WO2015006613A1 - End effector, apparatus, system and method for gripping and releasing articles and the like - Google Patents

Abstract

A passive gripping and releasing apparatus includes a gripper having an enclosure comprising a flexible, impermeable membrane with an opening fluidically coupled to a positive source of fluid ingress and a negative source of fluid egress in an evacuable sealing relationship, wherein the positive source is above atmospheric pressure. The apparatus may also have at least one port providing the source of fluid ingress and egress disposed in fluid connection with the opening of the membrane, and a granular material disposed within the membrane.

Description

END EFFECTOR, APPARATUS, SYSTEM AND METHOD FOR GRIPPING AND RELEASING ARTICLES AND THE LIKE

FIELD OF THIS DISCLOSURE;

[001] This disclosure related generally to handling and, more particularly, to arrangements for gripping and releasing articles for robotic applications and the like.

BACKGROUND OF THE DISCLOSURE

[002] End effectors such as universal robot grippers are intended to handle a wide variety of arbitrarily-shaped objects. Conventional universal g ippers range from vacuum-based suction grippers to hands with multiple fingers. Generally speaking, these grippers are either of the active or passive type. Active universal grippers typically have an anthropomorphic, multi-fingered design intended to mimic grasping and handling capabilities of the human hand. While active universal g ippers are usually capable of both grasping and manipulation, their operation involves extensive physical and computational complexity. Although useful, the complexities of operating active universal g ippers, and correspondingly high costs, have limited their applications and economic feasibility.

[003] Passive universal grippers, on the other hand, require minimal grasp planning. They are under actuated, and include components that passively conform to unique object geometries, giving them the ability to grip widely varying objects without readjustment. A passive gripper, for example, may include a plurality of independent telescoping pins, each of which slide passively in or out to conform to the shape of a target object, then pinch from the sides to grip the object.

[004] Passive universal grippers have generally been found simpler to use than active grippers and require minimal visual preprocessing of their environment. While beneficial, these grippers often have many passive components that are easily damaged and difficult to replace. Due to their ability to accommodate and grip many different objects, they are relatively less effective at gripping when used to for a single and distinct gripping application as compared to active grippers. Passive grippers, like active ones, have also been found expensive, and while advantageous, their widespread use has similarly met with limited success.

[005] In an effort to lower the threshold of gripping and, thereby, increase gripper effectiveness, deformable materials have been added, for instance, to gripping faces of a traditional jawed gripper to increase compliance of the surfaces. Alternatively, pockets of granular materials have been added to the gripping surfaces. Other attempts have utilized vacuum hardening grain-filled pockets to produce a custom gripper jew shape or a single membrane filled with granular material for gripping an object on its own and functioning as a passive universal gripper.

[008] More recently, passive universal grippers have been developed which take advantage of the temperature independent fluid-like to solid-like pseudo-phase transition of granular materials known as "jamming". These "jamming" grippers utilize three gripping modes of operation: (a) static friction from surface contact, (b) geometric constraints from capture of the object by interlocking, and (c) vacuum suction when an airtight seal is achieved on some portion of the object's surface. Through one or more of these modes, the jamming gripper may grip many different objects with widely varying shape, weight, and fragility, including objects that are traditionally challenging for other universal grippers such as a coin, a tetrahedron, a hemisphere, a raw egg, a jack toy, and a foam earplug. The gripper functions entirely in open loop, without grasp planning, vision, or sensory feedback. [007] When the gripped object is to be released by a jamming gripper, the gripper, in general, and the vacuum hardened granular material, in particular, is vented and returned to atmospheric pressure, causing the gripper to release the object. While advantageous, the pressure of the granular materials must be reset each time a gripping task is performed, limiting the performance of universal jamming grippers. In addition, it has often been found necessary to reset the gripper manually, such as by kneading or massaging the same, albeit imprecisely, to return it to a neutral state. Otherwise, its ability to grip objects may rapidly degrade.

[008] An improved passive universal gripping apparatus, system and method is, therefore, desired that improves gripping, handling and release of objects and hastens reset time.

OBJECTS AND SUMiMARY OF THE DISCLOSURE

[009] Accordingly, it is an object of the disclosure to provide a simple, efficient, reliable and economical gripper for robotic applications and the like.

[010] Another object of the disclosure is to provide a gripper thai avoids operating complexifies characteristic of active universal grippers without utilizing components that are easily damaged or difficult to replace.

[01 1] A further object of the disclosure is to provide a gripper that is effective not only at gripping when used for a single and distinct gripping application but also accommodates and grips many different object configurations.

[012] Yet another object of the disclosure is to provide a gripper for enhanced operation and performance without the necessity of manual resetting nor rapid degradation of its gripping effectiveness. [013] Still another object of the disclosure is to provide a device that not only provides for superior gripping, handling and release of objects, but also hastens reset time.

[014] One aspect of the present disclosure is directed to a passive gripping and releasing apparatus. The apparatus may include a gripper having an enclosure comprising a flexible, impermeable membrane with an opening fluidically coupled to a positive source of fluid ingress and a negative source of fluid egress source of fluid ingress and egress in an evacuable sealing relationship, wherein the positive source is above atmospheric pressure. The apparatus may also include at least one port providing the source of fluid ingress and egress disposed in fluid connection with the opening of the membrane, and a granular material disposed within the membrane.

[015] Another aspect of the present disclosure is directed to a gripping and releasing device including an enclosure comprising a flexible, impermeable membrane having an opening fluidically coupled to a source of fluid ingress and fluid egress in an evacuable sealing relationship, at least one port providing the source of fluid ingress and egress disposed in fluid connection with the opening of the membrane, and a resettable granular material disposed within the membrane.

[016] Another aspect of the present disclosure is directed to a method for gripping and releasing an object using a passive universal jamming gripper including a suitable jamming material characterized by a fluid-like to solid-like phase transition upon application of a vacuum, wherein the gripper is in a gripped state in which an object is being gripped. The method may comprise applying a vacuum to the jamming material to cause a fluid-like to solid-like phase transition to grip the object, and applying a positive fluid pressure to the jamming material to cause a solid-like to fluid-like phase transition, wherein the gripped object is actively released from the gripper.

[017] Another aspect of the present disclosure may be directed to a gripping and releasing apparatus that includes a flexible impermeable membrane defining an enclosure configured to contain a granular material. The apparatus may also include at least one port in fluid communication with the enclosure and in fluid communication with a source configured to apply a vacuum and a positive pressure, wherein the undeformed shape of the flexible impermeable membrane is a vertical ellipse.

