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Yu Q, Gravish N. Multimodal Locomotion in a Soft Robot Through Hierarchical Actuation. Soft Robot 2024; 11:21-31. [PMID: 37471221 DOI: 10.1089/soro.2022.0198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/22/2023] Open
Abstract
Soft and continuum robots present the opportunity for extremely large ranges of motion, which can enable dexterous, adaptive, and multimodal locomotion behaviors. However, as the number of degrees of freedom (DOF) of a robot increases, the number of actuators should also increase to achieve the full actuation potential. This presents a dilemma in mobile soft robot design: physical space and power requirements restrict the number and type of actuators available and may ultimately limit the movement capabilities of soft robots with high-DOF appendages. Restrictions on actuation of continuum appendages ultimately may limit the various movement capabilities of soft robots. In this work, we demonstrate multimodal behaviors in an underwater robot called "Hexapus." A hierarchical actuation design for multiappendage soft robots is presented in which a single high-power motor actuates all appendages for locomotion, while smaller low-power motors augment the shape of each appendage. The flexible appendages are designed to be capable of hyperextension for thrust, and flexion for grasping with a peak pullout force of 32 N. For propulsion, we incorporate an elastic membrane connected across the base of each tentacle, which is stretched slowly by the high-power motor and released rapidly through a slip-gear mechanism. Through this actuation arrangement, Hexapus is capable of underwater locomotion with low cost of transport (COT = 1.44 at 16.5 mm/s) while swimming and a variety of multimodal locomotion behaviors, including swimming, turning, grasping, and crawling, which we demonstrate in experiment.
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Affiliation(s)
- Qifan Yu
- Department of Mechanical and Aerospace Engineering, University of California San Diego, San Diego, California, USA
| | - Nick Gravish
- Department of Mechanical and Aerospace Engineering, University of California San Diego, San Diego, California, USA
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Wang H, Yang Y, Ye X, He Z, Jiao P. Combustion‐enabled underwater vehicles (CUVs) in dynamic fluid environment. J FIELD ROBOT 2023. [DOI: 10.1002/rob.22167] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Affiliation(s)
- Haipeng Wang
- Institute of Port, Coastal and Offshore Engineering, Ocean College Zhejiang University Zhejiang China
- Department of Civil Engineering Tsinghua University Beijing China
| | - Yang Yang
- Institute of Port, Coastal and Offshore Engineering, Ocean College Zhejiang University Zhejiang China
- Department of Electronic Engineering The Chinese University of Hong Kong Hong Kong SAR China
| | - Xinghong Ye
- Institute of Port, Coastal and Offshore Engineering, Ocean College Zhejiang University Zhejiang China
| | - Zhiguo He
- Institute of Port, Coastal and Offshore Engineering, Ocean College Zhejiang University Zhejiang China
- Hainan Institute of Zhejiang University Sanya Hainan China
- Engineering Research Center of Oceanic Sensing Technology and Equipment, Zhejiang University Ministry of Education Zhejiang China
| | - Pengcheng Jiao
- Institute of Port, Coastal and Offshore Engineering, Ocean College Zhejiang University Zhejiang China
- Hainan Institute of Zhejiang University Sanya Hainan China
- Engineering Research Center of Oceanic Sensing Technology and Equipment, Zhejiang University Ministry of Education Zhejiang China
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3
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Design and control of soft biomimetic pangasius fish robot using fin ray effect and reinforcement learning. Sci Rep 2022; 12:21861. [PMID: 36529776 PMCID: PMC9760642 DOI: 10.1038/s41598-022-26179-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022] Open
Abstract
Soft robots provide a pathway to accurately mimic biological creatures and be integrated into their environment with minimal invasion or disruption to their ecosystem. These robots made from soft deforming materials possess structural properties and behaviors similar to the bodies and organs of living creatures. However, they are difficult to develop in terms of integrated actuation and sensing, accurate modeling, and precise control. This article presents a soft-rigid hybrid robotic fish inspired by the Pangasius fish. The robot employs a flexible fin ray tail structure driven by a servo motor, to act as the soft body of the robot and provide the undulatory motion to the caudal fin of the fish. To address the modeling and control challenges, reinforcement learning (RL) is proposed as a model-free control strategy for the robot fish to swim and reach a specified target goal. By training and investigating the RL through experiments on real hardware, we illustrate the capability of the fish to learn and achieve the required task.
