Variable compliance finger assembly

Abstract

The present disclosure relates to a manipulation device comprising a finger assembly comprising a rigid body having an aperture and an expandable element received within the rigid body, wherein when the expandable element is expanded, a region of the expandable element forms a protrusion that penetrates the aperture, and wherein the manipulation device further comprises a controller configured to output an inflation control signal for pressurizing the expandable element according to a target pressure, where the target pressure is dependent on a characteristic of the object being manipulated.

Description

Technical Field

[0001] The present disclosure generally relates to the field of finger assemblies for operating devices, and more particularly to finger assemblies having a gripping surface with variable compliance.

Background Art

[0002] An automatic picking system requires a robotic picking station that can select an item from a first container such as a tote or other storage unit, grip the item, and then move the item into a second container such as a bag. When manipulating an item, it is beneficial for one or more components of the finger assembly of the operating device to have variable compliance so that rigid or fragile items can be gripped without risk of damage.

[0003] The present invention has been devised from such a background.

Summary of the Invention

[0004] Accordingly, in a first aspect, the present invention provides an operating device comprising: a finger assembly including a rigid body having a surface configured to engage an object and an inflatable element received within the rigid body, the surface comprising one or more apertures, wherein when the inflatable element is inflated, an area of the inflatable element projects through the one or more apertures to form one or more protrusions; a controller configured to output an inflation control signal for pressurizing the inflatable element according to a target pressure, the target pressure depending on the characteristics of the object; and pressure adjustment means configured to receive the inflation control signal and pressurize the inflatable element in response to the inflation control signal.

[0005] Preferably, the controller is configured to vary the pressure within the inflatable element within a range of 1 to 5 bar.

[0006] Preferably, the surface configured to engage the object has a first coefficient of friction, and the surface of the expandable element has a second coefficient of friction, where the first coefficient of friction is lower than the second coefficient of friction.

[0007] The mesh can be formed on the surface of the expandable element. The mesh can be formed on the surface of the expandable element that forms one or more protrusions. The application of the mesh can increase the stability of the protrusions when the expandable element is expanded and can increase the physical durability and elasticity of the expandable element.

[0008] The rigid body can include a back surface on the opposite side of the surface configured to engage the object and one or more reinforcing elements that connect the back surface to the surface configured to engage the object. The reinforcing elements increase the rigidity of the finger assembly and reduce the risk that the expansion of the expandable element distorts the finger assembly, for example, by bending the gripping surface.

[0009] At least one of the one or more apertures is substantially circular. Alternatively, at least one of the one or more apertures can be substantially elongated. Alternatively, in embodiments comprising a plurality of apertures, one of the plurality of apertures can be substantially circular and another of the plurality of apertures can be substantially elongated. Alternatively, the finger assembly can comprise apertures of different shapes and / or sizes.

[0010] The operating device can comprise an actuator configured to move the finger assembly in use. The actuator can move the finger assembly along a plurality of axes of movement and can be used to rotate the actuator about a plurality of axes of rotation. The controller is configured to output an actuation control signal for moving the finger assembly, where the actuator is configured to receive the actuation control signal and move the finger assembly in response to the actuation control signal.

[0011] The controller can inflate the inflatable element of the finger assembly according to the position of the finger assembly relative to the object. The controller can inflate the inflatable element when the finger assembly is moved so as to be close to the object. Alternatively, the controller can inflate the inflatable element of the finger assembly when the finger assembly is moved so as to contact the object.

[0012] In a second aspect, a method of operating an object using the operating device according to the first aspect is provided. The method includes moving a first finger assembly relative to a second finger assembly to engage the object, inflating the inflatable elements of the first and second finger assemblies, determining a target pressure within the inflatable elements according to the characteristics of the object, changing the pressure within the inflatable elements according to the target pressure, engaging the object with the first and second finger assemblies, and operating the object.

[0013] Preferably, the method further includes contracting the inflatable elements of the first and second finger assemblies and disengaging the first and second finger assemblies from the object.

[0014] Here, the above and other aspects of the present invention will be described merely by way of example with reference to the accompanying drawings.

Brief Description of the Drawings

[0015]

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DETAILED DESCRIPTION OF THE INVENTION

[0016] In the drawings, like features are denoted by like reference numerals as appropriate.

