the functions of 3DAII. The execution time of the end-tip positioning of a robotic arm has been compared among four operating devices: touchscreen, gamepad, joystick, and 3DAII. The results exhibit the advantages of 3DAII; we can directly instruct the movement direction and movement speed of the end-tip of the robotic arm, using the three-dimensional Euclidean vector outputs of 3DAII in which we can intuitively make the end-tip of the robotic arm move in three-dimensional space. Therefore, 3DAII would be one important alternative to an intuitive spatial user interface, e.g., an operation device of aerial robots, a center console of automobiles, and a 3D modelling system. A survey has been conducted to evaluate comfort and fatigue based on ISO/TS 9241-411 and ease of learning and satisfaction based on the USE questionnaire. We have identified several challenges related to visibility, workspace, and sensory feedback to users that we would like to address in the future.

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  • Zulhaj Aliansyah, Kohei Shimasaki, Mingjun Jiang, Takeshi Takaki, Idak ...
    Type: Paper
    2019 Volume 31 Issue 5 Pages 671-685
    Published: October 20, 2019
    Released: October 20, 2019
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    This study proposes a novel vision-based measurement method to capture small dynamic displacements at many points on a large-scale structure. The measurement points are aligned in the depth direction so that all points are observable in a single field of view with a high power zoom lens. To cope with insufficient incident light and lens blur when capturing video in a limited depth of field with large magnification, our method used highly retroreflective cubes as markers, combined with a strong coaxial lighting device for measuring image displacements with a tandem-layout in images. We conducted experiments to measure dynamic displacements of a 4 m long truss bridge model, and 18 corner cubes were attached as retroreflective markers. 752×2048 images were captured with a coaxial lighting device at 240 fps. The experimental results show that the deformation of the bridge model, its resonant frequencies, and mode shapes at a frequency of dozens of Hz can be determined by analyzing images captured from a single camera view.

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  • Toyoyuki Honjo, Hidehisa Yoshida
    Type: Paper
    2019 Volume 31 Issue 5 Pages 686-696
    Published: October 20, 2019
    Released: October 20, 2019
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    Bipedal walking locomotion is one of the characteristics of human behavior. Both the lower body and the upper body (trunk) behaviors affect walking characteristics. To achieve a suitable gait, it is important to understand the effect of the trunk behavior. Therefore, in this paper, the effects of three types of trunk swinging behavior on planar bipedal gait in a model with an upper body – forward swinging, backward swinging, and no swinging – were evaluated using numerical simulations. To reduce control inputs and reflect the effect of upper body behavior, an underactuated bipedal walker without knee joints was adopted. This walker walked down a gentle slope using only hip actuation between the stance leg and the trunk. As a result, unique gait characteristics that depended on the direction of the trunk swinging behavior were found, including a longer step length and a lower-frequency gait with forward trunk swinging behavior and a shorter step length and higher-frequency gait with smaller angular momentum with backward trunk swinging behavior.

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  • Yukio Morooka, Ikuo Mizuuchi
    Type: Paper
    2019 Volume 31 Issue 5 Pages 697-706
    Published: October 20, 2019
    Released: October 20, 2019
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    If a robot system can take various shapes, then it can play various roles, such as humanoid, dog robot, and robot arm. A modular robot is a robot system in which robots are configured using multiple modules, and it is possible to configure robots of other shapes by varying the combinations of the modules. In conventional modular robots, the shape is restricted by gravity, and configurable shapes are limited. In this study, we propose a gravity compensation modular robot to solve this problem. This paper describes the design and prototyping of the gravity compensation modular robot, and provides examples of robot shapes configured using the gravity compensation modules and motion experiments of the robots. In the experiments, there were motions that the robots could perform and could not perform. We considered the lack in the gravity compensation level and module rigidity as the main factor of the failures. This paper also discusses the solutions to these problems.

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  • Koki Sakakibara, Shunya Suzuki, Kazushi Shibata, Yuto Sawada, Satoshi ...
    Type: Development Report
    2019 Volume 31 Issue 5 Pages 707-714
    Published: October 20, 2019
    Released: October 20, 2019
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    Reduction of leakage is a major problem in water hydraulic systems. With a servo valve, it is possible to reduce the internal leakage by reducing the clearance between a spool and a sleeve. However, because the clearance is reduced, wear tends to occur easily between the spool and sleeves when the servo valve is driven. As a result, the durability of the servo valve is reduced. Attention is paid to the durability against wear of ceramic materials, and the wear can be suppressed by using ceramics as the materials of the spool and sleeve. Thus, one can check whether the wear between the spool and sleeve can be suppressed, thereby improving the durability of the servo valve.

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  • Junji Satake, Tsukasa Ushijima, Yusuke Kudo
    Type: Letter
    2019 Volume 31 Issue 5 Pages 715-718
    Published: October 20, 2019
    Released: October 20, 2019
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    In this study, we developed and tested a monitoring robot to measure the respiration of a person. Upon detecting any abnormality, such as a subject falling down of a person, the monitoring robot moves closer to the person. Subsequently, it automatically extracts the pectoral region from the images and determines the respiration using the measured pectoral movements. We demonstrated that our monitoring robot can automatically perform this series of operations.

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Latest Research Topics
  • Koichi Osuka
    Type: News
    2019 Volume 31 Issue 5 Pages 720-722
    Published: October 20, 2019
    Released: October 20, 2019
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    The adaptive behavior of living creatures is considered to be generated by interactions between the brain, body, and environment. However, to better understand this essence, it is important to study the minimalistic set of interactions between the brain, body, and environment and to extract the underlying control mechanism. Therefore, in this research, we propose a novel methodology for observing the behavior by stepwise inhibition (zombification) of the upper brain functions of living organisms.*

    * This article is a translation from the article: K. Osuka, “Source of Various Behaviors of Living Things that Understands from Zombification of Insects,” The 8th Conf. of Transdisciplinary Federation of Science and Technology, D-2-1, 2017 (in Japanese).

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  • Koichi Osuka, Tetsuya Kinugasa, Ryota Hayashi, Koji Yoshida, Dai Owaki ...
    Type: News
    2019 Volume 31 Issue 5 Pages 723-726
    Published: October 20, 2019
    Released: October 20, 2019
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    In this study, we have developed a centipede-like multi-legged robot named i-CentiPot. This robot was developed to demonstrate our concept presented in the CREST project. In the project, we show that the existence of implicit control is important. i-CentiPot plays the part of the anchor example for our project.*

    * This article is a translation from the article: K. Osuka et al., “Centipede type robot i-CentiPot: From machine to creatures,” The 8th Conf. of Transdisciplinary Federation of Science and Technology, D-2-4, 2017 (in Japanese).

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