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Dong X, Luo X, Zhao H, Qiao C, Li J, Yi J, Yang L, Oropeza FJ, Hu TS, Xu Q, Zeng H. Recent advances in biomimetic soft robotics: fabrication approaches, driven strategies and applications. SOFT MATTER 2022; 18:7699-7734. [PMID: 36205123 DOI: 10.1039/d2sm01067d] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Compared to traditional rigid-bodied robots, soft robots are constructed using physically flexible/elastic bodies and electronics to mimic nature and enable novel applications in industry, healthcare, aviation, military, etc. Recently, the fabrication of robots on soft matter with great flexibility and compliance has enabled smooth and sophisticated 'multi-degree-of-freedom' 3D actuation to seamlessly interact with humans, other organisms and non-idealized environments in a highly complex and controllable manner. Herein, we summarize the fabrication approaches, driving strategies, novel applications, and future trends of soft robots. Firstly, we introduce the different fabrication approaches to prepare soft robots and compare and systematically discuss their advantages and disadvantages. Then, we present the actuator-based and material-based driving strategies of soft robotics and their characteristics. The representative applications of soft robotics in artificial intelligence, medicine, sensors, and engineering are summarized. Also, some remaining challenges and future perspectives in soft robotics are provided. This work highlights the recent advances of soft robotics in terms of functional material selection, structure design, control strategies and biomimicry, providing useful insights into the development of next-generation functional soft robotics.
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Affiliation(s)
- Xiaoxiao Dong
- College of Mechanical and Transportation Engineering, China University of Petroleum-Beijing, Beijing 102249, China.
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton T6G 1H9, Canada.
| | - Xiaohang Luo
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum-Beijing, Beijing 102249, China
| | - Hong Zhao
- College of Mechanical and Transportation Engineering, China University of Petroleum-Beijing, Beijing 102249, China.
| | - Chenyu Qiao
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton T6G 1H9, Canada.
| | - Jiapeng Li
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum-Beijing, Beijing 102249, China
| | - Jianhong Yi
- Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China.
| | - Li Yang
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton T6G 1H9, Canada.
- Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China.
| | - Francisco J Oropeza
- Department of Mechanical Engineering, California State University, Los Angeles, California 90032, USA
| | - Travis Shihao Hu
- Department of Mechanical Engineering, California State University, Los Angeles, California 90032, USA
| | - Quan Xu
- State Key Laboratory of Heavy Oil Processing, China University of Petroleum-Beijing, Beijing 102249, China
| | - Hongbo Zeng
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton T6G 1H9, Canada.
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Huang Z, Ma S, Bagheri H, Ren C, Marvi H. The Impact of Dorsal Fin Design on the Swimming Performance of a Snake-Like Robot. IEEE Robot Autom Lett 2022. [DOI: 10.1109/lra.2022.3153903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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6
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Yang Z, Chen D, Levine DJ, Sung C. Origami-Inspired Robot That Swims via Jet Propulsion. IEEE Robot Autom Lett 2021. [DOI: 10.1109/lra.2021.3097757] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Talamini J, Medvet E, Nichele S. Criticality-Driven Evolution of Adaptable Morphologies of Voxel-Based Soft-Robots. Front Robot AI 2021; 8:673156. [PMID: 34222354 PMCID: PMC8247470 DOI: 10.3389/frobt.2021.673156] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 05/27/2021] [Indexed: 11/24/2022] Open
Abstract
The paradigm of voxel-based soft robots has allowed to shift the complexity from the control algorithm to the robot morphology itself. The bodies of voxel-based soft robots are extremely versatile and more adaptable than the one of traditional robots, since they consist of many simple components that can be freely assembled. Nonetheless, it is still not clear which are the factors responsible for the adaptability of the morphology, which we define as the ability to cope with tasks requiring different skills. In this work, we propose a task-agnostic approach for automatically designing adaptable soft robotic morphologies in simulation, based on the concept of criticality. Criticality is a property belonging to dynamical systems close to a phase transition between the ordered and the chaotic regime. Our hypotheses are that 1) morphologies can be optimized for exhibiting critical dynamics and 2) robots with those morphologies are not worse, on a set of different tasks, than robots with handcrafted morphologies. We introduce a measure of criticality in the context of voxel-based soft robots which is based on the concept of avalanche analysis, often used to assess criticality in biological and artificial neural networks. We let the robot morphologies evolve toward criticality by measuring how close is their avalanche distribution to a power law distribution. We then validate the impact of this approach on the actual adaptability by measuring the resulting robots performance on three different tasks designed to require different skills. The validation results confirm that criticality is indeed a good indicator for the adaptability of a soft robotic morphology, and therefore a promising approach for guiding the design of more adaptive voxel-based soft robots.