[0017] In the following description, some specific details are included to provide a complete understanding of the disclosed examples. However, one skilled in the art will recognize that one or more of these specific details may be omitted, or other examples may be implemented using other components, materials, etc., and that structural changes may be made without departing from the scope of the invention as defined in the appended claims. Further, references to terms having an implicit orientation in the following description are not intended to be limiting, but merely refer to the orientation of the features as shown in the accompanying drawings. In some examples, well-known features or systems such as processors, sensors, storage devices, network interfaces, fasteners, electrical connectors, etc. are not illustrated or described in detail to avoid unnecessarily obscuring the description of the disclosed embodiments.

[0018] Unless the context requires otherwise, throughout this specification and the appended claims, the words "comprise", "comprises" and "comprising" are to be construed in an open, inclusive sense, such as "including, but not limited to".

[0019] Throughout this specification, references to "one", "an" or "another" in connection with "embodiments", "examples" shall mean that a particular reference feature, structure, or characteristic described in connection with the embodiment, example, or implementation is included in at least one embodiment, example, or implementation. Thus, the appearances of the phrase "in one embodiment" and the like in various places throughout this specification are not necessarily all referring to the same embodiment. Further, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments, examples, or implementations.

[0020] It should be noted that, as used in this specification and the appended claims, the singular forms "a", "an", and "the" include plural referents unless the content clearly dictates otherwise. It should also be noted that the term "or" is generally used in the inclusive sense of "and / or" unless the content clearly dictates otherwise.

[0021] FIG. 1 shows a schematic view of an operating device 10 according to an embodiment of the present invention, comprising a first finger assembly 12a facing a second finger assembly 12b and a controller 14. Each of the first and second finger assemblies 12a, 12b includes an inflatable element (not shown in FIG. 1), and its outer surface is provided with a gripping surface arranged to grip an object 16 to be operated. The operating device 10 further comprises a first actuator 18a and a first pressure adjusting means 20a associated with the first finger assembly 12a, and a second actuator 18b and a second pressure adjusting means 20b associated with the second finger assembly 12b. The first and second pressure adjusting means 20a, 20b are connected to their associated finger assemblies 12a, 12b by respective pressure lines 27a, 27b and other suitable connectors. The controller 14 comprises an electronic processor 21 having one or more electrical inputs for receiving input signals, such as a visual data input signal 23 from an optical sensor 26 forming part of the operating device 10, and one or more electrical outputs for outputting one or more control signals 22a, 22b, 24a, 24b to the first and second actuators and pressure adjusting means 18a, 18b, 20a, 20b in response to the visual data input signal 23. For example, the controller 14 is configured to output a first actuation control signal 22a for moving the first finger assembly 12a based on the visual data input signal 23. The first actuator 18a receives the first actuation control signal 22a and is configured to move the first finger assembly 12a relative to the second finger assembly 12b in response to the first actuation control signal 22a. Similarly, the controller 14 can also output a second actuation control signal 22b for moving the second finger assembly 12b based on the visual data input signal 23. The second actuator 18b receives the second actuation control signal 22b and is configured to move the second finger assembly 12b relative to the first finger assembly 12a in response to the second actuation control signal 22b.These movements may include one of the first or second finger assemblies 12a, 12b rotating relative to the other of the first or second finger assemblies 12a, 12b with respect to a plurality of movement axes. Such movements may enable an object 16 to be gripped between the first finger assembly 12a and the second finger assembly 12b. The first and second finger assemblies 12a, 12b may be movable together such that an object 16 gripped therebetween can be moved from a first position to a second position. The controller 14 is configured to output inflation control signals 24a, 24b in response to a visual data input signal 23 in order to change the pressure inside the first or second finger elements 12a, 12b so as to change the compliance of each inflatable element, and to control the first or second pressure regulating means 20a, 20b. Specifically, the controller 14 is arranged to output a first inflation control signal 24a based on the visual data input signal 23, and the first pressure regulating means 20a is configured to receive the first inflation control signal 24a and pressurize the first finger assembly 12a in response to the first inflation control signal 24a. Similarly, the controller 14 is arranged to output a second inflation control signal 24b based on the visual data input signal 23, and the second pressure regulating means 20b is configured to receive the second inflation control signal 24b and pressurize the second finger assembly 12b in response to the second inflation control signal 24b to change the compliance of its inflatable element. To generate the control signals 22a, 22b, 24a, 24b, the controller 14 is electrically coupled to an electronic processor 21 and further includes a memory device 28 having instructions stored therein. The electronic processor 21 is configured to access the memory device 28 and execute the instructions stored therein to perform the processes described above.