BRIEF DESCRIPTION OF THE. DRAWINGS

[018] FIGS. 1 A and 1 B show arrangements for fluidization of granular materials contained within a flexible membrane by vibration;

[019] FIGS. 2A and 2B illustrate arrangements for fluidization of granular materials contained within a flexible membrane by mechanical expansion;

[020] FIGS. 3A and 3B show arrangements for fluidization of granular materials contained within a flexible membrane by mechanical shearing;

[021] FIGS. 4A, 4B, 4C, 4D, 4E, 4F, 4G, 4H, 4i, 4J, 4K, 4L, 4M, 4N, 40, 4P_; 4Q, 4R, 48, 4T, and 4U illustrate jamming-based grippers having sphere-like, vertical ellipse-like, horizontal ellipse-like, onion-iike or beli-like, heart-like, rectangular prismlike or cuboid-like, a cylindrical-like or hotdog-like, or torus-like shape, respectively;

[022] FIGS. 5A, 5B, 5C, and 5D illustrate devices for internal gripping and holding based on jamming of granular material;

[023] FIGS. 8A and 8B demonstrate a continuously flexible fixturing device based on the jamming of granular material; [024] FIGS. 7A, 7B, and 7C illustrate generally contact and shape sensing methods for encased granular materials;

[025] FiGS. 8A and 8B show jamming-based gripping and holding devices controlled by a human operator;

[026] FIGS, 9 illustrates membranes for jamming-based gripping and holding devices that utilize varying thickness, varying materia! composition, or varying texture;

[027] F!GS. 10A, 10B, 10C, 10D, 10E, 10F show jamming-based grippers having outer textures for improved gripping performance including dimpled or dotted, ridged, treaded, scaled, cracked, or regular/irregular patterns, respectively;

[028] FIG. 11 is a schematic drawing illustrating how a jamming gripper can achieve three separate gripping modes: static friction from surface contact (left), geometric constraints from interlocking (center), and vacuum suction from an airtight seal (right);

[029] FIG. 12 is an assembly drawing of a passive gripping and releasing apparatus, according to an exemplary embodiment of the disclosure;

[030] FIG. 13a shows different size hemispheres used as target object for test, ranging from 0.5 cm radius to 3.8 cm radius (left to right at top);

[031] FIG. 13b is a diagram of an experimental setup showing certain dimensions of an exemplary embodiment. The apparatus picks the object at the pick location (P1 ) and then moves to place the object at the place location (P2). The contact angle between the gripper and the object is indicated by Θ;

[032] FIG. 14 shows the results of gripping tests for one exemplary embodiment on hemispheres of different radius using a manually reset

gripping/release apparatus and an apparatus reset with positive pressure; (A) the success rate for gripping objects of varying size; (B) the force that the gripper applies to an object while deforming around it; and (C) the contact angle the gripping/release apparatus achieves. The horizontal dotted line in (C) indicates a 45° contact angle;

[033] FIG. 15 shows results from testing the embodied apparatus against errors in the location of the target object. In (A), an error tolerance of about 3 cm as well as an increase in error toierance of about 0,5 cm for the positive pressure apparatus can be seen for a hemisphere of 2.47 cm radius. In (B), error tolerance and reliability can be seen more generally for errors ranging from 0 to 4.5 cm and hemispheres ranging from 0.45 to 3.72 cm radius using the unitless value [(e2 + r2) 1 12J/R;

[034] FIG. 16 is a bar graph showing comparative results for holding force between positive pressure release and manual reset for 3D printed plastic shapes in one exemplary embodiment: helical spring, cylinder, cuboid, jack toy, cube, sphere, and regular tetrahedron. The sphere is 2.8 cm in diameter;

[035] FIG. 17 shows placement test results for the calibration of a robot arm, test of the positive pressure gripper, and test of the manually reset gripper in one exemplary embodiment. Ellipses represent 95% confidence regions;

[038] FIG. 18 shows a demonstration of throwing capability provided by a positive pressure apparatus, according to an illustrative aspect of the disclosure. The positive pressure jamming apparatus is shown throwing a table tennis ball into a hoop in six time stamped frames from a video;

[037] FIG. 19 shows nine starting configurations used to test the positive pressure jamming gripping/release of one exemplary embodiment apparatus's ability to grip multiple objects at once, shown from a top view, according to an illustrative aspect of the disclosure. [038] FIG. 20 shows testing results for different gripper fluidization mechanisms according to one exemplary embodiment.

[039] FIG. 21 shows photographs of a gripper and indenter at different points during the fluidization mechanism testing according to one exemplary embodiment.

[040] FIG. 22 is a plot of gripper volume (cc) vs. pu!l-off force (N) for different push-down forces (N) according to one exemplary embodiment.

[041] FIG. 23 is a plot of hemisphere size / g ipper size vs. maximum retention load for different gripper sizes according to one exemplary embodiment.

[042] FIG. 24 is a plot of gripper volume (cc) vs. pull-off force (N) for different push-down forces (N) and different gripper shapes according to one exemplary embodiment.

[043] FIGS. 25A and 25B are diagrams illustrating the deformation caused by contact between a gripper and target object for grippers with different shapes according to one exemplary embodiment.

[044] FIG. 26 is a plot of push-down force (N) vs. pull-off force (N) at different gripper volumes according to one exemplary embodiment.

[045] FIG. 27 is a plot of push-down force (N) vs. pull-off force (N) at different gripper volumes according to one exemplary embodiment.

[046] FIGS. 28A and 28B illustrate an embodiment of a prosthesis gripper.

[047] FIG. 29 is a plot of membrane thickness (cm) vs. number of grips at failure according to one exemplary embodiment.

[048] FIG. 30A are photographs of two different shaped grippers with uniform membrane thickness before and during contact with a target object according to one exemplary embodiment. [049] FIG. 30B are photographs of two different shaped grippers with varying membrane thickness before and during contact with a target object according to one exemplary embodiment,

[050] FIG. 31 shows arrangements of membrane surface features according to one exemplary embodiment.

[051] FIG. 32 are depictions of a membrane with surface features (i.e., nubs) and a membrane with texture according to one exemplary embodiment.

[052] FIG. 33 is a plot of push-down force (lbs) vs. maximum retention load (lbs) comparing a smooth sphere gripper to a sphere gripper having nubs according to one exemplary embodiment.

[053] The same numerals are used throughout the figure drawings to designate similar elements. Still other objects and advantages of the disclosure wiil become apparent from the following detailed description.

DETAILED DESCRIPTION

[054] Referring now to the drawings and, more particularly, to FiGS. 1 - 19, there is shown generally a specific, illustrative end effector, apparatus, system and method for gripping and releasing articles and the like, according to various aspects of the disclosure. For example, the end effector is a passive gripping and releasing apparatus including a gripper having an enclosure comprising a flexible,

impermeable membrane with an opening fluidically coupled to a source of fluid ingress and egress in an evacuable sealing relationship, with at least one port providing the source of fluid ingress and egress disposed in fluid connection with the opening of the membrane, and a resettable granular material disposed within the membrane. [055] The term "granular material" as used herein shall refer, for example, to a bulk material composed of large numbers of discrete particles (grains), each of which is large enough so that thermal influences on their behavior can be ignored, but the influences of gravity and friction cannot. The specific granular materials referred to may include, but are not limited to, small, individual solid granules or grains made from any type of metallic, insulating or semiconducting solid, including one or any combination of one or more of plastic or polymeric particles, coffee grounds, cornstarch, ground glass, sand or crushed rock, rice, sawdust, crushed nut shells, oats, cornmeal, metal particles, dried ground corn husk, salt, seeds, ground rubber, diatomaceous earth, and the like.

[056] The terms "membrane" or "flexible membrane" shall refer, for instance, to a balloon- or bag-type enclosure which may be manufactured

continuously or in parts from materials including, but not limited to, latex, nitrile, silicone, neoprene, polyurethane, butyl rubber, or other natural or synthetic flexible material.