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Affiliation(s)
- Jacopo Talamini
- Evolutionary Robotics and Artificial Life Lab, Department of Engineering and Architecture, University of Trieste, Trieste, Italy
| | - Eric Medvet
- Evolutionary Robotics and Artificial Life Lab, Department of Engineering and Architecture, University of Trieste, Trieste, Italy
| | - Stefano Nichele
- Department of Computer Science, Artificial Intelligence Lab, Oslo Metropolitan University, Oslo, Norway.,Department of Holistic Systems, Simula Metropolitan Center for Digital Engineering, Oslo, Norway
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Yurugi M, Shimanokami M, Nagai T, Shintake J, Ikemoto Y. Cartilage structure increases swimming efficiency of underwater robots. Sci Rep 2021; 11:11288. [PMID: 34050230 PMCID: PMC8163796 DOI: 10.1038/s41598-021-90926-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 05/17/2021] [Indexed: 12/03/2022] Open
Abstract
Underwater robots are useful for exploring valuable resources and marine life. Traditional underwater robots use screw propellers, which may be harmful to marine life. In contrast, robots that incorporate the swimming principles, morphologies, and softness of aquatic animals are expected to be more adaptable to the surrounding environment. Rajiform is one of the swimming forms observed in nature, which swims by generating the traveling waves on flat large pectoral fins. From an anatomical point of view, Rajiform fins consist of cartilage structures encapsulated in soft tissue, thereby realizing anisotropic stiffness. We hypothesized that such anisotropy is responsible for the generation of traveling waves that enable a highly efficient swimming. We validate our hypothesis through the development of a stingray robot made of silicone-based cartilages and soft tissue. For comparison, we fabricate a robot without cartilages, as well as the one combining soft tissue and cartilage materials. The fabricated robots are tested to clarify their stiffness and swimming performance. The results show that inclusion of cartilage structure in the robot fins increases the swimming efficiency. It is suggested that arrangement and distribution of soft and hard areas inside the body structure is a key factor to realize high-performance soft underwater robots.
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Affiliation(s)
- Masaki Yurugi
- Faculty of Science and Technology, Department of Mechanical Engineering, Meijo University, 1-501 Shiogamaguchi, Tempaku-ku, Nagoya, 468-8502, Japan
| | - Makoto Shimanokami
- Faculty of Science and Technology, Department of Mechanical Engineering, Meijo University, 1-501 Shiogamaguchi, Tempaku-ku, Nagoya, 468-8502, Japan
| | - Toshiaki Nagai
- Department of Mechanical and Intelligent Systems Engineering, The University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo, 182-8585, Japan
| | - Jun Shintake
- Department of Mechanical and Intelligent Systems Engineering, The University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo, 182-8585, Japan
| | - Yusuke Ikemoto
- Faculty of Science and Technology, Department of Mechanical Engineering, Meijo University, 1-501 Shiogamaguchi, Tempaku-ku, Nagoya, 468-8502, Japan.