[0022] Figures 2 through 10 show schematic views of a finger assembly 12' according to an embodiment of the present invention suitable for use in the operating device 10. The finger assembly 12' includes a rigid body 30 that receives an inflatable element 32.

[0023] Referring to FIG. 2, which is a schematic perspective view of the finger assembly 12', the rigid body 30 is substantially cubic and has a back surface 34 into which the actuator 18' is received. The rigid body 30 further includes a gripping surface 36 (not shown in FIG. 2) that faces the back surface 34. The gripping surface 36 is configured to engage an object 16 to be manipulated and is connected to the back surface 34 by two side surfaces 38 and two end surfaces 40. FIG. 3 shows a view of the gripping surface 36 having one or more apertures 42. In this embodiment, the gripping surface 36 has a plurality of apertures 42.

[0024] FIGS. 4 and 5 show schematic cross-sectional views of the rigid body 30. FIG. 4 shows a cross-section of the rigid body 30 in a plane parallel to and between the back surface and the gripping surfaces 34, 36. From this figure, it can be seen that the rigid body 30 includes a plurality of reinforcing elements 44, which in this embodiment comprise a plurality of columns 44. The plurality of columns 44 extend between the back surface 34 and the gripping surface 36, connecting them and increasing the rigidity of the rigid body 30. FIG. 4 shows the positions of the plurality of apertures 42 formed in the gripping surface 36 relative to the positions of the plurality of columns 44, with the plurality of apertures 42 shown as dotted lines. It can be seen that the plurality of columns 44 are arranged so as not to be located under one of the plurality of apertures 42. FIG. 5 shows a cross-section of the finger assembly 12' in a plane orthogonal to the gripping surface 36 (and further the back surface 34), showing the connection of the back surface 34 and the gripping surface 36 by the plurality of columns 44.

[0025] FIG. 6 shows a schematic view of the expandable element 32 having a plurality of openings 46. The plurality of openings 46 are arranged to align with a plurality of columns 44 formed in the rigid body 30 when the expandable element 32 is received within the rigid body 30. The material of the rigid body 30 has a first coefficient of friction, the material of the expandable element 32 has a second coefficient of friction, and the second coefficient of friction is higher than the first coefficient of friction.

[0026] FIG. 7 illustrates a schematic of the cross-sectional view of FIG. 5 in which the expandable element 32 is received within the rigid body 30 such that each of the plurality of posts 44 is received within a respective one of a plurality of openings 46 formed within the expandable element 32. The size of the openings 46 is larger than the size of the posts 44 such that the expandable element 32 is movable relative to the plurality of posts 44. FIG. 7 shows the expandable element 32 when in an unexpanded or inactive state, and FIG. 8 shows an outer side view of the finger assembly 12' when the expandable element 32 is in an unexpanded state. In an alternative embodiment, the expandable element 32 may substantially occupy the entire volume of the rigid body 30 in an unexpanded state and include a plurality of extrusions arranged to coincide with the positions of the plurality of openings 46. The extrusions are arranged such that their end faces are substantially flush with the gripping surface 36 of the rigid body 30 when the expandable element 32 is unexpanded. This arrangement allows the extrusions to engage the object 16 with little deformation of the expandable element 32 and means that the pressurization of the expandable element 32 can be reduced compared to the current embodiment.

[0027] In use, the expandable element 32 is expanded by the pressure regulating means 20' in accordance with the expansion control signal 24', and thus the expandable element 32 expands such that a portion of the expandable element 32 extends through a plurality of openings 42 formed within the gripping surface 36 to provide a number of contact points that conform to the object 16 and collectively form a suitably large frictional contact area. FIG. 9 shows a cross-sectional view of the finger assembly 12' when the expandable element 32 is in an expanded (or active) state within the rigid body 30. When the expandable element 32 is in this state, a plurality of protrusions 48 are formed, the diameter and position of the protrusions 48 being limited by the size and position of the apertures 42 formed within the gripping surface 36. FIG. 10 shows an outer side view of the finger assembly 12' when the expandable element 32 is in an expanded state, showing the plurality of protrusions 48 of the expandable element 32 above the gripping surface 36.