[057] It is considered desirable that the membrane or flexible membrane have one or more of the following attributes including, but not limited to: (i) a bending stiffness generally within a range of about IxiO^"5 Nm² to about IxlO^'4 Nm²; (ii)

impermeability to gas, such as air, so that a pressure differential can be maintained across the membrane; (iii) resistance to cuts, tearing, rupturing, wear, chemical instability, or other physical failures (however, even latex membranes, e.g., ASTM cut level 0— the lowest cut level rating, have considered suitable), a durable membrane prolonging the life of the gripper, but not necessarily being required to achieve the gripping function; (iv) a coefficient of static friction between the membrane and the target object of greater than approximately 0.2, with higher coefficients offering improved performance; (v) elasticity, i.e., elastic membranes with moduli generaiiy within a range of approximately 10 MPa and approximately 100 MPa being advantageous, though elasticity is not required; (vi) either a smooth or a textured surface, or a combination thereof; (vii) a somewhat sticky surface, the level of stickiness being selectively optimizable by the user depending on the application, adhesion to steel ranging from 0 oz/in width to approximately 10 oz/in width (ASTM D-3330) being preferred; (viii) no limitations in the permissible range of thickness range, typical membranes optionally having thicknesses from between about 0,01 mm to about 5 mm, where thinner membranes generally conform better to details of object geometry, whereas thicker membranes are generally more robust; (ix) be composed of composite materials, e.g., by incorporating the fear resistance of a cloth membrane with the friction and impermeability of an elastomeric coating, a composite material membrane being subject to the same considerations as outline above.

[058] This disclosure is directed to methods of fiuidizing granular material in gripping and holding devices. Benefits of pneumatically fiuidizing the granular material employed in a gripping and holding device for improved gripping

performance were first demonstrated in J.R. Amend, Jr. et al. , "A Positive Pressure Universal Gripper Based on the Jamming of Granular Materiai", IEEE Transactions on Robotics, vol, 28, pp. 341 -350, Apr. 2012 and are also detailed in International Patent Application No. PCT/US201 1/32429, entitled "Gripping and Releasing

Apparatus and Methods" filed by J.R. Amend, Jr. et al. on April 15, 201 1. Other methods for fiuidizing this granular material are possible and can offer considerable performance improvements. [059] Fluidization of the granular materia! by vibration is illustrated in FIG. 1 , where a gripping device consisting of a granular material (101) contained within a flexible membrane (102), being connected by one or more base components (103), and having some means of infernal access to the granular material (104), may fiuidize the granular material through one or more vibrating motors contained within the granular material (105) or attached to one of the base components (108). The vibration may be generated as well by other means, for example one or more piezoelectric speakers (107).

[060] Tests were conducted on one exemplary embodiment to determine whether fluidizing the granular material via vibration may soften the gripper as it pushes against a target object to increase its ability to confirm to the object and therefore increase the gripping performance (e.g., the retention force with which the gripper maintains hold of the object). For the tests, a spherical shaped gripper was inverted and placed on a vibratory rock tumbler (i.e., vibration means) and both were placed on an electronic scale. Above the gripper was a robotic arm at the end of which was an indenter (i.e., 13.65 mm diameter metal rod) that was pushed into the gripper in a neutral state (i.e., the differential pressure between the outside and inside of the membrane of the gripper was about zero). The indenter was pushed into the gripper a distance of approximately 23 mm from the initial contact position. The force with which the indenter was pushed into the gripper was measured by the electronic scale. The granular material inside the gripper was "fluidized" to soften the gripper by various means. For example, by inflating the gripper with positive pressure for a brief period (500 milliseconds), briefly vibrating the gripper using the vibratory rock tumbler, and by both inflating the gripper with positive pressure and vibrating it using the rock tumbler simultaneously. During the fluidizing step, the robot arm rigidly maintained the position of the indenter. The resulting force following fluidization was measured by the electronic scale.

[081] FIG. 20 is a plot showing the force load before fluidization and after fluidization. As shown in FIG. 20, inflating the gripper with positive pressure and vibrating the gripper decreases the contact load. Thus the results indicate that both inflating the gripper with positive pressure and vibrating the grains are both effective methods for fluidizing the grains, !n addition, based on FIG. 20, it appears that vibration alone decreases the load to about the same load as positive pressure and vibration.

[062] The reduction in contact load by fluidization may be a result of the granular materials ability to flow around the target object, which may help improve the ability of the gripper to conform to the target object and therefore improve the gripping performance. However, images form the tests, shown in FIG. 21 , suggest that fluidizing the grains may not necessarily cause the granular material to flow around the target object as indicated by the increased diameter of the "crater" surrounding the indenter before and after the fluidization step. Based on the images, it may be the case that fluidizing the granular material causes the bulk of the granular material to become so fluid-like (i.e., easily deformable under load) that the membrane dominates the gripper deformation during the fluidization step, resulting in the membrane's smoothed curvature and larger indention crater. It is contemplated that the effect of various fluidization methods (e.g., positive pressure and vibration) during non-inverted operation may produce differing results because gravity will likely pull the grains toward the target object.

[083] Fluidization of the granular material by mechanical expansion of the containing membrane is illustrated in FIG. 2, where a gripping device consisting of a granular material (201) contained within a flexible membrane (202), being connected by one or more base components (203), and having some means of internal access to the granular material (204), may fluidize the granular material by mechanically expanding the containing membrane as for example by means of a plunger device (205), thereby reducing the density of the granular material and increasing its ability to flow under stress. In another embodiment, mechanical expansion of the membrane could be achieved for example by a shape memory material such as a shape memory alloy or polymer that expands to its larger, natural shape upon the application of an electric field.

[084] Fluidization of the granular material by mechanical shearing is illustrated in FIG. 3, where a gripping device consisting of a granular material (301 ) contained within a flexible membrane (302), being connected by one or more base components (303), and having some means of internal access to the granular material (304), may fluidize the granular material by shearing the material in any number of ways, as for example by rotating auger or paddle (305) or by plunger (306).

[065] Fluidization of the granular material can also be accomplished by repelling the particles with an electrostatic charge. In this embodiment, a charge is applied to a granular material (for example a metallic powder) which results in mutua repulsion among the grains, thereby increasing the space between grains and fiuidizing the material. Later, charged particles can be grounded to eliminate the repulsive force.

[066] This disclosure also concerns the shape of gripping and holding devices utilizing the jamming of granular material. Jamming-based grippers produced with specific natural shapes can be advantageous for gripping different objects. Grippers may be produced in a variety of natural shapes a small portion of which are illustrated FIG. 4A to 4U. Any shape may be used. These shapes may or may not inciude a collar for support (401 ) and include but are not limited to a sphere (402), vertical ellipse (403), horizontal ellipse (404), onion or bell shape (405), a heart shape (406), a rectangular prism or cuboid (407), a cylindrical or hotdog shape (408), a torus shape (409), or a shape pre-deformed to fit the target object (e.g. 410). The purpose of any given shape may be decorative as well as functional,

[087] Normal force is used to create contact between the gripping and holding devices and the target object so that a tight grip in the jammed state may be formed. The use of normal force may present some challenges in applications where the device is limited in the force that may be applied to the target object due to the objects inability to sustain a significant normal force load (e.g., fragile target object). In consideration of this challenge, a gripper geometry that may increase contact with a target object and consequently increase the grip force, at a reduced norma! force would be beneficial. One such geometry of gripper, the vertical ellipse (403), was developed and when testing of an exemplary embodiment, exhibited such enhanced performance. To demonstrate the enhanced performance, spherical grippers between 260 and 2200 cubic centimeters in volume were tested and compared with vertical ellipse grippers of 260 and 620 cc, where the ellipse is a prolate ellipse. All the grip tests were conducted on a 23 mm diameter cylindrical rod.

