The Experts below are selected from a list of 219 Experts worldwide ranked by ideXlab platform
Hitoshi Kimura - One of the best experts on this subject based on the ideXlab platform.
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driving force and structural strength evaluation of a flexible mechanical system with a Hydrostatic Skeleton
Journal of Zhejiang University Science, 2010Co-Authors: Daisuke Maruyama, Hitoshi Kimura, Michihiko Koseki, Norio InouAbstract:The purpose of this study was to build a flexible mechanical system with a Hydrostatic Skeleton. The main components of this system are two type flexible bags. One is a structural bag with constant inner pressure. The other is an actuator bag with controlled inner pressure. To design the system, it was necessary to estimate both structural deformation and driving force. Numerical analysis of flexible bags, however, is difficult because of large nonlinear deformation. This study analyzed structural strength and driving force of flexible bags with the nonlinear finite element analysis (FEA) software ABAQUS. The stress concentration dependency on the bag shape is described and the driving force is calculated to include the large deformation. From the analytical results, this study derives an empirical equation of driving force. The validity of the equation was confirmed by condition-changed analyses and experimental results.
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hermetically sealed flexible mobile robot with Hydrostatic Skeleton
Journal of the Robotics Society of Japan, 2007Co-Authors: Hitoshi Kimura, Daisuke Maruyama, Fumihiro Kajimura, Michihiko Koseki, Norio InouAbstract:This study proposes a unique flexible robot with new Hydrostatic Skeleton driving mechanism. The main components of the robot are a hermetically-sealed outer cover with looped structure and flexible crawlers with Hydrostatic Skeleton named HS crawlers. This new robot provides remarkable advantages in narrow spaces as listed below: (i) the robot can change its shape adapting to terrain, (ii) all ground contact areas of the robot are driven toward the same direction. Performance of the first prototype robot is verified by experiments of wireless driving and passing narrow space. The prototype robot demonstrated a capability to pass through a space of 300 [mm] height, whereas the ordinary height of the robot is 420 [mm] .
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IROS - Hermetically-Sealed Flexible Mobile Robot with Hydrostatic Skeleton Driving Mechanism
2006 IEEE RSJ International Conference on Intelligent Robots and Systems, 2006Co-Authors: Hitoshi KimuraAbstract:This video shows a new hermetically-sealed flexible robot with Hydrostatic Skeleton driving mechanism, named HS crawler. All ground contact areas of the robot are driven into the same direction, and the robot can change its contour, adapting to the terrain. Thus, the robot can pass through narrow spaces. This video shows the driving motion of HS crawler. The video also includes the wireless driving motion and the driving experiment in narrow space. The prototype robot passed through a space of 300mm height, whereas the ordinary height of the robot is 400mm.
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IROS - Flexible Hermetically-Sealed Mobile Robot for Narrow Spaces Using Hydrostatic Skeleton Driving Mechanism
2006 IEEE RSJ International Conference on Intelligent Robots and Systems, 2006Co-Authors: Hitoshi Kimura, Daisuke Maruyama, Fumihiro Kajimura, Michihiko Koseki, Norio InouAbstract:Almost all of conventional mobile robots for narrow spaces exploration, e.g. rescue robots, adopt crawler or wheel mechanisms. However, in narrow spaces, such robot is often stuck because the robot body is sandwiched between both sides of a terrain. Especially, with normal crawler or wheel mechanisms, it is impossible to penetrate into narrow spaces lower than the height of the robot. In addition, sealing bushes of drive shaft cause unignorable energy loss because of rotational resistances. In order to solve these problems, this study proposes an innovative flexible robot with new Hydrostatic Skeleton driving mechanism. The main components of the robot are a hermetically-sealed outer cover with looped structure and flexible crawlers with Hydrostatic Skeleton named HS crawlers. This new robot provides remarkable advantages in narrow spaces as listed below: i) The robot can change its shape adapting to terrain; ii) All ground contact areas of the robot are driven toward the same direction. Thus, the robot is able to penetrate into narrow spaces changing its shape even if the terrain is rather narrower than the size of the robot. This paper describes the mechanisms of the robot and the detail of the HS crawler. Driving force of the HS crawler is discussed with comparison of simulation and experiment. Performance of first prototype robot is verified by experiments of wireless driving and passing narrow space. The prototype robot could pass through a space of 300 mm height, whereas the ordinary height of the robot is 420 mm
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Hermetically-Sealed Flexible Mobile Robot with Hydrostatic Skeleton Driving Mechanism
2006 IEEE RSJ International Conference on Intelligent Robots and Systems, 2006Co-Authors: Hitoshi KimuraAbstract:This video shows a new hermetically-sealed flexible robot with Hydrostatic Skeleton driving mechanism, named HS crawler. All ground contact areas of the robot are driven into the same direction, and the robot can change its contour, adapting to the terrain. Thus, the robot can pass through narrow spaces. This video shows the driving motion of HS crawler. The video also includes the wireless driving motion and the driving experiment in narrow space. The prototype robot passed through a space of 300mm height, whereas the ordinary height of the robot is 400mm.
