Soft clamp and soft clamp system

Abstract

The invention discloses a soft clamp system and a soft clamp. The soft clamp comprises: a plurality of clamp fingers, each of the plurality of clamp fingers comprising: a finger base defining a first surface and a second surface opposite the first surface, the finger base being provided with a network of pneumatic channels; an actuator coupled to the first surface, the actuator being provided with a pneumatic channel; a plurality of suction members coupled to the second surface, the plurality of suction members being in fluid communication with the network of pneumatic channels, where the finger base is biased into a curved state, where the actuator is actuatable to deflect the finger base from the curved state in response to a first negative pressure in the pneumatic channels, wherein each of the plurality of suction members provides a respective suction pressure in response to a second negative pressure in the pneumatic channel network.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to Singapore Patent Application No. 10202401061Y, filed on April 12, 2024, the contents of which are incorporated herein by reference in their entirety for all purposes. Technical Field

[0003] This application relates to the field of material handling, and more specifically to a soft clamp and a soft clamp system. Background Technology

[0004] Labor shortages, particularly in repetitive picking and placing tasks that do not require specialized skills, have become a major obstacle in general-purpose cluster grasping. An exemplary application scenario is in both traditional and vertical farming environments. Automation not only has the potential to alleviate labor shortages but also optimizes operating costs, playing a crucial role in efficiently meeting global food demand. However, this transformation process is not without its complexities. For example, the harvesting process is characterized by a variety of labor-intensive tasks, such as handling leaves and branches, precise stem cutting using tools, and fruit picking, all of which require the finely coordinated control of robotic arms and tools. This necessitates precise force control through tactile feedback during crop handling. Summary of the Invention

[0005] According to one aspect, a soft clamp is disclosed herein. The soft clamp includes: a plurality of clamping fingers, each of the plurality of clamping fingers including: a finger base defining a first surface and a second surface opposite to the first surface, the finger base having a network of pneumatic channels; an actuator coupled to the first surface, the actuator having a pneumatic channel; and a plurality of adsorption members coupled to the second surface, the plurality of adsorption members being in fluid communication with the pneumatic channel network, wherein the finger base is biased into a bent state, wherein the actuator can be actuated to deflect the finger base from the bent state in response to a first negative pressure in the pneumatic channels, wherein each of the plurality of adsorption members provides a respective adsorption pressure in response to a second negative pressure in the pneumatic channel network.

[0006] According to another aspect, a soft clamping system is disclosed herein. The soft clamping system includes a soft clamp as described above, and a pneumatic pressure source in controlled fluid communication with each clamping finger of the soft clamp. Attached Figure Description

[0007] Various embodiments of this disclosure will now be described in conjunction with the following accompanying drawings: Figure 1 This is a schematic diagram of a soft clamping system according to several embodiments; Figure 2A cross-sectional view of a soft clamp in a curved state according to various embodiments; Figure 3 A cross-sectional view of a soft clamp in an open state according to various embodiments; Figure 2 Figure 4 A bottom view of a soft clamp according to various embodiments; Figure 3 Figure 5 A top view of a soft clamp according to various embodiments; Figure 3 Figure 6 A schematic diagram of fluid communication between a pneumatic pressure source and a soft clamp according to various embodiments; Figure 7 A cross-sectional view of an adsorption member according to various embodiments; Figure 8 A cross-sectional view of an adsorption member handling an object according to various embodiments; Figure 7 Figure 9A A top view of a soft clamp according to various embodiments; Figure 9B A top view of another soft clamp according to various embodiments; Figures 10A-10D A schematic diagram of a soft clamp system in operation according to various embodiments; Figure 11 A scooping soft clamp according to exemplary embodiments is shown, comprising an array of suction cups with compliant stems designed to conform to and attach to a cluster of objects; Figure 12 A scooping mechanism of the scooping soft clamp of Figure 11 actuated by a bellow for surrounding a cluster of objects after initial grasping with suction; Figure 13 Various elements of the scooping soft clamp of Figure 11 are shown, along with an enlarged cross-sectional view of a passive suction cup: (i) compliant stem, (ii) suction cup, and (iii) passive membrane; Figure 14 A schematic diagram of vacuum channels of all suction cups in an array connecting to a single vacuum inlet. The size of the radiating arms surrounding the frame is 9.5 cm by 6 cm; Figure 15 A force-displacement measurement setup for material testing of passive suction cups is shown; Figure 16 Test results of suction cups without passive membranes on test bases at three different angles are shown. The combination of SS960 as the suction cup material and DS30 as the stem material yields the largest adsorption force; Figure 17 ​​​​Test results showing the optimal performance combination of the SS960 suction cup with the DS30 stem and determining the optimal passive thin film material. EF10 shows greater passive suction force compared to EF30, making it the preferred material; Figure 18 Example Finite Element (FEA) analysis validation of a pre-bent bellows actuator is shown; Figure 19A Manufacturing steps of a pre-bent bellows actuator (PBA) are shown: (i) using a three-piece mold and casting the pre-bent bellows segment in the open state using SmoothSil-960; (ii) using a two-piece mold and casting the flat closed segment of the pre-bent bellows actuator using SmoothSil-960; (iii) for the pre-bent bellows actuator, using uncured SmoothSil-960 slurry as an adhesive to precisely align and bond the open bellows segment with the flat segment; Figure 19B Manufacturing steps of a flat ray are shown: (i) using a two-piece mold and casting the first ray layer with a network of vacuum channels using Dragon Skin 30; (ii) using a two-piece mold and casting the second ray layer in a similar fashion using Dragon Skin 30 and using uncured Dragon Skin 30 to bond the second ray layer with the first ray layer after alignment, where the second ray layer has protrusions that connect the vacuum network of the first ray layer to the stem of the passive suction cup; Figure 19C Manufacturing steps of a passive suction cup are shown: (i) using a three-piece mold, casting the suction cup portion using SmoothSil-960 and casting the stem of the suction cup using Dragon Skin 30; (ii) using an in-house Direct Ink Writing apparatus to generate an uncured Eco Flex 10 flat passive thin film with a thickness of 1 mm; (iii) carefully placing the suction cup on the uncured Eco Flex 10; (iv) after curing, trimming by using a blade cutter along the edge of the suction cup to remove excess Eco Flex 10 layer, resulting in a passive suction cup; Figure 19D Opening state of the dipstick soft clamp ray under vacuum actuation by combining the pre-bent bellows actuator, flat ray, and passive suction cup using their respective uncured silicone; Figure 19E Passive suction cup of the dipstick soft clamp ray under vacuum actuation is shown; Figure 19F A scooping soft-jawed gripper arm is shown holding a mushroom by passive suction in an unactuated pre-bent state; Figure 19G A fully assembled scooping soft-jawed gripper arm in an open state is shown, combining a cast radiating arm and a Fused Deposition Modeling (FDM) printed Acrylonitrile Styrene Acrylate (ASA) part for modular interface, and including a gripper support or gripper base.