[068] F!G. 22 shows a plot of pull-off force (N) versus gripper volume for only the sphere shaped grippers at four different normal forces (i.e., push-down force) for one exemplary embodiment. As shown in FIG. 22, for a constant pushdown force, pull-off force increases with volume, but approaches a plateau and in some cases even decrease at the larger gripper sizes. This demonstrates that there may be an optimal balance between the gripper size and the size of the gripped object. This performance behavior was further investigated in order to optimize the ratio of gripper size to object size. Tests were conducted during which the gripper (sphere) size and target object (hemisphere) size were varied and the maximum retention !oad of the gripper on the object was measured. The results of these tests are illustrated by the plot in FIG. 23. The different gripper sizes used were 15 cm, 12 cm, and 6 cm. Numerous hemisphere sizes were tested. On the x-axis of FIG. 23 we have object diameter divided by gripper diameter. On the y-axis we have the maximum retention load as measured for each test. As illustrated by FIG. 23, the maximum retention load occurs when the object diameter is about half of the gripper diameter. Accordingly, one exemplary embodiment may include a gripper having a diameter that is about two times the diameter of the object being gripped.

[069] Although FIG. 23 demonstrates that an optimal gripper size range based on the size of the target object may exist, FIG. 22 demonstrates that increasing push-down force may offset for a sub-optimal size ratio. In addition, it appears if may be preferable when selecting a gripper size to err on the side of a smaller gripper because the smallest gripper in the test was able to achieve the highest increase in performance at large push-down force.

[070] FIG. 24 is a plot that includes all the test results of the spherical gripper from FIG. 22, but also includes the vertical ellipse tests, which are indicated by the hollow markers. As illustrated by FIG. 24, the vertical ellipse exhibited increased pull-off force at the same push-down force and same gripper volume. This increase performance may be a result of increased "geometric compliance" of the vertical ellipse, which allows it to make better contact at low normal force (i.e., pushdown force). For example, the sphere exhibits the same compliance in all direction, and therefore much of the deformation occurs radiaily, away from the object.

Whereas, the higher aspect ratio of the vertical ellipse limits the radial compliance and allows for more contact with the target object. This difference in geometric compliance may be demonstrated, for example, by FIGS. 25A and 25B. As shown in FIG. 25A, a sphere gripper 2501 deforms radially equally in all directions limiting the contact surface with target object 2502. In FIG. 25B, a vertical ellipse gripper 2503 is able to have greater contact with the surface of target object 2502 and therefore exhibit increased pull-off force.

[071] FIG. 26 is a plot of push-down force vs. pull-off force for four different volumes of sphere shaped grippers and FIG, 27 is a plot of push-down force vs. pull- off force for two different volumes of vertical ellipse grippers. As shown in FIGS. 28 and 27, similar trends in pull-out vs. push-down force are present; that is, that pushdown force increases performance, but that there appears to be asymptotic limit. Although the vertical ellipses generally out-perform the spheres at small push-down forces, both the spheres and vertical ellipses appear to approach the same limit.

[072] A device for internal gripping and holding based on the jamming of granular material may be inciuded in some embodiments. An internal gripping device contacts and holds an object from its interior. For example a deflated balloon may be inserted into a bottle and then expanded by inflation to generate internal pressure and grip the bottle. Jamming-based grippers may achieve internal grips as illustrated in the exemplary embodiment of FIG. 5. A gripping device consisting of a granular material (501 ) contained within a flexible membrane (502), being connected by one or more base components (503), and having some means of internal access to the granular materiai (504), may inflate the internal membrane by ingress of gas, liquid, or granular materiai in order to achieve expansion for internal gripping (505), or may deform the granuiar material (for example by means of a piunger) with or without the addition of vacuum-based hardening (506). !n another embodiment, expansion of the membrane may occur by application of an electric field to a shape memory material such as a shape memory polymer or alloy.

[073] A continuous flexible fixturing device based on the jamming of granular material may also be provided in some embodiments. A device simsiar to an active gripping and holding device based on the jamming of granular material may be employed as a passive fixturing device as illustrated in FIG. 6. A gripping device consisting of a granuiar material (601 ) contained within a flexible membrane (602), being connected by one or more base components (603), and having some means of internal access to the granular material (604), may be employed as a fixturing device for holding a workpiece (605). In one embodiment, the workpiece is pressed into the jamming-based fixturing device by a human operator, whereupon the fixturing device is vacuum-hardened to achieve a secure hold on the workpiece.

[074] This disclosure also relates to shape and contact sensing methods for encased granular materials. The shape of a jamming-based gripping device can be sensed in several ways as illustrated in FIG 7. A gripping device consisting of a granular material (701 ) contained within a flexible membrane (702), being connected by one or more base components (703), and having some means of internal access to the granuiar material (704), can be augmented to sense the 3D shape of the device through one or more conductive fibers (e.g. carbon, nickel, copper, gold, silver, or titanium) embedded in the granular material (705), one or more optical sensors (e.g. by sensing visible or infrared light with a photoelectric sensor) embedded in the granular material (706), or one or more conductive fibers (e.g. carbon, nickel, copper, gold, silver, or titanium) embedded within the membrane material (707).

[075] Still another aspect of this disclosure concerns manual operation of a jamming-based gripping and holding device by a human operator. Generally speaking, jamming-based gripping and holding devices can be controlled manually by a human operator as illustrated in FIG. 8A. A human operator (801 ) can maneuver and control a jamming-based gripping device that may be either self contained or tethered (802). The device may alternatively be incorporated into a prosthesis (803), as shown in FIG. 8B. FIG. 28A shows another embodiment of the device incorporated into a prosthesis 2801 . Prosthesis 2801 may include a sleeve 2802 configured to releaseably couple to a limb (e.g., hand, lower arm, upper arm, foot, or leg) of a human operator. The device may be releaseably and rotatably coupled to the end of the sleeve as shown in FIG. 28A. The device may include a collar 2803 and membrane 2804 as described herein. Membrane 2804 may have a diameter "D" that can vary in length. In one example, diameter D may be about 80 mm in length.

[076] FIG. 28B illustrates a cross-sectional view of one exemplary embodiment of prosethesis 2801 . The device of prosethesis 2801 may include one or more batteries 2805, at least one pump 2806, and at least one valve 2807.

Batteries 2805 can be used to power one or more of the device components (e.g. , pump 2806, valve 2807, or a controller not shown). Pump 2806, valve 2807, and a controller can be used to operate the device and perform jamming-based gripping and holding operations. Gripping and holding operations maybe controlled by the human operator. [077] Disclosed as well are membranes for jamming-based gripping and holding devices that utilize varying thickness, varying material composition, or varying texture. Jamming-based grippers produced with outer membrane materials that vary in thickness, utilize composite materials, or have specific textures, can improve gripping performance. For example, varying the thickness of the membrane can alleviate stress locations where bending or stretching often occur during use. Varying thickness can also be empioyed to reinforce contact areas subjected to excess abrasion during use. Varying material composition may be employed in a similar manner, for example to locate more flexibie materials at locations of higher bending or stretching, or to locate more durable materials at locations of higher abrasion. Similarly, the flexible membrane may be reinforced with a fiber mesh to improve durability and gripping performance. Any one or more of these techniques of varying membrane thickness or varying membrane material may be employed in a single membrane as illustrated in F!G. 9. A gripping device consisting of a granular material (901 ) contained within a flexible membrane (902), being connected by one or more base components (903), and having some means of internal access to the granular materia! (904), may for example have a flexible membrane that consists of fiber reinforced material A of thickness X (905), as well as material B of thickness Y (908), as well as material C of thickness Z (907), where A, B, C, D, X, Y, and Z are ail different.

