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Shen D, Zhang Q, Han Y, Tu C, Wang X. Design and Development of a Continuum Robot with Switching-Stiffness. Soft Robot 2023; 10:1015-1027. [PMID: 37184583 DOI: 10.1089/soro.2022.0179] [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: 05/16/2023] Open
Abstract
Continuum robots have the advantages of agility and adaptability. However, existing continuum robots have limitations of low stiffness and complex motion modes, and the existing variable stiffness methods cannot achieve a wide range of stiffness changes and fast switching stiffness simultaneously. A continuum robot structure, switching stiffness method, and motion principle are proposed in this article. The continuum robot is made up of three segments connected in series. Each segment comprises multiple spherical joints connected in series, and the joints can be locked by their respective airbag. A valve controls each airbag, quickly switching the segment between rigidity and flexibility. The motion of the segments is driven by three cables that run through the robot. The segment steers only when it is unlocked. When a segment becomes locked, it acts as a rigid body. As a result, by locking and unlocking each segment in sequence, the cables can alternately drive all the segments. The stiffness variation and movement of the continuum robot were tested. The segment's stiffness varies from 36.89 to 1300.95 N/m and the stiffness switching time is 0.25-0.48 s. The time-sharing control mode of segment stiffness and motion is validated by establishing a specific test platform and a mathematical model. The continuum robot's flexibility is demonstrated by controlling the fast bending of different segments sequentially.
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Affiliation(s)
- Donghua Shen
- School of Mechanical Engineering, Nanjing Institute of Technology, Nanjing, China
| | - Qi Zhang
- School of Automation, Nanjing University of Information Science and Technology, Nanjing, China
| | - Yali Han
- School of Mechanical Engineering, Nanjing Institute of Technology, Nanjing, China
| | - Chunlei Tu
- School of Mechanical Engineering, Southeast University, Nanjing, China
- Special Equipment Safety Supervision Inspection Institute of Jiangsu Province, Nanjing, China
| | - Xingsong Wang
- School of Mechanical Engineering, Southeast University, Nanjing, China
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2
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Abstract
In addition to high compliance to unstructured environments, soft robots can be further improved to gain the advantages of rigid robots by increasing stiffness. Indeed, realizing the adjustable stiffness of soft continuum robots can provide safer interactions with objects and greatly expand their application range. To address the above situation, we propose a tubular stiffening segment based on layer jamming. It can temporarily increase the stiffness of the soft robot in a desired configuration. Furthermore, we also present a spine-inspired soft robot that can provide support in tubular segments to prevent buckling. Theoretical analysis was conducted to predict the stiffness variation of the robot at different vacuum levels. Finally, we integrated the spine-inspired soft robot and tubular stiffening segment to obtain the tuneable-stiffness soft continuum robot (TSCR). Experimental tests were performed to evaluate the robot’s shape control and stiffness tuning effectiveness. Experimental results showed that the bending stiffness of the initial TSCR increased by more than 15× at 0°, 30× at 90°, and 60× in compressive stiffness.
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3
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Zhou P, Yao J, Wei C, Zhang S, Zhang H, Qi S. Design and kinematic of a dexterous bioinspired elephant trunk robot with variable diameter. BIOINSPIRATION & BIOMIMETICS 2022; 17:046016. [PMID: 35609564 DOI: 10.1088/1748-3190/ac72e0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Accepted: 05/24/2022] [Indexed: 06/15/2023]
Abstract
How to further improve the dexterity of continuum robots so that they can quickly change their structural size like flexible biological organs is a key challenge in the field of robotics. To tackle this dexterity challenge, this paper proposes a soft-rigid coupled bioinspired elephant trunk robot with variable diameter, which is enabled by combining a soft motion mechanism with a novel rigid variable-diameter mechanism (double pyramid deployable mechanism). The integration of these two mechanisms has produced three significant beneficial effects: (i) The coexistence of multi-degree-of-freedom motion capability and variable size function greatly improves the dexterity of the elephant trunk robot. (ii) The motion refinement can be improved by structural amplification, making up for the low resolution of soft actuators. (iii) Its stiffness can be increased by enlarging its diameter, while its reachable workspace can be increased by decreasing its diameter. Thus, the elephant trunk robot can optimize its performance when facing different tasks by opening and closing the rigid variable-diameter mechanism. Further, we established a kinematic model of the elephant trunk robot by the structure discretization method and the principle of mechanism equivalence, and experimentally verified its reasonableness. The demonstration experiments show that the elephant trunk robot has good flexibility. This work provides a new variable diameter configuration for continuum robots, and presents a method of how to analyze the kinematics of continuum mechanisms using rigid mechanism theory.