[0028] As described above in connection with FIG. 1, the controller 14 is configured to output an inflation control signal 24', which is received by respective pressure adjustment means 20' to pressurize the inflatable elements 32 associated therewith. The inflation control signal 24' is generated by the controller 14 in accordance with a target pressure and defines the level at which the inflatable elements 32 are to be pressurized. The target pressure is selected based on one or more characteristics of the object 16 being manipulated, such as its shape, weight, rigidity, fragility, etc., one or more of which are determined based on the visual data input signal 23 from the optical sensor 26 and / or can be utilized from the memory device 28 by the electronic processor 21. By varying those pressures, the compliance of the inflatable elements 32 and the force exerted thereon on the object 16 being manipulated can be increased or decreased in accordance with the selected characteristics.

[0029] The target pressure can be in the range of 1 to 5 bar and is varied within this range to change the compliance of the inflatable elements 32. That is, for example, when the inflatable elements 32 are pressurized to 4 bar, as shown in FIG. 11, the protrusions 48 are substantially rigid and can resist significant deformation when manipulating the object 16. Such an arrangement may be used when the object 16 being manipulated is determined to be heavy but rigid, thereby enabling it to withstand the normal force 50 exerted by the protrusions 48 over a relatively small contact area and allowing the object 16 to be held with a large force.

[0030] Conversely, for example, when the inflatable element 32 is pressurized to 1.5 bar, as shown in FIG. 12, the protrusions 48 are relatively soft, so there is a much higher likelihood that they will deform according to the portion of the object 16 with which they are engaged. In this arrangement, because the compliance of the protrusions 48 is greater, a relatively large contact area is formed compared to the arrangement shown in FIG. 11, the frictional contact formed between the object 16 and the deformed protrusions 48 increases, and the normal force 50 acting on the object 16 is reduced. Such an arrangement may be desirable when the object 16 being manipulated is fragile and / or has low rigidity.

[0031] FIGS. 13 through 16 show schematic views of an alternative example of a finger assembly 12' suitable for use in the operating device 10. The finger assembly 12' is as described above with reference to FIGS. 2 through 10, except that the gripping surface 36 of the rigid body 30 includes three elongated apertures 42 and the reinforcing element 44 includes two elongated supports. As a result, the inflatable element 32 includes two elongated apertures 46 having a size and position within the inflatable element 32 that allow the inflatable element 32 to be received within the rigid body 30. As described above, when the inflatable element 32 is in a non-inflated state, the inflatable element 32 is fully received within the rigid body 30. When the inflatable element 32 is inflated, a portion of the inflatable element 32 projects through the elongated openings 42 of the gripping surface 36 and may form a plurality of protrusions 48. In this example, the protrusions 48 include three linear protrusions extending along a portion of the length of the gripping surface 36.

[0032] The rigid body 30 can be formed by additive manufacturing, injection molding, or other conventional machining techniques. As described above, the reinforcing element 44 connects the back surface and the gripping surfaces 34, 36 to increase the rigidity of the rigid body 30 and reduce the deformation of the gripping surface 36 when the expandable element 32 is expanded. The reinforcing element 44 also acts to limit the movement of the expandable element 32 during expansion. The rigid body 30 may be formed of two halves that are connected to each other so as to surround the expandable element 32. The expandable element 32 preferably has a single inlet that provides a fluid connection between the interior of the expandable element 32 and the corresponding pressure line 27', through which it can be expanded. The expandable element 32 can be formed from a flexible silicone material. The expandable element 32 may be formed of two layers or a flexible silicone material, which can be firmly connected to each other, for example, by the use of an adhesive. The inlet can be formed from a rigid silicone material that can receive a pressurized air supply. The pressure regulating means 20' can be configured to contract the expandable element 32 so that a partial vacuum exists within the expandable element 32 in the non-expanded state, ensuring that all of the expandable element 32 is stored within the rigid body 30. A mesh can be applied to the surface of the expandable element 32 that forms the protrusions 48 when expanded. The mesh reinforces the expandable element 32 and makes it more elastic. Also, the patterning of the mesh can further increase the coefficient of friction of the protrusions 48 formed when the expandable element 32 is expanded. The mesh also reduces the amount by which the expandable element 32 can be expanded, allowing higher pressures to be applied, and thus enabling a greater gripping force and a lower compliance. In an alternative embodiment, the mesh may be embedded within the expandable element 32.