[078] Varying the thickness of the membrane may also vary the durability (e.g., cycles before failure) of the membrane. Accordingly, based on the membrane thickness an estimate of the number of grips (e.g., cycles) before failure may be determined. FIG. 29 illustrates a plot of membrane thickness in centimeters (cm) versus number of grips at failure for one exemplary embodiment. As illustrated by the plot, as the thickness of the membrane increases the number of grips at failure also increases. Identifying this relationship can enable prediction of membrane failure and allow for replacement of the membrane prior to failure. The

characteristics (e.g., abrasiveness) of a target object may also be found to increase or decrease the durability of the membrane and based on this behavior a thicker membrane may be selected for applications where the target object is more abrasive so that the durability and the longevity of the membrane is increased,

[079] Disclosed as well are gripper's where the radial deformation of the membrane is limited. By limiting the radial deformation of the membrane, a gripper's gripping performance (e.g., the retention force with which the gripper maintains hold of the object) may be improved. This may be achieved because as a gripper pushes against a target object, some granular material may be displaced in order for the gripper to conform to the target object and if the radial (i.e., outward) expansion of the gripper can be limited, then the granular material can be forced to be displaced downward toward the object to further encompass the target object. Further encompassing the target object can therefore increase the contact area between the target object and gripper, increasing the gripping performance. There are numerous ways of limiting radial deformation. For example, at least a portion of the gripper membrane may be encompassed in a rigid shell, at least a portion of the gripper membrane may be encompassed in a flexible sheath (e.g., a mesh fabric), the gripper membrane may be composed of various material with varying properties (e.g., integrating a fabric or stiffer elastomer into at least a portion of the membrane), or the gripper membrane may be composed of a single material but with varying thickness. [080] FIG. 30A illustrates two embodiments of gripper membranes and FIG. SOB illustrates two corresponding embodiments of gripper membrane where the membrane has more than one thickness along its length. As shown in FIG. SOB, the membrane at the top portion (darker portion) is thicker than the bottom portion of the gripper membrane. As illustrated by FIGS. 30A and 30B, as the membrane gripper pushes against the target object, the membrane with the variable thickness allows for more of the granular material to deform downward into the target object rather than outward due to the reduction in radial deformation of the membrane. This produces and increased area of contact between the gripper membrane and the target object, which results in improved gripping performance.

[081] A variety of outer textures and surface features have also been found improve gripping performance for specific items. Outer membrane textures and surface features are shown in Fig. 10 and include but are not limited to: dimpled or dotted (1001), ridged (1002), treaded (1003), scaled ( 004), cracked (1005), or more exotic patterns that may be regular or irregular (e.g. 1006). These textures and surface features may be integrated into the gripper's membrane to improve the ability of the gripper to locally confirm to a target object (e.g., by fitting under ridges, into small concave features on a target object, etc.). The features may be composed of material other than the base membrane material. For example, a higher friction material may be added to portions of the membrane to improve gripping

performance by increasing the friction between the target object and the gripper. Illustrations of how the features may be integrated into an exemplary embodiment of the gripper membrane are presented in FIG. 31. As shown in FIG. 31 , membrane "a" may be configured such that the surface feature creates a cavity in which f!uidized granular material may flow and collect. Membrane ^!,b" may be configured such that the surface feature is a solid projection formed of the membrane material. Membrane "c" may be configured such that the surface feature is a solid mass formed of a materia! distinct (e.g., membrane material #2) from that of the base membrane material (e.g., membrane material #1 ). These textures and features can be added to exterior surface of the gripping membrane to improve the frictional contact between the gripper and target object. The textures and features may or may not cover the entire surface of the outer membrane, and may be decorative as well as functional.

[082] FIG. 32 illustrates two embodiments of gripper membrane with different surface features and textures. The membrane of gripper "a", as shown in FIG. 32, includes numerous hemispherical projections (e.g., nubs) extruding from the surface of the membrane. The membrane of gripper "b", as shown in FIG. 32, is a textured membrane gripper. The texture of the membrane may be created by a variety of different processes. One process that may be used for example is chemical etching.

[083] A test was conducted on one exemplary embodiment to determine the benefit (e.g., increase in maximum retention load) of one variety of surface feature (i.e., nubs) on a sphere membrane gripper vs. that of a smoother sphere membrane gripper. Both membrane grippers (3.5 inch diameter spheres) were pushed down on a target object {23-mm diameter rigid cylinder) and the object was gripped. After which the load required to pull the objection out of the gripper's grasp was measured and recorded as the maximum retention load. This test was performed at two different push-down forces (i.e., 15 lbs and 20 lbs). The results of the test are shown in FIG. 33. As illustrated by FIG. 33, at the reduced push-down force (i.e., 15 lbs) the membrane gripper with the nubs achieved greater retention loads than the gripper with the smooth membrane. However, at the greater push-down force (i.e., 20 lbs) the retention loads of the two membrane grippers were substantially equal.

Accordingly, surface features may be particularly beneficial in applications where there are limitations on push-down force because of the characteristics of the target object (e.g., fragile object).

[084] According to one arrangement, a passive universal jamming gripper is provided which utilizes an elastic-type membrane (e.g., a balloon) containing a selected amount of granular material (e.g., coffee grounds, sand, other). At atmospheric pressure, the granular material is in a fluid-like phase such that it can flow, pour, or even splash. However, when a vacuum is applied, the granular material undergoes a pseudo-jamming-phase transition into a solid-like phase such that there is essentially no relative movement of the grains relative to one another. When the vacuum is released and the system returns to atmospheric pressure, the granular material returns to the fluid-like phase (either on its own over time or more quickly with external manipulation). This pseudo-phase transition is believed to arise from inherent solid-liquid duality of granular systems.

[085] Illustrated in FIG. 12 is an exemplary embodiment of a passive gripping and releasing apparatus 100. The apparatus utilizes both positive and negative pressure so that once the apparatus has passively contacted an object to be gripped and conformed to the shape of the object, a vacuum may be applied to vacuum-harden the filled membrane to rigidly grip the object and subsequently. When gripping is to be released, one or more bursts of positive pressure are applied to reverse the fluid-like to solid-like phase transition (jamming), forcibly releasing the object and returning (resetting) the filled membrane to a deformable, ready state, in its simplest form, an exemplary jamming gripper includes a selected granular material contained in an evacuable membrane enclosure coupled to a negative pressure source in order to achieve its gripping behavior (e.g., the combination of ground coffee and a latex balloon, noting that traditional actuators are not generally required, just an off-board pump to evacuate the air from the gripper).

[086] According to another aspect, exemplary passive gripping and releasing apparatus 100 includes an optional base 1 , an optional external collar 2, an elastic membrane 3 (e.g., a latex balloon), a granular filling materia! 4 (e.g., coffee grounds) within the membrane, an optional air filter 5, a vacuum line port 6, a positive pressure port 7, and an optional internal pump P (e.g., a reversible roller pump). As shown, membrane 3 is pinched between the base and collar so as to produce an airtight (evacuable) seal. Other sealing apparatus and methods including, but are not limited to, clamping, gluing, and others known in the art may also be effectively utilized.