[0008] Figure 20A A scooping soft-jawed gripper is shown grasping a half pepper (due to 250 gram load capacity): (i) the scooping soft-jawed gripper holding the half pepper in an open state; (ii) the scooping soft-jawed gripper grasping the half pepper in a closed / bent state.

[0009] Figure 20B A scooping soft-jawed gripper is shown grasping individual shimeji mushrooms: (i) the scooping soft-jawed gripper holding the individual shimeji mushrooms in an open state; (ii) the scooping soft-jawed gripper grasping the shimeji mushroom cluster in a closed / bent state.

[0010] Figure 20C A scooping soft-jawed gripper is shown grasping cherry tomatoes: (i) the scooping soft-jawed gripper holding the individual cherry tomatoes in an open state; (ii) the scooping soft-jawed gripper grasping the cherry tomato cluster in a closed / bent state.

[0011] Figure 20D A scooping soft-jawed gripper is shown grasping an orange: (i) the scooping soft-jawed gripper holding the orange in an open state; (ii) the scooping soft-jawed gripper grasping the orange in a closed / bent state.

[0012] Figure 21A A scooping soft-jawed gripper is shown grasping bok choy despite limited suction due to uneven bok choy leaf surfaces.

[0013] Figure 21B A scooping soft-jawed gripper is shown grasping a large mushroom despite limited suction due to the wet and porous surface of the large mushroom; and

[0014] Figure 21C A scooping soft-jawed gripper is shown grasping a cluster of shimeji mushrooms despite limited suction due to the highly uneven surface of the heavy cluster of shimeji mushrooms. DETAILED DESCRIPTION

[0015] The following detailed description is made with reference to the accompanying drawings, in which the details of the disclosure are shown for purposes of explanation. Features described in the context of one embodiment can correspondingly be applied to the same or similar features in other embodiments, even if not explicitly described in those other embodiments. Additions and / or combinations and / or alternatives of features described in the context of one embodiment can correspondingly be applied to the same or similar features in other embodiments.

[0016] In the context of multiple embodiments, the terms “a”, “an”, and “the” when used in reference to a feature or element include one or more of that feature or element.

[0017] In the context of multiple embodiments, the term “about” or “approximately” when applied to a numerical value encompasses the exact numerical value and reasonable deviations in the relevant technical field that are generally understood to be within the scope of the term, for example within 10% of the stated numerical value.

[0018] As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items.

[0019] The term “pose” can include a position and an orientation of an object or a portion of an object. The term “position” can refer to a location or coordinates (e.g. X coordinate, Y coordinate, Z coordinate) of an object or a portion of an object in a space or coordinate system. The term “orientation” can refer to an orientation or angle (e.g. X direction vector, Y direction vector, Z direction vector) of an object or a portion of an object in a space or coordinate system.

[0020] The term “negative pressure” can refer to a fluid pressure in a pneumatic line or channel that is lower than atmospheric pressure, for example 0.5 bar. The term “negative pressure” can also refer to a negative pressure difference between an environment and a pneumatic line, where the pressure in the pneumatic line is lower than the environmental pressure. In an example, the negative pressure can be close to or substantially close to absolute zero pressure.

[0021] The term “positive pressure” can refer to a fluid pressure in a pneumatic line or channel that is higher than atmospheric pressure, for example 1.5 bar. The term “positive pressure” can also refer to a positive pressure difference between an environment and a pneumatic line, where the pressure in the pneumatic line is higher than the environmental pressure.

[0022] The terms “crop”, “plant”, “grain” can be used interchangeably to refer to one or the sum of harvested products, for example a cereal crop, a fruit or a vegetable.

[0023] One of the challenges faced by robotic end effectors for tasks such as handling of agricultural crops is to minimize damage to the produce during the harvesting process. Moreover, due to the granular and irregular shape of the agricultural crops and fruits, this poses a challenge to traditional robotic grippers or robotic end effectors, which require precise force control, complex grasping techniques, and customization to traditional robotic grippers, often leading to bulky and inefficient solutions.

[0024] In view of the above non-exhaustive limitations, the present disclosure takes a different approach to tackle the challenges of agricultural crop handling. Instead of complex manipulations, a soft gripper and soft gripper system actuated by negative pressure is presented herein for handling of agricultural crops and fruits. The presented soft gripper can be a reconfigurable gripper that can switch between different states to achieve different modes of object handling. In some embodiments, the presented soft gripper can switch or reconfigure between a scooping / grasping state, a suction state, or a combination thereof. The reconfigurability of the soft gripper allows for real-time customization and allows the soft gripper to employ different modes of operation during a single pick / handling operation.

[0025] In various embodiments, one or more gripper fingers of the soft gripper can be biased towards a curved state or curved profile, thereby defining an at least partially closed volume. This is analogous to wrapping one's fingers around one or more objects. The at least partially closed volume can include a fully closed volume or a partially closed volume that is operable to hold or grasp the one or more objects. Typically, the curved state corresponds to one or more support surfaces to hold or grasp the one or more objects against gravity. In exemplary embodiments, a single gripper finger in the curved state can also define a partially closed volume by assuming a shape similar to a spoon or a ladle.

[0026] Further, one or more gripper fingers of the soft gripper can be actuated to displace to an open state, thereby reducing the closed / partially closed volume. This is analogous to spreading one's fingers to release an object. Typically, the open state corresponds to a reduction in support surfaces to hold the one or more objects against gravity.

[0027] In the open state, each of the gripper fingers can controllably and / or selectively provide a suction pressure or suction force. In various embodiments, each of the gripper fingers can also controllably and / or selectively provide a suction pressure or suction force in the curved state.

