Design and feasibility tests of a flexible gripper based on inflatable rubber pockets

Choi, Hyungsoo; Koç, Muammer

doi:10.1016/j.ijmachtools.2005.10.009

Cited by 82 publications

(43 citation statements)

References 19 publications

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“…15,28,29). A gripper with an elastic membrane might conform to protruding parts of objects (as in Fig.…”

Section: Resultsmentioning

confidence: 99%

“…For reliable robotic gripping, the standard design approach is based on a hand with two or more fingers (1)(2)(3)(4)(5), and typically involves a combination of visual feedback and force sensing at the fingertips. A large number of optimization schemes for finger placement as well as the use of compliant materials for adaptive grasping have been discussed (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15). Given the evolutionary success of the multifingered hand in animals, this approach clearly has many advantages.…”

mentioning

confidence: 99%

“…A few designs have envisioned systems where moveable jaws with highly compliant surfaces contact the object from two or more sides, partially enveloping and thus securing it. For example, Choi and Koc recently presented a gripper whose jaws were outfitted with inflatable rubber pockets (15). Earlier, Schmidt (17) and Perovskii (18) introduced the idea of attaching elastic bags loosely filled with granular material, such as small pellets or spheres, to the gripper jaws.…”

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confidence: 99%

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Universal robotic gripper based on the jamming of granular material

Brown

Rodenberg

Amend

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

1,276

817

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Gripping and holding of objects are key tasks for robotic manipulators. The development of universal grippers able to pick up unfamiliar objects of widely varying shape and surface properties remains, however, challenging. Most current designs are based on the multifingered hand, but this approach introduces hardware and software complexities. These include large numbers of controllable joints, the need for force sensing if objects are to be handled securely without crushing them, and the computational overhead to decide how much stress each finger should apply and where. Here we demonstrate a completely different approach to a universal gripper. Individual fingers are replaced by a single mass of granular material that, when pressed onto a target object, flows around it and conforms to its shape. Upon application of a vacuum the granular material contracts and hardens quickly to pinch and hold the object without requiring sensory feedback. We find that volume changes of less than 0.5% suffice to grip objects reliably and hold them with forces exceeding many times their weight. We show that the operating principle is the ability of granular materials to transition between an unjammed, deformable state and a jammed state with solid-like rigidity. We delineate three separate mechanisms, friction, suction, and interlocking, that contribute to the gripping force. Using a simple model we relate each of them to the mechanical strength of the jammed state. This advance opens up new possibilities for the design of simple, yet highly adaptive systems that excel at fast gripping of complex objects.stress-strain | packing density | friction | suction | interlocking

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“…15,28,29). A gripper with an elastic membrane might conform to protruding parts of objects (as in Fig.…”

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Universal robotic gripper based on the jamming of granular material

Brown

Rodenberg

Amend

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

1,276

817

View full text Add to dashboard Cite

show abstract

“…Robotic hands [1][2][3][4][5][6][7][8][9][10][11][12][13] have essential roles as end-effectors to complete such tasks. In order to substitute for the hands of a human, robotic hands must be able to perform a wide variety of functions to grasp and manipulate objects.…”

Section: Introductionmentioning

confidence: 99%

Identification of danger state for grasping delicate tofu with fingertips containing viscoelastic fluid

Adachi

Fujihira

Watanabe

2015

2015 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)

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Abstract-In this study, we experimentally investigated the process leading to fracture in tofu grasping by deformable fingertips filled with a fluid. In our previous papers [1, 2], we developed deformable fingertips using a rubber bag filled with a viscoelastic fluid, and presented a strategy for delicate tofu grasping without any advance knowledge about fracture. However, the predication point was close to fracture, and the prediction was then still a gamble. In order to realize fracture prediction at an earlier stage, we examined the process leading to fracture when pushing tofu by the deformable fingertips. The stiffness of the fingertips can be controlled with the pressure of the fluid inside the fingertips. The pushing force and fluid pressure were examined for different levels of stiffness of the fingertips. The main findings and contributions are as follows. 1) The convergence of the ratio of the contact force to fluid pressure gives an indication of dent occurrence. This convergence could be seen when fingertip rubber bag was not filled (low stiffness). 2) It was easier for a dent to occur when the fingertip rubber bag was not filled than when it was filled (high stiffness). 3) Changes in the rate of increase of the fluid pressure as the tofu was pushed were repeatedly observed. We defined this as a phase change and present a method for detecting such changes. The phase change points were detected by comparing the fitting accuracies of different approximation models. 4) The last and second to the last phase changes before fracture were detected by detecting the first phase change (after the convergence of the rate of the contact force to fluid pressure if the fingertip bag was not completely filled). The detected points can be regarded as alert points indicating a fracture risk that is not close to the fracture point.

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“…The current approach to reduce the impact forces is to couple the gripper to the drive unit of the placement device while leaving 1 DOF unconstrained using a flexible part, wherein the gripper that contacts the component, has a relatively low mass [11][12][13][14][15][16][17][18][19]. In this setup the drive unit will move relatively to the gripper at the end of the component placement.…”

Section: Introductionmentioning

confidence: 99%

Statically Determined Gripper Construction

Plak¹,

Görtzen²,

Puik³

Micro-Assembly Technologies and Applications

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The current approach to reducing impact forces during component placement in micro-assembly is to couple the gripper with 5 Degrees Of Freedom (DOF) to the drive unit of the placement device, wherein the mass of the gripper has been reduced maximally. At the end of the placement motion the drive unit will move relatively to the gripper, as linear as possible given the limitations of the construction. During this motion generally stress builds up in the gripper and it becomes over-constrained due to the extra constraints added by the contact between gripper/component and the substrate. Due to this tension the gripper will start vibrating when the gripper rebounces or when the component is released, resulting in significant placement inaccuracies. A solution has been found to prevent the gripper from becoming over-constrained by adding an extra tilting member to the gripper, leading to a reduction of the placement inaccuracies.

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Design and feasibility tests of a flexible gripper based on inflatable rubber pockets

Cited by 82 publications

References 19 publications

Universal robotic gripper based on the jamming of granular material

Universal robotic gripper based on the jamming of granular material

Identification of danger state for grasping delicate tofu with fingertips containing viscoelastic fluid

Statically Determined Gripper Construction

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