William M. Kier - One of the best experts on this subject based on the ideXlab platform.
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COMMENTARY The diversity of Hydrostatic Skeletons
2020Co-Authors: William M. KierAbstract:Summary A remarkably diverse group of organisms rely on a Hydrostatic Skeleton for support, movement, muscular antagonism and the amplification of the force and displacement of muscle contraction. In Hydrostatic Skeletons, force is transmitted not through rigid skeletal elements but instead by internal pressure. Functioning of these systems depends on the fact that they are essentially constant in volume as they consist of relatively incompressible fluids and tissue. Contraction of muscle and the resulting decrease in one of the dimensions thus results in an increase in another dimension. By actively (with muscle) or passively (with connective tissue) controlling the various dimensions, a wide array of deformations, movements and changes in stiffness can be created. An amazing range of animals and animal structures rely on this form of skeletal support, including anemones and other polyps, the extremely diverse wormlike invertebrates, the tube feet of echinoderms, mammalian and turtle penises, the feet of burrowing bivalves and snails, and the legs of spiders. In addition, there are structures such as the arms and tentacles of cephalopods, the tongue of mammals and the trunk of the elephant that also rely on Hydrostatic skeletal support but lack the fluidfilled cavities that characterize this skeletal type. Although we normally consider arthropods to rely on a rigid exoSkeleton, a Hydrostatic Skeleton provides skeletal support immediately following molting and also during the larval stage for many insects. Thus, the majority of animals on earth rely on Hydrostatic Skeletons.
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Differences in scaling and morphology between lumbricid earthworm ecotypes.
The Journal of Experimental Biology, 2015Co-Authors: Jessica A Kurth, William M. KierAbstract:ABSTRACT Many soft-bodied invertebrates use a flexible, fluid-filled Hydrostatic Skeleton for burrowing. The aim of our study was to compare the scaling and morphology between surface-dwelling and burrowing earthworm ecotypes to explore the specializations of non-rigid musculoskeletal systems for burrowing locomotion. We compared the scaling of adult lumbricid earthworms across species and ecotypes to determine whether linear dimensions were significantly associated with ecotype. We also compared the ontogenetic scaling of a burrowing species, Lumbricus terrestris , and a surface-dwelling species, Eisenia fetida , using glycol methacrylate histology. We show that burrowing species are longer, thinner and have higher length-to-diameter ratios than non-burrowers, and that L. terrestris is thinner for any given body mass compared with E. fetida . We also found differences in the size of the musculature between the two species that may correlate with surface crawling or burrowing . Our results suggest that adaptations to burrowing for soft-bodied animals include a disproportionately thin body and strong longitudinal muscles.