[0028] In several embodiments, the clamping fingers can be actuated from a bent state to an open state by providing negative pressure or pressure below atmospheric pressure via a vacuum pump. Furthermore, the adsorption pressure provided by the clamping fingers can also be provided by the vacuum pump. Further, a single vacuum pump can be used simultaneously to actuate all clamping fingers and provide adsorption via their respective pneumatic valves. This allows a single pneumatic source to be used for the soft clamp, thereby reducing the complexity of the soft clamping system and simplifying hardware setup.

[0029] Figure 1 A schematic diagram of a soft gripper system 50 for handling crops 80 according to several embodiments of the present disclosure is shown. The soft gripper system 50 may include a soft gripper 100 coupled to a robotic arm 60. The robotic arm 60 can controllably change the pose (including position and orientation) of the soft gripper 100. Furthermore, the soft gripper 100 may be connected to a pneumatic pressure source 70, such as a vacuum pump. In several embodiments, the soft gripper 100 can be actuated by reducing the pneumatic pressure in multiple pneumatic lines or channels. Therefore, the soft gripper 100 can be considered to be actuated by one or more negative pressures.

[0030] In several embodiments, the soft gripper 100 may include a gripper base 110 and one or more gripper fingers 200 coupled to the gripper base 110. In several embodiments, the gripper base 110 may be coupled to the robotic arm 60. The gripper base 110 may serve as a reference body or reference point for controlling the robotic arm 60.

[0031] In such Figure 1 In some examples shown, the soft clamp 100 may include a pair of opposing clamp fingers 200. In other examples, the soft clamp 100 may include four clamp fingers 200 or two pairs of opposing clamp fingers 200. In still other examples, the soft clamp 100 may include a single clamp finger 200. Each of the clamp fingers 200 may be in controlled fluid communication with a single pneumatic pressure source 70. Therefore, each of the clamp fingers 200 may be actuated by the single pneumatic pressure source 70.

[0032] In several embodiments, each gripper finger 200 may include a finger base 210 that generally defines the shape and configuration of the gripper finger 200. The finger base 210 may be generally planar and flexible. In several embodiments, the finger base 210 may be generally triangular in shape or at least include generally triangular ends, but is not limited thereto. This allows the gripper fingers 200 to form closed volumes and / or partially closed volumes without overlapping each other. In some examples, the finger base 210 may be shaped like ray or starfish arms. In other examples, the finger base 210 may be leaf-shaped. In still other examples, the finger base 210 may be quadrilateral, such as a rhombus. In several embodiments, the finger base 210 may be generally planar. In other embodiments, the finger base 210 may be formed in a curved shape.

[0033] In several embodiments, the finger base 210 may be biased into a curved shape. In other words, the finger base 210 may be in a curved state in its unactuated state. In several embodiments, each gripper finger 200 may also include an actuator 230 coupled to a first surface of the finger base 210, and a plurality of suction members 250 coupled to an opposing second surface of the finger base 210. The actuator 230 may be formed and / or coupled to the finger base 210 such that the actuator 230 biases the finger base 210 into a curved state with a curved profile. This curved state corresponds to the unactuated state of the finger base 210. In an exemplary embodiment, the actuator 230 may be formed as a curved member such that the finger base 210 adhering to the actuator 230 also presents a curved profile.

[0034] In other embodiments, the finger base 210 may be formed as a curved member. Therefore, the finger base 210 can be biased into a curved state without the assistance of the actuator 230. In some embodiments, the finger base 210 may also be biased into a curved state with the assistance of the actuator 230, which is also a curved member.

[0035] In response to a first negative pressure provided or generated by the pneumatic pressure source 70, the actuator 230 can be actuated to deflect the finger base 210 from a bent state, such as Figure 1 As indicated by the dashed arrows in the diagram. Furthermore, each of the plurality of adsorption members 250 can provide its own adsorption pressure in response to a second negative pressure provided or generated by the pneumatic pressure source 70. It should be noted that the first negative pressure and the second negative pressure can be controllably and independently provided to the actuator 230 and each of the plurality of adsorption members 250.

[0036] Figures 2-5Several embodiments of a soft clamp 100 for handling crop 80 according to this disclosure are shown. The soft clamp 100 includes a plurality of clamping fingers 200, for example, two clamping fingers 200. Each of the clamping fingers 200 includes a finger base 210 defining a central plane 211. The finger base 210 may further have a rear end 202 to a front end 204. The finger base 210 may have a network of pneumatic channels 212 formed or provided.

[0037] See Figure 4 In several embodiments, the pneumatic channel network 212 may extend from the rear end 202 to the front end 204. Furthermore, the pneumatic channel network 212 may be arranged along a transverse axis 213, which is generally transverse to the central plane 211. In some embodiments, the pneumatic channel network 212 may include multiple parallel branches in fluid communication with a common inlet 215 disposed on or coupled to the finger base 210. In other embodiments, the pneumatic channel network 212 may have multiple independent and fluid-isolated pneumatic regions, each in fluid communication with its respective inlet.

[0038] In several embodiments, the finger base 210 may be made of an elastic material, thereby allowing the finger base 210 to bend about a transverse axis 213. In several embodiments, the finger base 210 may be generally planar in shape, and further define a first surface 214 and a second surface 216 opposite to the first surface 214. Thus, the first surface 214 and the second surface 216 may generally be transverse to the central plane 211.

[0039] In an exemplary embodiment, the pneumatic channel network 212 may be disposed or formed between the first surface 214 and the second surface 216. In other words, the pneumatic channel network 212 may be embedded within the finger base 210. In other embodiments, the pneumatic channel network 212 may be formed on the surface of the finger base 210, for example, on the second surface 216.

[0040] In several embodiments, each of the clamp fingers 200 may further include an actuator 230 coupled to a first surface 214 of the finger base 210. The actuator 230 may be a pneumatic actuator including one or more internal pneumatic chambers. In several embodiments, the actuator 230 may be made of an elastic material. The actuator 230 may include a plurality of bellows 231 and a pneumatic actuation channel 232 in fluid communication with each of the plurality of bellows 231. See also Figure 5The plurality of bellows 231 can be aligned along the central plane 211 of the finger base 210. A pneumatic actuation channel 232 allows fluid communication between each of the plurality of bellows 231 and terminates at an inlet 235. This allows the pressure in each of the plurality of bellows 231 to be controlled or changed either holistically or simultaneously.

[0041] In several embodiments, the actuator 230 may be configured to have a curved profile. In several embodiments, the stiffness of the actuator 230 and / or the plurality of bellows 231 may be higher than the stiffness of the finger base 210. Therefore, by coupling the actuator 230 to the finger base 210, the actuator 230 can bias the finger base 210 into a curved state or an unactuated state, such as... Figure 2 As shown.