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Li Y, Tang Y, Shi H. A Study on Soft Material Parameter Determination by Iterative Force-Displacement Curve Fitting. IEEE Robot Autom Lett 2021. [DOI: 10.1109/lra.2021.3067235] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Shen Z, Zhong H, Xu E, Zhang R, Yip KC, Chan LL, Chan LL, Pan J, Wang W, Wang Z. An Underwater Robotic Manipulator with Soft Bladders and Compact Depth-Independent Actuation. Soft Robot 2020; 7:535-549. [PMID: 32109180 PMCID: PMC7591381 DOI: 10.1089/soro.2019.0087] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
An underwater manipulator is essential for underwater robotic sampling and other service operations. Conventional rigid body underwater manipulators generally required substantial size and weight, leading to hindered general applications. Pioneering soft robotic underwater manipulators have defied this by offering dexterous and lightweight arms and grippers, but still requiring substantial actuation and control components to withstand the water pressure and achieving the desired dynamic performance. In this work, we propose a novel approach to underwater manipulator design and control, exploiting the unique characteristics of soft robots, with a hybrid structure (rigid frame+soft actuator) for improved rigidity and force output, a uniform actuator design allowing one compact hydraulic actuation system to drive all actuators, and a novel fully customizable soft bladder design that improves performances in multiple areas: (1) force output of the actuator is decoupled from the working depth, enabling wide working ranges; (2) all actuators are connected to the main hydraulic line without actuator-specific control loop, resulting in a very compact actuation system especially for high-dexterity cases; (3) dynamic responses were improved significantly compared with the counter system without bladder. A prototype soft manipulator with 4-DOFs, dual bladders, and 15 N payload was developed; the entire system (including actuation, control, and batteries) could be mounted onto a consumer-grade remotely operated vehicle, with depth-independent performances validated by various laboratory and field test results across various climatic and hydrographic conditions. Analytical models and validations of the proposed soft bladder design were also presented as a guideline for other applications.
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Affiliation(s)
- Zhong Shen
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong SAR, China
| | - Hua Zhong
- Department of Computer Science, The University of Hong Kong, Hong Kong SAR, China
| | - Erchao Xu
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong SAR, China
| | - Runzhi Zhang
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong SAR, China
| | - Ki Chun Yip
- State Key Laboratory of Marine Pollution and Shenzhen Key Laboratory for the Sustainable Use of Marine Biodiversity, City University of Hong Kong, Hong Kong SAR, China
| | - Lawrence Long Chan
- State Key Laboratory of Marine Pollution and Shenzhen Key Laboratory for the Sustainable Use of Marine Biodiversity, City University of Hong Kong, Hong Kong SAR, China
| | - Leo Lai Chan
- State Key Laboratory of Marine Pollution and Shenzhen Key Laboratory for the Sustainable Use of Marine Biodiversity, City University of Hong Kong, Hong Kong SAR, China
| | - Jia Pan
- Department of Computer Science, The University of Hong Kong, Hong Kong SAR, China
| | - Wenping Wang
- Department of Computer Science, The University of Hong Kong, Hong Kong SAR, China
| | - Zheng Wang
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong SAR, China
- Department of Mechanical and Energy Engineering, Southern University of Science and Technology, Shenzhen, China
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Zhou Z, Mittal R. Computational modeling of swimming in marine invertebrates with implications for soft swimming robots. BIOINSPIRATION & BIOMIMETICS 2020; 15:046010. [PMID: 32320957 DOI: 10.1088/1748-3190/ab8bee] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Marine flatworms (polyclads) employ a wide variety of body kinematics for swimming. In the current study, we employ computational fluid dynamics to study the hydrodynamics and swimming performance of a large variety of swimmers inspired directly from flatworms as well as two other marine invertebrates: Aplysia and Spanish dancers. The free-swimming performance is evaluated via two metrics: Froude efficiency and terminal swimming speed. The study examines the effect of the flapping of the lateral margins of the body as well as body undulation, which are used in various combinations by these animals to achieve swimming. The simulations suggest that a spanwise compact wake with distinct vortex ring structures is well correlated with a high swimming performance. We find that the addition of even a small magnitude of body undulation to lateral flapping results in significant changes in the wake patterns and noticeable improvements in the swimming performance compared to swimmers that employ only lateral flapping. Periodic body-bending synchronized with lateral flapping, as employed by the Spanish dancer, is found to be a very effective swimming gait. Some gaits that employ body undulations but no lateral flapping are found to generate high swimming speeds but with limited swimming efficiencies. Taken together, this study provides insights that could inform the design of swimming robots.