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scaling of the Hydrostatic Skeleton in the earthworm lumbricus terrestris
The Journal of Experimental Biology, 2014Co-Authors: Jessica A Kurth, William M. KierAbstract:The structural and functional consequences of changes in size or scale have been well studied in animals with rigid Skeletons, but relatively little is known about scale effects in animals with Hydrostatic Skeletons. We used glycol methacrylate histology and microscopy to examine the scaling of mechanically important morphological features of the earthworm Lumbricus terrestris over an ontogenetic size range from 0.03 to 12.89 g. We found that L. terrestris becomes disproportionately longer and thinner as it grows. This increase in the length to diameter ratio with size means that, when normalized for mass, adult worms gain ~117% mechanical advantage during radial expansion, compared with hatchling worms. We also found that the cross-sectional area of the longitudinal musculature scales as body mass to the ~0.6 power across segments, which is significantly lower than the 0.66 power predicted by isometry. The cross-sectional area of the circular musculature, however, scales as body mass to the ~0.8 power across segments, which is significantly higher than predicted by isometry. By modeling the interaction of muscle crosssectional area and mechanical advantage, we calculate that the force output generated during both circular and longitudinal muscle contraction scales near isometry. We hypothesize that the allometric scaling of earthworms may reflect changes in soil properties and burrowing mechanics with size.
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The Diversity of Hydrostatic Skeletons
The Journal of Experimental Biology, 2012Co-Authors: William M. KierAbstract:Summary A remarkably diverse group of organisms rely on a Hydrostatic Skeleton for support, movement, muscular antagonism and the amplification of the force and displacement of muscle contraction. In Hydrostatic Skeletons, force is transmitted not through rigid skeletal elements but instead by internal pressure. Functioning of these systems depends on the fact that they are essentially constant in volume as they consist of relatively incompressible fluids and tissue. Contraction of muscle and the resulting decrease in one of the dimensions thus results in an increase in another dimension. By actively (with muscle) or passively (with connective tissue) controlling the various dimensions, a wide array of deformations, movements and changes in stiffness can be created. An amazing range of animals and animal structures rely on this form of skeletal support, including anemones and other polyps, the extremely diverse wormlike invertebrates, the tube feet of echinoderms, mammalian and turtle penises, the feet of burrowing bivalves and snails, and the legs of spiders. In addition, there are structures such as the arms and tentacles of cephalopods, the tongue of mammals and the trunk of the elephant that also rely on Hydrostatic skeletal support but lack the fluid-filled cavities that characterize this skeletal type. Although we normally consider arthropods to rely on a rigid exoSkeleton, a Hydrostatic Skeleton provides skeletal support immediately following molting and also during the larval stage for many insects. Thus, the majority of animals on earth rely on Hydrostatic Skeletons.
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the functional morphology of the tentacle musculature of nautilus pompilius
2010Co-Authors: William M. KierAbstract:The morphology of the musculature of cephalopods, and indeed that of many mollusks, is characterized by a tightly packed three-dimensional arrangement of muscle fibers that lack extensive fluid-filled cavities or hardened skeletal elements. Previous research on the arms and tentacles of squids (Kier, 1982) and the arms of octopuses (Kier, 1987) suggests that the skeletal support of these appendages is provided by a type of Hydrostatic Skeleton that differs from the classic conception of a Hydrostatic Skeleton (e.g., Chapman, 1958, 1975; Clark, 1964, 1981; Clark and Cowey, 1958; Wainwright, 1970, 1982) in that the musculature both creates movement and provides skeletal support. These appendages, termed muscular-hydrostats, are capable of diverse, complex, and highly controlled movements (Kier and Smith, 1985). This study of the functional morphology of Nautilus tentacles was undertaken to explore further the diversity of muscular arrangement and function in cephalopods.
Norio Inou - One of the best experts on this subject based on the ideXlab platform.