[0042] In several embodiments, each of the clamp fingers 200 may further include a plurality of adsorption members 250 coupled to the second surface 216. The plurality of adsorption members 250 may be configured as a plurality of suction cups 250. The plurality of adsorption members 250 may be in fluid communication with the pneumatic channel network 212.

[0043] See Figure 2 In several embodiments, the bent finger base 210 corresponds to at least partially closed volume 90 defined by the plurality of gripper fingers 200. The at least partially closed volume 90 may include a fully closed volume or a partially closed volume (e.g., Figure 2 As shown, it is operable to hold or grasp crop 80. Typically, the bent state corresponds to one or more support surfaces for holding crop 80 against gravity. In several embodiments, for handling small-particle crops, the plurality of adsorption members 250 may set the scooping surface in response to the finger base 210 being in a bent state.

[0044] In several embodiments, actuator 230 may be actuated in response to a first negative pressure in pneumatic actuation channel 232 to deflect finger base 210 from a bent state toward an open state. Simultaneously or independently, each of the plurality of adsorption members 250 may provide its respective adsorption pressure in response to a second negative pressure in pneumatic channel network 212.

[0045] See Figure 3In response to a first negative pressure in the pneumatic actuation channel 232, the pressure in the plurality of bellows 231 is lower than the ambient pressure, thereby creating a negative pressure difference. Therefore, the plurality of bellows 231 deform or collapse under the pressure difference, causing the finger base 210 to bend or displace toward the open state. Conversely, in the absence of the first negative pressure in the pneumatic channel, i.e., when the pressure in the pneumatic actuation channel 232 is equal to or higher than the ambient pressure, the plurality of bellows 231 bend the finger base 210 to bias it back to the bent state. In some embodiments, a small positive pressure in the pneumatic channel can help move the finger base 210 back to the bent state. In some embodiments, a small positive pressure can also help reduce one or more gaps / spacings formed between adjacent gripper fingers 200.

[0046] See Figure 3 As an example, the open state of the finger base 210 may include the finger base 210 or the clamp finger 200 presenting an overall planar shape. For example... Figure 3 As shown, with the actuation of the finger base 210 toward the open state, the partially closed volume formed by the plurality of gripping fingers 200 decreases. In the open state, the plurality of gripping fingers 200 are generally spaced apart from each other and spread out relative to each other. Therefore, when the finger base 210 is in the open state, a second negative pressure forms a respective adsorption effect from each of the plurality of adsorption members 250, thereby allowing the plurality of gripping fingers 200 to pick up crops 80 or objects by adsorption. This allows crops to be processed by adsorption pressure, thereby avoiding excessive gripping force on the crops 80 during processing. Furthermore, by using adsorption, irregularly shaped crops can be processed without specific requirements and / or customization of the gripper shape and configuration.

[0047] In such Figure 4 In several embodiments shown, the pneumatic channel network 212 may include a plurality of connection nodes 217. Each of the plurality of connection nodes 217 may be in fluid communication with a respective adsorption member of the plurality of adsorption members 250. In several embodiments, the plurality of adsorption members 250 may be uniformly distributed on the second surface 216. This maximizes the reach of the adsorption members 250 when picking up the crop 80. In several embodiments, the plurality of adsorption members 250 may be symmetrically arranged about the central plane 211, thereby allowing symmetrical adsorption forces to be applied to relatively large crops.

[0048] In such Figure 5In the various embodiments shown, each of the plurality of bellows 231 defines a respective bellows width (BW). Each of these bellows widths (BW) can be set parallel to the transverse axis 213. In various embodiments, the respective bellows width BW of the plurality of bellows 231 can vary along the central plane 211. In various embodiments, the respective bellows width (BW) of the plurality of bellows 231 decreases from the rear end 202 to the front end 204. Therefore, larger bellows 231 are arranged at the rear end 202, while smaller bellows 231 are arranged at the front end 204. This allows for a large bend in the finger base 210 at the rear end 202, thereby facilitating a faster and more efficient deflection of the finger base 210 from a bent state.

[0049] See Figure 6 In various embodiments of the soft clamp system 50 and the soft clamp 100, a common or single pneumatic pressure source 70 may be fluidly coupled or connected to each of the plurality of clamp fingers 200a / … / 200n. Furthermore, the single pneumatic pressure source 70 may be in fluid communication with the respective pneumatic channel networks 212a / … / 212n and the respective pneumatic channels 232a / … / 232n of the plurality of clamp fingers 200a / … / 200n. Additionally, a first valve 72a / … / 72n may be connected between the single pneumatic pressure source 70 and the respective pneumatic channel networks 212a / 212n. Similarly, a second valve 74a / … / 74n may be connected between the single pneumatic pressure source 70 and the respective pneumatic channels 232a / … / 232n. Therefore, by controlling each of the first valves 72a / … / 72n, the adsorption pressure / adsorption force from each of the clamp fingers 200a / … / 200n can be controlled. Furthermore, by controlling each of the second valves 74a / ... / 74n, the state (bent or open) of each of the clamp fingers 200a / ... / 200n can also be controlled. This makes it possible to use a single pneumatic pressure source 70 for a simple pneumatic setup for soft clamps.

[0050] See now Figure 7 and Figure 8 In several embodiments of this disclosure, each of the plurality of adsorption members 250 may include a suction cup 252 and a rod 254 coupled between the second surface 216 and the suction cup 252. The stiffness or modulus of elasticity of the rod 254 may be lower than that of the suction cup 252. This allows the rod 254 to deform according to the contour of the crop 80. In several embodiments, the rod 254 and the suction cup 252 may define an internal space 251. This internal space 251 may be in fluid communication with the pneumatic channel network 212 via respective connection nodes 217. Therefore, the internal space 251 may serve as part of a fluid passage for generating adsorption forces on the crop 80.