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Affiliation(s)
- Pan Zhou
- Hebei Provincial Key Laboratory of Parallel Robot and Mechatronic System, Yanshan University, Qinhuangdao, 066004, People's Republic of China
| | - Jiantao Yao
- Hebei Provincial Key Laboratory of Parallel Robot and Mechatronic System, Yanshan University, Qinhuangdao, 066004, People's Republic of China
- Key Laboratory of Advanced Forging & Stamping Technology and Science (Yanshan University), Ministry of Education of China, Qinhuangdao, 066004, People's Republic of China
| | - Chunjie Wei
- Hebei Provincial Key Laboratory of Parallel Robot and Mechatronic System, Yanshan University, Qinhuangdao, 066004, People's Republic of China
| | - Shuai Zhang
- Hebei Provincial Key Laboratory of Parallel Robot and Mechatronic System, Yanshan University, Qinhuangdao, 066004, People's Republic of China
| | - Hongyu Zhang
- Hebei Provincial Key Laboratory of Parallel Robot and Mechatronic System, Yanshan University, Qinhuangdao, 066004, People's Republic of China
- Faculty of Science and Engineering, University of Groningen, 9747 AG Groningen, The Netherlands
| | - Shupeng Qi
- Hebei Provincial Key Laboratory of Parallel Robot and Mechatronic System, Yanshan University, Qinhuangdao, 066004, People's Republic of China
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Jiang Y, Ma J, Chen D, Liu Z, Li Y, Paik J. Compact Pneumatic Clutch With Integrated Stiffness Variation and Position Feedback. IEEE Robot Autom Lett 2021. [DOI: 10.1109/lra.2021.3083236] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Abstract
Compliant continuum robots (CCRs) have slender and elastic bodies. Compared with a traditional serial robot, they have more degrees of freedom and can deform their flexible bodies to go through a constrained environment. In this paper, we classify CCRs according to basic transmission units. The merits, materials and potential drawbacks of each type of CCR are described. Drive systems depend on the basic transmission units significantly, and their advantages and disadvantages are reviewed and summarized. Variable stiffness and intrinsic sensing are desired characteristics of CCRs, and the methods of obtaining the two characteristics are discussed. Finally, we discuss the friction, buckling, singularity and twisting problems of CCRs, and emphasise the ways to reduce their effects, followed by several proposing perspectives, such as the collaborative CCRs.
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Zhou L, Ren L, Chen Y, Niu S, Han Z, Ren L. Bio-Inspired Soft Grippers Based on Impactive Gripping. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2021; 8:2002017. [PMID: 33977041 PMCID: PMC8097330 DOI: 10.1002/advs.202002017] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 12/17/2020] [Indexed: 05/23/2023]
Abstract
Grasping and manipulation are fundamental ways for many creatures to interact with their environments. Different morphologies and grasping methods of "grippers" are highly evolved to adapt to harsh survival conditions. For example, human hands and bird feet are composed of rigid frames and soft joints. Compared with human hands, some plants like Drosera do not have rigid frames, so they can bend at arbitrary points of the body to capture their prey. Furthermore, many muscular hydrostat animals and plant tendrils can implement more complex twisting motions in 3D space. Recently, inspired by the flexible grasping methods present in nature, increasingly more bio-inspired soft grippers have been fabricated with compliant and soft materials. Based on this, the present review focuses on the recent research progress of bio-inspired soft grippers based on impactive gripping. According to their types of movement and a classification model inspired by biological "grippers", soft grippers are classified into three types, namely, non-continuum bending-type grippers, continuum bending-type grippers, and continuum twisting-type grippers. An exhaustive and updated analysis of each type of gripper is provided. Moreover, this review offers an overview of the different stiffness-controllable strategies developed in recent years.