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driving force and structural strength evaluation of a flexible mechanical system with a Hydrostatic Skeleton
Journal of Zhejiang University Science, 2010Co-Authors: Daisuke Maruyama, Hitoshi Kimura, Michihiko Koseki, Norio InouAbstract:The purpose of this study was to build a flexible mechanical system with a Hydrostatic Skeleton. The main components of this system are two type flexible bags. One is a structural bag with constant inner pressure. The other is an actuator bag with controlled inner pressure. To design the system, it was necessary to estimate both structural deformation and driving force. Numerical analysis of flexible bags, however, is difficult because of large nonlinear deformation. This study analyzed structural strength and driving force of flexible bags with the nonlinear finite element analysis (FEA) software ABAQUS. The stress concentration dependency on the bag shape is described and the driving force is calculated to include the large deformation. From the analytical results, this study derives an empirical equation of driving force. The validity of the equation was confirmed by condition-changed analyses and experimental results.
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hermetically sealed flexible mobile robot with Hydrostatic Skeleton
Journal of the Robotics Society of Japan, 2007Co-Authors: Hitoshi Kimura, Daisuke Maruyama, Fumihiro Kajimura, Michihiko Koseki, Norio InouAbstract:This study proposes a unique flexible robot with new Hydrostatic Skeleton driving mechanism. The main components of the robot are a hermetically-sealed outer cover with looped structure and flexible crawlers with Hydrostatic Skeleton named HS crawlers. This new robot provides remarkable advantages in narrow spaces as listed below: (i) the robot can change its shape adapting to terrain, (ii) all ground contact areas of the robot are driven toward the same direction. Performance of the first prototype robot is verified by experiments of wireless driving and passing narrow space. The prototype robot demonstrated a capability to pass through a space of 300 [mm] height, whereas the ordinary height of the robot is 420 [mm] .
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IROS - Flexible Hermetically-Sealed Mobile Robot for Narrow Spaces Using Hydrostatic Skeleton Driving Mechanism
2006 IEEE RSJ International Conference on Intelligent Robots and Systems, 2006Co-Authors: Hitoshi Kimura, Daisuke Maruyama, Fumihiro Kajimura, Michihiko Koseki, Norio InouAbstract:Almost all of conventional mobile robots for narrow spaces exploration, e.g. rescue robots, adopt crawler or wheel mechanisms. However, in narrow spaces, such robot is often stuck because the robot body is sandwiched between both sides of a terrain. Especially, with normal crawler or wheel mechanisms, it is impossible to penetrate into narrow spaces lower than the height of the robot. In addition, sealing bushes of drive shaft cause unignorable energy loss because of rotational resistances. In order to solve these problems, this study proposes an innovative flexible robot with new Hydrostatic Skeleton driving mechanism. The main components of the robot are a hermetically-sealed outer cover with looped structure and flexible crawlers with Hydrostatic Skeleton named HS crawlers. This new robot provides remarkable advantages in narrow spaces as listed below: i) The robot can change its shape adapting to terrain; ii) All ground contact areas of the robot are driven toward the same direction. Thus, the robot is able to penetrate into narrow spaces changing its shape even if the terrain is rather narrower than the size of the robot. This paper describes the mechanisms of the robot and the detail of the HS crawler. Driving force of the HS crawler is discussed with comparison of simulation and experiment. Performance of first prototype robot is verified by experiments of wireless driving and passing narrow space. The prototype robot could pass through a space of 300 mm height, whereas the ordinary height of the robot is 420 mm
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Flexible Hermetically-Sealed Mobile Robot for Narrow Spaces Using Hydrostatic Skeleton Driving Mechanism
2006 IEEE RSJ International Conference on Intelligent Robots and Systems, 2006Co-Authors: Hitoshi Kimura, Daisuke Maruyama, Fumihiro Kajimura, Michihiko Koseki, Norio InouAbstract:Almost all of conventional mobile robots for narrow spaces exploration, e.g. rescue robots, adopt crawler or wheel mechanisms. However, in narrow spaces, such robot is often stuck because the robot body is sandwiched between both sides of a terrain. Especially, with normal crawler or wheel mechanisms, it is impossible to penetrate into narrow spaces lower than the height of the robot. In addition, sealing bushes of drive shaft cause unignorable energy loss because of rotational resistances. In order to solve these problems, this study proposes an innovative flexible robot with new Hydrostatic Skeleton driving mechanism. The main components of the robot are a hermetically-sealed outer cover with looped structure and flexible crawlers with Hydrostatic Skeleton named HS crawlers. This new robot provides remarkable advantages in narrow spaces as listed below: i) The robot can change its shape adapting to terrain; ii) All ground contact areas of the robot are driven toward the same direction. Thus, the robot is able to penetrate into narrow spaces changing its shape even if the terrain is rather narrower than the size of the robot. This paper describes the mechanisms of the robot and the detail of the HS crawler. Driving force of the HS crawler is discussed with comparison of simulation and experiment. Performance of first prototype robot is verified by experiments of wireless driving and passing narrow space. The prototype robot could pass through a space of 300 mm height, whereas the ordinary height of the robot is 420 mm
Michael Yu Wang - One of the best experts on this subject based on the ideXlab platform.