[0033] When the finger assembly 12’ is operated to contact the object 16 to be held, the finger assembly 12’ preferably has low friction while they are positioned relative to the object 16. Thereafter, the finger assembly 12’ preferably has high friction so that the object 16 can be effectively held and manipulated, for example, by picking up the object 16 and moving it from a first position to a second position. The finger assembly 12’ addresses this problem because the friction surface on the lower side of the finger assembly 12’ can be used to engage the object 16 when the expandable element 32 is not expanded. Once contact is made, the expandable element 32 is expanded, and thus, the expanded protrusions 48 with higher friction can hold the object 16 so that it can be manipulated. The higher friction of the expanded protrusions 48 allows a greater frictional force to be applied to the object 16. As described above, the protrusions 48 can have a flexibility such that the object 16 can be prevented from being damaged by being held too tightly. Once the object 16 is manipulated, for example, the object 16 can be moved from a first position to a second position, and then the expandable element 32 can be deflated and the finger assembly 12’ disengaged from the object 16.

[0034] Instead of or in addition to the optical sensor 26, the operating device 10 may comprise a contact sensor (not shown in FIG. 1). The contact sensor detects when the gripping surfaces 36 of the first and second finger assemblies 12a, 12b are in contact with the object 16 and outputs one or more signals that are received as input signals by the electronic processor 21 of the controller 14. The electronic processor 21 then outputs one or more inflation control signals 24' to the pressure regulating means 20' in response to the input signal in order to inflate the inflatable element 32 when both the first finger assembly 12a and the second finger assembly 12b are in contact with the object 16. Alternatively or additionally, the operating device 10 may comprise a proximity sensor (not shown in FIG. 1) that detects when the gripping surfaces 36 of the first and second finger assemblies 12a, 12b are within a specified distance from the object 16. The output signal of the proximity sensor is then received as an input signal by the electronic processor 21 of the controller 14, and the controller 14 outputs one or more inflation control signals 24' to the pressure regulating means 20' based on the input signal in order to inflate the inflatable element 32 when the first and second finger assemblies 12a, 12b are sufficiently close to the object 16 to be gripped. The outputs from both the proximity sensor and the contact sensor can be used to determine the inflation of the inflatable element 32.

[0035] Without departing from the scope of the present invention, many modifications and variations can be made to the embodiments described above. For example, the number, size, and shape of the apertures 42 formed in the gripping surface 36 can be changed. For example, some embodiments of the finger assembly 12' may comprise a single aperture 42 within the gripping surface 36 that is relatively larger than those used in the finger assembly 12' comprising a plurality of apertures 42. Depending on the application, it may be preferable for the protrusions 48 to be actuated in different regions of the gripping surface 36. In such cases, the finger assembly 12' may comprise a plurality of inflatable elements 32, each of which can be inflated or deflated independently in a controllable manner.

[0036] The above description is presented for illustrative purposes only and is not intended to be exhaustive or to limit the invention to the exact embodiments disclosed. It will be understood that modifications and variations can be made to the described embodiments without departing from the scope of the invention as defined by the appended claims. The following matters described in the claims of the original application are appended as they are. [1] An operating device, comprising: a finger assembly including a rigid body having a surface configured to engage an object and an expandable element received within the rigid body, the surface including one or more apertures, and when the expandable element is expanded, an area of the expandable element protrudes through the one or more apertures to form one or more protrusions; a controller configured to output an inflation control signal for pressurizing the expandable element according to a target pressure, the target pressure depending on characteristics of the object; pressure adjustment means for receiving the inflation control signal and configured to pressurize the expandable element in response to the inflation control signal; and an operating device comprising the same. [2] The operating device according to [1], wherein the controller is configured to vary the pressure within the expandable element within a range of 1 to 5 bar. [3] The operating device according to [1] or [2], wherein the surface configured to engage the object has a first coefficient of friction, the surface of the expandable element has a second coefficient of friction, and the first coefficient of friction is lower than the second coefficient of friction. [4] The operating device according to any one of [1] to [3], wherein a mesh is formed on the surface of the expandable element. [5] The rigid body includes a back surface on the opposite side of the surface configured to engage the object, and the finger assembly further includes one or more reinforcing elements extending between the back surface and the surface configured to engage the object. The operating device according to any one of [1] to [4]. [6] The operating device according to any one of [1] to [5], wherein at least one of the one or more apertures is substantially circular. [7] The operating device according to any one of [1] to [5], wherein at least one of the one or more apertures is substantially elongated. [8] The finger assembly further includes an actuator, and the controller is further configured to output an operation control signal for moving the finger assembly, and the actuator is configured to receive the operation control signal and move the finger assembly according to the operation control signal. The operating device according to any one of [1] to [7]. [9] The controller is configured to inflate the inflatable element according to the position of the finger assembly relative to the object. The operating device according to any one of [1] to [8].

