@article{Lee2025,

title = {Bleeding-Mimetic Damage-Detecting and Self-Healing Modular Skin for Inflatable Structures},

author = {Hyun Jae Lee, Ryuma Niiyama},

doi = {10.1002/adrr.202500009},

year  = {2025},

date = {2025-04-24},

urldate = {2025-04-24},

journal = {Advanced Robotics Research},

abstract = {The extension of the lifespan of soft robots necessitates the establishment of an effective self-healing system accompanied by rapid damage detection. Inspired by the mechanisms of bleeding and blood coagulation, a novel damage-detecting and self-healing modular skin is developed for inflatable structures. This alternative structural material is realized using a liquid conductive polymer composed of an elastomer, conductive particles, and a dispersant. Encapsulated in a thin layer, this conductive polymer is found to be capable of both damage detection through generating an electric current and subsequent self-healing through its solidification in the damaged area. The repeated and reproducible generation of electric current is confirmed both prior to and subsequent to the infliction of damage to the patch. A comparison of conductive polymers with distinct mixing ratios reveals that the changes in electric current following the solidification on the patches are different. The applicability of the modular skins is confirmed by their conduciveness to assembly for various curvatures and larger areas of inflatable structures. The proposed modular skins feature an easy fabrication process, a simple chemical mechanism, and high adaptability to inflatable structures, thus displaying considerable potential for pioneering a new methodology for effective damage detection and self-healing systems in inflatable robots.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Lee2025b,

title = {Chemochromic Damage Detecting and Recovery System Using Affordable Hydrogel},

author = {Hyun Jae Lee, Ryuma Niiyama},

doi = {10.1021/acsami.5c08719},

year  = {2025},

date = {2025-07-08},

urldate = {2025-07-08},

journal = {ACS Applied Materials & Interfaces},

volume = {17},

issue = {29},

pages = {42407-42419},

abstract = {A multipurpose chemochromic protector is proposed with a hydrogel made from a mixture of sodium chloride, starch, and water, and the deposition of a copper layer on the nylon polyethylene film surrounding the hydrogel. This hydrogel is found to be chemically stable, water-retaining, shock-absorbent, biocompatible, cost-effective, and highly reactive with copper enough to realize its chemochromic characteristics. The varying chemical compositions of the hydrogel show that the presence of poly(acrylic acid) (PAA) inside can enhance the damage-detecting and recovery capabilities of the protector. The compressive strength measurement reveals that the hydrogel becomes effectively solidified with the formation of copper chloride and the evaporation of water molecules to cover the damaged areas. In the shear strength experiment, the PAA-included hydrogel is proven to have the high adhesiveness necessary for the recovery of the protector. The damage-detecting and recovery experiment successfully presents the copper-specific chemochromic properties of the protector, implying that the addition of PAA intensifies the color changes of the hydrogel as well as its increased stiffness in the damaged areas. The chemochromically operating surface protector with a simple fabrication process, intuitive measurement, and an alternative working mechanism would be able to promote related studies and contribute to the development of additional protective measures such as for diverse protective clothing, miscellaneous robotic structures, and numerous space applications.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Takahashi2025_ARR,

title = {Edible Pouch Motors},

author = {Keigo Takahashi, Kazuma Takai, Ryuma Niiyama, Jun Shintake},

doi = {10.1002/adrr.202500118},

year  = {2025},

date = {2025-11-04},

urldate = {2025-11-04},

journal = {Advanced Robotics Research},

number = {e202500118},

abstract = {Edible robotics offers novel applications in which actuators play a key role. However, most existing edible actuators rely on 3D

structures that require complex and laborious fabrication processes, hindering rapid prototyping and deployment. To address this

issue, this study explores the use of planar configurations, specifically pouch motors, for edible actuators. These actuators are lightweight

and can be fabricated quickly via heat sealing. Two types of edible pouch motors are developed using an agar-based film:

linear and angular actuators, and their actuation performances are characterized. The linear pouch motor (1.16 g) exhibits a strain of

30.6% and a force of 13.6 N at an input pressure of 5 kPa, demonstrating performance comparable to nonedible counterparts and

durability up to 1000 actuation cycles. The angular pouch motor (0.42 g) achieves a rotation angle of 121.3° at 10 kPa and a torque of

0.11N m at 16 kPa. Experimental results closely align with theoretical predictions. Furthermore, an edible pouch gripper (2.6 g)

successfully performs a pick-and-place operation with a 97.0 g potato and fully dissolves in hot water while maintaining its grip.

These findings validate the feasibility of planar edible actuators and highlight their potential for advancing future edible robotics.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Gangadhara2024,

title = {Augmenting Compliance with Motion Generation Through Imitation Learning Using Drop-Stitch Reinforced Inflatable Robot Arm with Rigid Joints},

author = {Gubbala Gangadhara Naga Sai, Masato Nagashima, Hiroki Mori, Young Ah Seong, Hiroki Sato, Ryuma Niiyama, Yuki Suga, Tetsuya Ogata},

doi = {10.1109/LRA.2024.3446270},

year  = {2024},

date = {2024-08-20},

urldate = {2024-08-20},

journal = {IEEE Robotics and Automation Letters},

volume = {9},

issue = {10},

pages = {8595-8602},

abstract = {Safe physical human-robot collaboration is possible with soft robots due to their inherent compliance and low inertia. Soft bodies inherently possess passive compliance, providing adaptability in collaborative tasks because of their deformations; however, the same features add complexity to modeling and dynamic control. We focus on motion generation for a 3 degrees of freedom (3DOF) inflatable robot arm, which consists of soft inflatable body links and rigid joints. This research explores the limitations of relying solely on soft robot compliance for completing contact-based tasks. Our goal is to generate adaptive motion for contact-based tasks by exploiting the compliance of soft links. We compare contact-based tasks involving an inflatable robot with and without a learning model. Improved performance is achieved when soft robot compliance is augmented with imitation learning. The combination of soft robot compliance and the adaptability of the machine learning model demonstrates the potential for collaborative robots to safely interact with humans and their surroundings.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Niiyama2024,

title = {Augmented Bodily Self in Performing a Button-Touching Task with Soft Supernumerary Robotic Arms},

author = {Ryuma Niiyama, Honoka Yoshida, Ryogo Kawamata, Katsuki Higo, Sotaro Shimada},

doi = {10.20965/jrm.2024.p0856},

year  = {2024},

date = {2024-08-20},

urldate = {2024-08-20},

journal = {Journal of Robotics and Mechatronics},

volume = {36},

issue = {4},

pages = {856-863},

abstract = {Extra or supernumerary robotic limbs are actively exploited in the field of body augmentation. The science of self-recognition of additional body parts is an interesting subject. Although the field is primarily led by psychological studies in virtual reality, which facilitate flexible experimental designs, we believe that assessments employing real robots are also essential. In this study, we investigated the sense of body ownership and agency of a dual-arm wearable robotic arm using an inexpensive and safe inflatable structure. We report the results of functional near-infrared spectroscopy (fNIRS) analysis of brain activity during the use of the robotic arm. The questionnaire results from the experiment, which involved a button-touching task, revealed that both the sense of ownership and sense of agency were significantly higher in the goal-oriented collaborative experience compared to the non-goal-oriented condition. This indicates that humans feel ownership of and agency toward an autonomous robot or a remote-controlled robotic arm operated by another person. The analysis of the fNIRS data included a two-factor analysis of variance for the learning and trial phases. While there was no main effect for the conditions within each phase, a significant interaction was observed between the two brain regions of the right angular gyrus and right postcentral gyrus.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Manome2024,