[087] In one present embodiment, the base and collar were manufactured from 3D printed plastic, which permits the intricate internal structures of the base. The optional collar is considered advantageous in helping to guide the

gripping/release apparatus as it conforms to an object, increasing the surface contact on vertical faces of the object and maximizing the potential for the

interlocking gripping mode. The illustrated gripping/release apparatus may be easily interfaced to a commercial robot arm. The simple mechanical construction of gripping/release apparatus 100 lowers cost and provides ease of manufacturabiiity.

[088] Also according to one example, the gripping/release apparatus includes, for instance, a latex balloon membrane pinched between the base and collar producing an airtight seal. The balloon membrane thickness was about 0.33 mm and it was filled with ground coffee beans to a volume of about 350 cm³. At this volume, the balloon membrane is full but the membrane is not significantly stretched, such that the membrane can easily be deformed in the unjammed state when contacted with an object. Such membrane, when filled, has a radius of approximately 4.3 cm. The relatively low density of ground coffee has been found beneficial because it can be used in larger quantities without weighing down the apparatus or straining the membrane in the way that a heavier granular material, e.g., sand, may do.

[089] Although the apparatus has been shown and described using a latex balloon as the membrane, other membrane materials may be used, within the spirit and scope of the disclosure, including, but not limited to, elastomers, latex, vinyl, coated cloth, metal foil, ylar, and the like.

[090] Various granular filling materials may also be utilized and materials will advantageously undergo about a 5% or less change in volume over the fluid-like to solid-like pseudo-phase transition (jamming). It has aiso been found beneficial that moisture in the system be substantially eliminated (i.e., when the fluid is not a liquid) as if has been found to slow the unjamming transition due to additional capillary forces in the granular filling. A desiccant may optionally be used in the membrane and/or in the filter. Alternatively, a dry fluid such as nitrogen or an inert gas, for instance, could be used as the positive pressure fluid. A conventional air drying system could aiso be attached to the air lines of the apparatus.

[091] in another example, the embodied gripping/release apparatus is mounted on a commercial robot arm. Positive pressure is provided by a pump at 620 kPa and a flow rate of 2.18 Lis. One or more fluid pressurized reservoirs are optionally used in place of, or in combination with, a positive pressure pump, which may enable a faster solid-like to fluid-like phase transition of the granular material. A vacuum is provided using an off board vacuum pump. A maximum vacuum flow rate of 0,25 Lis may be provided with a purnp rated for a maximum vacuum of 25 microns. For gripping, the jamming transition, in this scenario, is deemed complete when the pressure in the gripper drops to about -85 kPa, although usable vacuum pressures up to about -30 kPa may be used. The pressure in the gripping/release apparatus could also be neutralized by the atmosphere, and is preferably used when the apparatus is pressed onto an object. Solenoid valves controlled by serial communication through the robot arm modulate the pressure in the gripper. A 100% joint angle speed is used by the robot arm, which corresponds to approximately 23.7 cm/s linear speed of the gripping/release apparatus.

[092] The gripping/release apparatus has been found reliable for gripping objects of varying size. In one embodiment, all objects located at a position on a table may be hardcoded into a robot's software (the pick position). Upon instruction and operation in open loop, the robot moves to the pick position and presses the gripping/release apparatus onto an object, then actuates the apparatus to induce the rigid state. Next, the robot moves to a place position, releases the vacuum, and applies a short burst of positive pressure to eject the object.

[093] As shown in FIG. 13, jamming grippers may also be used suitably to pick up hemispherically shaped objects, e.g., wooden hemispheres ranging from about 0.5 cm radius to about 3.8 cm radius with a surface texture not smooth enough to permit an airtight seal between the gripper membrane and the hemisphere, and therefore not inducing the vacuum mode of gripping. With objects such as

hemispheres, it is considered difficult to achieve the interlocking gripping mode. To improve effectiveness, for instance, each hemisphere may be located in line with the central axis of the gripper, so that the contact angle 8 is as consistent as possible around the hemisphere. Representative dimensions, according to FIG. 13, are as follows:

hi = 4.8 cm, hi = 1 1.5 cm, h3 = 13 cm, d = 20 cm.

[094] FIG. 14 illustrates graphically on the x-axis the object size as a percentage of membrane size to account for the scalability of the gripping/release apparatus. It also shows the performance of an exemplary positive pressure gripping/release apparatus compared to a passive universal gripper that must be manually reset by the user. Plots of success rate, applied force, and contact angle are shown. Success rate was determined over 30 trials for each hemisphere and represents how reliably the apparatus could grip hemispheres of varying size in the exemplary embodiment. Applied force means, for instance, the force that a gripper applies to an object as it is deformed around it. This force is measured with a scale located beneath the test object. The term contact angle generally refers to the maximum angle at which the gripper membrane and the object touch (indicated by 8 in FIG, 13).

[095J For a passive universal gripper not utilizing positive pressure, the gripper's success rate generally falls off sharply as the hemispherical object radius reaches about 85% of the membrane radius, and falls to about 0% for contact angles near 45° (the critical angle for gripping to occur). Generally speaking, it has been found that the applied force increases with increasing object size, as more grains inside the membrane need to be displaced around larger objects. Adding positive pressure has been found to dramatically increase the success rate of the

gripping/release apparatus by as much as 85% for some hemispheres by increasing contact angle. Positive pressure also decreases the force applied to the object by as much as 90%. [096] As demonstrated by FIGS. 15-15B, the gripping/release apparatus also provides suitable tolerance to errors in the location of the target object, where the target object is located between about 0 and about 4.5 cm away from the pick location P1 , thus causing the hemisphere to be unaligned with the central axis of the gripping/release apparatus. FIG. 15B illustrates a more general relationship between target object size, location error, and gripping success rate, with errors ranging from 0 to 4.5 cm and hemispheres ranging from 0.45 to 3.72 cm radius.

[097] Using the expression [(e2 + r)1 12]/R, the Euclidean distance from the apex of the target object to the point where the membrane touches the table along its central axis, compared with the radius of the membrane, a simple approximation is provided for the total surface area the membrane will contact (table plus target object) as if attempts to wrap around the object to the critical contact angle, compared with the available surface area of the membrane. While an analytical calculation of the two surface areas would likely produce a more accurate quantity, such a calculation has been found difficult due to the deformation and stretching of the membrane that occurs during the gripping process.

[098] In general, the error tolerance for the apparatus is considered large considering its open loop function. In FIG. 15A, for example, using a positive pressure, a 3.5 cm radius membrane can successfully pick up a 2.47 cm radius hemisphere 100% of the time, even when the hemisphere is 2.5 cm away from its target location.

[099] As shown in FIG. 16, the positive pressure gripping/release apparatus is also capable of gripping and retaining a range of shapes including a helical spring, cylinder, cuboid, jack toy, cube, sphere, and regular tetrahedron, each having a selected mass, e.g., of about 15.5 g ± 0.8 g, a minimum cross section of approximately 2,6 cm, and not being smooth enough for an airtight seal to be achieved.