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Dynamic modeling and simulation of inchworm movement towards bio-inspired soft robot design.
Bioinspiration & Biomimetics, 2019Co-Authors: Jinhua Zhang, Tao Wang, Jin Wang, Baotong Li, Jun Hong, John X. J. Zhang, Michael Yu WangAbstract:: Inchworms have been one of the most widely used bionic templates for designing soft robotic devices. Bioresearch has shown that muscles of inchworms exhibit nonlinear hysteresis and their body structures are with Hydrostatic Skeleton. But effects of these properties on their dynamic movements have not been studied yet. In this work, a dynamic model based on the principle of virtual power of an inchworm is established to examine the problem. A spring-damper model with time-varying stiffness and damping coefficients is used to model controllable nonlinear properties of the inchworm muscles. The Hydrostatic Skeleton is applied to the model as a constant volume constraint for each segment. Based on this, simulations of three typical movements including omega-shaped arching motion, cantilevered probing motion and surprising fast looping motion are presented. The effects of the nonlinear properties including variable stiffness and damping properties of muscles on these dynamic behaviors of inchworms are illustrated. Some inspiration for designing bio-inspired crawling robots and soft slender robotic devices is obtained. And we think this work will hopefully provide better understanding and guidance for design and control of these robotic devices.
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A Fluid-Filled Tubular Dielectric Elastomer Variable Stiffness Structure Inspired by the Hydrostatic Skeleton Principle *Research supported by the National Natural Science Foundation of China (No.51675413).
2018 IEEE International Conference on Robotics and Automation (ICRA), 2018Co-Authors: Tao Wang, Jinhua Zhang, Jun Hong, Yue Li, Yuanjie Li, Michael Yu WangAbstract:This work presents a novel variable stiffness structure consisting of a fiber-constrained dielectric elastomer tube filled with insulating oil. The tensile stiffness of the structure can be adjusted by voltages and its initial value can be customized according to the initial pre-stretch of the material. The structure has a dimension of ~30 mm diameter × 50 mm length. A mathematical analysis is established to predict the initial tensile stiffness of the structure. The changes of the tensile stiffness of the structure under voltages are verified experimentally. The results show a decrease of the tensile stiffness of the device by 25% at 4 kV and the decrement is also related to the elongation of the structure. With different pre-stretches and dimensions of the dielectric elastomer, one can obtain devices with different variation ranges of tensile stiffness.
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ICRA - A Fluid-Filled Tubular Dielectric Elastomer Variable Stiffness Structure Inspired by the Hydrostatic Skeleton Principle *Research supported by the National Natural Science Foundation of China (No.51675413).
2018 IEEE International Conference on Robotics and Automation (ICRA), 2018Co-Authors: Tao Wang, Jinhua Zhang, Jun Hong, Yue Li, Yuanjie Li, Michael Yu WangAbstract:This work presents a novel variable stiffness structure consisting of a fiber-constrained dielectric elastomer tube filled with insulating oil. The tensile stiffness of the structure can be adjusted by voltages and its initial value can be customized according to the initial pre-stretch of the material. The structure has a dimension of ∼30 mm diameter × 50 mm length. A mathematical analysis is established to predict the initial tensile stiffness of the structure. The changes of the tensile stiffness of the structure under voltages are verified experimentally. The results show a decrease of the tensile stiffness of the device by 25% at 4 kV and the decrement is also related to the elongation of the structure. With different pre-stretches and dimensions of the dielectric elastomer, one can obtain devices with different variation ranges of tensile stiffness.