title = {Hybrid RobOstrich Manipulator with Intrinsic and Extrinsic Actuations},

author = {Takeru Manome and Ryuma Niiyama},

doi = {10.20965/jrm.2024.p1448},

year  = {2024},

date = {2024-12-20},

urldate = {2024-12-20},

journal = {Journal of Robotics and Mechatronics},

volume = {36},

number = {6},

pages = {1448-1457},

abstract = {Ostrich neck-inspired manipulators have attracted attention in the field of bio-inspired robotics. They achieve unique movements that are difficult for conventional robots, owing to their flexibility. However, it is difficult to mimic the length, mass, and actuation redundancy of ostrich necks. This is because the longer and heavier the robotic arm, the greater is the load on the joints. Furthermore, if a robotic arm exhibits actuation redundancy, its structure and control become more complex. In this study, we developed a hybrid RobOstrich manipulator with both intrinsic and extrinsic actuations. This is the third-generation of the RobOstrich series. The manipulator consists of a servomotor attached to each joint that performs intrinsic actuation and two servomotors on the base that perform extrinsic actuation through wires. We conducted an experiment to reproduce the rolling pattern, which is a unique movement of the ostrich neck, to verify the effect of hybrid actuation. The results indicated that the joint angle error and required torque were reduced by applying hybrid actuation.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Nakano2023,

title = {RobOstrich Manipulator: A Novel Mechanical Design and Control Based on the Anatomy and Behavior of an Ostrich Neck},

author = {Kazashi Nakano, Megu Gunji, Masahiro Ikeda, Keung Or, Mitsuhito Ando, Katsuma Inoue, Hiromi Mochiyama, Kohei Nakajima, Ryuma Niiyama, Yasuo Kuniyoshi},

doi = {10.1109/LRA.2023.3265301},

year  = {2023},

date = {2023-04-06},

urldate = {2023-04-06},

journal = {IEEE Robotics and Automation Letters},

volume = {8},

number = {5},

pages = {3062-3069},

abstract = {Flexible manipulators have high degrees of freedom and deformability, enabling dexterous movements and allowing for unexpected contacts with the environment. Underactuated tendon-drive mechanisms are the most widely adopted because of their simplicity and effectiveness. However, they suffer from difficulty in modeling and in achieving dexterity and structural stability. In this letter, we focus on ostriches, which can dexterously and swiftly move their flexible necks. We carried out a detailed dissection of ostrich necks and identified a specific musculo-tendon-skeletal structure. Based on the findings related to the structure, we came up with a novel mechanical design and control method manifested as a “RobOstrich” manipulator. Our actual robot experiments confirm that it exhibits similar movement patterns as an ostrich neck. It is also flexible yet structurally stable, enabling dexterous reaching movements. This work also contributes to biology by providing constructive understanding of the functionality of the morphology of an ostrich neck.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Or2023,

title = {Curriculum-reinforcement learning on simulation platform of tendon-driven high-degree of freedom underactuated manipulator},

author = {Keung Or, Kehua Wu, Kazashi Nakano, Masahiro Ikeda,Mitsuhito Ando, Yasuo Kuniyoshi, Ryuma Niiyama},

doi = {10.3389/frobt.2023.1066518},

year  = {2023},

date = {2023-07-12},

urldate = {2023-07-12},

journal = {Frontiers in Robotics and AI},

volume = {10},

pages = {1-15},

abstract = {A high degree of freedom (DOF) benefits manipulators by presenting various postures when reaching a target. Using a tendon-driven system with an underactuated structure can provide flexibility and weight reduction to such manipulators. The design and control of such a composite system are challenging owing to its complicated architecture and modeling difficulties. In our previous study, we developed a tendon-driven, high-DOF underactuated manipulator inspired from an ostrich neck referred to as the Robostrich arm. This study particularly focused on the control problems and simulation development of such a tendon-driven high-DOF underactuated manipulator. We proposed a curriculum-based reinforcement-learning approach. Inspired by human learning, progressing from simple to complex tasks, the Robostrich arm can obtain manipulation abilities by step-by-step reinforcement learning ranging from simple position control tasks to practical application tasks. In addition, an approach was developed to simulate tendon-driven manipulation with a complicated structure. The results show that the Robostrich arm can continuously reach various targets and simultaneously maintain its tip at the desired orientation while mounted on a mobile platform in the presence of perturbation. These results show that our system can achieve flexible manipulation ability even if vibrations are presented by locomotion.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Niiyama2023,

title = {Inflatable Humanoid Cybernetic Avatar for Physical Human–Robot Interaction},

author = {Ryuma Niiyama, Masahiro Ikeda, Young Ah Seong},

doi = {10.20965/ijat.2023.p0277},

year  = {2023},

date = {2023-05-05},

urldate = {2023-05-05},

journal = {International Journal of Automation Technology (IJAT)},

volume = {17},

number = {3},

pages = {277–283},

abstract = {In a digital twin, a humanoid robot can be the counterpart of a simulated agent in the real world. In addition, a human, virtual avatar, and avatar robot might constitute digital triplets. We propose an inflatable cybernetic avatar (CA) with a humanoid upper body using an inflatable structure that can represent gestures. This inflatable CA is much lighter, safer, and cheaper than conventional humanoid robots and can be folded when deflated. These properties are ideal for physical human–robot interaction (pHRI) and allow real-time collection of human behavior through interaction. In the experiment, basic movements such as nodding and raising arms were measured using motion capture systems. This paper demonstrates the proposed inflatable CA in a hybrid event. We also conducted an experiment to measure the touch interactions using tactile sensors attached to the fabric of the inflatable part. A psychologically secure inflatable humanoid CA is a promising platform for physical interaction experiments.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Niikura2022,

title = {Giraffe Neck Robot: First Step Toward a Powerful and Flexible Robot Prototyping Based on Giraffe Anatomy},

author = {Atsuhiko Niikura, Hiroyuki Nabae, Gen Endo, Megu Gunji, Kent Mori, Ryuma Niiyama, Koichi Suzumori},

doi = {10.1109/LRA.2022.3146611},

year  = {2022},

date = {2022-01-27},

urldate = {2022-01-27},

journal = {IEEE Robotics and Automation Letters},

volume = {7},

number = {2},

pages = {3539-3546},

abstract = {The neck of a giraffe has excellent characteristics that can serve as a good alternative for designing a large robotic mechanism. For example, the neck can rapidly move when performing necking, a motion where the giraffes strike each other’s necks. Furthermore, the neck of a giraffe helps prevent impacts and adapts to the shape and hardness of the opponent’s neck during necking. In contrast, a conventional robotic mechanism is limited in its capability to achieve such powerfulness and flexibility characteristics; that is, being powerful while having robustness against impacts and kinematic and dynamic adaptability to the opponent. This study focuses on applying those excellent characteristics of a giraffe neck to develop robotic mechanisms. Specifically, roboticists and animal anatomists have combined efforts to develop a powerful and flexible long musculoskeletal robot based on the anatomy of a giraffe neck. The musculoskeletal robot prototype is actuated using thin McKibben pneumatic artificial muscles that bend easily. The results confirm the coordination between the muscles and ligaments and the shape adaptability to an external force.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Mochiyama2022,