[0051] In several embodiments, the internal space 251 may terminate at the opening 255 of the suction cup 252. A film 256 may be arranged to cover the opening 255 of the suction cup 252. The stiffness or modulus of elasticity of the film 256 may be lower than that of the suction cup 252. Therefore, the film 256 is more deformable than the suction cup 252. See also Figure 8 The film 256 can serve as a seal between the suction cup 252 and the crop 80, improving the sealing contact by deforming to conform to the crop 80. Furthermore, the film 256 increases the contact area with the crop 80, thereby minimizing potential damage to the crop 80 due to adsorption. In some embodiments, the stiffness or modulus of elasticity of the film 256 may also be lower than that of the rod 254. Therefore, when in contact with the crop 80, the film 256 deforms first to conform to the crop 80 before the rod 254 deforms. The film 256 also serves to enable all suction cups 252 to be activated simultaneously based on a common pneumatic channel network. Since it is often difficult to ensure or determine whether all suction cups are in contact with the crop 80, the film 256 helps to prevent the pneumatic channels from being exposed to the atmosphere, thereby helping to prevent adsorption pressure failure or reduction. As an example, without the film, suction cups not in contact with the crop may result in a decrease in overall adsorption force, since each of the suction cups 252 is connected to a single common pneumatic channel network.

[0052] See Figure 9A and Figure 9B In several embodiments, the gripper base 110 may be coupled along the gripper axis 112 (perpendicular to the drawing) or may be coupled to a robotic arm (not shown). In the illustrated exemplary embodiment, the gripper base 110 may be coupled to a plurality of gripper fingers 200, for example, three gripper fingers 200 ( Figure 9A ) and four clamps refer to 200 ( Figure 9B In several embodiments, the plurality of clamping fingers 200 may be arranged radially symmetrically about the clamping axis 112. This allows the plurality of clamping fingers 200 to form a closed volume therebetween.

[0053] Figures 10A-10D The illustration shows a series of operations performed by a soft clamp system 50 and a soft clamp 100 on an object 80 according to several embodiments of the present disclosure. The object 80 may be a crop or fruit. The soft clamp 100 may include a pair of clamp fingers 200. The soft clamp 100 may be fluidly connected to a common or single pneumatic pressure source 70. Thus, the common pneumatic pressure source 70 is configured to control each of the clamp fingers 200.

[0054] See Figure 10AInitially, each gripper finger 200 of the soft clamp 100 is in an initial, unacted state, corresponding to a bent finger base 210. The bent finger base 210 generally corresponds to a bent shape of the gripper finger 200. In this bent state or shape, a first negative pressure 76 is provided to the actuator 230 of the gripper finger 200 to actuate and deflect the finger base 210 from the bent state. Therefore, the finger base 210 or the gripper finger 200 is actuated toward an open state (e.g., ...). Figure 10B (As shown).

[0055] See Figure 10B When the gripper finger 200 is in the open state, the robotic arm 60 can move the soft gripper 200 toward the object 80. When the soft gripper 200 is adjacent to the object 80, the pneumatic pressure source 70 provides a second negative pressure 78 to the plurality of adsorption members 250, so that each of the plurality of adsorption members 250 provides its own adsorption pressure. This adsorption pressure allows adjacent adsorption members among the plurality of adsorption members 250 to hold the object 80 by adsorption pressure. This minimizes potential damage to the object 80 because the contact forces on the object 80 are minimized.

[0056] See further Figure 10C The first negative pressure 76 from the pneumatic pressure source 70 stops, causing the finger base 210 to return to its bent state, and thus the gripper finger 200 returns to its bent shape. While the finger base 210 returns to its bent state, a second negative pressure 78 is maintained on the plurality of suction members 250 to hold the object 80 by suction pressure. This allows the soft gripper 100 to hold the object 80 within the partially closed volume formed by the gripper fingers 200.

[0057] See next Figure 10D When the object 80 is reliably or securely held by the soft clamp 100, the second negative pressure 78 stops, so that the object 80 is held only by the scooping surface formed by the plurality of adsorption components 250 without adsorption pressure.

[0058] In an alternative embodiment, Figure 10A and Figure 10B The operation is performed in a similar manner to that described above. However, unlike the previous operation, positive pressure is applied to the base of the finger 210 to apply a more secure grip to the object 80. See again Figure 10C To facilitate the return of the finger base 210 to its bent state, a small positive pressure 79 can be applied to the actuator 230, causing the gripper finger 200 to exert a greater gripping force on the object 80 to firmly hold the object 80. Similarly, see again Figure 10D As the second negative pressure 78 stops, the small positive pressure 79 is maintained to keep a larger gripping force applied to the object 80, thereby achieving a more secure grip.

[0059] Exemplary Embodiments

[0060] See Figures 11-21C This document presents an exemplary embodiment of a scooping soft gripper. The scooping soft gripper can be configured to grip granular objects and / or irregularly shaped objects. The scooping soft gripper includes: (1) an array of suction cups having compliant rods designed to conform to various surface shapes, and (2) a scooping mechanism for surrounding a cluster of objects after initial gripping using suction.

[0061] Passive Suction Cup

[0062] This study chose a flat suction cup shape due to its reliable performance on various flat or slightly curved objects. However, other suction cup shapes, such as bellows or elliptical suction cups, could also be used. The decision to choose a flat shape stems from its simplicity. In most automated solutions based on active adsorption, a single suction cup is typically used, rather than an array of suction cups involving a fully interconnected open circuit driven by a single vacuum source. This is because ensuring a consistent seal for all suction cups in an array presents inherent challenges, especially in unstructured environments such as agricultural equipment. Failure to maintain a seal can lead to leakage and cause overall adsorption failure. On the other hand, using an independent vacuum source for each individual suction cup is impractical. To overcome this challenge and enable the use of suction cup arrays in scoop-type soft grippers, this application implements the concept of passive adsorption. Figure 13 As shown, a thin film is added to each suction cup in the array, and the entire network is powered by a single vacuum source (see [reference]). Figure 14 This allows for passive adsorption actuation at the interface between the suction cups and the object, ensuring a continuous seal for all suction cups. The passive suction cups can be evenly distributed at the base of the four fingers or on the radial arms of the scoop-type soft clamp.