[0100] The strength with which each object is retained may be determined from the force required to puli each object out of the solidified (evacuated)

membrane. Resetting the apparatus with positive pressure has been found to improve the holding force for objects that displace a larger volume of grains in the membrane, but has been found to decrease the holding force for smaller objects. The enhanced f!owabiiity of the positive pressure apparatus allows for a larger contact angle as seen in FIG. 14C, and thus an enhanced holding force for the larger objects that displace a larger volume of grains. Generally speaking, strength has been found to be dependent on the volume of grains displaced upon engagement with the object. Enhanced fiowability allows more grains to fall to the side of the object, possibly leaving a gap between the grains and the apparatus base. This may be seen, for instance, in FIG. 14B which shows low values of applied force for the positive pressure apparatus, which are comparable to the weight of the grains for small objects. When the membrane is evacuated, the grains may partially contract toward the open space near the base rather than toward the target object, resulting in less holding force. This phenomenon may be countered by applying more force to the target object, either by sensing the pick height to the target object size, or by using a robot arm with force feedback.

[0101] For the test setup in FIG. 13, a maximum gripping rate can be calculated. The limiting factors are the maximum speed of the robot arm, the time required to complete the jamming transition, the time required to reset the gripper between grips, and the time required to release the gripped object. The maximum speed of the robot arm was measured at 23.7 cm/s, which limits the maximum grip rate to 24 picks/min for the time required simply to move from P1 to P2 and back again. The jamming transition may be constdred complete when the pressure inside the membrane has dropped to -85 kPa, which takes 1.1 s for our 350 cm³ membrane - this further limits the maximum gripping rate down to 18.7 picks/min.

[0102] An exemplary positive pressure jamming gripping/release apparatus requires only 0.1 seconds to release the object and reset the gripper with a single burst of positive pressure, which limits the maximum gripping rate finally to 16.2 picks/min. For a manually reset gripper, releasing the object and resetting the gripper may be a bit more complicated. The time required to release an object depends on the geometry of the object, and slower release times limit the gripping rate. In one embodiment, the slowest release times were measured at 0.6 seconds. Manually resetting the gripper requires the operator to perform an imprecise kneading or massaging routine, which took at least 2.0 seconds during testing. Thus for a manually reset passive universal gripper, the maximum gripping rate is limited to 10.2 picks/min. The benefit of including positive pressure thus was found to be 39% increase in gripping rate, in addition the benefit of increasing automation of the system and the elimination of possible human error when resetting the gripper.

[0103] Typically, placement accuracy has been recognized as a sacrifice made when deveioping a passive universal gripper in order to maximize the range of objects that may be gripped. However, placement accuracy is also a performance measure for grippers used in manufacturing settings. Here, one exemplary

embodiment of a jamming gripping/release apparatus is evaluated for the accuracy with which it can place objects, again using the same test setup from FIG. 13 with slight modifications. [0104] To determine the accuracy of the robot arm itself, a calibration procedure is preferably performed. For instance, a pen maybe firmly mounted to the wrist of the robot, extending to approximately the same point at which the

membrane's bottom edge makes contact with the tabie. A similar procedure to that depicted in FIG. 13 was then executed, with the pen marking a fixed piece of paper at the pick and place positions P1 and P2. With this setup, the precision of the arm in an exemplary embodiment was determined to be ± 0.35 mm in the worst case for 95% confidence, with an average offset of 0.76 mm from the goal. This result is an order of magnitude larger than the manufacturer's reported repeatability of ± 0.05 mm.

[0105] Next, in the exemplary calibration, the pen was removed from the robot arm and the apparatus was reattached. The robot arm was programmed to execute a pick and place routine with the hemisphere, again using the setup from FIG. 13. Following placement of the hemisphere, the deviation from its intended position in the plane of the table was measured. In this embodiment, only the 1.82 cm radius hemisphere was used. This hemisphere is similar to the part sizes used in the shape evaluation performed and discussed herein and is well within the 100% success rate range in the reliability assessment. The dimensions of FIG. 13 were modified slightly for this test to maximize placement accuracy: when testing the positive pressure gripper, h2 was set at 8.8 cm, and when testing the manually reset gripper, h2 was set at 7.1 cm. The results are shown in FIG. 17.

[0108] FIG. 7 indicates that the positive pressure apparatus of an exemplary embodiment places the hemisphere more accurately than the manually reset gripper, while the manually reset gripper is slightly more precise in this exemplary embodiment. Specifically, the average deviation of the positive pressure apparatus is 0.98 mm from the arm's calibration center, with a precision of ± 1.00 mm in the worst case for 95% confidence, while the average deviation for the manually reset gripper is 2.63 mm from the arm's calibration center, with a precision of ± 0,76 mm in the worst case for 95% confidence.

[0107] The angular placement accuracy of the two grippers was found to be comparable. Here however, the manually reset gripper was slightly more accurate, while the positive pressure apparatus was found to be slightly more precise. The manually reset gripper rotated the hemisphere by 5.4° on average, ± 3.4° for 95% confidence in this exemplary embodiment. The positive pressure apparatus rotated the hemisphere by 7.5° on average, ± 1 .8° for 95% confidence in this exemplary embodiment.

[0108] The placement accuracy improvement that was observed in this exemplary embodiment for the positive pressure jamming apparatus enables the repeatable shooting behavior shown in FIG. 18, which shows the embodied positive pressure apparatus throwing a table tennis bail into a hoop in six time-stamped frames from a video.

[0109] Disclosed according to an exemplary arrangement is a passive, universal, jamming, gripping and releasing apparatus that incorporates both positive and negative pressure. The apparatus is capable of gripping objects of different size and shape, and has an increased reliability of at least up to 85%, an increase in tolerance for errors in the target object location, and an increase in speed of 39% over a manual reset a passive, universal, jamming gripper. The positive pressure apparatus also applied up to 90% less force on target objects, and demonstrated an increase in placement accuracy, which enabled a new throwing capability for the gripper. This ability to throw objects may be useful for tasks like, but not limited to, sorting objects into bins in a factory or throwing away trash in a home.

[01 10] The apparatus of this disclosure enables objects of very different shape, weight, and fragility to be gripped, and multiple objects can be gripped at once while maintaining their relative distance and orientation. This diversity of abilities may make the apparatus well suited for use in unstructured domains ranging from military environments to the home. The apparatus's airtight construction also provides the potential for use in wet or volatile environments and permits easy cleaning. Its thermal limits are determined only by the membrane material due to the temperature independence of the jamming phase transition, so use in high-or low- temperature environments may be possible. Further, the soft malleable state that the membrane assumes between gripping/releasing tasks could provide an improvement in safety when deployed in close proximity with humans, as in the home, for example.

[01 1 1 j All references, including publications, patent applications and patents cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein. The recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein.

[01 12] All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., "such as") provided herein, is intended merely to better illuminate embodiments of the disclosure and does not impose a limitation on the scope of the disclosure unless otherwise claimed. No language in the specification should be construed as indicating any non- claimed element as essential to the practice of the disclosure.

[01 13] Various modifications and alterations may be appreciated based on a review of this disclosure. These changes and additions are intended to be within the scope and spirit of thereof.

Claims

WHAT IS CLAIMED IS:

1 . A passive gripping and releasing apparatus, including

a gripper having an enclosure comprising a flexible, impermeable membrane with an opening fluidicaiiy coupled to a positive source of fluid ingress and a negative source of fluid egress source of fluid ingress and egress in an evacuable sealing relationship, wherein the positive source is above atmospheric pressure;

at least one port providing the source of fluid ingress and egress disposed in fluid connection with the opening of the membrane; and

a granular material disposed within the membrane,

2. The apparatus set forth in claim 1 , wherein the gripper enclosure is about twice the size of a target object,

3. The apparatus set forth in claim 1 or 2, wherein the granular material is fluidized pneumatically by positive pressure.