title = {Ostrich-Inspired Soft Robotics: A Flexible Bipedal Manipulator for Aggressive Physical Interaction},

author = {Hiromi Mochiyama, Megu Gunji, Ryuma Niiyama},

doi = {10.20965/jrm.2022.p0212},

year  = {2022},

date = {2022-04-20},

urldate = {2022-04-20},

journal = {Journal of Robotics and Mechatronics},

volume = {34},

number = {2},

pages = {212-218},

abstract = {In this letter, ostrich-inspired soft robotics, an approach to intelligent robots that can achieve dexterous manipulation and locomotion without hesitating to collide with the surrounding environment, is proposed. The rationale behind the approach is described from the history of bio-inspired mechanisms, biology, and the theory of robot control. This letter focuses on the manipulator. The first prototype of an ostrich-inspired manipulator was developed to investigate its feasibility. This prototype is a serial chain of 18 rigid links connected with rotation joints moving in a vertical plane and driven through two asymmetric antagonistic wire systems connected to two levers that are directly operated by a human operator playing the role of the controller. Therefore, this manipulator is a highly underactuated mechanism that is flexible against external forces. The experimental results show that a human operator can control this manipulator so that its tip (i.e., the head) can reach several positions, including an upper position against gravity, indicating the potential of ostrich-inspired manipulators.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Misu2022,

title = {Robostrich Arm: Wire-Driven High-DOF Underactuated Manipulator},

author = {Kenji Misu, Masahiro Ikeda, Keung Or, Mitsuhito Ando, Megu Gunji, Hiromi Mochiyama, Ryuma Niiyama},

doi = {10.20965/jrm.2022.p0328},

year  = {2022},

date = {2022-04-20},

urldate = {2022-04-20},

journal = {Journal of Robotics and Mechatronics},

volume = {34},

number = {2},

pages = {328-338},

abstract = {We propose a wire-driven robotic arm inspired by the ostrich neck. It can pick up a small piece of feed from the ground while colliding with it. This arm is named robostrich arm (shortened form of robotic ostrich arm). It consists of a serial chain of 18 rigid bodies connected by free rotational joints that are designed to have angle limitations similar to the bones of a real ostrich. It moves in a vertical plane and is driven by two DC motors through antagonistic wires. The task considered in this study was to lift the arm tip (the “head” of the robostrich arm). The experimental results indicate that the tensioner balance and timing between the two wires are important for achieving the head-up task. This paper indicates the contribution of antagonist muscles to the performance of head-up tasks by high-degree-of-freedom underactuated manipulators in robotics and ostrich necks in biological studies.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Suzumori2022,

title = {Special Issue on Science of Soft Robots},

author = {Koichi Suzumori, Ryuma Niiyama, Kenjiro Fukuda, and Kohei Nakajima},

doi = {https://doi.org/10.20965/jrm.2022.p0193},

year  = {2022},

date = {2022-04-20},

urldate = {2022-04-20},

journal = {Journal of Robotics and Mechatronics},

volume = {34},

number = {2},

pages = {193-194},

abstract = {The science of soft robots, or soft robotics, is currently one of the most active fields in robotics. While traditional robots consist of rigid bodies, powerful servomotors, and carefully coded programs to realize power, precision, and reliability, soft robots consist of soft and flexible bodies, actuators, and intelligence for adaptability. They are not rigid, but instead flexible toward their surroundings. These differences have the potential to make soft robotics a great new field in robotics.



A JSPS KAKENHI project “Science of Soft Robots” has been in progress in Japan since 2018. Part of this special issue is made in collaboration with this project. This special issue consists of 46 works in total: 2 review papers, 29 letters, and 15 papers. One review paper, 29 letters, and 3 research papers report research activities from the JSPS KAKENHI project, and the other review paper and 12 research papers have been contributed from outside the project. As this issue will make clear, the science of soft robots is a very interdisciplinary academic field, a collaboration of many researchers from various fields, such as mechanical/electrical engineering, computer science, material sciences, biology, zoology, medicine, and nursing, among others. We believe interdisciplinary work to be a key point for the exploration of soft robotics.



The editors thank all of the authors and reviewers of the contributions, and are confident that this special issue will greatly contribute to further progress in robotics.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Ikeda2022,

title = {Proposal of Manufacturing Method for New Passive Elastic Joint and Prototype of Human Phantom},

author = {Masahiro Ikeda, Ryuma Niiyama, Yasuo Kuniyoshi},

doi = {10.20965/jrm.2022.p0402},

year  = {2022},

date = {2022-04-20},

urldate = {2022-04-20},

journal = {Journal of Robotics and Mechatronics},

volume = {34},

number = {2},

pages = {402-412},

abstract = {Fabricating a soft robot using conventional molding methods is difficult and time-consuming. Moreover, the types of materials used in the process are limited, and the elasticity cannot be changed incrementally. In this paper, we explain the detailed process of manufacturing molds for silicone joints. We construct a prototype molded silicone joint. We measure the elastic modulus of this joint and confirm that the elastic modulus and anisotropy change depending on the density, size, and arrangement of the surface grooves in the mold. We also develop a prototype human phantom using the proposed joint. We aim to contribute to the medical field by applying new techniques made possible by soft robotics.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{nokey,

title = {Characterization of continuum robot arms under reinforcement learning and derived improvements},

author = {Ryota Morimoto, Masahiro Ikeda, Ryuma Niiyama, Yasuo Kuniyoshi},

doi = {https://doi.org/10.3389/frobt.2022.895388},

year  = {2022},

date = {2022-09-01},

urldate = {2022-09-01},

journal = {Frontiers in Robotics and AI},

volume = {9},

abstract = {In robotics, soft continuum robot arms are a promising prospect owing to their redundancy and passivity; however, no comprehensive study exists that examines their characteristics compared to rigid manipulators. In this study, we examined the advantages of a continuum robot arm as compared to a typical and rigid seven-degree-of-freedom (7-DoF) robot manipulator in terms of performing various tasks through reinforcement learning. We conducted simulations for tasks with different characteristics that require control over position and force. Common tasks in robot manipulators, such as reaching, crank rotation, object throwing, and peg-in-hole were considered. The initial conditions of the robot and environment were randomized, aiming for evaluations including robustness. The results indicate that the continuum robot arm excels in the crank-rotation task, which is characterized by uncertainty in environmental conditions and cumulative rewards. However, the rigid robot arm learned better motions for the peg-in-hole task than the other tasks, which requires fine motion control of the end-effector. In the throwing task, the continuum robot arm scored well owing to its good handling of anisotropy. Moreover, we developed a reinforcement-learning method based on the comprehensive experimental results. The proposed method successfully improved the motion learning of a continuum robot arm by adding a technique to regulate the initial state of the robot. To the best of our knowledge, ours is the first reinforcement-learning experiment with multiple tasks on a single continuum robot arm and is the first report of a comparison between a single continuum robot arm and rigid manipulator on a wide range of tasks. This simulation study can make a significant contribution to the design of continuum arms and specification of their applications, and development of control and reinforcement learning methods.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Niiyama2022,

title = {Soft Actuation and Compliant Mechanisms in Humanoid Robots},

author = {Ryuma Niiyama},

doi = {10.1007/s43154-022-00084-7},

year  = {2022},

date = {2022-07-21},

urldate = {2022-07-21},

journal = {Current Robotics Reports},

volume = {3},

pages = {111-117},

abstract = {Purpose of Review

We aimed to reveal the impact of soft robotics, which has developed in the last decade, on humanoid robotics research. Although humanoid robots are usually classified as hard robotics, softness should be integrated because soft materials and mechanisms are used extensively in the human body.