[10] The controller is configured to inflate the inflatable element when the finger assembly is moved so as to be close to the object. The operating device according to [9].

[11] The controller is configured to inflate the inflatable element when the finger assembly is moved so as to contact the object. The operating device according to [9].

[12] A method of operating an object using the operating device according to any one of [1] to

[11] , comprising: a) moving a first finger assembly relative to a second finger assembly to engage the object; b) inflating the inflatable elements of the first and second finger assemblies; c) determining a target pressure in the inflatable element according to the characteristics of the object; d) changing the pressure in the inflatable element according to the target pressure; e) engaging the object with the first and second finger assemblies; f) operating the object The method comprising.

[13] g) contracting the inflatable elements of the first and second finger assemblies; h) disengaging the first and second finger assemblies from the object The method according to

[12] , further comprising.

Claims

Claim 1 An operating device comprising: A finger assembly having a rigid body with a surface configured to engage an object and an inflatable element received within the rigid body, the surface comprising one or more apertures, and when the inflatable element is inflated, an area of the inflatable element protrudes through the one or more apertures to form one or more protrusions; A controller configured to output an inflation control signal for pressurizing the inflatable element according to a target pressure, the target pressure depending on the characteristics of the object; Pressure adjustment means for receiving the inflation control signal and configured to pressurize the inflatable element in response to the inflation control signal Comprising The rigid body comprises a back surface on the opposite side of the surface configured to engage the object, and the finger assembly further comprises one or more reinforcing elements extending between the back surface and the surface configured to engage the object; The inflatable element comprises one or more openings (46) aligned with the one or more reinforcing elements. An operating device. Claim 2 The operating device according to claim 1, wherein the controller is configured to vary the pressure within the inflatable element within a range of 1 to 5 bar. Claim 3 The operating device according to claim 1 or 2, wherein the surface configured to engage the object has a first coefficient of friction, the surface of the inflatable element has a second coefficient of friction, and the first coefficient of friction is lower than the second coefficient of friction. Claim 4 The operating device according to any one of claims 1 to 3, wherein a mesh is formed on the surface of the inflatable element. Claim 5 The operating device according to any one of claims 1 to 4, wherein at least one of the one or more apertures is substantially circular. Claim 6 The operating device according to any one of claims 1 to 4, wherein at least one of the one or more apertures is substantially elongated. Claim 7 The operating device according to any one of claims 1 to 6, wherein the finger assembly further comprises an actuator, the controller is further configured to output an actuation control signal for moving the finger assembly, and the actuator is configured to receive the actuation control signal and move the finger assembly in response to the actuation control signal.

8. The operating device according to any one of claims 1 to 7, wherein the controller is configured to inflate the inflatable element according to the position of the finger assembly relative to the object.

9. The operating device according to claim 8, wherein the controller is configured to inflate the inflatable element when the finger assembly is moved so as to be close to the object.

10. The operating device according to claim 8, wherein the controller is configured to inflate the inflatable element when the finger assembly is moved so as to contact the object.

11. A method of operating an object using the operating device according to any one of claims 1 to 10, comprising: a) moving a first finger assembly relative to a second finger assembly to engage the object; b) inflating the inflatable elements of the first and second finger assemblies; c) determining a target pressure in the inflatable element according to the characteristics of the object; d) changing the pressure in the inflatable element according to the target pressure; e) engaging the object with the first and second finger assemblies; f) operating the object The method comprising.

12. g) contracting the inflatable elements of the first and second finger assemblies; h) disengaging the first and second finger assemblies from the object The method according to claim 11, further comprising.

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