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Affiliation(s)
- Liang Zhou
- Key Laboratory of Bionic EngineeringMinistry of EducationJilin UniversityChangchunJilin130022P. R. China
| | - Lili Ren
- Key Laboratory of Bionic EngineeringMinistry of EducationJilin UniversityChangchunJilin130022P. R. China
| | - You Chen
- Key Laboratory of Bionic EngineeringMinistry of EducationJilin UniversityChangchunJilin130022P. R. China
| | - Shichao Niu
- Key Laboratory of Bionic EngineeringMinistry of EducationJilin UniversityChangchunJilin130022P. R. China
| | - Zhiwu Han
- Key Laboratory of Bionic EngineeringMinistry of EducationJilin UniversityChangchunJilin130022P. R. China
| | - Luquan Ren
- Key Laboratory of Bionic EngineeringMinistry of EducationJilin UniversityChangchunJilin130022P. R. China
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A Versatile Pneumatic Actuator Based on Scissor Mechanisms: Design, Modeling, and Experiments. IEEE Robot Autom Lett 2021. [DOI: 10.1109/lra.2021.3057286] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Xing Z, Wang F, Ji Y, McCoul D, Wang X, Zhao J. A Structure for Fast Stiffness-Variation and Omnidirectional-Steering Continuum Manipulator. IEEE Robot Autom Lett 2021. [DOI: 10.1109/lra.2020.3037858] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Boettcher G, Lilge S, Burgner-Kahrs J. Design of a Reconfigurable Parallel Continuum Robot With Tendon-Actuated Kinematic Chains. IEEE Robot Autom Lett 2021. [DOI: 10.1109/lra.2021.3057557] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Yan K, Yan W, Zeng W, Ding Q, Chen J, Yan J, Lam CP, Wan S, Cheng SS. Towards a Wristed Percutaneous Robot With Variable Stiffness for Pericardiocentesis. IEEE Robot Autom Lett 2021. [DOI: 10.1109/lra.2021.3062583] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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11
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Ibrahimi M, Paternò L, Ricotti L, Menciassi A. A Layer Jamming Actuator for Tunable Stiffness and Shape-Changing Devices. Soft Robot 2020; 8:85-96. [PMID: 32456553 DOI: 10.1089/soro.2019.0182] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Changing the shape and the stiffness of a device in a dynamic and controlled way enables important advancements in the field of robotics and wearable robotics. Variable stiffness materials and technologies can be used to address this challenge. In particular, layer jamming actuation is a very promising technology, featured by high efficiency and low cost. In this article, a stiffness- and shape-changing device based on a novel mechanism including a multiple-chamber structure is proposed. It allows to effectively modulate the shape and stiffness of a device, by activating two jamming chambers while pressurizing/depressurizing one or more interposed inflatable chambers. Prototypes with a size of 45 × 270 mm2 and an average thickness ranging from 4.4 to 13 mm were developed and their ability to undergo a stiffness change over two orders of magnitude was demonstrated. The prototypes were also able to change their shape according to the position and inflation level of the interposed inflatable chambers, thus resulting in an overall deflection >10 mm. The possibility to wear the system as an orthotic brace was also demonstrated: this technology increased the patient comfort in static positions, yet keeping a supportive function when needed (e.g., in dynamic conditions). The device working principle highlighted in this article could also be exploited in other domains, for example, to build walking soft robots, prostheses, or grippers, as demonstrated through additional tests.