Recent Findings

In recent years, new soft actuators based on hybrid approaches, such as the combination of electricity and fluid, have emerged. Physically compliant robotic systems that are safe and robust are needed to take on higher-risk tasks and to tolerate large numbers of trials in the process of machine learning.

Summary

Emerging soft actuators are enabling humanoid robots to achieve rapid movements with physical impacts. Efforts to integrate soft robotics and humanoid robots are still on their way. A potential direction for humanoid robots is their application to physical human-robot interaction, where further exploitation of softness is expected.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Niiyama2022,

title = {A 3D Printed Hydrostatic Skeleton for Earthworm-inspired Soft Burrowing Robot},

author = {Ryuma Niiyama, Kazuma Matsushita, Masahiro Ikeda, Keung Or, Yasuo Kuniyoshi},

doi = {10.1039/D2SM00882C},

year  = {2022},

date = {2022-10-11},

urldate = {2022-10-11},

journal = {Soft Matter},

volume = {18},

issue = {41},

pages = {7990-7997},

abstract = {Moving through soil is challenging for robots, particularly for soft robots. Herein, we propose a support structure, based on the hydrostatic skeleton of earthworms, to overcome this problem. To create extremely flexible, thin-walled, worm-sized deformed segments, a specialized 3D printer for low-hardness rubber was utilized. To obtain large radial deformation, we investigated the properties of the soft materials for 3D printing and the geometry of the segments. Notably, segments are deformed with multiply-wound shape memory alloy wires. We constructed an earthworm robot by connecting shape memory alloy-driven segments in series and experimentally demonstrated that this robot could propel in the soil. The proposed robot is unique in that it has a small diameter of 10 mm and exhibits a peristaltic motion in soil.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{新山2022,

title = {社会的相互作用の拡張のためのヒト型インフレータブル・サイバネティック・アバター},

author = {新山 龍馬, 池田 昌弘, ソン ヨンア},

doi = {10.18974/tvrsj.27.4_381},

year  = {2022},

date = {2022-12-28},

urldate = {2022-12-28},

journal = {日本バーチャルリアリティ学会論文誌},

volume = {27},

number = {4},

pages = {381-384},

abstract = {This paper proposes a humanoid cybernetic avatar (CA) that can replicate and extend human presence inexpensively and create social interactions that are difficult to simulate among humans. Standard life-size humanoid robots are expensive and have the disadvantage of being difficult to customize and use multiple units. Therefore, we constructed a humanoid robot with an inflatable structure, omitting work and walking abilities and focusing only on appearance and gestures. Humanoid inflatable CAs are lightweight, contact-safe, foldable when deflated, and can be customized in shape and texture at low cost. The social interactions enabled by such robots are discussed and categorized.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Tanaka2021,

title = {Immediate generation of jump-and-hit motions by a pneumatic humanoid robot using a lookup table of learned dynamics},

author = {Kazutoshi Tanaka, Satoshi Nishikawa, Ryuma Niiyama, Yasuo Kuniyoshi},

doi = {10.1109/LRA.2021.3076959},

year  = {2021},

date = {2021-04-30},

urldate = {2021-04-30},

journal = {IEEE Robotics and Automation Letters},

volume = {6},

number = {3},

pages = {5557-5564},

abstract = {This letter focuses on the jump-and-hit motion of a humanoid robot, wherein a robot instantaneously jumps forward and hits a flying ball in the air, similar to how human players behave in volleyball games. We propose a Immediate Motion generation using a Lookup table of learned dynamics (IMoLo) for generating the motions of a pneumatic humanoid robot. To test this method, we developed a humanoid robot called “Liberobot” with eight joints applying structure-integrated pneumatic cable cylinders. Using simulations, the prediction errors of the robot hand positions during the jump-and-hit motions measured via nonlinear interpolation when using IMoLo was smaller than without it in cases having a small number of training trials. In the experiments, the robot jumped and hit the flying ball 16 times out of 20 trials using the proposed motion generation method. The results indicate that a pneumatic humanoid robot using IMoLo can instantaneously perform dynamic whole-body motions, such as jump-and-hit motions, with a changing target within a specified time. Our humanoid robot is the first pneumatic humanoid robot capable of executing such dynamic motions.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Saito2022,

title = {Insect wing 3D printing},

author = {Kazuya Saito, Hiroto Nagai, Kai Suto, Naoki Ogawa, Young ah Seong, Tomohiro Tachi, Ryuma Niiyama, Yoshihiro Kawahara},

doi = {10.1038/s41598-021-98242-y},

year  = {2021},

date = {2021-10-14},

urldate = {2021-10-14},

journal = {Scientific reports},

volume = {11},

number = {1},

pages = {1-8 (18631)},

abstract = {Insects have acquired various types of wings over their course of evolution and have become the most successful terrestrial animals. Consequently, the essence of their excellent environmental adaptability and locomotive ability should be clarified; a simple and versatile method to artificially reproduce the complex structure and various functions of these innumerable types of wings is necessary. This study presents a simple integral forming method for an insect-wing-type composite structure by 3D printing wing frames directly onto thin films. The artificial venation generation algorithm based on the centroidal Voronoi diagram, which can be observed in the wings of dragonflies, was used to design the complex mechanical properties of artificial wings. Furthermore, we implemented two representative functions found in actual insect wings: folding and coupling. The proposed crease pattern design software developed based on a beetle hindwing enables the 3D printing of foldable wings of any shape. In coupling-type wings, the forewing and hindwing are connected to form a single large wing during flight; these wings can be stored compactly by disconnecting and stacking them like cicada wings.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Chen2021,

title = {Wireless powered dielectric elastomer actuator},

author = {Lai Chen, Takuya Sasatani, Keung Or, Satoshi Nishikawa, Yoshihiro Kawahara, Ryuma Niiyama, Yasuo Kuniyoshi},

doi = {10.1109/LRA.2021.3097271},

year  = {2021},

date = {2021-07-14},

urldate = {2021-07-14},

journal = {IEEE Robotics and Automation Letters},

volume = {6},

number = {4},

pages = {7278-7274},

abstract = {The need for cable connection with soft robotic systems suppresses the benefits granted by their softness and flexibility. Such systems can be untethered by equipping batteries or by relying on non-electrical actuation mechanisms. However, these approaches cannot simultaneously support long-term and intelligent operations. This research examines a proposed wireless soft actuator based on wireless power transfer (WPT) and dielectric elastomer actuator (DEA) technology, thereby realizing soft robomore diversified application and long-term locomotion. A compact conical DEA fabrication process is presented with 6 mm periodic linear output and design of a lightweight WPT receiver that weighs only 13 g integrated with a driver circuit. Evaluation results show that this system remotely powers the DEA and the intelligent peripheral circuits for system control. Furthermore, our design seamlessly bridges the WPT system, power-efficient in low-voltage output conditions, and the DEA, which requires high-voltage input (kV) for deformation, by leveraging high-voltage boost-converters. Experimentally obtained results demonstrate untethered DEA operation at 170 mm from the transmitter. Also, we demonstrated applying this DEA as a wireless pump.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Niiyama2021_InflatableRobot,