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Affiliation(s)
- Zhuoyu Zhou
- Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218, United States of America
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12
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A Flapped Paddle-Fin for Improving Underwater Propulsive Efficiency of Oscillatory Actuation. IEEE Robot Autom Lett 2020. [DOI: 10.1109/lra.2020.2975747] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Sinatra NR, Teeple CB, Vogt DM, Parker KK, Gruber DF, Wood RJ. Ultragentle manipulation of delicate structures using a soft robotic gripper. Sci Robot 2019; 4:4/33/eaax5425. [DOI: 10.1126/scirobotics.aax5425] [Citation(s) in RCA: 96] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Accepted: 08/05/2019] [Indexed: 11/02/2022]
Abstract
Here, we present ultragentle soft robotic actuators capable of grasping delicate specimens of gelatinous marine life. Although state-of-the-art soft robotic manipulators have demonstrated gentle gripping of brittle animals (e.g., corals) and echinoderms (e.g., sea cucumbers) in the deep sea, they are unable to nondestructively grasp more fragile soft-bodied organisms, such as jellyfish. Through an exploration of design parameters and laboratory testing of individual actuators, we confirmed that our nanofiber-reinforced soft actuators apply sufficiently low contact pressure to ensure minimal harm to typical jellyfish species. We then built a gripping device using several actuators and evaluated its underwater grasping performance in the laboratory. By assessing the gripper’s region of acquisition and robustness to external forces, we gained insight into the necessary precision and speed with which grasping maneuvers must be performed to achieve successful collection of samples. Last, we demonstrated successful manipulation of three live jellyfish species in an aquarium setting using a hand-held prototype gripper. Overall, our ultragentle gripper demonstrates an improvement in gentle sample collection compared with existing deep-sea sampling devices. Extensions of this technology may improve a variety of in situ characterization techniques used to study the ecological and genetic features of deep-sea organisms.
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Abstract
In this work, we design a type of soft robots for flipping locomotion, called the FifoBots. Different from most of the current soft robots that perform crawling, rolling, or jumping locomotion, the proposed FifoBots can flip forward and backward like a piece of self-foldable paper. The FifoBots have simple actuation and avoid complicated balance control. This article presents the principle and analysis of the flipping locomotion as well as the prototypes and experiments of the FifoBots. Two schemes of the flipping locomotion are proposed, and each scheme has the linear and quadrilateral morphologies, enabling the straight and biaxial movements, respectively. The movement performance in each stage of the flipping locomotion is analyzed oriented to the parameter design. The prototypes are constructed by using customized bidirectional Curl pneumatic artificial muscles as the flexible hinges and 3D printed parts as the rigid limbs. Feasibility and adaptability of the proposed robots are validated by locomotion experiments. The FifoBots have potential applications in space exploration in complicated environments with slope, gap, obstacle, or rocky terrain.
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Affiliation(s)
- Jiangbei Wang
- Research Institute of Robotics, Shanghai Jiao Tong University, Shanghai, China
| | - Yanqiong Fei
- Research Institute of Robotics, Shanghai Jiao Tong University, Shanghai, China
| | - Zhaoyu Liu
- Research Institute of Robotics, Shanghai Jiao Tong University, Shanghai, China
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Chen X, Yi J, Li J, Zhou J, Wang Z. Soft-Actuator-Based Robotic Joint for Safe and Forceful Interaction With Controllable Impact Response. IEEE Robot Autom Lett 2018. [DOI: 10.1109/lra.2018.2854409] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Li X, Wen R, Shen Z, Wang Z, Luk KDK, Hu Y. A Wearable Detector for Simultaneous Finger Joint Motion Measurement. IEEE TRANSACTIONS ON BIOMEDICAL CIRCUITS AND SYSTEMS 2018; 12:644-654. [PMID: 29877827 DOI: 10.1109/tbcas.2018.2810182] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
This paper presents a wearable and stretchable detector for simultaneous finger joint motion measurement, providing the feasible technical solutions to solve the problems existing in the current devices. The sensor array installed in the detector consists of 14 custom-made bending sensors and an inertial measurement unit with high accuracy. The glove support for a sensor array, which is made of three silicone materials with different elasticity, not only overcomes the drawbacks of cloth support, but also addresses the compatibility between the stretch substrate and the inelastic sensing components. Besides, two-section electrical connection avoids the problems caused by the external wires in traditional solutions to enhance the durability of glove. The experiment results indicated that the wearable detector offers a good user experience by exerting a small force on fingers. The device also shows a strong durability as it worked properly after tens of thousands of bending. The measurement tests on a single sensor demonstrated that two kinds of sensors are both with high accuracy. Besides, the hand goniometric system has an excellent performance in terms of hand motion detection. The measurement error of the device in subjects with different hand sizes is within a reasonable range. The good properties of the sensory detector allow it to be applied in clinical applications.
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