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Affiliation(s)
- Michele Ibrahimi
- The Biorobotics Institute, Scuola Superiore di Studi Universitari e di Perfezionamento Sant'Anna, Pontedera, Italy.,Department of Excellence in Robotics & AI, Scuola Superiore di Studi Universitari e di Perfezionamento Sant'Anna, Pontedera, Italy
| | - Linda Paternò
- The Biorobotics Institute, Scuola Superiore di Studi Universitari e di Perfezionamento Sant'Anna, Pontedera, Italy.,Department of Excellence in Robotics & AI, Scuola Superiore di Studi Universitari e di Perfezionamento Sant'Anna, Pontedera, Italy
| | - Leonardo Ricotti
- The Biorobotics Institute, Scuola Superiore di Studi Universitari e di Perfezionamento Sant'Anna, Pontedera, Italy.,Department of Excellence in Robotics & AI, Scuola Superiore di Studi Universitari e di Perfezionamento Sant'Anna, Pontedera, Italy
| | - Arianna Menciassi
- The Biorobotics Institute, Scuola Superiore di Studi Universitari e di Perfezionamento Sant'Anna, Pontedera, Italy.,Department of Excellence in Robotics & AI, Scuola Superiore di Studi Universitari e di Perfezionamento Sant'Anna, Pontedera, Italy
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12
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Zhang Y, Lu M. A review of recent advancements in soft and flexible robots for medical applications. Int J Med Robot 2020; 16:e2096. [PMID: 32091642 DOI: 10.1002/rcs.2096] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 02/05/2020] [Accepted: 02/19/2020] [Indexed: 11/06/2022]
Abstract
BACKGROUND Soft and flexible robots for medical applications are needed to change their flexibility over a wide range to perform tasks adequately. The mechanism and theory of flexibility has been a scientific issue and is of interest to the community. METHODS Recent advancements of bionics, flexible actuation, sensing, and intelligent control algorithms as well as tunable stiffness have been referenced when soft and flexible robots are developed. The benefits and limitations of these relevant studies and how they affect the flexibility are discussed, and possible research directions are explored. RESULTS The bionic materials and structures that demonstrate the potential capabilities of the soft medical robot flexibility are the fundamental guarantee for clinical medical applications. Flexible actuation that used to provide power, intelligent control algorithms which are the exact executors, and the wide range stiffness of the soft materials are the three important influence factors for soft medical robots. CONCLUSION Some reasonable suggestions and possible solutions for soft and flexible medical robots are proposed, including novel materials, flexible actuation concepts with a built-in source of energy or power, programmable flexibility, and adjustable stiffness.
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Affiliation(s)
- Yongde Zhang
- Intelligent Machine Institute, Harbin University of Science and Technology, Harbin, China
| | - Mingyue Lu
- Intelligent Machine Institute, Harbin University of Science and Technology, Harbin, China
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Abstract
Variable-stiffness artificial muscles are important in many applications including running and hopping robots, human–robot interaction, and active suspension systems. Previously used technologies include pneumatic muscles, layer and granular jamming, series elastic actuators, and shape memory polymers. All these are limited in terms of cost, complexity, the need for fluid power supplies, or controllability. In this article, we present a new concept for variable-stiffness artificial muscles (the twisted rubber artificial muscle, TRAM) made from twisted rubber cord that overcomes these limitations. Rubber cord is inexpensive, readily available, and inherently compliant. When an extended piece of rubber cord is twisted, the tensile force it exerts is reduced and its stiffness is altered. This behavior makes twisted rubber ideal for use as an artificial muscle, because its output force and natural stiffness are both controllable by varying twist angle. We investigate the behavior of four types of rubber cord and evaluate which type of rubber allows for the greatest reversible reduction in average stiffness (fluoroelastomer [FKM standard] rubber, 56.42% reduction) and initial stiffness (silicone rubber, 92.62%). Tensile force and stiffness can be further altered by increasing the twist angle of the artificial muscle beyond a threshold angle, which initiates nonlinear buckling behavior. This, however, can cause plastic deformation of the artificial muscle. Using a single TRAM, we show how the equilibrium position and natural frequency of a system can be simultaneously altered by controlling twist angle. We further demonstrate independent position and stiffness control of a functional robotic arm system using an antagonistic pair of TRAMs. TRAMs are ready for immediate inclusion in a wide range of robotic systems.
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Affiliation(s)
- Tim Helps
- Department of Engineering Mathematics, University of Bristol, Bristol, United Kingdom.,Bristol Robotics Laboratory, Bristol, United Kingdom
| | - Majid Taghavi
- Department of Engineering Mathematics, University of Bristol, Bristol, United Kingdom.,Bristol Robotics Laboratory, Bristol, United Kingdom
| | - Sihan Wang
- Department of Engineering Mathematics, University of Bristol, Bristol, United Kingdom
| | - Jonathan Rossiter
- Department of Engineering Mathematics, University of Bristol, Bristol, United Kingdom.,Bristol Robotics Laboratory, Bristol, United Kingdom
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Clark AB, Rojas N. Assessing the Performance of Variable Stiffness Continuum Structures of Large Diameter. IEEE Robot Autom Lett 2019. [DOI: 10.1109/lra.2019.2905980] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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15
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Toward a Flexible Variable Stiffness Endoport for Single-Site Partial Nephrectomy. Ann Biomed Eng 2018; 46:1498-1510. [DOI: 10.1007/s10439-018-2060-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Accepted: 05/25/2018] [Indexed: 01/29/2023]
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