[0063] Pre-bent bellows actuator

[0064] In this exemplary embodiment, a starfish-shaped base with four finger bases / radial arms is chosen to achieve an overall radially symmetrical scooping shape when the finger bases / radial arms are folded. A vacuum-actuated bellows is used to actuate each of the scooping soft gripper's radial arms. Conventional grippers with actuable finger bases / radial arms typically employ both vacuum and positive pressure (two different actuation modes) simultaneously during the forward and reverse bending of the finger bases / radial arms, thus requiring complex control. Since the bottom surface of the gripper's radial arms is occupied by a passive suction cup, the bellows actuator is integrated into the top surface of the gripper's radial arms. This means that when a cluster of objects is attached to the suction cup, in order to achieve a scooping shape from an initial flat position ( Figure 11Achieving complete encapsulation requires applying a large positive pressure within the bellows. However, relying solely on a large positive pressure to achieve forward curling to form a closed scooping structure increases the risk of leakage and rupture. As a safer and more durable alternative, this application employs an innovative method involving a pre-bent bellows (see...). Figure 13 In this setup, the scooping soft clamp inherently forms a nearly closed scooping shape in the unacted state, and can be converted to a flat state simply by vacuum, or even achieve the reverse curling of the radiating arms when needed. This method requires very little or no positive pressure to achieve complete scooping closure (see [link to documentation]). Figure 12 This improves safety and durability, and minimizes the risk of leakage and breakage.

[0065] To achieve the desired effect, optimizations were performed on two key fixture components: (1) the passive suction cup, and (2) the pre-bent bellows actuator (PBA). See also Figure 13 The passive suction cup has three distinct features: (i) a compliant suction cup rod that facilitates independent movement to enhance surface adhesion; (ii) a rigid suction cup body that provides structural stability to prevent vacuum failure; and (iii) a passive diaphragm fixed to the suction cup edge to provide a reliable seal to improve the effectiveness of passive adsorption. The pre-bent bellows actuator is designed to allow the entire finger base / radiating arm to robustly bend from a pre-bent scoop configuration to a flat configuration, and even further to a reverse-curved configuration, for access to confined spaces.

[0066] To estimate the curvature of the pre-bent bellows actuator, the four finger bases / radial arms (of approximate shape) are visualized in a flat or planar setting. The finger bases / radial arms are then bent in this visualization to form a nearly completely closed or sealed scooping structure with minimized gaps. If any remaining gaps remain, they can be closed by applying a small positive pressure.

[0067] The components of the scoop-type soft clamp are manufactured using platinum-catalyzed room temperature vulcanized (RTV) silicone. Initial candidate materials included Ecoflex 00-10 (EF10), Ecoflex 00-30 (EF30), Dragon Skin30 (DS30), and SmoothSil 960 (SS960). Table 1 summarizes the material properties of the materials used. It should be noted that the mechanical properties of RTV silicone may deviate significantly from publicly available technical data due to differences in manufacturing processes, material formulations, curing methods, or test parameters such as tensile speed. Therefore, to improve characterization accuracy, parameters for five hyperelastic models (specifically the Yeoh and Ogden models) were determined through a fitting process based on experimental data and subsequently incorporated into finite element analysis (FEA) simulations.

[0068] Material optimization of passive suction cup

[0069] To select the materials for the suction cup rod, suction cup body, and passive film, two sets of tests were conducted. A force-displacement measurement system consisting of an Imada ZTA-DPU-500N force gauge and an EMX-1000N-L-FA electric test bench was used to measure the suction force of the suction cup on the test surface (see [link]). Figure 15 The test surface consisted of an acrylonitrile-styrene-acrylate (ASA) base with a glass top layer for smoothness, which was fixed to the test bench base. A smooth surface was chosen to eliminate the influence of surface texture on the adsorption force, as the experimental objective was to select the optimal material combination that ensured rod compliance and provided sufficient passive adsorption force. The test surface was adjusted to different angles to evaluate the suction cup's adaptability to object orientation. Each test suction cup was preloaded with a compression of 1 ± 0.001 mm on the test base before testing. Subsequently, a vacuum of -80 kPa was applied, and the suction cup was then pulled off at a tensile speed of 0.2 mm / s.

[0070] The first set of tests was used to confirm the optimal materials for the suction cup body and its rod without employing a passive film. The second set of tests, based on the best-performing suction cup-rod combination from the first set of tests, added passive films of different materials to determine the optimal combination. Figure 16 and Figure 17This document provides an overview of the different parameter combinations used in two sets of tests and the measured adsorption forces (average of four measurements). The material combination of SS960 as the suction cup body and DS30 as the rod achieved the highest adsorption force at all base angles, reaching 4N on a horizontal base. This highlights the advantages of using a dual-material suction cup (characterized by a more robust base and a more flexible rod) in improving both adsorption force and adaptability. Furthermore, EF10 was identified as the preferred material for passive films due to its maximized adsorption force.

[0071] Finite element analysis validation of pre-bent bellows actuator

[0072] SmoothSil 960 was identified as the optimal material for the bellows of the pre-bent bellows actuator. A softer material, Dragon Skin 30, was selected for the closure section of the pre-bent bellows actuator, which uses the same material as the finger base / radial arm of the scoop-type soft clamp. The estimation of the unactuated curvature of the pre-bent bellows actuator depends on the configuration of the finger base / radial arm of the scoop-type soft clamp in its steady-state position. Assuming each bellows provides a consistent bending angle, an initial pre-bent bellows actuator design with seven bellows is considered in the simulation, where the width of the first four bellows is set to 28 mm, the width of the last three bellows is set to 24 mm, and the bellows wall thickness remains constant at 1 mm. The reduction in bellows width ensures that all bellows can be accommodated even with the radial arm's width decreasing from the base to the end. The design, bending amount, and material combination of the pre-bent bellows actuator with these parameters were verified by finite element analysis using Dassault Systems' ABAQUS.

[0073] In the finite element analysis simulation, hyperelastic Yeoh and Ogden constitutive models were used for SmoothSil 960 and Dragon Skin 30, respectively (Table 1). See also Figure 18 The pre-bent bellows actuator was modeled as a three-dimensional deformable body. The walls of the first bellows were constrained using ENCASTRE boundary conditions, and a uniform negative pressure load of -80 kPa was applied to the inner wall during the static analysis step to reproduce vacuum actuation. Tetrahedral elements (C3D10H) with a hybrid formula were employed, combined with standard contact controls including inelastic normal contact and frictionless tangential contact. Simulation results confirmed that the selected design parameters ensured that the radiating arm fully unfolded from the pre-bent position to a flat orientation under vacuum.

[0074] Table 1. Mechanical properties and material models of all materials used.

[0075] The modulus was measured at 100% strain.