title = {Blower-powered Soft Inflatable Joints for Physical Human-Robot Interaction},

author = {Ryuma Niiyama, Young Ah Seong, Yoshihiro Kawahara, Yasuo Kuniyoshi},

doi = {10.3389/frobt.2021.720683},

year  = {2021},

date = {2021-08-24},

urldate = {2021-08-24},

journal = {Frontiers in Robotics and AI},

volume = {8},

pages = {1-12 (720683)},

abstract = { Inflatables are safe and lightweight structures even at the human scale. Inflatable robots are expected to be applied to physical human-robot interaction (pHRI). Although active joint mechanisms are essential for developing inflatable robots, the existing mechanisms are complex in structure and it is difficult to integrate actuators, which diminish the advantages of inflatables. This study proposes blower-powered soft inflatable joints that are easy to fabricate and contain enough space for an actuation inside. The joints are driven by tendon wires pulled by linear actuators. We derived a theoretical model for both unilateral and bilateral joints and demonstrated a hugging robot with multiple joints as an application of the proposed joint mechanism. The novelty of the proposed joint mechanism and the inflatable robot is that rigid parts have been thoroughly eliminated and the tendons for actuation have been successfully hidden inside. Moreover, the active control of the internal pressure makes inflatables resistant to punctures. We expect that the contact safety of inflatable robots will facilitate advancement of the pHRI field},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{McCaffrey2020,

title = {Continuum Robotic Caterpillar with Wirelessly Powered Shape Memory Alloy Actuators},

author = {Colm McCaffrey, Takuya Umedachi, Weiwei Jiang, Takuya Sasatani, Yoshiaki Narusue, Ryuma Niiyama,Yoshihiro Kawahara},

doi = {10.1089/soro.2019.0090},

year  = {2020},

date = {2020-03-30},

urldate = {2020-03-30},

journal = {Soft Robotics},

volume = {7},

number = {6},

pages = {700-710},

abstract = {Wireless power transfer (WPT) has the significant potential for soft-bodied continuum robots to extend the operational time limitlessly and reduce weight. However, rigid power receiver coils, widely used in WPT, hinder the continuum deformation of the robot, and as a result, the function realization using the continuum deformation (e.g., locomotion) is impaired. Therefore, this article introduces that a soft-bodied continuum robot can be designed by using thin film receiver coils and an inductively coupled wireless powering solution without sacrificing the continuum deformation and locomotion ability. A system is described for powering and controlling a soft robotic caterpillar consisting of nothing more than its continuum structure, actuators, and thin/flexible power receiving coils.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Saito2020_PNAS,

title = {Earwig fan designing: Biomimetic and evolutionary biology applications},

author = {Kazuya Saito, Ricardo Pérez-de la Fuente, Kôichi Arimoto, Young ah Seong, Hitoshi Aonuma, Ryuma Niiyama, and Zhong You},

doi = {10.1073/pnas.2005769117},

year  = {2020},

date = {2020-07-28},

urldate = {2020-07-28},

journal = {Proceedings of the National Academy of Sciences (PNAS)},

volume = {117},

number = {30},

pages = {17622-17626},

abstract = {Technologies to fold structures into compact shapes are required in multiple engineering applications. Earwigs (Dermaptera) fold their fanlike hind wings in a unique, highly sophisticated manner, granting them the most compact wing storage among all insects. The structural and material composition, in-flight reinforcement mechanisms, and bistable property of earwig wings have been previously studied. However, the geometrical rules required to reproduce their complex crease patterns have remained uncertain. Here we show the method to design an earwig-inspired fan by considering the flat foldability in the origami model, as informed by X-ray microcomputed tomography imaging. As our dedicated designing software shows, the earwig fan can be customized into artificial deployable structures of different sizes and configurations for use in architecture, aerospace, mechanical engineering, and daily use items. Moreover, the proposed method is able to reconstruct the wing-folding mechanism of an ancient earwig relative, the 280-million-year-old Protelytron permianum. This allows us to propose evolutionary patterns that explain how extant earwigs acquired their wing-folding mechanism and to project hypothetical, extinct transitional forms. Our findings can be used as the basic design guidelines in biomimetic research for harnessing the excellent engineering properties of earwig wings, and demonstrate how a geometrical designing method can reveal morphofunctional evolutionary constraints and predict plausible biological disparity in deep time.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Narumi2020,

title = {Liquid Pouch Motors: Tube-less Planar Pneumatic Actuators Driven by Liquid-to-gas Phase Change},

author = {Koya Narumi, Hiroki Sato, Kenichi Nakahara, Young ah Seong, Kunihiko Morinaga, Yasuaki Kakehi, Ryuma Niiyama, Yoshihiro Kawahara},

doi = {10.1109/LRA.2020.2983681},

year  = {2020},

date = {2020-07-01},

urldate = {2020-07-01},

journal = {IEEE Robotics and Automation Letters},

volume = {5},

number = {3},

pages = {3912-3922},

abstract = {Conventional planar pneumatic actuators have not been able to make the most of their thin, lightweight, and flexible nature due to tubes and pumps inevitably connected to them. In this article, we build upon our prior work and propose Liquid Pouch Motors, a family of printable soft actuators that consist of one or more gas-tight bladders (called pouches) filled with low boiling point liquid. When the heat over 34 ∘C is applied to them, the liquid inside the pouch evaporates and the whole structure inflates. Especially, we newly presented roll-to-roll mass production of Liquid Pouch Motors with the rectangular form factor in addition to the previously reported CNC heat drawing. We also discussed the suitable material selection and the volume of liquid needed for the actuators. Based on this fabrication procedure, we evaluated the mechanical properties of the proposed actuators. By leveraging the benefits of the actuators, we then implemented three shape-changing interfaces: (1) electrically driven printable paper robots combined with printed paper circuit; (2) an untethered architecture facade that passively actuates by ambient heat; and (3) dresses that change their color and texture by the incident light and the body temperature. We believe that Liquid Pouch Motors will work as a new toolbox for the fabrication and application of soft actuators in interactive scenarios.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Hamaguchi2020,

title = {Soft Inductive Tactile Sensor Using Flow-Channel Enclosing Liquid Metal},

author = {Shota Hamaguchi, Takumi Kawasetsu, Takato Horii, Hisashi Ishihara, Ryuma Niiyama, Koh Hosoda, and Minoru Asada},