Tao Wang - One of the best experts on this subject based on the ideXlab platform.
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Dynamic modeling and simulation of inchworm movement towards bio-inspired soft robot design.
Bioinspiration & Biomimetics, 2019Co-Authors: Jinhua Zhang, Tao Wang, Jin Wang, Baotong Li, Jun Hong, John X. J. Zhang, Michael Yu WangAbstract:: Inchworms have been one of the most widely used bionic templates for designing soft robotic devices. Bioresearch has shown that muscles of inchworms exhibit nonlinear hysteresis and their body structures are with Hydrostatic Skeleton. But effects of these properties on their dynamic movements have not been studied yet. In this work, a dynamic model based on the principle of virtual power of an inchworm is established to examine the problem. A spring-damper model with time-varying stiffness and damping coefficients is used to model controllable nonlinear properties of the inchworm muscles. The Hydrostatic Skeleton is applied to the model as a constant volume constraint for each segment. Based on this, simulations of three typical movements including omega-shaped arching motion, cantilevered probing motion and surprising fast looping motion are presented. The effects of the nonlinear properties including variable stiffness and damping properties of muscles on these dynamic behaviors of inchworms are illustrated. Some inspiration for designing bio-inspired crawling robots and soft slender robotic devices is obtained. And we think this work will hopefully provide better understanding and guidance for design and control of these robotic devices.
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A Fluid-Filled Tubular Dielectric Elastomer Variable Stiffness Structure Inspired by the Hydrostatic Skeleton Principle *Research supported by the National Natural Science Foundation of China (No.51675413).
2018 IEEE International Conference on Robotics and Automation (ICRA), 2018Co-Authors: Tao Wang, Jinhua Zhang, Jun Hong, Yue Li, Yuanjie Li, Michael Yu WangAbstract:This work presents a novel variable stiffness structure consisting of a fiber-constrained dielectric elastomer tube filled with insulating oil. The tensile stiffness of the structure can be adjusted by voltages and its initial value can be customized according to the initial pre-stretch of the material. The structure has a dimension of ~30 mm diameter × 50 mm length. A mathematical analysis is established to predict the initial tensile stiffness of the structure. The changes of the tensile stiffness of the structure under voltages are verified experimentally. The results show a decrease of the tensile stiffness of the device by 25% at 4 kV and the decrement is also related to the elongation of the structure. With different pre-stretches and dimensions of the dielectric elastomer, one can obtain devices with different variation ranges of tensile stiffness.
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ICRA - A Fluid-Filled Tubular Dielectric Elastomer Variable Stiffness Structure Inspired by the Hydrostatic Skeleton Principle *Research supported by the National Natural Science Foundation of China (No.51675413).
2018 IEEE International Conference on Robotics and Automation (ICRA), 2018Co-Authors: Tao Wang, Jinhua Zhang, Jun Hong, Yue Li, Yuanjie Li, Michael Yu WangAbstract:This work presents a novel variable stiffness structure consisting of a fiber-constrained dielectric elastomer tube filled with insulating oil. The tensile stiffness of the structure can be adjusted by voltages and its initial value can be customized according to the initial pre-stretch of the material. The structure has a dimension of ∼30 mm diameter × 50 mm length. A mathematical analysis is established to predict the initial tensile stiffness of the structure. The changes of the tensile stiffness of the structure under voltages are verified experimentally. The results show a decrease of the tensile stiffness of the device by 25% at 4 kV and the decrement is also related to the elongation of the structure. With different pre-stretches and dimensions of the dielectric elastomer, one can obtain devices with different variation ranges of tensile stiffness.