[0076] Manufacturing of scoop soft clamp

[0077] During the manufacturing preparation stage, components A and B of the respective silicone materials are weighed according to the supplier's ratio (EF10 and DS30 are in a 1:1 weight ratio; SS960 is in a 10:1 weight ratio). They are then mixed for 1 minute at 2000 rpm using an ARE-310 Thinky Mixer, followed by a defoaming treatment at 2200 rpm for 2 minutes. For parts manufactured by compression molding, a small amount of ThiVex (Smooth-On) (1% of component B by weight) is added to the mixed silicone to increase the material viscosity. Conversely, for parts manufactured by injection molding, Silicone Thinner (Smooth-On) (5% of the total weight of A+B) is added to the mixed silicone to reduce viscosity, thereby promoting smoother material flow in fine structures. The viscosity-adjusted mixture is then placed in a degassing chamber for 5 minutes before molding.

[0078] The molds used in the manufacturing process are printed from acrylonitrile-styrene-acrylate (ASA) material using fused deposition modeling (FDM). After applying a thin, uniform Ease Release™ 200 (Smooth-On) coating to the mold surface by spraying, the prepared silicone material is manually applied to the mold or injected into the mold using an air-pressure driven dispensing syringe. The filled mold is then cured at 60°C for 3 hours, after which the part is demolded. The four radial arms of the scoop-type soft clamp are manufactured in a flat state, which will subsequently take the shape of a pre-bent bellows actuator. To determine the shape of the radial arms, the scoop volume is visualized. This volume is cut through two mutually perpendicular planes to obtain scoop volumes representing the four quadrants of the radially arranged radial arms of the scoop-type soft clamp. A surface flattening operation is performed on the scoop volume of one quadrant to provide the final shape of the flat radial arm. The entire manufacturing process of the scoop-type soft clamp involves three main components: a pre-bent bellows actuator, a flat radial arm, and a passive suction cup.

[0079] Manufacturing of pre-bent bellows actuator (PBA)

[0080] By coating a viscous layer of SmoothSil-960 in a three-piece mold, the pre-bent bellows actuator is cast in the open state. Figure 19A (i) Separately, using a two-piece mold, the flat closing section of the actuator is cast ( Figure 19A(ii)). After curing, the bellows section is precisely aligned with the flat section, and uncured SmoothSil-960 paste is used as an adhesive to bond them together, thereby creating a pre-bent bellows actuator. Figure 19A (iii) Subsequently, the bending ability of the actuator was tested by inserting a silicone tube into the actuator inlet and bonding it firmly with uncured SmoothSil-960 paste, followed by applying a pressure of -80 kPa using an external vacuum pump.

[0081] Manufacturing of flat finger base / radiating arms

[0082] Dragon Skin 30 was chosen as the material for the scoop-type soft gripper radial arms due to its softer properties compared to SmoothSil 960. This choice was based on the requirement that each radial arm maintain a minimum thickness of at least 5 mm to accommodate the rods of the passive suction cups and the embedded vacuum channel network that connects all passive suction cups to a single vacuum inlet. Thicker layers of higher-stiffness materials could potentially hinder the radial arms from bending from a pre-bent position to a flat position. Therefore, a softer material was chosen to allow the radial arms to be cast in a flat configuration and bonded to a higher-stiffness pre-bent bellows actuator after bonding. Each radial arm is cast in two distinct layers. The first layer, containing the vacuum channel network, is cast by applying an adhesive layer of Dragon Skin 30 in a two-piece mold. Figure 19B (i)). The second layer has protrusions that connect the vacuum network to the passive suction cup rod, which uses another two-piece mold and undergoes a similar casting process. Figure 19B (ii) After both layers have cured, they are precisely aligned and bonded together using an ultra-thin coating of uncured DragonSkin 30 as an adhesive to obtain the assembled radiating arm. The radiating arm is then fixed to a pre-bent bellows actuator, secured in place by a mold jig, and bonded together using uncured DragonSkin 30 as an adhesive. The bending capability of the assembled radiating arm is then evaluated by applying a vacuum to the inlet of the pre-bent bellows actuator.

[0083] Manufacturing of passive suction cup

[0084] The passive suction cup is cast using a three-piece mold. First, the bottom two pieces of the mold are aligned, and SmoothSil 960 with added silicone thinner is injected into the mold. This process continues until the material fills to the starting position of the suction cup rod. Then, Dragon Skin 30 with added silicone thinner is injected until the edge of the mold is reached. Figure 19C(i) was then used in conjunction with a third closed mold. After the suction cup cured, it was placed on a 1 mm thick uncured Ecoflex 10 flat passive film, which was prepared using a homemade ink direct-write device. Figure 19C (ii) and Figure 19C (iii)). After curing, use a blade cutter to precisely remove any excess Ecoflex 10 layers along the edge of the suction cup to obtain a passive suction cup. Figure 19C (iv) The inner diameter of the passive chuck rod matches the outer diameter of the protrusion extending from the radiation arm, allowing the passive chuck to connect to one of the vacuum channel networks within the radiation arm. After all passive chucks are cast, they are bonded to the radiation arm using uncured DragonSkin 30 as an adhesive, with the protrusion inserted into the rod cavity of the passive chuck. Through this process, the passive chuck ( Figure 19D , Figure 19E and Figure 19F The scoop-type soft gripper radiation arm was fabricated. The passive adsorption effect within the radiation arm was then evaluated by applying a vacuum to the inlet. After the radiation arm was completed, an acrylonitrile-styrene-acrylate component printed by fused deposition modeling was used as a modular interface, and assembled using a gripper bracket or gripper base to complete the scoop-type soft gripper. Figure 19G ).

[0085] Gripping operation of scoop soft clamp

[0086] A scoop-type soft gripper was mounted on a Ufactory xArm 7 robotic arm, and its gripping capability was tested with various objects. The gripping process began with the gripper in the open state (the pre-bent bellows actuator was actuated). In the open state, the passive suction cup of the radiating arm was preloaded and pressed against the test sample to ensure a sufficient seal at the surface interface. A vacuum was then activated to initiate passive adsorption. Since objects in good contact with the passive suction cup maintained an effective seal, the gripper was raised to a certain height, and with the object attached to the passive suction cup, the vacuum within the pre-bent bellows actuator was switched from -80 kPa to a positive pressure of 60 kPa, transitioning the gripper to scoop mode. The vacuum for passive adsorption was then closed, as the closed scoop state proved sufficient to hold clusters of objects firmly without requiring continuous adsorption (see [link to documentation]). Figures 20A-20D ).