doi = {10.1109/LRA.2020.2985573},

year  = {2020},

date = {2020-07-01},

urldate = {2020-07-01},

journal = {IEEE Robotics and Automation Letters},

volume = {5},

number = {3},

pages = {4028-4034},

abstract = {There are structural challenges in increasing the softness of conventional soft tactile sensors because rigid electrical elements have to be installed around the sensing areas, which should be compressive, stretchable, and durable. To solve these issues, we propose an inductive tactile sensor whose silicone-rubber body has only two liquid-metal reservoirs connected by an elongated flow channel. When one reservoir is placed around the sensing area, another one can be placed at a non-sensing area. Furthermore, in this structure, touch can be detected by monitoring the inflow and outflow of the liquid-metal in the latter reservoir by using a separately placed coil circuit based on the eddy-current effect. The proposed method requires no direct electrical connections with liquid metal in the reservoirs or flow channels. This means that the sensor body has no inhibitor that reduces its compressibility and stretchability, and that deteriorates its durability. The experimental results demonstrated that larger reservoir diameters provided larger sensitivity and higher signal-to-noise ratio of approximately 65 dB. Additionally, we observed that the bending of the body does not affect the sensor response as much as gravity. Therefore, we conclude that our sensor has structural advantages for tactile-sensor installation, especially in soft actuators, because our completely soft sensor does not experience reduction or deterioration in its functionality owing to its softness.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Hiraki2020,

title = {Laser Pouch Motors: Selective and Wireless Activation of Soft Actuators by Laser-powered Liquid-to-gas Phase Change},

author = {Takefumi Hiraki, Kenichi Nakahara, Koya Narumi, Ryuma Niiyama, Noriaki Kida, Naoki Takamura, Hiroshi Okamoto, Yoshihiro Kawahara},

doi = {10.1109/LRA.2020.2982864},

year  = {2020},

date = {2020-07-01},

urldate = {2020-07-01},

journal = {IEEE Robotics and Automation Letters},

volume = {5},

number = {3},

pages = {4180-4187},

abstract = {Untethered control of soft-bodied robots is attractive for interactions in a variety of unstructured and dynamic environments. However, soft robotics systems are currently limited in terms of wireless, selective, and scalable control of multiple actuators. Therefore, we propose a method to wirelessly drive multiple soft actuators by laser projection. A small amount of low-boiling-point liquid inside a planar thin pouch can be heated by a laser and evaporated to inflate the whole body. Laser projection enables both wireless energy supply and the selection of target actuators. Further, the low-boiling-point liquid serves as an actuation source and as a receiver of laser irradiation. Thus, we do not need additional components such as electric circuits and batteries to achieve simple and scalable implementation of multiple soft actuators. We evaluated the mechanical properties and demonstrated that the system can wirelessly control the gestures of fingers of a robot hand. We also verified that our method can activate a group of mobile soft robots simultaneously and individually while tracking the actuator positions. Our approach contributes to the scalable deployment of soft robotic systems by removing tethers for power and communication.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Seong2020,

title = {Workshop Design for Hands-on Exploration Using Soft Robotics and Onomatopoeia},

author = {Young Ah Seong, Hiroshi Sugihara, Ryuma Niiyama, Yasuaki Kakehi, Yoshihiro Kawahara},

doi = {10.1109/MPRV.2019.2940194},

year  = {2020},

date = {2020-01-17},

urldate = {2020-01-17},

journal = {IEEE Pervasive Computing},

volume = {19},

number = {1},

pages = {52-61},

abstract = {Hands-on exploration with robotics has been developed as a tool for creativity, but there are limitations with regard to accessibility. As a new method of creative and pervasive exploration for children and students, we propose a workshop using inflatable soft robots with short video recipes and onomatopoeia as a prompt. This method does not require prior knowledge or high fabrication costs and includes open-ended designs. Based on the soft robots obtained from five practical workshops with 131 participants, about 88% showed new structures and 61% exhibited advanced trials, which require deep consideration of the structures. The participants discovered new mechanisms themselves through exploration and used the given onomatopoeia to imagine their own storytelling for exploration. The results indicate the potential of our method to encourage both structure discovery and diverse expressions. It can be used as a tool for creative learning and a guideline for designing other approaches.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Takaki2019,

title = {Acoustic Length Sensor for Soft Extensible Pneumatic Actuators with a Frequency Characteristics Model},

author = {Ken Takaki, Yoshitaka Taguchi, Satoshi Nishikawa, Ryuma Niiyama, Yoshihiro Kawahara},

doi = {10.1109/LRA.2019.2931273},

year  = {2019},

date = {2019-10-01},

urldate = {2019-10-01},

journal = {IEEE Robotics and Automation Letters},

volume = {4},

issue = {4},

pages = {4292-4297},

abstract = {In this study, we present a length sensor that can be used for extensible soft pneumatic actuators. Conventional length sensors detect the changes in electrical resistance and capacitance owing to the deformation of the actuator; hence, deterioration and destruction occur when they are used with an actuator that has a large expansion ratio. In addition, their low resolution and linearity makes them unsuitable for use in actuator control. Our proposed sensor comprises only a speaker and a microphone installed at one end of the actuator. We propose a method to deterministically measure the length of a tube by generating a broadband acoustic signal in a tube and measuring the resonance characteristics determined by the shape of the tube. Our experimental results demonstrate that the error in the measurement with our sensor is not more than 4% with a strain up to 200%. Unlike conventional acoustic sensing methods that measure the time of flight by using ultrasound, our proposed method yields accurate results even when the tube is bent. Therefore, the proposed method can be applied to various types of pneumatic actuators.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Mori2019,

title = {High-Speed Humanoid Robot Arm for Badminton Using Pneumatic-Electric Hybrid Actuators},

author = {Shotaro Mori, Kazutoshi Tanaka, Satoshi Nishikawa, Ryuma Niiyama, Yasuo Kuniyoshi},

doi = {10.1109/LRA.2019.2928778},

year  = {2019},

date = {2019-10-01},

urldate = {2019-10-01},

journal = {IEEE Robotics and Automation Letters},

volume = {4},

issue = {4},

pages = {3601-3608},

abstract = {We describe the development of a robot configured to play badminton, a dynamic sport that requires high accuracy. We used pneumatic-electric hybrid actuators, each combining a pneumatic actuator, with high-speed and lightweight attributes, and an electric motor with good controllability. Our first objective was to develop hybrid actuators that are lightweight and compact and with integrated sections. Using parts made of lightweight materials such as plastics and aluminum coils, and using wire for power transmission, we made actuators much lighter and smaller than previous ones. In addition, for high accuracy and power, tension sensor units and a heat countermeasure mechanism were also incorporated. As practice partners, we consider badminton robots to be more useful if they were humanoid in appearance and have a variety of shots. We, therefore, developed a humanoid robot arm. By incorporating actuators as link structures, the overall weight was reduced, and both complex degrees of freedom (DoFs) and a large range of motion were realized. Subsequently, we developed a robot with seven DoFs, three DoFs for the shoulder, two for the elbow, and two for the wrist, similar to the configuration of human arms. The robot, therefore, roughly reproduces human movements. At 19 m/s, the maximum speed of the racket was quite fast. The hybrid control reduced the motion variance, allowing improvements in accuracy of more than three times that of motions with only pneumatic control. In addition, performing path planning and tracking control with high precision was possible, tasks that are difficult for conventional pneumatic dynamic robots.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{山岡2019,