4. The apparatus set forth in claim 1 or 2, wherein the granular material is fluidized by vibration.

5. The apparatus set forth in claim 1 or 2, wherein the granular material is fluidized by vibration and pneumatically by positive pressure simultaneously,

6. The apparatus set forth in claim 1 or 2, wherein the granular material is fluidized by one of mechanical expansion of the membrane, mechanical shearing, and repelling particles of the granular material with an electrostatic charge.

7. The apparatus set forth in any of claims 1 to 6, wherein the gripper has a sphere-like shape.

8. The apparatus set forth in any of claims 1 to 6, wherein the gripper has a vertical ellipse-like shape,

9. The apparatus set forth in any of claims 1 to 6, wherein the gripper has a horizontal ellipse-like shape.

10. The apparatus set forth in any of claims 1 to 6, wherein the gripper has one of an onion-like, bell-like shape, and heart-like shape.

1 1. The apparatus set forth in any of claims 1 to 6, wherein the gripper has one of a rectangular prism-like and cuboid-Sike shape.

12. The apparatus set forth in any of claims 1 to 6, wherein the gripper has one of a cylindrical-like and hotdog-like shape.

13. The apparatus set forth in any of claims 1 to 8, wherein the gripper has a torus-like shape.

14. The apparatus set forth in any of claims 1 to 6, wherein the gripper has a shape pre-deformed to fit an object.

15. The apparatus set for in any of claims 1 to 8, wherein the gripper size is selected based on the size of an object that is to be gripped and released.

18. The apparatus set forth in any of claims 1 to 15, further including a continuously flexible fixturing device based on the jamming of granular material.

17. The apparatus set forth in any of claims 1 to 16, further including a device configured to sense a shape and contact of the gripper.

18. The apparatus set forth in any of claims 1 to 17, further comprising a sleeve releasably and rotably coupled to the apparatus, wherein the sleeve is configured to releasably couple to a limb of a human.

19. The apparatus set forth in any of claims 1 to 18, further including at least one battery, at least one pump, and at least one valve contained within the apparatus configured to produce and control the source of fluid ingress and egress.

20. The apparatus set forth in any of claims 1 to 19, wherein the

membrane includes at !east one of varying thickness, varying material composition, and varying texture membrane materials.

21 . The apparatus set forth in any of claims 1 to 20, wherein at least a portion of the membrane is configured to limit radial deformation of the membrane using one of thicker membrane, a rigid shell, and a mesh fabric within that portion of the membrane.

22. The apparatus set forth in any of claims 1 to 21 , wherein the gripper utilizes an outer membrane having one or more of the following surface textures or features: nubs, ridges, treads, scales, or cracks.

23. The apparatus set forth in any of claims 1 to 22, wherein the granular material disposed within the membrane includes granules made from any type of metallic, insuiating or semiconducting solid, including one or any combination of one or more of plastic or polymeric particles, coffee grounds, corn starch, ground glass, sand, rice, sawdust, crushed nut shells, oats, cornmeal, metal particles, dried ground corn husk, salt, seeds, ground rubber, rocks.

24. The apparatus set forth in any of claims 1 to 23, further wherein the deformable membrane includes a plurality of independently controlled regions to which positive and negative fluid pressures can be selectively applied.

25. The apparatus set forth in claim 24, further wherein the independently controlled regions are self-contained and each includes a granular material.

28. The apparatus set forth in any of claims 1 to 25, further comprising an internal membrane disposed internally of the impermeable membrane, wherein the granular material between the impermeable membrane and internal membrane includes a finer-grained material and the granular material inside the internal membrane includes a coarser-grained granular material.

27. A gripping and releasing device, including an enclosure comprising a flexible, impermeable membrane having an opening fiuidicaliy coupled to a positive source of fluid ingress and a negative source of fluid egress in an evacuab!e sealing relationship; at least one port providing the source of fluid ingress and egress disposed in fluid connection with the opening of the membrane; and a resettable granular material disposed within the membrane.

28. The device set forth in claim 27, wherein the passive gripping and releasing apparatus is coupled to a controllable robotic arm.

29. A method for gripping and releasing an object using a passive universal jamming gripper including a suitable jamming material characterized by a fluid-like to solid-like phase transition upon application of a vacuum, wherein the gripper is in a gripped state in which an object is being gripped, comprising:

applying a vacuum to the jamming material to cause a fluid-like to solid-like phase transition to grip the object; and

applying a positive fluid pressure to the jamming material to cause a solid-like to fluid-like phase transition, wherein the gripped object is actively released from the gripper.

30. The method set forth in claim 29, further comprising ejecting the gripped object by applying a sufficient positive fluid pressure.

31. The method set forth in any of claims 29 to 30, further comprising venting the membrane to the atmosphere when it is contacting the object.

32. The method set forth in any of claims 29 to 31 , further comprising alternating the positive and negative fluid pressure between releasing the gripped object and gripping the object.

33. The method set forth in any of claims 29 to 32, further comprising vibrating the gripper between releasing the gripped object and gripping the object.

34. The method set forth in any of claims 29 to 33, wherein the step of applying a positive fluid pressure further comprises using one of a gas and a liquid.

35. The method set forth in claim 34, wherein the gas is one of air, nitrogen, and inert gas.

38. The method set for in claims 29 to 35, further comprising selecting the gripper membrane material and size based on the object abrasiveness and size.

37. A gripping and releasing apparatus, comprising:

a flexible impermeable membrane defining an enclosure configured to contain a granular material; and

at least one port in fluid communication with the enclosure and in fluid communication with a source configured to apply a vacuum and a positive pressure;

wherein the undeformed shape of the flexible impermeable membrane is a vertical ellipse.

38. The apparatus of claim 37, wherein application of a vacuum causes a fluid-like to solid-like phase transition of the granular material.

39. The apparatus of claims 37 or 38, wherein the flexible impermeable membrane has an outer surface, and at least a portion of the outer surface has a texture.

40. The apparatus of claim 39, wherein the texture produces a coefficient of static friction greater than about 0.2

41 . A gripping and releasing apparatus, comprising:

a flexible impermeable membrane defining an enclosure configured to contain a resettable granular material; and

at least one port in fluid communication with the enclosure and a positive source of fluid ingress and a negative source of fluid egress;

wherein the impermeable membrane has an outer surface, and at least a portion of the outer surface has at least one of a texture or a surface feature.

42. The apparatus of claim 41 , wherein the texture produces a coefficient of static friction greater than about 0.2

43. The apparatus of claims 41 or 42, wherein the surface feature includes a plurality of nubs.

44. The apparatus of any of claims 41 to 43, wherein the texture or surface feature covers the entire outer surface of the impermeable membrane.

45. The apparatus of any of claims 41 to 44, wherein the granular material is fluidized pneumatically.

48. The apparatus of claim 43, wherein the nubs form cavities in fluid communication with the enclosure configured to allow flow of the granular material within the cavities.

47. The apparatus of claim 43, wherein the nubs are formed of the same material as the flexible impermeable membrane and are solid features.

48. The apparatus of claim 43, wherein the nubs are formed of a material different than that of the flexible impermeable membrane and the material of the dimples has a higher coefficient of friction than the material forming the flexible impermeable membrane.