[0087] Compared to traditional finger-based soft grippers, scoop-type soft grippers offer two significant advantages. First, their scooping capability allows for immediate discontinuation of adsorption after the radial arm closes (until pickup is complete), unlike other adsorption-based solutions that require continuous adsorption throughout the entire gripping process (pickup and placement). In scenarios where a lengthy robotic arm movement occurs between pickup and placement into a container, the immediate discontinuation of adsorption after the radial arm closes translates to energy savings. Second, they address a key challenge in robotic arm operation—preventing object slippage throughout the movement trajectory, the length of which can vary depending on the task. Vibrations and sudden jerks caused by acceleration pose a risk of slippage, especially in adsorption-based gripping scenarios.

[0088] The scooping mode allows clusters of objects to be moved at higher speeds and accelerations, something that cannot be achieved by adsorption alone. This advantage is particularly pronounced when handling clusters of multiple objects, and the scooping soft gripper is adept at handling such applications.

[0089] The proposed scoop-type soft gripper can be used for grasping clusters of objects in agricultural automation devices. Combining passive adsorption and scooping functions, the proposed gripper significantly improves grasping efficiency. In particular, compared to traditional finger-based soft grippers that typically only grasp single objects, the scoop-type soft gripper can grasp multiple objects (e.g., an average of 3-4 mushrooms per gripper), demonstrating superior capability. By introducing a dual-material configuration to enhance the flexibility of the suction cup, the adsorption force (compared to suction cups using a single SS960 material) is increased by 116%, while the use of a softer EF10 passive film further improves the adsorption force by 6% compared to EF30 film. Furthermore, despite various adsorption limitations on different crop surfaces, the proposed scoop-type gripper can still be used to handle large mushrooms or small bok choy (Brassica rapa var. chinensis) with uneven leaf surfaces, such as… Figures 21A-21C As shown.

[0090] The parameters related to suction cup type, effective adsorption area, suction cup density and arrangement, passive film meniscus angle, suction cup shape, suction cup orientation, and integration of additional features such as lips or support ribs mentioned in this disclosure are exemplary and not exhaustive. Furthermore, the parameters related to the pre-bent bellows actuator in this disclosure, such as material composition, bellows wall thickness, and bellows dimensions, can also be optimized as needed to improve scooping force and enhance the adhesion of the radiating arm to uneven surfaces of object clusters; these parameters are also exemplary and not exhaustive.

[0091] All examples described herein, whether methods, materials, or products, are shown for illustrative and understanding purposes and are not intended to be limiting or exhaustive. Modifications can be made by those skilled in the art without departing from the scope of the claimed invention.

Claims

1. A soft clamp, comprising: A plurality of clamping fingers, each of the plurality of clamping fingers comprising: The finger base defines a first surface and a second surface opposite to the first surface, and the finger base is provided with a network of pneumatic channels; An actuator coupled to the first surface, the actuator having a pneumatic channel; A plurality of adsorption components are coupled to the second surface, and the plurality of adsorption components are in fluid communication with the pneumatic channel network. The base of the finger is biased into a bent state. The actuator can be actuated to deflect the finger base from the bent state in response to a first negative pressure in the pneumatic channel. Each of the plurality of adsorption components provides its own adsorption pressure in response to a second negative pressure in the pneumatic channel network.

2. The soft clamp according to claim 1, wherein the finger base in the bent state corresponds to a volume at least partially closed as defined by the plurality of clamp fingers.

3. The soft clamp according to any one of the preceding claims, wherein the finger base is biased to the bent state by the actuator.

4. The soft clamp according to any one of the preceding claims, wherein the pneumatic channel network is arranged between the first surface and the second surface.

5. The soft clamp according to any one of the preceding claims, wherein the pneumatic channel network comprises a plurality of parallel branches, the plurality of parallel branches being in fluid communication with a common inlet disposed on the finger base.

6. The soft clamp according to any one of the preceding claims, wherein the pneumatic channel network comprises a plurality of connection nodes, each of the plurality of connection nodes being in fluid communication with a respective adsorption member of the plurality of adsorption members.

7. The soft clamp according to any one of the preceding claims, wherein each of the plurality of adsorption members further comprises: Suction cup; A rod portion coupled between the second surface and the suction cup; And a thin film covering the opening of the suction cup.

8. The soft clamp according to claim 7, wherein the stiffness of the rod portion is lower than the stiffness of the suction cup.

9. The soft clamp according to claim 8, wherein the stiffness of the film is lower than the stiffness of the suction cup and the rod.

10. The soft clamp according to any one of the preceding claims, wherein the actuator comprises a plurality of bellows aligned along the central plane of the finger base, the plurality of bellows being in fluid communication with the pneumatic channel.

11. The soft clamp of claim 10, wherein the plurality of bellows are configured to bend the finger base about a transverse axis in response to the lack of a first negative pressure in the pneumatic channel, thereby biasing the finger base into the bent state, wherein the transverse axis is transverse to the central plane.

12. The soft clamp of claim 11, wherein each of the plurality of bellows defines a respective bellows width parallel to the transverse axis, the respective bellows width of the plurality of bellows changing along the central plane.

13. The soft clamp of claim 12, wherein the respective bellows width of the plurality of bellows decreases from the rear end of the finger base to the front end of the finger base.

14. The soft clamp according to any one of claims 10 to 13, wherein the stiffness of the plurality of bellows is higher than the stiffness of the finger base.

15. The soft clamp according to any one of claims 10 to 14, wherein the plurality of adsorption members are arranged symmetrically about the central plane.

16. The soft clamp according to any one of the preceding claims, wherein the pneumatic channel and the network of pneumatic channels are fluidly coupled to a single pneumatic pressure source.

17. The soft clamp according to any one of the preceding claims, wherein the plurality of adsorption members define a scooping surface in response to the finger base being in the bent state.

18. The soft clamp according to any one of the preceding claims, wherein the plurality of adsorption members are uniformly distributed on the second surface.

19. The soft clamp according to claim 18 further includes a clamp base coupled to the plurality of clamp fingers, the clamp base being coupled to the robotic arm along the clamp axis.

20. The soft clamp according to claim 19, wherein the plurality of clamps are arranged radially symmetrically about the clamp axis.

21. A soft clamping system, comprising: The soft clamp according to any one of the preceding claims; as well as A pneumatic pressure source, wherein the pneumatic pressure source is in controllable fluid communication with each of the at least one clamp finger.

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