title = {BlowFab: レーザ加工による再利用可能で硬質なインフレータブル構造体の造形},

author = {山岡 潤一, 新山 龍馬, 筧 康明},

doi = {10.11184/his.21.1_61},

year  = {2019},

date = {2019-02-25},

urldate = {2019-02-25},

journal = {ヒューマンインタフェース学会論文誌},

volume = {21},

issue = {1},

pages = {61-72},

abstract = {We propose BlowFab, a prototyping method used to create a 2.5- dimensional prototype in a short time by combining laser cutting and blow molding techniques. The user creates adhesive areas and inflatable areas by engraving and cutting multilayered plastic sheets using a laser cutter. These adhesive areas are fused automatically by overlapping two crafted sheets and softening them with a heater. The user can then create hard prototypes by injecting air into the sheets. Objects can be bent in any direction by cutting incisions or engraving a resistant resin. The user can create uneven textures by engraving a pattern with a heat-resistant lm. In this study, the design process is described using the proposed method. The study also evaluates possible bending mechanisms and texture expression methods along with various usage scenarios and discusses the resolution, strength, and reusability of the prototype developed.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Fujita2018_JIIAE,

title = {Physical Reservoir Computing in Tensegrity with Structural Softness and Ground Collision Dynamics},

author = {Kenichi Fujita, Shogo Yonekura, Satoshi Nishikawa, Ryuma Niiyama, Yasuo Kuniyoshi},

doi = {10.12792/jiiae.6.92},

year  = {2018},

date = {2018-04-25},

urldate = {2018-04-25},

journal = {Journal of the Institute of Industrial Applications Engineers},

volume = {6},

number = {2},

pages = {92-99},

abstract = {This paper describes the effects of body structures and environments around the bodies on their computational abilities. This type of computation outsourced for body structures is called morphological computation. Physical reservoir computing, which uses the body itself as a neural network-like system, is one approach to this computation. In this research, a tensegrity-like structure, designed by the compressive elements and the tensile elements that are made of springs, is used as a body structure. We demonstrated that the structure has a higher computational ability when the structure is easier to move with a smaller spring constant, or when the structure's input amplitude was set to be smaller. In addition, the environments around the body were shown to have large effects on the computational ability. The results of these previous experiments were summarized into four features. First, the softer body has a higher computational ability. Second, the input amplitude can control the memories of the system. Third, the best input position exists which maximizes the computational ability. Fourth, the environments around the structure have effects on the system and its computational ability. Furthermore, this paper suggests that a parallel link structure (i.e., closed-loop link structure) is a prerequisite for physical reservoir computing, and tensegrity structures have ability to learn different functions at the same time.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Nishikawa2018_RA-L,

title = {Coordinated Use of Structure-Integrated Bistable Actuation Modules for Agile Locomotion},

author = {Satoshi Nishikawa, Yusuke Arai, Ryuma Niiyama, Yasuo Kuniyoshi},

doi = {10.1109/LRA.2018.2794617},

year  = {2018},

date = {2018-04-01},

urldate = {2018-04-01},

journal = {IEEE Robotics and Automation Letters},

volume = {3},

number = {2},

pages = {1018-1024},

abstract = {It is difficult to design agile soft-bodied robots owing to their inherent softness. To overcome this problem, we propose a structure-integrated bistable module that uses snap-through buckling for agile motions. First, we confirmed that a 0.05-m-long module was able to jump to 0.13 m high. Through investigation, we found a range of command parameters within which the module jumps consistently. Moreover, we showed that jumping performance had strong relation to the bending amplitude. Next, we induced a robot with two serially connected modules to roll forward and jump over an obstacle. In rolling, the robot became round for quick locomotion. In jumping, we found that buckling in one module induced buckling in the other module. The difference in buckling time between the two modules was shortened from the order of 0.1 s to the order of 0.01 s. This might be effective for error correction or useful for coordinated motions. These results show the effectiveness of the proposed structure-integrated bistable modules for making agile soft-bodied robots, and suggest ways of exploiting them.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Mori2018_RA-L,

title = {High-speed and Lightweight Humanoid Robot Arm for a Skillful Badminton Robot},

author = {Shotaro Mori, Kazutoshi Tanaka, Satoshi Nishikawa, Ryuma Niiyama, Yasuo Kuniyoshi},

doi = {10.1109/LRA.2018.2803207},

year  = {2018},

date = {2018-07-01},

urldate = {2018-07-01},

journal = {IEEE Robotics and Automation Letters},

volume = {3},

number = {3},

pages = {1727-1734},

abstract = {Sports, especially badminton, require participants to perform dynamic and skillful motions. Previous robots have had difficulty in performing like a human because of their severe limitations of low operating speed, heavy bodies, and simplistic mechanisms. In this letter, we propose a new robot design that consists of a structure integrated with pneumatic actuators and noninterfering many-degree-of-freedom joints, for the realization of a high-speed and lightweight humanoid robot. We made a four-degree-of-freedom robot arm for badminton, which is an especially dynamic sport, aiming for maximum speed while meeting geometric requirements. The robot swung with a racket-head speed of 21 m/s, which is a value higher than speeds achieved by previous robotic arms. The robot also realized a skillful shot, namely the spin net shot, which cannot be performed by previous badminton robots having simple mechanisms. A pneumatic robot is considered difficult to control, especially in terms of feedback control. We found that the reproducibility of the robot was as fine as 10-40 mm at the racket head for four kinds of strong swings. Using feedforward control, we also conducted an experiment in which the robot hits a flying shuttle, and achieved a high hitting rate of 69.7% for powerful swings. We believe that this research expands the possibilities of the pneumatic robot and is the first step toward developing a skillful humanoid badminton robot.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Saito2017_PNAS,

title = {Investigation of Hindwing Folding in Ladybird Beetles by Artificial Elytron Transplantation and Micro Computed Tomography},

author = {Kazuya Saito, Shuhei Nomura, Shuhei Yamamoto, Ryuma Niiyama, Yoji Okabe},

doi = {10.1073/pnas.1620612114},

year  = {2017},

date = {2017-03-15},

urldate = {2017-03-15},

journal = {Proceedings of the National Academy of Sciences (PNAS)},

volume = {114},

number = {22},

pages = {5624-5628},

abstract = {Ladybird beetles are high-mobility insects and explore broad areas by switching between walking and flying. Their excellent wing transformation systems enabling this lifestyle are expected to provide large potential for engineering applications. However, the mechanism behind the folding of their hindwings remains unclear. The reason is that ladybird beetles close the elytra ahead of wing folding, preventing the observation of detailed processes occurring under the elytra. In the present study, artificial transparent elytra were transplanted on living ladybird beetles, thereby enabling us to observe the detailed wing-folding processes. The result revealed that in addition to the abdominal movements mentioned in previous studies, the edge and ventral surface of the elytra, as well as characteristic shaped veins, play important roles in wing folding. The structures of the wing frames enabling this folding process and detailed 3D shape of the hindwing were investigated using microcomputed tomography. The results showed that the tape spring-like elastic frame plays an important role in the wing transformation mechanism. Compared with other beetles, hindwings in ladybird beetles are characterized by two seemingly incompatible properties: (i) the wing rigidity with relatively thick veins and (ii) the compactness in stored shapes with complex crease patterns. The detailed wing-folding process revealed in this study is expected to facilitate understanding of the naturally optimized system in this excellent deployable structure.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Niiyama2015_SoftRobotics,

title = {Pouch Motors: Printable Soft Actuators Integrated with Computational Design},

author = {Ryuma Niiyama, Xu Sun, Cynthia Sung, Byoungkwon An, Daniela Rus, Sangbae Kim},

doi = {10.1089/soro.2014.0023},

year  = {2015},

date = {2015-06-18},

urldate = {2015-06-18},

journal = {Soft Robotics},

volume = {2},

number = {2},

pages = {59-70},

abstract = {We propose pouch motors, a new family of printable soft actuators integrated with computational design. The pouch motor consists of one or more inflatable gas-tight bladders made of sheet materials. This printable actuator is designed and fabricated in a planar fashion. It allows both easy prototyping and mass fabrication of affordable robotic systems. We provide theoretical models of the actuators compared with the experimental data. The measured maximum stroke and tension of the linear pouch motor are up to 28% and 100 N, respectively. The measured maximum range of motion and torque of the angular pouch motor are up to 80° and 0.2 N, respectively. We also develop an algorithm that automatically generates the patterns of the pouches and their fluidic channels. A custom-built fabrication machine streamlines the automated process from design to fabrication. We demonstrate a computer-generated life-sized hand that can hold a foam ball and perform gestures with 12 pouch motors, which can be fabricated in 15 min.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Nishikawa2014_AdvancedRobotics,

title = {A Musculoskeletal Bipedal Robot Designed with Angle-Dependent Moment Arm for Dynamic Motion from Multiple States},

author = {Satoshi Nishikawa, Kazutoshi Tanaka, Kazuya Shida, Toshihiko Fukushima, Ryuma Niiyama, Yasuo Kuniyoshi},

doi = {10.1080/01691864.2013.876936},

year  = {2014},

date = {2014-01-14},

urldate = {2014-01-14},

journal = {Advanced Robotics},

volume = {28},

issue = {7},

pages = {487-496},

abstract = {When robots make smooth transitions in dynamic motions, they must exert large force over widely various postures. To expand the range of postures that robots can take during dynamic motions, we propose that robots be designed with an Angle-Dependent Moment Arm (ADMA) with biased pivot, for which torque characteristics of actuators attached to joints are adjustable. From jumping simulations of robotic legs designed with ADMA, we demonstrate that ADMA improves robustness to postural and motion timing changes by shifts of the optimal posture, which are also observed in jumping experiments using a full-sized, bipedal robot.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Niiyama2012_AdvancedRobotics,

title = {Biomechanical Approach to Open-loop Bipedal Running with a Musculoskeletal Athlete Robot},

author = {Ryuma Niiyama, Satoshi Nishikawa, Yasuo Kuniyoshi},

doi = {10.1163/156855311X614635},

year  = {2012},

date = {2012-04-13},

urldate = {2012-04-13},

journal = {Advanced Robotics},

volume = {26},

issue = {3-4},

pages = {383-398},

abstract = {In this study, a musculoskeletal robot is used as a tool to investigate how animals control their complex body. Sprinting is a challenging task that requires maximizing the potential resources of a musculoskeletal structure. Our approach to robotic sprinting is the Athlete Robot — a musculoskeletal robot with elastic blade feet controlled by feedforward motor command. We use a catapult launcher to provide a stable start to a sprint, and then examine the relation between the initial velocity imparted by the launcher and the change in orientation of the robot. We also investigate the influence of the change in elasticity of the blade foot. The results show that acceleration causes anterior inclination after the first step. The elasticity of the foot dominates the duration of the support phase. The musculoskeletal system of the Athlete Robot is modified to suit catapulted running. Based on the results from real robot experiments, we can provide a consistent propelling force using the catapult launcher. We demonstrate the Athlete Robot running for five steps after a catapult launch, using only feedforward command.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{AlexandrePitti2010_AutonomousRobots,

title = {Creating and Modulating Rhythms by Controlling the Physics of the Body},

author = {Alexandre Pitti, Ryuma Niiyama, Yasuo Kuniyoshi},

doi = {10.1007/s10514-009-9176-1},

year  = {2010},

date = {2010-04-01},

urldate = {2010-04-01},

journal = {Autonomous Robots},

volume = {28},

number = {3},

pages = {317-329},

abstract = {The motion behaviors of vertebrates require the correct coordination of the muscles and of the body limbs even for the most stereotyped ones like the rhythmical patterns. It means that the neural circuits have to share some part of the control with the material properties and the body morphology in order to rise any of these motor synergies. To this respect, the chemical downward neuromodulators that supervise the pattern generators in the spinal cord create the conditions to merge (or to disrupt) them by matching the phase of the neural controllers to the body dynamics. In this paper, we replicate this control based on phase synchronization to implement neuromodulators and investigate the interplay between control, morphology and material. We employ this mechanism to control three robotic setups of gradual complexity and actuated by McKibben type air muscles: a single air muscle, an elbow-like system and a leg-like articulation. We show that for specific values, the control parameters modulate the internal dynamics to match those of the body and of the material physics to either the rhythmical and non-rhythmical gait patterns.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{Niiyama2010_IndustrialRobot,

title = {Design Principle Based on Maximum Output Force Profile for a Musculoskeletal Robot},

author = {Ryuma Niiyama, Yasuo Kuniyoshi},

doi = {10.1108/01439911011037640},

year  = {2010},

date = {2010-05-03},

urldate = {2010-05-03},

journal = {Industrial Robot - The international journal of robotics research and application},

volume = {37},

number = {3},

pages = {250-255},

abstract = {Purpose

The purpose of this paper is to focus on an engineering application of the vertebrate musculoskeletal system. The musculoskeletal system has unique mechanisms such as bi‐articular muscle, antagonistic muscle pairs and muscle‐tendon elasticity. The “artificial musculoskeletal system” is achieved through the use of the pneumatic artificial muscles. The study provides a novel method to describe the force property of the articulated mechanism driven by muscle actuator and a transmission.



Design/methodology/approach

A musculoskeletal system consists of multiple bodies connected together with rotational joints and driven by mono‐ and bi‐articular actuators. The paper analyzes properties of the musculoskeletal system with statically calculated omni‐directional output forces. A set of experiments has been performed to demonstrate the physical ability of the musculoskeletal robot.



Findings

A method to design a musculoskeletal system is proposed based on an analysis of the profile of convex polygon of maximum output forces. The result shows that the well‐designed musculoskeletal system enables the legged robot to jump 0.6 m high and land softly from 1.0 m drop off.



Originality/value

The paper provides a design principle for a musculoskeletal robot. The musculoskeletal system is the bio‐inspired mechanism for all multi‐degrees‐of‐freedom articulated devices, and has the advantages of optimized actuator configuration and force control.},

keywords = {},

pubstate = {published},

tppubtype = {article}

}

@article{新山2008_JJBSE,

title = {人工筋骨格アーキテクチャを備えたヒト型ロボットとバランス制御},

author = {新山龍馬},

year  = {2008},

date = {2008-04-15},

urldate = {2008-04-15},

journal = {バイオメカニクス研究},

volume = {11},

number = {4},

pages = {327-337},

keywords = {},

pubstate = {published},

tppubtype = {article}

}